Teradyne (TER) 10-K2 Mar 202019 FY Annual reportFinancial data

Company Profile

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
Cover Page - USD ($) $ in Billions	Dec. 31, 2019	Feb. 24, 2020	Jun. 28, 2019
Cover [Abstract]
Amendment Flag	false
Document Type	10-K
Document Fiscal Year Focus	2019
Entity Central Index Key	0000097210
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Document Period End Date	Dec. 31, 2019
Entity Registrant Name	TERADYNE, INC
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 7.3
Trading Symbol	TER
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity File Number	001-06462
Entity Incorporation, State or Country Code	MA
Entity Tax Identification Number	04-2272148
Entity Address, Address Line One	600 RIVERPARK DRIVE
Entity Address, City or Town	NORTH READING
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01864
City Area Code	978
Local Phone Number	370-2700
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		166,784,497

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents		$ 773,924	$ 926,752
Marketable securities		137,303	190,096
Accounts receivable, less allowance for doubtful accounts of $1,736 and $1,673 in 2019 and 2018, respectively		362,368	291,267
Inventories, net		196,691	153,541
Prepayments and other current assets		188,598	170,826
Total current assets		1,658,884	1,732,482
Property, plant and equipment, net		320,216	279,821
Lease right-of-use assets		57,539
Marketable securities		104,490	87,731
Deferred tax assets		75,185	70,848
Retirement plans assets		18,457	16,883
Other assets		10,332	11,509
Acquired intangible assets, net		125,480	125,482
Goodwill		416,431	381,850
Total assets	[1]	2,787,014	2,706,606
Current liabilities:
Accounts payable		126,617	100,688
Accrued employees' compensation and withholdings		163,883	148,566
Deferred revenue and customer advances		104,876	77,711
Other accrued liabilities		70,871	78,272
Operating lease liabilities		19,476
Contingent consideration		9,106	34,865
Income taxes payable		44,200	36,185
Total current liabilities		539,029	476,287
Retirement plans liabilities		134,471	117,456
Long-term deferred revenue and customer advances		45,974	32,750
Long-term contingent consideration		30,599	35,678
Deferred tax liabilities		14,070	20,662
Long-term other accrued liabilities		19,535	37,547
Long-term operating lease liabilities		45,849
Long-term income taxes payable		82,642	83,891
Debt		394,687	379,981
Total liabilities		1,306,856	1,184,252
Commitments and contingencies (Note M)
SHAREHOLDERS' EQUITY
Common stock, $0.125 par value, 1,000,000 shares authorized, 166,410 and 175,522 shares issued and outstanding at December 31, 2019 and 2018, respectively		20,801	21,940
Additional paid-in capital		1,720,129	1,671,645
Accumulated other comprehensive loss		(18,854)	(13,040)
Accumulated deficit		(241,918)	(158,191)
Total shareholders' equity		1,480,158	1,522,354
Total liabilities and shareholders' equity		$ 2,787,014	$ 2,706,606

[1]	Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable, less allowance for doubtful accounts	$ 1,736	$ 1,673
Common stock, par value	$ 0.125	$ 0.125
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	166,410,000	175,522,000
Common stock, shares outstanding	166,410,000	175,522,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Revenues:
Total revenues	[2]	$ 2,294,965	[1]	$ 2,100,802	[1]	$ 2,136,606
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		955,136		880,408		915,153
Gross profit		1,339,829		1,220,394		1,221,453
Operating expenses:
Selling and administrative		437,084		390,669		348,913
Engineering and development		322,824		301,505		307,305
Acquired intangible assets amortization		40,147		39,191		30,530
Restructuring and other		(13,880)		15,232		9,362
Total operating expenses		786,175		746,597		696,110
Income from operations		553,654		473,797		525,343
Non-operating (income) expense:
Interest income		(24,785)		(26,704)		(17,805)
Interest expense		23,145		31,269		21,663
Other (income) expense, net		29,522		1,431		(2,927)
Income before income taxes		525,772		467,801		524,412
Income tax provision		58,304		16,022		266,720
Net income		$ 467,468		$ 451,779		$ 257,692
Net income per common share:
Basic		$ 2.74		$ 2.41		$ 1.30
Diluted		$ 2.60		$ 2.35		$ 1.28
Weighted average common shares—basic		170,425		187,672		198,069
Weighted average common shares—diluted		179,459		192,605		201,641
Cash dividend declared per common share		$ 0.36		$ 0.36		$ 0.28
Product [Member]
Revenues:
Total revenues		$ 1,887,674		$ 1,729,621		$ 1,784,695
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		782,047		727,138		760,967
Service [Member]
Revenues:
Total revenues		407,291		371,181		351,911
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		$ 173,089		$ 153,270		$ 154,186

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Revenues attributable to a country are based on location of customer site.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 467,468	$ 451,779	$ 257,692
Other comprehensive income, net of tax:
Foreign currency translation adjustment, net of tax of $0, $0, $0	(10,991)	(28,442)	37,840
Available-for-sale marketable securities:
Unrealized gains (losses) on debt securities arising during period, net of tax of $1,659, $(722), $1,903, respectively	6,015	(2,110)	1,863
Less: Reclassification adjustment for (gains) losses included in net income, net of tax of $(192), $(21), $(297), respectively	(690)	1,337	(441)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total	5,325	(773)	1,422
Defined benefit pension and post-retirement plans:
Amortization of prior service benefit included in net periodic pension and post-retirement benefit, net of tax $(43), $(71), $(154), respectively	(148)	(245)	(272)
Other comprehensive (loss) income	(5,814)	(29,460)	38,990
Comprehensive income	$ 461,654	$ 422,319	$ 296,682

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Foreign currency translation adjustments, tax	$ 0	$ 0	$ 0
Unrealized (losses) gains on marketable securities arising during period, net of tax	1,659	(722)	1,903
Reclassification adjustment for losses (gains) included in net income, net of tax	(192)	(21)	(297)
Amortization of prior service (credit) cost included in net periodic pension and post-retirement expense/income, net of tax	$ (43)	$ (71)	$ (154)

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total		Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balance at Dec. 31, 2016	$ 1,828,659		$ 24,897	$ 1,593,684	$ (20,214)	$ 230,292
Balance, Shares at Dec. 31, 2016			199,177
Net issuance of common stock under stock-based plans	11,024		$ 277	10,747
Net issuance of common stock under stock-based plans (in shares)			2,211
Stock-based compensation expense	33,982			33,982
Repurchase of common stock	(200,304)		$ (730)			(199,574)
Repurchase of common stock (in shares)			(5,840)
Tax benefit related to stock options and restricted stock units	39,081					39,081
Cash dividends	(55,478)					(55,478)
Net income	257,692					257,692
Other comprehensive loss	38,990				38,990
Balance at Dec. 31, 2017	1,953,646		$ 24,444	1,638,413	18,776	272,013
Balance, Shares at Dec. 31, 2017			195,548
Net issuance of common stock under stock-based plans	129		$ 201	(72)
Net issuance of common stock under stock-based plans (in shares)			1,613
Stock-based compensation expense	33,304			33,304
Repurchase of common stock	(832,356)		$ (2,705)			(829,651)
Repurchase of common stock (in shares)			(21,639)
Cash dividends	(67,367)					(67,367)
Net income	451,779					451,779
Other comprehensive loss	(29,460)				(29,460)
Reclassification of unrealized gains on equity securities					(3,125)	3,125
Reclassification of tax effects resulting from the Tax Reform Act	769	[1]			769	(769)
Balance at Dec. 31, 2018	1,522,354		$ 21,940	1,671,645	(13,040)	(158,191)
Balance, Shares at Dec. 31, 2018			175,522
Cumulative effect of changes in accounting principle related to revenue recognition	12,679					12,679
Net issuance of common stock under stock-based plans	10,622		$ 223	10,399
Net issuance of common stock under stock-based plans (in shares)			1,784
Stock-based compensation expense	38,085			38,085
Repurchase of common stock	(491,202)		$ (1,362)			(489,840)
Repurchase of common stock (in shares)			(10,896)
Cash dividends	(61,355)					(61,355)
Net income	467,468					467,468
Other comprehensive loss	(5,814)				(5,814)
Balance at Dec. 31, 2019	$ 1,480,158		$ 20,801	$ 1,720,129	$ (18,854)	$ (241,918)
Balance, Shares at Dec. 31, 2019			166,410

[1]	In the year ended December 31, 2018, Teradyne early adopted ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” As a result, the stranded tax effects resulting from the Tax Reform Act enacted in December 2017 were reclassified from accumulated other comprehensive income to retained earnings.

CONSOLIDATED STATEMENTS OF SH_2

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Common Stock, Dividends, Per Share, Cash Paid	$ 0.09	$ 0.09	$ 0.07

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 467,468	$ 451,779	$ 257,692
Adjustments to reconcile net income from operations to net cash provided by operating activities:
Depreciation	70,834	67,415	66,122
Amortization	49,821	45,809	41,953
Stock-based compensation	37,897	33,577	34,097
Deferred taxes	(9,456)	28,340	37,105
Provision for excess and obsolete inventory	15,244	11,242	8,844
Investment impairment	15,000
Contingent consideration fair value adjustment	(19,257)	987	7,820
(Gains) losses on investments	(6,033)	3,494	(878)
Retirement plans actuarial losses (gains)	8,176	(3,316)	(6,624)
Property insurance recovery, net			(4,309)
Other	766	1,083	1,585
Changes in operating assets and liabilities, net of businesses acquired:
Accounts receivable	(70,440)	(17,938)	(80,584)
Inventories	(27,408)	(29,498)	44,960
Prepayments and other assets	(23,784)	(58,402)	2,254
Accounts payable and other liabilities	49,279	13,693	43,574
Deferred revenue and customer advances	39,313	13,379	4,984
Retirement plans contributions	(5,086)	(4,334)	(5,902)
Income taxes	(13,584)	(80,429)	173,802
Net cash provided by operating activities	578,750	476,881	626,495
Cash flows from investing activities:
Purchases of property, plant and equipment	(134,642)	(114,379)	(105,375)
Proceeds from government subsidy for property, plant and equipment		7,920
Purchases of marketable securities	(662,701)	(918,744)	(1,391,917)
Proceeds from maturities of marketable securities	611,927	1,270,439	701,681
Proceeds from sales of marketable securities	105,586	846,122	527,746
Proceeds from insurance	2,912	1,126	5,064
Purchase of investment and acquisition of businesses, net of cash acquired	(79,742)	(169,474)
Net cash (used for) provided by investing activities	(156,660)	923,010	(262,801)
Cash flows from financing activities:
Issuance of common stock under stock purchase and stock option plans	29,312	20,973	24,493
Repurchase of common stock	(500,000)	(823,478)	(200,304)
Dividend payments	(61,305)	(67,322)	(55,447)
Payments related to net settlement of employee stock compensation awards	(14,741)	(20,023)	(12,881)
Payments of contingent consideration	(27,615)	(13,571)	(1,050)
Net cash used for financing activities	(574,349)	(903,421)	(245,189)
Effects of exchange rate changes on cash and cash equivalents	(569)	439	3,454
(Decrease) Increase in cash and cash equivalents	(152,828)	496,909	121,959
Cash and cash equivalents at beginning of year	926,752	429,843	307,884
Cash and cash equivalents at end of year	773,924	926,752	429,843
Cash paid for:
Interest	5,996	6,205	6,446
Income taxes	$ 81,410	$ 72,811	$ 53,775

The Company

The Company	12 Months Ended
The Company	Dec. 31, 2019
The Company	A. THE COMPANY Teradyne, Inc. (“Teradyne”) is a leading global supplier of automation equipment for test and industrial applications. Teradyne designs, develops, manufactures and sells automatic test systems used to test semiconductors, wireless products, data storage and complex electronics systems in the consumer electronics, wireless, automotive, industrial, computing, communications, and aerospace and defense industries. Teradyne’s industrial automation products include collaborative robotic arms, autonomous mobile robots, and advanced robotic control software used by global manufacturing and light industrial customers to improve quality, increase manufacturing and material handling efficiency and decrease manufacturing costs. Teradyne’s automatic test equipment and industrial automation products and services include: • semiconductor test (“Semiconductor Test”) systems; • industrial automation (“Industrial Automation”) products; • defense/aerospace (“Defense/Aerospace”) test instrumentation and systems, storage test (“Storage Test”) systems, and circuit-board test and inspection (“Production Board Test”) systems (collectively these products represent “System Test”); and • wireless test (“Wireless Test”) systems. On February 26, 2018, Teradyne acquired Energid Technologies Corporation (“Energid”) for a total purchase price of approximately $27.6 million. Energid’s technology enables and simplifies the programming of complex robotic motions used in a wide variety of end markets, ranging from heavy industry to healthcare, utilizing both traditional robots and collaborative robots. Energid is included in Teradyne’s Industrial Automation segment. On April 25, 2018, Teradyne acquired Mobile Industrial Robots ApS (“MiR”), a Danish limited liability company . MiR is a of approximately $145.2 million a nd in fair value Contingent consideration for 2018 was $30.8 million and was paid in March 2019. Contingent consideration for 2019 was $9.1 million and is expected to be paid in March 2020. MiR is ’s Industrial Automation segment. On January 30, 2019, Teradyne acquired all of the issued and outstanding shares of Lemsys SA (“Lemsys”) for a total purchase price of approximately $9.1 million. Lemsys strengthens Teradyne’s position in the electrification of vehicles, solar and wind power, and industrial applications. Lemsys is included in Teradyne’s Semiconductor Test segment. On June 3, 2019, Teradyne invested $15.0 million in RealWear, Inc. (“RealWear”). RealWear, a private company, develops and sells advanced wearable technology including industrial, hands-free, head-mounted augmented reality devices that make the workplace safer and more productive. On February 28, 2020, RealWear’s debt holder demanded repayment of its $25.0 million loan to RealWear. As a result, in the fourth quarter of 2019, Teradyne recorded an impairment charge of $15.0 million to reduce its investment in RealWear to zero as of December 31, 2019. On November 1 3 , membership interests . T he total purchase price was approximately $81.7 million, which included cash paid of approximately $57.8 million and $24.0 million in fair value of contingent consideration payable upon achievement of certain performance targets, extending potentially through 2022. The maximum contingent consideration that could be paid million. AutoGuide’s AMRs are used for material transport of payloads up to 4,500 kg in manufacturing, warehouse and logistics applications. These products complement MiR’s lower payload products. AutoGuide is included in our Industrial Automation segment.

Accounting Policies

Accounting Policies	12 Months Ended
Accounting Policies	Dec. 31, 2019
Accounting Policies	B. ACCOUNTING POLICIES The consolidated financial statements include the accounts of Teradyne and its wholly-owned subsidiaries. All significant intercompany balances and transactions are eliminated. Certain prior years’ amounts were reclassified to conform to the current year presentation. Preparation of Financial Statements and Use of Estimates The preparation of consolidated financial statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent liabilities. On an on-going contingent consideration liabil ities , Revenue Recognition Revenue from Contracts with Customers Teradyne adopted Accounting Standard Codification (“ASC”) 606 “ Revenue from Contracts with Customers” In accordance with ASC 606, Teradyne recognizes revenues, when or as control is transferred to a customer. Teradyne’s determination of revenue is dependent upon a five step process outlined below. • Teradyne accounts for a contract with a customer when there is written approval, the contract is committed, the rights of the parties, including payment terms, are identified, the contract has commercial substance and consideration is probable of collection. • Teradyne periodically enters into contracts with customers in which a customer may purchase a combination of goods and services, such as products with extended warranty obligations. Teradyne determines performance obligations by assessing whether the products or services are distinct from the other elements of the contract. In order to be distinct, the product or service must perform either on its own or with readily available resources and must be separate within the context of the contract. • Teradyne considers the amount stated on the face of the purchase order to be the transaction price. Teradyne does not have material variable consideration which could impact the stated purchase price agreed to by Teradyne and the customer. • Transaction price is allocated to each individual performance obligation based on the standalone selling price of that performance obligation. Teradyne uses standalone transactions when available to value each performance obligation. If standalone transactions are not available, Teradyne will estimate the standalone selling price through market assessments or cost plus a reasonable margin analysis. Any discounts from standalone selling price are spread proportionally to each performance obligation. • In order to determine the appropriate timing for revenue recognition, Teradyne first determines if the transaction meets any of three criteria for over time recognition. If the transaction meets the criteria for over time recognition, Teradyne recognizes revenue as the good or service is delivered. Teradyne uses input variables such as hours or months utilized or costs incurred to determine the amount of revenue to recognize in a given period. Input variables are used as they best align consumption with benefit to the customer. For transactions that do not meet the criteria for over time recognition, Teradyne will recognize revenue at a point in time based on an assessment of the five criteria for transfer of control. Teradyne has concluded that revenue should be recognized when shipped or delivered based on contractual terms. Typically, acceptance of Teradyne’s products and services is a formality as Teradyne delivers similar systems, instruments and robots to standard specifications. In cases where acceptance is not deemed a formality, Teradyne will defer revenue recognition until customer acceptance. Performance Obligations Products Teradyne products consist primarily of semiconductor test systems and instruments, defense/aerospace test instrumentation and systems, storage test systems and instruments, circuit-board test and inspection systems and instruments, industrial automation products and wireless test systems. Teradyne’s hardware is recognized at a point in time upon transfer of control to the customer. Services Teradyne services consist of extended warranties, training and application support, service agreement, post contract customer support (“PCS”) and replacement parts. Each service is recognized based on relative standalone selling price. Extended warranty, training and support, service agreements and PCS are recognized over time based on the period of service. Replacement parts are recognized at a point in time upon transfer of control to the customer. Teradyne does not allow customer returns or provide refunds to customers for any products or services. Teradyne products include a standard 12-month As of December 31, 2019 and 2018, deferred revenue and customer advances consisted of the following and are included in the short and long-term deferred revenue and customer advances: 2019 2018 (in thousands) Maintenance , service $ 63,815 $ 58,362 Extended warranty 30,677 27,422 Customer advances, undelivered elements and other 56,358 24,677 Total deferred revenue and customer advances $ 150,850 $ 110,461 Product Warranty Teradyne generally provides a one-year Amount (in thousands) Balance at December 31, 2016 $ 7,203 Accruals for warranties issued during the period 14,223 Accruals related to pre-existing (379 ) Settlements made during the period (12,847 ) Balance at December 31, 2017 8,200 Acquisition 41 Accruals for warranties issued during the period 13,045 Accruals related to pre-existing 921 Settlements made during the period (14,298 ) Balance at December 31, 2018 7,909 Acquisition 14 Accruals for warranties issued during the period 14,106 Accruals related to pre-existing 4,026 Settlements made during the period (17,059 ) Balance at December 31, 2019 $ 8,996 When Teradyne receives revenue for extended warranties, beyond one year, it is deferred and recognized on a straight-line basis over the contract period. Related costs are expensed as incurred. The balance below is included in short and long-term deferred revenue and customer advances: Amount (in thousands) Balance at December 31, 2016 $ 28,200 Deferral of new extended warranty revenue 20,513 Recognition of extended warranty deferred revenue (24,275 ) Balance at December 31, 2017 24,438 Deferral of new extended warranty revenue 23,753 Recognition of extended warranty deferred revenue (20,769 ) Balance at December 31, 2018 27,422 Deferral of new extended warranty revenue 23,271 Recognition of extended warranty deferred revenue (20,016 ) Balance at December 31, 2019 $ 30,677 Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The volatility of the industries that Teradyne serves can cause certain of its customers to experience shortages of cash flows, which can impact their ability to make required payments. Teradyne maintains allowances for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments. Estimated allowances for doubtful accounts are reviewed periodically taking into account the customer’s recent payment history, the customer’s current financial statements and other information regarding the customer’s credit worthiness. Account balances are written off against the allowance when it is determined the receivable will not be recovered. Teradyne sells certain trade accounts receivables on a non-recourse are are Inventories Inventories are stated at the lower of cost (first-in, first-out Investments Teradyne accounts for its investments in debt and equity securities in accordance with the provisions of ASC 320-10, Investments—Debt and Equity Securities 320-10 available-for-sale held-to-maturity • The length of time and the extent to which the market value has been less than cost; • The financial condition and near-term prospects of the issuer; and • The intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value. Teradyne uses the market and income approach techniques to value its financial instruments and there were no changes in valuation techniques during the twelve months ended December 31, 2019 and 2018. As defined in ASC 820-10, Fair Value Measurements and Disclosures, 820-10 Level 1: Quoted prices in active markets for identical assets as of the reporting date; Level 2: Inputs other than Level 1, that are observable either directly or indirectly as of the reporting date. For example, a common approach for valuing fixed income securities is the use of matrix pricing. Matrix pricing is a mathematical technique used to value securities by relying on the securities’ relationship to other benchmark quoted prices, and is considered a Level 2 input; or Level 3: Unobservable inputs that are not supported by market data. Unobservable inputs are developed based on the best information available, which might include Teradyne’s own data. In accordance with ASC 820-10, Financial Assets and Financial Liabilities In January 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities Investment in Other Company Teradyne holds an investment in a private company that develops and sells advanced wearable technology. Teradyne does not have the ability to exert significant influence over the company. The investment was recorded at cost and is evaluated for impairment or an indication of changes in fair value resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer on a quarterly basis. See Note D: “Acquisitions and Investment in Other Company.” Prepayments Prepayments consist of the following and are included in prepayments and other current assets on the balance sheet: 2019 2018 (in thousands) Contract manufacturer and supplier prepayments $ 143,392 $ 131,642 Prepaid taxes 8,046 9,646 Prepaid maintenance and other services 8,503 8,487 Other prepayments 16,753 12,744 Total prepayments $ 176,694 $ 162,519 Retirement and Postretirement Plans Teradyne recognizes net actuarial gains and losses and the change in the fair value of the plan assets in its operating results in the year in which they occur or upon any interim remeasurement of the plans. Teradyne calculates the expected return on plan assets using the fair value of the plan assets. Actuarial gains and losses are generally measured annually as of December 31 and, accordingly, recorded during the fourth quarter of each year or upon any interim remeasurement of the plans. Retirement Benefits In March 2017, the FASB issued ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost non-service compensation costs and the non-service components of net benefit costs such as interest cost, expected return on assets, amortization of prior service cost, and actuarial gains or losses are reported within other (income) expense, net. In the twelve months ended December 31, 2017 , million , due to the removal of net actuarial pension gains and increased non-operating (income) expense by the same amount with no impact to net income. Goodwill, Intangible and Long-Lived Assets Teradyne accounts for goodwill and intangible assets in accordance with ASC 350-10, Intangibles-Goodwill and Other. 350-10, two-step two-step In accordance with ASC 360-10, Impairment or Disposal of Long-Lived Assets, carrying Business Combination Teradyne recognizes the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The fair value of identifiable intangible assets is based on detailed cash flow valuations that use information and assumptions provided by management. Teradyne estimates the fair value of contingent consideration at the time of the acquisition using all pertinent information known to us at the time to assess the probability of payment of contingent amounts or through the use of a Monte Carlo simulation model. Teradyne allocates any excess purchase price over the fair value of the net tangible and intangible assets acquired and liabilities assumed to goodwill. The assumptions used in the valuations for our acquisitions may differ materially from actual results depending on performance of the acquired businesses and other factors. While Teradyne believes the assumptions used were appropriate, different assumptions in the valuation of assets acquired and liabilities assumed could have a material impact on the timing and extent of impact on our statements of operations. Goodwill is assigned to reporting units as of the date of the related acquisition. Property, Plant and Equipment Property, plant and equipment are stated at cost and depreciated over the estimated useful lives of the assets. Leasehold improvements and major renewals are capitalized and included in property, plant and equipment accounts while expenditures for maintenance and repairs and minor renewals are charged to expense. When assets are retired, the assets and related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in the consolidated statements of operations. Teradyne provides for depreciation of its assets principally on the straight-line method with the cost of the assets being charged to expense over their useful lives as follows: Buildings 40 years Building improvements 5 to 10 years Leasehold improvements Lesser of lease term or 10 years Furniture and fixtures 10 years Test systems manufactured internally 6 years Machinery , and software 3 to 5 years Test systems manufactured internally are used by Teradyne for customer evaluations and manufacturing and support of its customers. Teradyne depreciates the test systems manufactured internally over a six Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842)” right-of-use 2018-11, “Leases (Topic 842): Targeted Improvements,” Under ASC 842, a contract is or contains a lease when Teradyne has the right to control the use of an identified asset. Teradyne determines if an arrangement is a lease at inception of the contract, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. Teradyne determines if the lease is an lease For leases commencing after January 1, 2019, the lease liability is measured at the present value of future lease payments, discounted using the discount rate for the lease at the commencement date. As Teradyne is typically unable to determine the implicit rate, Teradyne uses an incremental borrowing rate based on the lease term and economic environment at commencement date. Teradyne initially measures payments based on an index by using the applicable rate at lease commencement. Variable payments that do not depend on an index are not included in the lease liability and are recognized as they are incurred. The ROU asset is initially measured as the amount of lease liability, adjusted for any initial lease costs, prepaid lease payments, and reduced by any lease incentives. Teradyne’s contracts often include non-lease non-lease Engineering and Development Costs Teradyne’s products are highly technical in nature and require a large and continuing engineering and development effort. Software development costs incurred prior to the establishment of technological feasibility non-recurring Stock Compensation Plans and Employee Stock Purchase Plan Stock-based compensation expense is based on the grant-date fair value estimated in accordance with the provisions of ASC 718-10, Compensation-Stock Compensation In March 2016, the FASB issued ASU 2016-09, “Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.” Adoption of this ASU required recognition of a cumulative effect adjustment to retained earnings for any prior year excess tax benefits or tax deficiencies not previously recorded. The cumulative effect adjustment of $39 million was recorded in the first quarter of 2017 as an increase to retained earnings and deferred tax assets. This ASU also required a change in how Teradyne recognizes the excess tax benefits or tax deficiencies related to stock-based compensation. Prior to adopting ASU 2016-09, paid-in 2016-09, ASU 2016-09 In addition, under ASU 2016-09, Upon adoption of ASU 2016-09, Under its stock compensation plans, Teradyne has granted stock options, restricted stock units and performance-based restricted stock units, and employees are eligible to purchase Teradyne’s common stock through its Employee Stock Purchase Plan (“ESPP”). Income Taxes Deferred tax assets and liabilities are determined based on differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the “Accounting for Income Taxes.” tax-planning Advertising Costs Teradyne expenses all advertising costs as incurred. Advertising costs were $16.6 million, $15.4 million and $9.1 million in 2019, 2018 and 2017, respectively. Translation of Non-U.S. The functional currency for all non-U.S. non-monetary Net foreign exchange gains and losses resulting from remeasurement are included in other (income) expense, net. For the years ended December 31, 2019, 2018, and 2017, (gains) losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $(1.6) million, $(2.5) million, and $2.9 million, respectively. These amounts do not reflect the corresponding (gains) losses from foreign exchange contracts. See Note H: “Financial Instruments” regarding foreign exchange contracts. Net Income (Loss) per Common Share Basic net income (loss) per common share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Except where the result would be anti-dilutive, diluted net income (loss) per common share is calculated by dividing net income (loss) by the sum of the weighted average number of common shares plus common stock equivalents, if applicable. With respect to its convertible debt issued in 2016, Teradyne has determined that it has the ability and intent to settle the principal of the convertible debt in cash; accordingly, the principal amount is excluded from the determination of diluted earnings per share. As a result, Teradyne is accounting for the conversion spread using the treasury stock method. Comprehensive Income (Loss) Comprehensive income (loss) includes net income, unrealized pension and postretirement prior service costs and benefits, unrealized gains and losses on investments in debt marketable securities and foreign currency translation adjustment. Prior to 2018, comprehensive income (loss) included unrealized gains and losses on investments in equity marketable securities.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	12 Months Ended
Recently Issued Accounting Pronouncements	Dec. 31, 2019
Recently Issued Accounting Pronouncements	C. RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS On January 26, 2017, the FASB issued ASU 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment.” one-step

Acquisitions and Investment In

Acquisitions and Investment In Other Company	12 Months Ended
Acquisitions and Investment In Other Company	Dec. 31, 2019
Acquisitions and Investment In Other Company	D. ACQUISITIONS AND INVESTMENT IN OTHER COMPANY Acquisitions AutoGuide LLC On November 1 3 me mbership interests . The total purchase price was approximately $81.7 million, which included cash paid of approximately $57.8 million and $ million in fair value of contingent consideration payable upon achievement of certain performance targets, extending potentially through 2022. At December 31, 2019, the maximum contingent consideration that could be paid is $ million. The contingent consideration is payable upon achievement o t 1 2 The valuation of the contingent consideration is dependent on the following assumptions: forecasted revenues, revenue volatility, earnings before interest and taxes, and discount rate. These assumptions were estimated based on a review of the historical and projected results. The AutoGuide acquisition was accounted for as a business combination and, accordingly, the results have been included in Teradyne’s consolidated results of operations from the date of acquisition. AutoGuide’s AMRs are used for material transport of payloads up to 4,500 kg in manufacturing, warehouse and logistics applications. These products complement MiR’s lower payload products and expand the Industrial Automation segment , which is a key c omponent of Teradyne ’ s growth strateg y. The preliminary allocation of the total purchase price to AutoGuide’s net tangible assets and identifiable intangible assets was based on their estimated preliminary fair values as of the acquisition date. The excess of the purchase price over the identifiable intangible assets and net tangible assets in the amount of $41.4 million was allocated to goodwill, which is deductible for tax purposes. AutoGuide’s results have been included in Teradyne’s Industrial Automation segment from the date of acquisition. The following table represents the preliminary allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 41,372 Intangible assets 37,660 Tangible assets acquired and liabilities assumed: Other c 3,661 Non-current 1,227 Accounts payable and current liabilities (1,223 ) Long-term other (949 ) Total purchase price $ 81,748 Teradyne estimated the fair value of intangible assets using the income approach. Forecasted revenues is the key assumption for estimating the fair value. Acquired intangible assets are amortized on a straight-line basis over their estimated useful lives. Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Developed technology $ 24,590 6.0 Customer relationships 7,360 6.0 Trademarks and tradenames 5,450 7.0 Backlog 260 0.3 Total intangible assets $ 37,660 6.1 For the period from November 13, 2019 to December 31, 2019, AutoGuide contributed $ 1.4 (0.9) Lemsys SA On January 30, 2019, Teradyne acquired all of the issued and outstanding shares of Lemsys SA (“Lemsys”) for a total purchase price of approximately $ 9.1 and wind power , 1.4 4.6 5.2 3.1 Mobile Industrial Robots On April 25, 2018, Teradyne acquired all of a The total purchase price of $ 197.8 145.2 52.6 achievement of certain thresholds and targets for revenue and earnings before interest and taxes for periods from January 1, 2018 to December 31, 2018; January 1, 2018 to December 31, 2019; and January 1, 2018 to December 31, 2020. Contingent consideration for the period from January 1, 2018 to December 31, 2018 was $31.0 million and was paid in March 2019. Contingent consideration for the period from January 1, 201 8 $ 9.1 million , based on the results during the period and modifi ca tion of t he earn - , At December 31, 2019, the remaining maximum amount of contingent consideration that could be paid is $63.2 million. The valuation of the contingent consideration is dependent on the following assumptions: forecasted revenues, revenue volatility, earnings before interest and taxes, and discount rate. These assumptions were estimated based on a review of the historical and projected results. The MiR acquisition was accounted for as a business combination and, accordingly, the results have been included in Teradyne’s consolidated results of operations from the date of acquisition. MiR’s products will help expand the Industrial Automation segment, which is a key component of our growth strategy. The allocation of the total purchase price to MiR’s net tangible liabilities and identifiable intangible assets was based on their estimated fair values as of the acquisition date. The excess of the purchase price over the identifiable intangible assets and net tangible liabilities in the amount of $136.0 million was allocated to goodwill, which is not deductible for tax purposes. MiR’s results have been included in Teradyne’s Industrial Automation segment from the date of acquisition. The following table represents the final allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 135,976 Intangible assets 80,670 Tangible assets acquired and liabilities assumed: Current assets 6,039 Non-current 1,336 Accounts payable and current liabilities (7,336 ) Long-term deferred tax liabilities (18,007 ) Other long-term liabilities (900 ) Total purchase price $ 197,778 Teradyne estimated the fair value of intangible assets using the income and cost approaches. Acquired intangible assets are amortized on a straight-line basis over their estimated useful lives. Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Developed technology $ 58,900 7.0 Trademarks and tradenames 13,240 11.0 Customer relationships 8,500 2.5 Backlog 30 0.2 Total intangible assets $ 80,670 7.2 For the period from April 25, 2018 to December 31, 2018, MiR contributed $24.1 million of revenues and had a $( 7.6 Energid Technologies Corporation On February 26, 2018, Teradyne acquired all of the issued and outstanding shares of Energid for a total purchase price of approximately $27.6 million. Energid’s technology enables and simplifies the programming of complex robotic motions used in a wide variety of end markets, ranging from heavy industry to healthcare, utilizing both traditional robots and collaborative robots. The Energid acquisition was accounted for as a business combination and, accordingly, Energid’s results have been included in Teradyne’s Industrial Automation segment from the date of acquisition. As of the acquisition date, Teradyne’s purchase price allocation was goodwill of $14.4 million which is deductible for tax purposes, acquired intangible assets of $12.3 million with an average estimated useful life of 7.7 years, and $1.0 million of net tangible assets. The acquisition was not material to Teradyne’s consolidated financial statements. Pro Forma Information The following unaudited pro forma information gives effect to the acquisition of AutoGuide as if the acquisition occurred on January 1, 2018 and the acquisition of MiR as if the acquisition occurred on January 1, 2017. The unaudited pro forma results are not necessarily indicative of what actually would have occurred had the acquisition been in effect for the periods presented: For the Year Ended December 31, 2019 December 31, 2018 (in thousands, except per share amounts) Revenues $ 2,303,737 $ 2,111,373 Net income $ 464,602 $ 442,082 Net income per common share: Basic $ 2.73 $ 2.36 Diluted $ 2.59 $ 2.30 Pro forma results for the year ended December 31, 2019 were adjusted to exclude $1.2 million of AutoGuide acquisition related costs and $0.1 million of AutoGuide non-recurring Pro forma results for the year ended December 31, 2018 were adjusted to include $1.2 million of AutoGuide acquisition related costs and $0.4 million of AutoGuide non-recurring Pro forma results for the year ended December 31, 2018 were adjusted to exclude $2.9 million of MiR acquisition related costs and $0.4 million of MiR non-recurring Investment in Other Company On June 3, 2019, Teradyne invested $15.0 million in RealWear, Inc. (“RealWear”). RealWear, a private company, develops and sells advanced wearable technology including industrial, hands-free, head-mounted augmented reality devices that make the workplace safer and more productive. The investment was recorded at cost and is evaluated for impairment or an indication of changes in fair value resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer on a quarterly basis. On February 28, 2020, RealWear’s debt holder demanded repayment of its $25.0 million loan to RealWear. As a result, in the fourth quarter of 2019, Teradyne recorded an impairment charge of $15.0 million to reduce its investment in RealWear to zero as of December 31, 2019.

Revenue

Revenue	12 Months Ended
Revenue	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue	E. REVENUE Disaggregation of Revenue The following table provides information about disaggregated revenue by timing of revenue recognition, primary geographical market, and major product lines. Semiconductor Industrial Automation System Test Wireless Test Corporate and Other Total System on-a-chip Memory Universal Mobile AutoGuide Energid (in thousands) For the Year Ended December 31, 2019 (1) Timing of Revenue Recognition Point in Time $ 1,070,375 $ 247,221 $ 244,515 $ 44,329 $ 1,144 $ — $ 237,686 $ 148,322 $ (515 ) $ 1,993,077 Over Time 216,065 18,910 3,952 74 234 3,891 49,769 8,993 — 301,888 Total $ 1,286,440 $ 266,131 $ 248,467 $ 44,403 $ 1,378 $ 3,891 $ 287,455 $ 157,315 $ (515 ) $ 2,294,965 Geographical Market Asia Pacific $ 1,152,881 $ 238,714 $ 67,806 $ 9,513 $ — $ 221 $ 132,826 $ 126,549 $ — $ 1,728,510 Americas 73,257 23,826 70,165 14,438 1,378 1,761 129,840 24,234 (515 ) 338,384 Europe, Middle East and Africa 60,302 3,591 110,496 20,452 — 1,909 24,789 6,532 — 228,071 Total $ 1,286,440 $ 266,131 $ 248,467 $ 44,403 $ 1,378 $ 3,891 $ 287,455 $ 157,315 $ (515 ) $ 2,294,965 For the Year Ended December 31, 2018 (1) Timing of Revenue Recognition Point in Time $ 1,010,493 $ 259,366 $ 231,895 $ 24,115 $ — $ 553 $ 167,418 $ 122,536 $ (1,205 ) $ 1,815,171 Over Time 208,456 14,102 2,200 — — 2,689 48,714 9,470 — 285,631 Total $ 1,218,949 $ 273,468 $ 234,095 $ 24,115 $ — $ 3,242 $ 216,132 $ 132,006 $ (1,205 ) $ 2,100,802 Geographical Market Asia Pacific $ 1,067,879 $ 245,264 $ 58,381 $ 5,950 $ — $ 111 $ 90,989 $ 107,872 $ — $ 1,576,446 Americas 78,498 17,353 68,938 7,326 — 1,540 96,763 19,166 (1,205 ) 288,379 Europe, Middle East and Africa 72,572 10,851 106,776 10,839 — 1,591 28,380 4,968 — 235,977 Total $ 1,218,949 $ 273,468 $ 234,095 $ 24,115 $ — $ 3,242 $ 216,132 $ 132,006 $ (1,205 ) $ 2,100,802 (1) Includes $8.4 million and $12.0 million in 2019 and 2018, respectively, for leases of Teradyne’s systems recognized outside of ASC 606: “Revenue from Contracts with Customers.” Contract Balances For the year s , 1-3

Inventories

Inventories	12 Months Ended
Inventories	Dec. 31, 2019
Inventories	F. INVENTORIES Inventories, net consisted of the following at December 31, 2019 and 2018: 2019 2018 (in thousands) Raw material $ 118,595 $ 89,365 Work-in-process 32,695 31,014 Finished g 45,401 33,162 $ 196,691 $ 153,541 Inventory reserves for the years ended December 31, 2019 and 2018 were $103.6 million and $100.8 million, respectively.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
Property, Plant and Equipment	Dec. 31, 2019
Property, Plant and Equipment	G. PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment, net consisted of the following at December 31, 2019 and 2018: 2019 2018 (in thousands) Land $ 16,561 $ 16,561 Buildings 107,282 105,935 Machinery , and s oftware 834,970 752,722 Furniture and fixtures 29,157 27,432 Leasehold improvements 59,378 52,536 Construction in progress 2,537 6,276 1,049,885 961,462 Less: accumulated depreciation 729,669 681,641 $ 320,216 $ 279,821 Depreciation of property, plant and equipment for the years ended December 31, 2019, 2018, and 2017 was $70.8 million, $67.4 million, and $66.1 million, respectively. As of December 31, 2019 and 2018, the gross book value included in machinery and equipment for internally manufactured test systems being leased by customers was $5.4 million and $5.5 million, respectively. As of December 31, 2019 and 2018, the accumulated depreciation on these test systems was $5.1 million and $5.2 million, respectively.

Financial Instruments

Financial Instruments	12 Months Ended
Financial Instruments	Dec. 31, 2019
Financial Instruments	H. FINANCIAL INSTRUMENTS Cash Equivalents Teradyne considers all highly liquid investments with maturities of three months or less at the date of acquisition to be cash equivalents. Marketable Securities Effective January 1, 2018, Teradyne adopted ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, Teradyne’s available-for-sale fixed income securities priced by third party pricing vendors. These pricing vendors utilize the most recent observable market information in pricing these securities or, if specific prices are not available, use other observable inputs like market transactions involving identical or comparable securities. During the years ended December 31, 2019 and 2018, there were no transfers in or out of Level 1, Level 2, or Level 3 financial instruments. Realized gains recorded in 2019, 2018, and 2017 were $1.3 million, $4.0 million, and $1.1 million, respectively. Realized losses recorded in 2019, 2018, and 2017 were $0.2 million, $1.6 million, and $0.3 million, respectively. Realized gains are included in interest income and realized losses are included in interest expense. Unrealized gains on equity securities recorded during the years ended December 31, 2019 and 2018 were $5.3 million and $1.4 million, respectively. Unrealized losses on equity securities recorded during the years ended December 31, 2019 and 2018 were $0.4 million and $7.4 million, respectively. Unrealized gains on equity securities are included in interest income and unrealized losses are included in interest expense. Unrealized gains and losses on available-for-sale The cost of securities sold is based on the specific identification method. The following table sets forth by fair value hierarchy Teradyne’s financial assets and liabilities that were measured at fair value on a recurring basis as of December 31, 2019 and 2018: December 31, 2019 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 311,975 $ — $ — $ 311,975 Cash equivalents 410,285 51,664 — 461,949 Available for sale securities: Corporate debt securities — 97,307 — 97,307 Commercial paper — 54,149 — 54,149 U.S. Treasury securities — 42,382 — 42,382 U.S. government agency securities — 9,952 — 9,952 Debt mutual funds 6,888 — — 6,888 Certificates of deposit and time deposits — 4,751 — 4,751 Non-U.S. government securities — 592 — 592 Equity securities: Equity mutual funds 25,772 — — 25,772 Total $ 754,920 $ 260,797 $ — $ 1,015,717 Derivative assets — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Contingent consideration $ — $ — $ 39,705 $ 39,705 Derivative liabilities — 203 — 203 Total $ — $ 203 $ 39,705 $ 39,908 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 722,260 $ 51,664 $ — $ 773,924 Marketable securities — 137,303 — 137,303 Long-term marketable securities 32,660 71,830 — 104,490 Prepayments — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Other current liabilities $ — $ 203 $ — $ 203 Contingent consideration — — 9,106 9,106 Long-term contingent consideration — — 30,599 30,599 Total $ — $ 203 $ 39,705 $ 39,908 December 31, 2018 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 312,512 $ — $ — $ 312,512 Cash equivalents 253,525 360,715 — 614,240 Available for sale securities: U.S. Treasury securities — 109,721 — 109,721 Commercial paper — 86,117 — 86,117 Corporate debt securities — 40,020 — 40,020 U.S. government agency securities — 9,611 — 9,611 Certificates of deposit and time deposits — 7,604 — 7,604 Debt mutual funds 3,187 — — 3,187 Non-U.S. — 376 — 376 Equity securities: Equity mutual funds 21,191 — — 21,191 $ 590,415 $ 614,164 $ — $ 1,204,579 Derivative assets — 79 — 79 Total $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Contingent consideration $ — $ — $ 70,543 $ 70,543 Derivative liabilities — 514 — 514 Total $ — $ 514 $ 70,543 $ 71,057 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 566,037 $ 360,715 $ — $ 926,752 Marketable securities — 190,096 — 190,096 Long-term marketable securities 24,378 63,353 — 87,731 Prepayments — 79 — 79 $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Other current liabilities $ — $ 514 $ — $ 514 Contingent consideration — — 34,865 34,865 Long-term contingent consideration — — 35,678 35,678 $ — $ 514 $ 70,543 $ 71,057 Changes in the fair value of Level 3 contingent consideration for the years ended December 31, 2019 and 2018 were as follows: Contingent Consideration (in thousands) Balance at December 31, 2017 $ 45,102 Acquisition of MiR 52,547 Foreign currency impact (3,540 ) Payments ( 1 (24,553 ) Fair value adjustment ( 2 987 Balance at December 31, 2018 70,543 Acquisition of AutoGuide 23,976 Foreign currency impact (967 ) Payments (3) (34,590 ) Fair value adjustment (4) (19,257 ) Balance at December 31, 2019 $ 39,705 (1) During the year ended December 31, 201 8 24.6 earn-out Un iversal Robots. (2) During the year ended December 31, 2018, the fair value of contingent consideration for the earn-out in connection with the acquisition of MiR was increased by $17.7 million primarily due to an increase in forecasted revenues. During the year ended December 31, 2018, earn-out de 16.7 a de (3) During the year ended December 31, 201 9 30.8 and $3.8 million earn-out s s MiR a d , respectively (4) During the year ended December 31, 201 9 earn-out de 22.2 de partially offset by the impact from modification of the earn-out structure. 9 earn-out Auto G in 3.0 n in c rease revenues The following table provides quantitative information associated with the fair value measurement of Teradyne’s Level 3 financial instrument: Liability December 31, 2019 Fair Value Valuation Technique Unobservable Inputs Weighted Average (in thousands) Contingent c (AutoGuide) $ 26,952 Monte Carlo simulation Revenue Volatility 11.5 % Discount Rate 2.6 % Contingent c (MiR) $ 12,753 Monte Carlo simulation Revenue Volatility 14.0 % Discount Rate 0.2 % (1) Contingent consideration related to MiR of $ 9.1 20 As of December 31, 2019, the significant unobservable inputs used in the Monte Carlo simulation to fair value the AutoGuide and MiR contingent value measurement. As of December 31, 2019, the maximum amount of contingent consideration that could be paid in connection with the acquisition of AutoGuide is $ million. The earn-out periods end on December 31, 2020, December 31, 2021 and December 31, 2022 . As of December 31, 2019, the remaining maximum amount of contingent consideration that could be paid in connection with the acquisition of MiR is $63.2 million. The remaining earn-out period ends on December 31, 2020. The carrying amounts and fair values of Teradyne’s financial instruments at December 31, 2019 and 2018 were as follows: December 31, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 773,924 $ 773,924 $ 926,752 $ 926,752 Marketable securities 241,793 241,793 277,827 277,827 Derivative assets 528 528 79 79 Liabilities Contingent consideration 39,705 39,705 70,543 70,543 Derivative liabilities 203 203 514 514 Convertible debt (1) 394,687 1,010,275 379,981 547,113 (1) The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note which includes the equity conversion features. The fair values of accounts receivable, net and accounts payable approximate the carrying amount due to the short term nature of these instruments. The following tables summarize the composition of available-for-sale December 31, 2019 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Corporate debt securities $ 93,267 $ 4,081 $ (41 ) $ 97,307 $ 2,009 Commercial paper 54,124 26 (1 ) 54,149 1,391 U.S. Treasury securities 42,167 431 (216 ) 42,382 17,556 U.S. government agency securities 9,942 14 (4 ) 9,952 3,043 Debt mutual funds 6,753 135 — 6,888 — Certificates of deposit and time deposits 4,751 — — 4,751 — Non-U.S. government securities 592 — — 592 — $ 211,596 $ 4,687 $ (262 ) $ 216,021 $ 23,999 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 137,144 $ 160 $ (1 ) $ 137,303 $ 2,922 Long-term marketable securities 74,452 4,527 (261 ) 78,718 21,077 $ 211,596 $ 4,687 $ (262 ) $ 216,021 $ 23,999 December 31, 2018 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 110,969 $ 112 $ (1,360 ) $ 109,721 $ 75,040 Commercial paper 86,130 13 (26 ) 86,117 85,094 Corporate debt securities 41,133 432 (1,545 ) 40,020 24,767 U.S. government agency securities 9,646 1 (36 ) 9,611 7,077 Certificates of deposit and time deposits 7,604 — — 7,604 — Debt mutual funds 3,153 34 — 3,187 — Non-U.S. government securities 376 — — 376 — $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 190,100 $ 88 $ (92 ) $ 190,096 $ 140,262 Long-term marketable securities 68,911 504 (2,875 ) 66,540 51,716 $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978 As of December 31, 2019, the fair market value of investments with unrealized losses les s than one year totaled As of December 31, 2018, the fair market value of investments with unrealized losses totaled $192.0 million. Of this value, $28.5 million had unrealized losses of $1.6 million greater than one year and $163.5 million had unrealized losses of $1.4 million for less than one year. Teradyne reviews its investments to identify and evaluate investments that have an indication of possible impairment. Based on this review, Teradyne determined that the unrealized losses related to these investments at December 31, 2019 and 2018, were not other than temporary. The contractual available-for-sale Cost Fair Value (in thousands) Due within one year $ 137,144 $ 137,303 Due after 1 year through 5 years 15,264 15,351 Due after 5 years through 10 years 14,436 14,576 Due after 10 years 37,999 41,903 Total $ 204,843 $ 209,133 The fair value of the outstanding contracts was a gain of $0.3 million and a Gains and losses on foreign currency forward contracts and foreign currency remeasurement gains and losses on monetary assets and liabilities are included in other (income) expense, net. The following table summarizes the fair value of derivative instruments as of December 31, 2019 and 2018: December 31, 2019 December 31, 2018 (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Prepayments $ 528 $ 79 Foreign exchange contracts Other current liabilities (203 ) (514 ) Total $ 325 $ (435 ) The following table summarizes the effect of derivative instruments in the statements of operations recognized for the years ended December 31, 2019, 2018, and 2017. Location of (Gains) Losses Recognized in Statement of Operations December 31, 2019 December 31, 2018 December 31, 2017 (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 5,960 $ 7,386 $ (1,133 ) (1) The table does not reflect the corresponding gains and losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. (2) For the years ended December 31, 2019 and 2018, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $ 1.6 2.5 (3) For the year ended December 31, 2017, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $ 2.9 See Note J: “Debt” regarding derivatives related to the convertible senior notes. Concentration of Credit Risk Financial instruments which potentially subject Teradyne to concentrations of credit risk consist principally of cash equivalents, marketable securities, forward currency contracts and accounts receivable. Teradyne’s cash equivalents consist primarily of money market funds invested in U.S. Treasuries and government agencies. Teradyne’s fixed income available-for-sale or more

Leases

Leases	12 Months Ended
Leases	Dec. 31, 2019
Lease	I. LEASES On January 1, 2019, Teradyne adopted ASC 842 using the modified retrospective approach. Under this method of adoption, the comparative information in the consolidated financial statements has not been revised and continues to be reported under the previously applicable lease accounting guidance (ASC 840). Adoption of ASC 842 resulted in recording ROU assets and lease liabilities of approximately $50.1 million and $54.3 million, respectively. The adoption of ASC 842 did not have a material impact on beginning retained earnings, the consolidated statement of operations, cash flows, or earnings per share. Teradyne has facility and auto leases, which are accounted for as operating leases. Teradyne’s facility leases are primarily used for administrative functions, research and development, manufacturing, and storage and distribution. Remaining lease terms range from less than one year to twelve Total lease expense for the year ended December 31, 2019 was $35.6 million and included $11.1 million of variable lease costs and $2.6 million of costs related to short-term leases , At December 31, 2019, the weighted average remaining lease term and weighted average discount rate for operating leases was 4.5 years and 5.0%, respectively. Supplemental cash flow information related to leases was as follows: For the Year December 31, 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities included in operating cash flows $ 19,400 Right-of-use 26,739 Maturities of lease liabilities as of December 31, 2019 were as follows: Operating Lease (in thousands) 2020 $ 21,874 2021 17,638 2022 12,944 2023 6,496 2024 5,106 Thereafter 8,388 Total lease payments 72,446 Less imputed interest (7,121 ) Total lease liabilities $ 65,325 As of December 31, 2018, future non-cancelable Operating Lease (in thousands) 2019 $ 19,570 2020 18,293 2021 13,578 2022 9,693 2023 5,449 Thereafter 9,472 Total lease payments $ 76,055

Debt

Debt	12 Months Ended
Debt	Dec. 31, 2019
Debt	J. DEBT Convertible Senior Notes On December 12, 2016, Teradyne completed a private offering of $460.0 million aggregate principal amount of 1.25% convertible senior unsecured notes (the “Notes”) due December 15, 2023 and received net proceeds, after issuance costs, of approximately $ million, $ million of which was used to pay the net cost of the convertible note hedge transactions and $ million of which was used to repurchase million shares of ’s common stock under its existing stock repurchase program from purchasers of the Notes in privately negotiated transactions effected through one of the initial purchasers or its affiliates conducted concurrently with the pricing of the Note offering. The Notes will mature on December , , unless earlier repurchased or converted. The Notes bear interest at a rate of % per year . The Notes will be convertible at the option of the at any time prior to the close of business on the business day immediately preceding , only under the following circumstances: during any calendar quarter beginning after March , (and only during such calendar quarter), if the closing sale price of ’s common stock, for at least trading days (whether or not consecutive) during a period of consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than % of the conversion price on each applicable trading day; during the business day period after any consecutive trading day period (the “measurement period”) in which the trading price (as defined in the Indenture) per $ principal amount of Notes for each trading day of the measurement period was less than % of the product of the closing sale price of the ’s common stock and the conversion rate on each such trading day; and upon the occurrence of specified corporate events. On or after September , until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their Notes at any time, regardless of the foregoing circumstances. may satisfy its conversion obligation by paying or delivering cash, shares of its common stock or a combination of cash and shares of its common stock, at ’s election. As of December , , the conversion price was approximately $ per share of ’s common stock. The conversion rate is subject to adjustment under certain circumstances. Concurrent with the offering of the Notes, Teradyne entered into convertible note hedge transactions (the “Note Hedge Transactions”) with the initial purchasers or their affiliates (the “Option Counterparties”). The Note Hedge Transactions cover, subject to customary anti-dilution adjustments, the number of shares of the common stock that underlie the Notes, with a strike price equal to the conversion price of the Notes of $31.62. The Note Hedge Transactions cover, subject to customary anti-dilution adjustments, approximately 14.5 million shares of Teradyne’s common stock. Separately and concurrent with the pricing of the Notes, Teradyne entered into warrant transactions with the Option Counterparties (the “Warrant Transactions”) in which it sold net-share-settled The Note Hedge Transactions are expected to reduce the potential dilution to Teradyne’s common stock upon any conversion of the Notes. However, the Warrant Transactions could separately have a dilutive effect to the extent that the market value per share of Teradyne’s common stock exceeds the applicable strike price of the warrant. The net cost of the Note Hedge Transactions, after being partially offset by the proceeds from the sale of the warrants, was approximately $33.0 million. In connection with establishing their initial hedge of these convertible note hedge and warrant transactions, the Option Counterparties have entered into various derivative transactions with respect to Teradyne’s common stock and/or purchased shares of Teradyne’s common stock or other securities, including the Notes, concurrent with, or shortly after, the pricing of the Notes. In addition, the Option Counterparties may modify their hedge positions by entering into or unwinding various derivative transactions with respect to Teradyne’s common stock or by selling Teradyne’s common stock or other securities, including the Notes, in secondary market transactions (and may do so during any observation period related to the conversion of the Notes). These activities could adversely affect the value of Teradyne’s common stock and the Notes. Teradyne considered the guidance of ASC 815-40, “Derivatives and Hedging—Contracts in Entity’s Own Equity,” fixed-for-fixed Teradyne assessed whether the convertible note hedge should be classified as equity under ASC 815-40. 815-40 Teradyne analyzed the Warrant Transactions under ASC 815-40, “Derivatives and Hedging—Contracts in Entity’s Own Equity,” paid-in The provisions of ASC 470-20, Debt with Conversion and Other Options, 470-20 The below tables represents the key components of Teradyne’s convertible senior notes: December 31, December 31, (in thousands) Debt p $ 460,000 $ 460,000 Unamortized discount 65,313 80,019 Net c $ 394,687 $ 379,981 For the year ended December 31, December 31, (in thousands) Contractual interest expense on the coupon $ 5,750 $ 5,750 Amortization of the discount component and debt issue fees recognized as interest expense 14,706 13,995 Total interest expense on the convertible debt $ 20,456 $ 19,745 As of December 31, 2019, the unamortized discount was $65.3 million, which will be amortized over four years using the effective interest rate method. The carrying amount of the equity component was $100.8 million. As of December 31, 2019, the conversion price was approximately $31. 62 Revolving Credit Facility On June 27, 2019, Teradyne terminated its credit agreement, which Teradyne entered into with Barclays Bank PLC on April 27, 2015. The terminated credit agreement , which w as und r a w at ter mination , a , senior secured revolving credit facility of up to $ million .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
Accumulated Other Comprehensive Income (Loss)	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss)	K. ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME Changes in accumulated other comprehensive (loss) income, which is presented net of tax, consist of the following: Foreign Currency Translation Adjustment Unrealized Gain s (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Balance at December 31, 2017, net of tax of $0, $1,815, $(932) $ 15,919 $ 1,362 $ 1,495 $ 18,776 Other comprehensive loss (28,442 ) (2,110 ) — (30,552 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(21), $(71) — 1,337 (245 ) 1,092 Net current period other comprehensive loss (28,442 ) (773 ) (245 ) (29,460 ) Reclassification of tax effects resulting f rom net of tax of — 691 78 769 Reclassification of unrealized gains on equity securities, net of tax of — (3,125 ) — (3,125 ) Balance at December 31, 2018, net of tax of $0, $(521), $(1,081) (12,523 ) (1,845 ) 1,328 (13,040 ) Other comprehensive (loss) (10,991 ) 6,015 — (4,976 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(192), $(43) — (690 ) (148 ) (838 ) Net current period other comprehensive (loss) (10,991 ) 5,325 (148 ) (5,814 ) Balance at December 31, 2019, net of tax of $0, $946, $(1,124) $ (23,514 ) $ 3,480 $ 1,180 $ (18,854 ) (a) In the year ended December 31, 2018, Teradyne early adopted ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” (b) In the year ended December 31, 2018, Teradyne adopted ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities Reclassifications out of accumulated other comprehensive income to the statements of operations for the years ended December 31, 2019, 2018, and 2017, were as follows: Details about Accumulated Other Comprehensive Income Components For the year ended Affected Line Item in the Statements of Operations December 31, 2019 December 31, 2018 December 31, 2017 (in thousands) Available-for-sale Unrealized gains $ 690 $ (1,337 ) $ 441 Interest income (expense) Defined benefit pension and postretirement plans: Amortization of prior service benefit, net of tax of $43, $71, $154 148 245 272 (a) Total reclassifications, net of tax of $235, $92, $451 $ 838 $ (1,092 ) $ 713 Net income (a) The amortization of prior service credit is included in the computation of net periodic pension cost and postretirement benefit; see Note P: “Retirement Plans.”

Goodwill And Intangible Assets

Goodwill And Intangible Assets	12 Months Ended
Goodwill And Intangible Assets	Dec. 31, 2019
Goodwill and Intangible Assets	L. GOODWILL AND INTANGIBLE ASSETS Goodwill Teradyne performs its annual goodwill impairment test as required under the provisions of ASC 350-10, Intangibles—Goodwill and Other, Teradyne has the option to perform a qualitative assessment (“Step zero”) to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If Teradyne determines this is the case, Teradyne is required to perform the two-step two-step two-step , weighting the fair value determined under each approach to determine an estimated fair value for a report ing unit business combination, whereby the estimated fair value of the reporting unit is allocated to all of the assets and a business combination and the fair value of the reporting unit was the purchase price paid. If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. In the fourth quarter of 201 9 two-step , MiR and Energid units , AutoGuide 9 Based on Teradyne’s December 31, 2019 goodwill impairment test, the MiR reporting unit’s estimated fair value exceeded its carrying value by 14%. The MiR goodwill amount is $123.6 million as of December 31, 2019. Key assumptions in the goodwill valuation model are forecasted revenues, discount rate, earnings before interest and taxes, and revenue multiples from comparable companies. A change in any of these key assumptions could result in the reporting unit being impaired in a future period. In the fourth quarter of 201 8 two-step , MiR , and Energi d 8 In the fourth quarter of 2017, Teradyne performed the annual goodwill impairment test. Teradyne completed step one of the two-step The changes in the carrying amount of goodwill by reportable segments for the years ended December 31, 2019 and 2018 are as follows: Industrial Automation Wireless Test Semiconductor Test System Test Total (in thousands) Balance at December 31, 2017: Goodwill $ 233,519 $ 361,819 $ 260,540 $ 158,699 $ 1,014,577 Accumulated impairment losses — (353,843 ) (260,540 ) (148,183 ) (762,566 ) 233,519 7,976 — 10,516 252,011 MiR acquisition 135,976 — — — 135,976 Energid acquisition 14,394 — — — 14,394 Foreign currency translation adjustment (20,531 ) — — — (20,531 ) Balance at December 31, 2018: Goodwill 363,358 361,819 260,540 158,699 1,144,416 Accumulated impairment losses — (353,843 ) (260,540 ) (148,183 ) (762,566 ) 363,358 7,976 — 10,516 381,850 Lemsys acquisition — — 1,428 — 1,428 Auto G 41,372 — — — 41,372 Foreign currency translation adjustment (8,247 ) — 28 — (8,219 ) Balance at December 31, 2019: Goodwill 396,483 361,819 261,996 158,699 1,178,997 Accumulated impairment losses — (353,843 ) (260,540 ) (148,183 ) (762,566 ) $ 396,483 $ 7,976 $ 1,456 $ 10,516 $ 416,431 Intangible Teradyne reviews long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable or that the useful lives of these assets are no longer appropriate. There were no events or circumstances indicating that the carrying value of intangible and long-lived assets may not be recoverable in 2019 , 2018 2017 Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheets: December 31, 2019 Gross Carrying Amount (1 ) Accumulated Amortization (2) Foreign Net Carrying Amount (in thousands) Developed technology $ 361,787 $ (279,000 ) $ (5,709 ) $ 77,078 Customer relationships 75,669 (59,077 ) (455 ) 16,137 Tradenames and trademarks 70,120 (36,671 ) (1,184 ) 32,265 Backlog 260 (260 ) — — Total intangible assets $ 507,836 $ (375,008 ) $ (7,348 ) $ 125,480 December 31, 2018 Gross Carrying Amount Accumulated Amortization Foreign Net Carrying Amount (in thousands) Developed technology $ 336,308 $ (252,080 ) $ (4,079 ) $ 80,149 Customer relationships 97,153 (83,448 ) (340 ) 13,365 Tradenames and trademarks 64,420 (31,653 ) (799 ) 31,968 Non-compete 320 (320 ) — — Backlog 30 (30 ) — — Total intangible assets $ 498,231 $ (367,531 ) $ (5,218 ) $ 125,482 (1) Includes intangible assets acquired in 2019, $37.7 million from the AutoGuide Lemsys (2) In 2019, $32.7 million of amortizable intangible assets became fully amortized and have been eliminated from the gross carrying amount and accumulated amortization. Aggregate intangible assets amortization expense for the years ended December 31, 2019, 2018, and 2017, was $40.1 million, $39.2 million, and $30.5 million, respectively. Estimated intangible assets amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2020 $ 30,606 2021 20,593 2022 19,700 2023 19,226 2024 18,921 Thereafter 16,434

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2019
Commitments and Contingencies	M. COMMITMENTS Purchase Commitments As of December 31, 2019, Teradyne non-cancelable Legal Claims Teradyne is subject to legal proceedings, claims and investigations that arise in the ordinary course of business such as, but not limited to, patent, employment, commercial and environmental matters. Teradyne believes that it has meritorious defenses against all pending claims and intends to vigorously contest them. While it is not possible to predict or determine the outcomes of any pending claims or to provide possible ranges of losses that may arise, Teradyne believes the potential losses associated with all of these actions are unlikely to have a material adverse effect on its business, financial position or results of operations. Guarantees and Indemnification Obligations Teradyne provides indemnification, to the extent permitted by law, to its officers, directors, employees and agents for liabilities arising from certain events or occurrences while the officer, director, employee, or agent, is or was serving, at Teradyne’s request in such capacity. Teradyne has entered into indemnification agreements with certain of its officers and directors. With respect to acquisitions, Teradyne provides indemnifications to or assumes indemnification obligations for the current and former directors, officers and employees of the acquired companies in accordance with the acquired companies’ by-laws Teradyne enters into agreements in the ordinary course of business with customers, resellers, distributors, integrators and suppliers. Most of these agreements require Teradyne to defend and/or indemnify the other party against intellectual property infringement claims brought by a third party with respect to Teradyne’s products. From time to time, Teradyne also indemnifies customers and business partners for damages, losses and liabilities they may suffer or incur relating to personal injury, personal property damage, product liability, breach of confidentiality obligations and environmental claims relating to the use of Teradyne’s products and services or resulting from the acts or omissions of Teradyne, its employees, authorized agents or subcontractors. On occasion, Teradyne has also provided guarantees to customers regarding the delivery and performance of its products in addition to the warranty described below. As a matter of ordinary course of one-year the revenue - , In addition, in the ordinary course of business, Teradyne provides minimum purchase guarantees to certain vendors to ensure continuity of supply against the market demand. Although some of these guarantees provide penalties for cancellations and/or modifications to the purchase commitments as the market demand decreases, most of the guarantees do not. Therefore, as the market demand decreases, Teradyne re-evaluates With respect to its agreements covering product, business or entity divestitures and acquisitions, Teradyne provides certain representations, warranties and covenants to purchasers and agrees to indemnify and hold such purchasers harmless against breaches of such representations, warranties and covenants. Many of the indemnification claims have a definite expiration date while some remain in force indefinitely. With respect to its acquisitions, Teradyne may, from time to time, assume the liability for certain events or occurrences that took place prior to the date of acquisition. As a matter of ordinary course of business, Teradyne occasionally guarantees certain indebtedness obligations of its subsidiary companies, limited to the borrowings from financial institutions, purchase commitments to certain vendors, and lease commitments to landlords. Based on historical experience and information known as of December 31, 2019, and 2018, except for product warranty, Teradyne has not recorded any liabilities for these guarantees and obligations because the amount would be immaterial.

Net Income (Loss) per Common Sh

Net Income (Loss) per Common Share	12 Months Ended
Net Income (Loss) per Common Share	Dec. 31, 2019
Net Income per Common Share	N. NET INCOME PER COMMON SHARE The following table sets forth the computation of basic and diluted net income per common share: 2019 2018 2017 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 467,468 $ 451,779 $ 257,692 Weighted average common shares-basic 170,425 187,672 198,069 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) 4,909 2,749 1,298 Convertible note hedge warrant shares (2) 2,698 485 112 Restricted stock units 1,236 1,385 1,800 Stock options 178 278 335 Employee stock purchase rights 13 36 27 Dilutive potential common shares 9,034 4,933 3,572 Weighted average common shares-diluted 179,459 192,605 201,641 Net income per common share-basic $ 2.74 $ 2.41 $ 1.30 Net income per common share-diluted $ 2.60 $ 2.35 $ 1.28 (1) Incremental shares from the assumed conversion of the convertible notes was calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.62, multiplied by 14.5 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period. (2) Convertible notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.68, multiplied by 14.5 million shares. The result of this calculation, representing the total intrinsic value of the warrant, was divided by the average Teradyne stock price for the period. The computation of diluted net income per common share for 2018 excludes the effect of the potential exercise of stock options to purchase approximately 0.1 million shares and restricted stock units to purchase approximately 0.5 million shares because the effect would have been anti-dilutive. The computation of diluted net income per common share for 2017 excludes the effect of the potential exercise of stock options to purchase approximately 0.1 million shares because the effect would have been anti-dilutive.

Restructuring and Other

Restructuring and Other	12 Months Ended
Restructuring and Other	Dec. 31, 2019
Restructuring and Other	O. RESTRUCTURING AND OTHER During the year ended December 31, 2019, Teradyne recorded a gain 22.2 million for the , parti a ffset by increase in the fair value of the AutoGuide contingent consideration liability , Industrial Automation, and $2.5 . During the year ended December 31, 2018, Teradyne recorded an expense of $17.7 million for the increase in the fair value of the MiR contingent consideration liability, $8.7 million of severance charges related to headcount reductions primarily in Semiconductor Test, and $4.5 million for acquisition related expenses and compensation, partially offset by a gain of $ 16.7 During the year ended December 31, 2017, Teradyne recorded an expense of $7.8 million for the increase in the fair value of the Universal Robots contingent consideration liability, $3.8 million of severance charges related to headcount reductions primarily in Semiconductor Test, $1.1 million for an impairment of fixed assets in Semiconductor Test, $1.0 million for a lease impairment of a Wireless Test facility in Sunnyvale, CA, which was terminated in September 2017, and $0.8 million of expenses related to an earthquake in Kumamoto, Japan, partially offset by $5.1 million of property insurance recovery related to the Japan earthquake.

Retirement Plans

Retirement Plans	12 Months Ended
Retirement Plans	Dec. 31, 2019
Retirement Plans	P. RETIREMENT PLANS ASC 715 , Compensation—Retirement Benefits, Defined Benefit Pension Plans Teradyne has defined benefit pension plans covering a portion of domestic employees and employees of certain non-U.S. During 2018, Teradyne purchased a group annuity contract for its retiree participants in the U.S. qualified pension plan. Under the group annuity, the accrued pension obligations for approximately 1,700 retiree participants were transferred to an insurance company. The reduction in the pension benefit obligation and pension assets was $151.3 million. During 2018, Teradyne recorded a settlement loss of $0.3 million related to the retiree group annuity transaction. The December 31 balances of these defined benefit pension plans assets and obligations are shown below: 2019 2018 United States Foreign United States Foreign (in thousands) Assets and Obligations Change in benefit obligation: Projected benefit obligation: Beginning of year $ 178,237 $ 39,146 $ 363,026 $ 39,353 Service cost 1,608 751 2,196 786 Interest cost 7,189 691 8,940 687 Actuarial loss 24,447 4,520 (30,136 ) 773 Benefits paid (7,690 ) (836 ) (14,793 ) (741 ) Retiree annuity purchase — — (151,341 ) — Liability loss due to settlement — — 345 — Non-U.S. — (320 ) — (1,712 ) End of year 203,791 43,952 178,237 39,146 Change in plan assets: Fair value of plan assets: Beginning of year 144,301 1,400 324,506 1,307 Company contributions 2,805 923 2,587 822 Actual return on plan assets 27,516 64 (16,658 ) 50 Benefits paid (7,690 ) (836 ) (14,793 ) (741 ) Retiree annuity purchase — — (151,341 ) — Non-U.S. — 35 — (38 ) End of year 166,932 1,586 144,301 1,400 Funded status $ (36,859 ) $ (42,366 ) $ (33,936 ) $ (37,746 ) The following table provides amounts recorded within the account line items of the statements of financial position as of December 31: 2019 2018 United States Foreign United States Foreign (in thousands) Retirement plans assets $ 18,457 $ — $ 16,883 $ — Accrued employees’ compensation and withholdings (2,826 ) (922 ) (2,676 ) (852 ) Retirement plans liabilities (52,490 ) (41,444 ) (48,143 ) (36,894 ) Funded status $ (36,859 ) $ (42,366 ) $ (33,936 ) $ (37,746 ) The following table provides amounts recognized in accumulated other comprehensive income as of December 31: 2019 2018 United States Foreign United States Foreign (in thousands) Deferred taxes related to prior service cost recognized in other comprehensive income $ 560 $ — $ 560 $ — The accumulated benefit obligation for the United States defined benefit pension plans was $198.2 million and $172.8 million at December 31, 2019 and 2018, respectively. The accumulated benefit obligation for foreign defined benefit pension plans was $39.9 million and $35.6 million at December 31, 2019 and 2018, respectively. Information for pension plans with an accumulated benefit obligation in excess of plan assets as of December 31: 2019 2018 United States Foreign United States Foreign (in millions) Projected benefit obligation $ 55.3 $ 44.0 $ 50.8 $ 39.1 Accumulated benefit obligation 53.2 39.9 48.6 35.6 Fair value of plan assets — 1.6 — 1.4 Expense For the years ended December 31, 2019, 2018, and 2017, Teradyne’s net periodic pension cost 2019 2018 2017 United States Foreign United States Foreign United States Foreign (in thousands) Components of Net Periodic Pension Cost Service cost $ 1,608 $ 751 $ 2,196 $ 786 $ 2,239 $ 818 Interest cost 7,189 691 8,940 687 13,151 852 Expected return on plan assets (6,042 ) (29 ) (9,049 ) (19 ) (12,008 ) (165 ) Amortization of prior service cost — — 58 — 70 — Net actuarial loss 2,973 4,485 (4,429 ) 743 (6,712 ) (310 ) Settlement loss — — 345 — — — Total net periodic pension cost $ 5,728 $ 5,898 $ (1,939 ) $ 2,197 $ (3,260 ) $ 1,195 Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Reversal of amortization items: Prior service cost — — (58 ) — (70 ) — Total recognized in other comprehensive income — — (58 ) — (70 ) — Total recognized in net periodic pension cost and other comprehensive income $ 5,728 $ 5,898 $ (1,997 ) $ 2,197 $ (3,330 ) $ 1,195 Weighted Average Assumptions to Determine Net Periodic Pension Cost at January 1: 2019 2018 2017 United States Foreign United States Foreign United States Foreign Discount rate 4.1 % 1.8 % 3.4 % 1.8 % 3.9 % 1.8 % Expected return on plan assets 4.3 2.0 4.3 1.5 4.0 2.0 Salary progression rate 2.5 2.5 2.3 2.7 2.6 2.7 Weighted Average Assumptions to Determine Pension Obligations at December 31: 2019 2018 United States Foreign United States Foreign Discount rate 3.0 % 1.1 % 4.1 % 1.8 % Salary progression rate 2.6 2.5 2.5 2.6 In developing the expected return on plan assets assumption, Teradyne evaluates input from its investment manager and pension consultants, including their forecast of asset class return expectations. Teradyne believes that 4.25% was an appropriate rate to use for fiscal 2019 for the U.S. Qualified Pension Plan (“U.S. Plan”). Teradyne recognizes net actuarial gains and losses and the change in the fair value of the plan assets in its operating results in the year in which they occur or upon any interim remeasurement of the plans. Teradyne calculates the expected return on plan assets using the fair value of the plan assets. Actuarial gains and losses are generally measured annually as of December 31 and, accordingly, recorded during the fourth quarter of each year or upon any interim remeasurement of the plans. The discount rate utilized to determine future pension obligations for the U.S. Plan is based on FTSE Pension Index adjusted for the plan’s expected cash flows and was 3.10% at December 31, 2019, down Plan Assets As of December 31, 2019, the fair value of Teradyne’s pension plans’ assets totaled $168.5 million of which $166.9 million was related to the U.S. Plan and $1.6 million was related to the Taiwan defined benefit pension plan. Substantially all of Teradyne’s pension plans’ assets are held in individual trusts, which were established for the investment of assets of Teradyne’s sponsored retirement plans. The following table provides weighted average pension asset allocation by asset category at December 31, 2019 and 2018: 2019 2018 United States Foreign United States Foreign Fixed income securities 94.0 % — % 94.0 % — % Equity securities 5.0 — 5.0 — Other 1.0 100.0 1.0 100.0 100.0 % 100.0 % 100.0 % 100.0 % The assets of the U.S. Plan are overseen by the Teradyne Fiduciary Committee which is comprised of members of senior management drawn from appropriate diversified levels of the management team. The Fiduciary Committee is responsible for setting the policy that provides the framework for management of the U.S. Plan assets. In accordance with its responsibilities, the Fiduciary Committee meets on a regular basis to review the performance of the U.S. Plan assets and compliance with the investment policy. The policy sets forth an investment structure for managing U.S. Plan assets, including setting the asset allocation ranges, which are expected to provide an appropriate level of overall diversification required to maximize the long-term return on plan assets for a prudent and reasonable level of risk given prevailing market conditions, total investment return over the long term, and preservation of capital, while maintaining sufficient liquidity to pay the benefits of the U.S. Plan. The investment portfolio will not, at any time, have a direct investment in Teradyne stock. It may have indirect investment in Teradyne stock, if one of the funds selected by the investment manager invests in Teradyne stock. In developing the asset allocation ranges, third party asset allocation studies are periodically performed that consider the current and expected positions of the plan assets and funded status. Based on this study and other appropriate information, the Fiduciary Committee establishes asset allocation ranges taking into account acceptable risk targets and associated returns. The investment return objectives are to avoid excessive volatility and produce a rate of return that at least matches the Policy Index identified below. The manager’s investment performance is reviewed at least annually. Results for the total portfolio and for each major category of assets are evaluated in comparison with The target asset allocation and the index for each asset category for the U.S. Plan, per the investment policy, are as follows: Asset Category: Policy Index: Target Allocation U.S. corporate fixed income Barclays U.S. Corporate A or Better Index 75 % Global equity MSCI World Minimum Volatility Index 5 U.S. government fixed income Barclays U.S. Long Government Bond Index 14 High yield fixed income Barclays U.S. High Yield Index 5 Cash Citigroup Three Month U.S. Treasury Bill Index 1 Teradyne’s U.S. Plan invests primarily in common trust funds. Units held in the common trust funds are valued at the unit price as reported by the investment manager based on the asset value of the underlying investments; underlying investments in equity securities are valued at the last reported sales price, and underlying investments in fixed-income securities are generally valued using methods based upon market transactions for comparable securities. In 2017, the U.K. defined benefit pension was terminated and the obligations and assets of the plan were transferred to an insurance company. During the year ended December 31, 2019, there were no transfers of pension assets in or out of Level 1, Level 2, and Level 3. During the year ended December 31, 2018, $2.7 million of pension assets were transferred out of Level 3 to Level 2. The fair value of pension plan assets by asset category and by level at December 31, 2019 and December 31, 2018 were as follows: December 31, 2019 United States Foreign Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in thousands) Fixed income securities: Corporate debt securities $ — $ 133,792 $ — $ 133,792 $ — $ — $ — $ — U.S. government securities — 23,186 — 23,186 — — — — Global equity — 8,344 — 8,344 — — — — Other — — — — — 1,586 — 1,586 Cash and cash equivalents 1,610 — — 1,610 — — — — Total $ 1,610 $ 165,322 $ — $ 166,932 $ — $ 1,586 $ — $ 1,586 December 31, 2018 United States Foreign Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in thousands) Fixed income securities: Corporate debt securities $ — $ 115,424 $ — $ 115,424 $ — $ — $ — $ — U.S. government securities — 20,176 — 20,176 — — — — Global equity — 7,252 — 7,252 — — — — Other — — — — — 1,400 — 1,400 Cash and cash equivalents 1,449 — — 1,449 — — — — Total $ 1,449 $ 142,852 $ — $ 144,301 $ — $ 1,400 $ — $ 1,400 Changes in the fair value of Level 3 group annuity insurance contracts for the year ended December 31, 2018 were Group Annuity Insurance Contracts (in thousands) Balance at December 31, 2017 $ 3,166 Transfer out of level 3 (2,658 ) Purchase s f insurance ontracts (512 ) Interest and market value adjustments 59 Benefits paid (40 ) Other (15 ) Balance at December 31, 2018 $ — Contributions Teradyne’s funding policy is to make contributions to the plans in accordance with local laws and to the extent that such contributions are tax deductible. During 2019, Teradyne contributed $2.8 million to the U.S. supplemental executive defined benefit pension plan and $0.9 million to certain qualified plans for non-U.S. non-U.S. 2020 non-U.S. Expected Future Pension Benefit Payments Future benefit payments are expected to be paid as follows: United States Foreign (in thousands) 2020 $ 8,027 $ 1,237 2021 8,416 985 2022 9,163 982 2023 9,785 1,258 2024 10,558 1,098 2025-2029 59,665 6,129 Postretirement Benefit Plans In addition to receiving pension benefits, U.S. Teradyne employees who meet early retirement eligibility requirements as of their termination dates may participate in Teradyne’s Welfare Plan, which includes medical and dental benefits up to age 65. Death benefits provide a fixed sum to retirees’ survivors and are available to all retirees. Substantially all of Teradyne’s current U.S. employees could become eligible for these benefits, and the existing benefit obligation relates primarily to those employees. The December 31 balances of the postretirement assets and obligations are shown below: 2019 2018 (in thousands) Assets and Obligations Change in benefit obligation: Projected benefit obligation: Beginning of year $ 9,256 $ 6,177 Service cost 41 39 Interest cost 347 196 Actuarial loss 717 25 Benefits paid (1,358 ) (889 ) Special termination benefits — 3,708 End of year 9,003 9,256 Change in plan assets: Fair value of plan assets: Beginning of year — — Company contributions 1,358 889 Benefits paid (1,358 ) (889 ) End of year — — Funded status $ (9,003 ) $ (9,256 ) The following table provides amounts recorded within the account line items of financial position as of December 31: 2019 2018 (in thousands) Accrued employees’ compensation and withholdings $ (1,231 ) $ (1,310 ) Retirement plans liability (7,772 ) (7,946 ) Funded status $ (9,003 ) $ (9,256 ) The following table provides amounts recognized in accumulated other comprehensive income as of December 31: 2019 2018 (in thousands) Prior service credit, before tax $ (58 ) $ (249 ) Deferred taxes (1,684 ) (1,641 ) Total recognized in other comprehensive income, net of tax $ (1,742 ) $ (1,890 ) Expense For the years ended December 31, 2019, 2018, and 2017, Teradyne’s net periodic postretirement benefit cost (income) was comprised of the following: 2019 2018 2017 (in thousands) Components of Net Periodic Postretirement Benefit Cost (income): Service cost $ 41 $ 39 $ 34 Interest cost 347 196 201 Amortization of prior service credit (191 ) (373 ) (496 ) Net actuarial loss 717 25 398 Special termination benefits — 3,708 591 Total net periodic postretirement benefit cost 914 3,595 728 Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Prior service cost — — — Reversal of amortization items: Prior service credit 191 373 496 Total recognized in other comprehensive income 191 373 496 Total recognized in net periodic postretirement cost and other comprehensive income $ 1,105 $ 3,968 $ 1,224 Weighted Average Assumptions to Determine Net Periodic Postretirement Benefit Income as of January 1: 2019 2018 2017 Discount rate 4.0 % 3.4 % 3.9 % Initial health care cost trend rate 7.5 7.9 7.3 Ultimate health care cost trend rate 4.5 4.5 5.0 Year in which ultimate health care cost trend rate is reached 2026 2026 2023 Weighted Average Assumptions to Determine Postretirement Benefit Obligation as of December 31: 2019 2018 2017 Discount rate 3.0 % 4.0 % 3.4 % Initial medical trend 7.1 7.5 7.9 Ultimate health care trend 4.5 4.5 4.5 Medical cost trend rate decrease to ultimate rate in year 2026 2026 2026 Assumed health care trend rates could have a significant effect on the amounts reported for health care plans. A one percentage point change in the assumed health care cost trend rates for the year ended December 31, 2019 would have the following effects: 1 Percentage Point Increase 1 Percentage Point Decrease (in thousands) Effect on total service and interest cost components $ 6 $ (6 ) Effect on postretirement benefit obligations 139 (133 ) Expected Future Benefit Payments Future benefit payments are expected to be paid as follows: Benefit Payments (in thousands) 2020 $ 1,231 2021 1,171 2022 958 2023 789 2024 662 2025-2029 1,965

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
Stock-Based Compensation	Dec. 31, 2019
Stock-Based Compensation	Q. STOCK-BASED COMPENSATION Stock Compensation Plans On July 17, 2019 (the “Retirement Date”), former Chief Financial Officer Gregory Beecher retired as Vice President and Senior Advisor of Teradyne, and Teradyne entered into an agreement (the “Retirement Agreement”) with Mr. Beecher. Under the Retirement Agreement, Mr. Beecher’s unvested time-based restricted stock units and stock options granted prior to 2019 were modified to allow continued vesting; unvested time-based restricted stock units and stock options granted in 2019 were modified to allow continued vesting through January 31, 2023 (the “Non-Competition pro-rated pro-rated Non-Competition Under Teradyne’s stock compensation plans, Teradyne grants time-based , stock s Time-based restricted stock unit awards granted to employees vest in equal annual installments over four years. Restricted stock unit awards granted to non-employee after a one ear p eriod, with f he - P - granted Teradyne’ s may vest upon the three-year anniversary of the grant date. The TSR PRSUs are valued using a Monte Carlo simulation model. The number of units expected to be earned, based upon the achievement of the TSR market condition, is factored into the grant date Monte Carlo valuation. Compensation expense is recognized on a straight-line basis over the shorter of the three-year service period or the period from the grant to the date described in the retirement provisions below. Compensation expense for employees meeting the retirement provisions prior to the grant date will be recognized in full on the date of the grant. Compensation expense is recognized regardless of the eventual number of units that are earned based upon the market condition, provided the executive officer remains an employee at the end of the three-year period. Compensation expense is reversed if at any time during the three-year service period the executive officer is no longer an employee, subject to the retirement and termination eligibility provisions noted below. PRSUs Teradyne’s may also have three-year non-GAAP Non-GAAP non-cash non-recurring shorter of the or the period from the grant date to the date described in the retirement provisions below. Compensation expense for employees meeting the retirement provisions prior to the grant date will be recognized in full on the date of grant If a PRSU recipient’s employment ends prior to the determination of the performance percentage due to (1) permanent disability or death or (2) retirement or termination other than for cause, after attaining both at least age sixty three Stock options to purchase Teradyne’s common stock at 100% of the fair market value on the grant date vest in equal annual installments over four years from the grant date and have a maximum term of seven years. During 2019, 2018 and 2017, Teradyne granted 0.8 million, 0.6 million and 0.8 million of service-based restricted stock unit awards to employees at a weighted average grant date fair value of $37.65, $45.92 and $28.19, respectively. During 2019, 2018 and 2017, Teradyne granted 0.1 million of service-based restricted stock unit awards to non-employee directors at a weighted average grant date fair value of $48.03, $35.81 and $34.48, respectively. During 2019, 2018 and 2017, Teradyne granted 0.1 million TSR PRSUs, with a grant date fair value of $51.51, $54.85 and $35.66 respectively. The fair value was estimated using the Monte Carlo simulation model with the following assumptions: 2019 2018 2017 Risk-free interest rate 2.6 % 2.2 % 1.5 % Teradyne volatility-historical 31.9 % 26.8 % 26.6 % NYSE Composite Index volatility-historical 11.9 % 12.4 % 13.4 % Dividend yield 1.0 % 0.8 % 1.0 % Expected volatility was based on the historical volatility of Teradyne’s stock and the NYSE Composite Index for each of the 2019, 2018 and 2017 grants over the most recent three-year period. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of each of the grants . Dividend yield was based upon an estimated annual dividend amount of $0.36 per share for 2019 and 2018 and $0.28 per share for 2017 , grants , $47.70 for the 2018 grants and $28.56 for 2017 grants . During 2019, 2018 and 2017, Teradyne granted 0.1 million of During , and , granted million of service-based stock options to executive officers at a weighted average grant date fair value of $ , $ and $ , respectively. The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: 2019 2018 2017 Expected life (years) 5.0 5.0 5.0 Risk-free interest rate 2.5 % 2.4 % 2.0 % Volatility-historical 30.1 % 26.4 % 27.8 % Dividend yield 1.00 % 0.80 % 1.00 % Teradyne determined the stock options’ expected life based upon historical exercise data for executive officers, the age of the executive officers and the terms of the stock option grant . Volatility was determined using historical volatility for a period equal to the expected life. The risk-free interest rate was determined using the U.S. Treasury yield curve in effect at the time of grant. Dividend yield was based upon an estimated annual dividend amount of $0.36 per share divided by Teradyne’s stock price on the grant date of $37.95 for the 2019 grants, $47.70 for the 2018 grants and $28.56 for the 2017 grants. Stock compensation plan activity for the years 2019, 2018, and 2017, is as follows: 2019 2018 2017 (in thousands) Restricted Stock Units: Non-vested 2,454 3,174 3,778 Awarded 1,139 790 939 Vested (1,237 ) (1,382 ) (1,434 ) Forfeited (87 ) (128 ) (109 ) Non-vested 2,269 2,454 3,174 Stock Options: Outstanding at January 1 506 531 926 Granted 102 69 111 Exercised (280 ) (94 ) (501 ) Forfeited (7 ) — — Expired (2 ) — (5 ) Outstanding at December 31 319 506 531 Vested and expected to vest at December 31 319 506 531 Exercisable at December 31 85 256 233 Total shares available for the years 2019, 2018, and 2017: 2019 2018 2017 (in thousands) Shares available: Available for grant at January 1 7,874 8,605 9,546 Options granted (102 ) (69 ) (111 ) Options forfeited 7 — — Restricted stock units awarded (1,139 ) (790 ) (939 ) Restricted stock units forfeited 87 128 109 Available for grant at December 31 6,727 7,874 8,605 Weighted average restricted stock unit award date fair value information for the years 2019, 2018, and 2017 , 2019 2018 2017 Non-vested $ 29.22 $ 21.71 $ 18.27 Awarded 39.08 45.99 28.91 Vested 23.59 20.20 17.90 Forfeited 35.60 24.67 20.35 Non-vested $ 35.58 $ 29.22 $ 21.71 Restricted stock unit awards aggregate intrinsic value information at December 31 for the years 2019, 2018 , 2019 2018 2017 (in thousands) Vested $ 46,110 $ 63,688 $ 40,649 Outstanding 154,752 77,015 132,875 Expected to vest 152,374 77,187 130,594 Restricted stock units weighted average remaining contractual terms (in years) information at December 31 for the years 2019, 2018, and 2019 2018 2017 Outstanding 1.02 0.92 1.00 Expected to vest 1.02 0.91 0.99 Weighted average stock options exercise price information for the year ended December 31, 2019 is as follows: 2019 Outstanding at January 1 $ 19.06 Options granted 37.95 Options exercised 13.20 Options forfeited 36.75 Options cancelled 1.48 Outstanding at December 31 29.91 Exercisable at December 31 14.97 The total cash received from employees as a result of employee stock options exercises during the years ended December 31, 2019, 2018, and 2017, was $3.7 million, $1.0 million and $6.8 million, respectively. In connection with these exercises, the tax benefit realized by Teradyne for the years ended December 31, 2019, 2018, and 2017, was $2.0 million, $0.4 million, and $2.5 million, respectively. Stock option aggregate intrinsic value information for the years ended December 31, 2019, 2018, and 2017 is as follows: 2019 2018 2017 (in thousands) Exercised $ 9,232 $ 2,960 $ 8,035 Outstanding 12,218 7,359 14,831 Vested and expected to vest 7,701 7,359 14,831 Exercisable 4,517 5,905 9,076 Stock options weighted average remaining contractual terms (in years) information at December 31, for the years 2019, 2018, and 2017 is as follows: 2019 2018 2017 Outstanding 4.2 3.6 4.1 Vested and expected to vest 5.0 3.6 4.1 Exercisable 2.1 2.4 2.8 As of December 31, 2019, total unrecognized expense related to non-vested Employee Stock Purchase Plan Under the ESPP, eligible employees may purchase shares of common stock through regular payroll deductions of up to 10% of their compensation, to a maximum of shares with a fair market value of $25,000 per calendar year, not to exceed 6,000 shares. Under the plan, the price paid for the common stock is equal to 85% of the stock price on the last business day of the six-month In July 2019, 0.3 million shares of common stock were issued to employees who participated in the plan during the first half of 2019 at the price of $40.72 per share. In January 2020, Teradyne issued 0.2 million shares of common stock to employees who participated in the plan during the second half of 2019 at the price of $57.96 per share. In July 2018, 0.3 million shares of common stock were issued to employees who participated in the plan during the first half of 2018 at the price of $32.36 per share. In January 2019, Teradyne issued 0.4 million shares of common stock to employees who participated in the plan during the second half of 2018 at the price of $26.67 per share. In July 2017, 0.3 million shares of common stock were issued to employees who participated in the plan during the first half of 2017 at the price of $25.53 per share. In January 2018, Teradyne issued 0.3 million shares of common stock to employees who participated in the plan during the second half of 2017 at the price of $35.59 per share. As of December 31, 2019, there were 1.8 million shares available for grant under the ESPP. The following table provides the effect to income from operations for recording stock-based compensation for the years ended December 31, 2019, 2018, and 2017: 2019 2018 2017 (in thousands) Cost of revenues $ 3,480 $ 3,129 $ 3,212 Engineering and development 9,913 9,181 9,370 Selling and administrative 24,504 21,267 21,515 Stock-based compensation 37,897 33,577 34,097 Income tax benefit (8,360 ) (12,036 ) (10,462 ) Total stock-based compensation expense after income taxes $ 29,537 $ 21,541 $ 23,635

Savings Plan

Savings Plan	12 Months Ended
Savings Plan	Dec. 31, 2019
Savings Plan	R. SAVINGS PLAN Teradyne sponsors a defined contribution employee retirement savings plan (“Savings Plan”) covering substantially all U.S. employees. Under the Savings Plan, employees may contribute up to 20% of their compensation (subject to Internal Revenue Service limitations). The Savings Plan provides for a discretionary employer match that is determined each year. In 2019, 2018 and 2017, Teradyne matched 100% of eligible employee contributions up to 4% of their compensation for employees not accruing benefits in the U.S. Qualified Pension Plan. There was no match for employees still actively accruing benefits in the U.S. Qualified Pension Plan. Teradyne’s contributions vest 25% per year for the first four years of employment, and contributions for those employees with four years of service vest immediately. In addition, Teradyne sponsors an unfunded U.S. Supplemental Savings Plan to provide savings benefits in excess of those allowed by the Employee Retirement Income Security Act of 1974 and the Internal Revenue Code. The provisions of this plan are the same as the Savings Plan. The liability for the U.S. Supplemental Savings Plan at December 31, 2019 and 2018, was $32.7 million and $24.4 million, respectively, and is included in retirement plan liabilities. Teradyne contributes to defined contributions savings plans for its foreign employees. Under Teradyne’s savings plans, amounts charged to the statements of operations for the years ended December 31, 2019, 2018, and 2017 were $20.9 million, $19.4 million, and $16.8 million, respectively.

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2019
Income Taxes	S. INCOME TAXES The components of income (loss) before income taxes and the provision (benefit) for income taxes as shown in the consolidated statements of operations were as follows: 2019 2018 2017 (in thousands) Income before income taxes U.S. $ 192,442 $ 189,691 $ 76,699 Non-U.S. 333,330 278,110 447,713 $ 525,772 $ 467,801 $ 524,412 Provision (benefit) for income taxes Current: U.S. Federal $ 19,297 $ (59,122 ) $ 162,679 Non-U.S. 52,810 45,083 64,313 State (4,347 ) 1,721 2,623 67,760 (12,318 ) 229,615 Deferred: U.S. Federal (4,522 ) 29,252 43,687 Non-U.S. (8,007 ) (1,243 ) (6,476 ) State 3,073 331 (106 ) (9,456 ) 28,340 37,105 Total provision for income taxes $ 58,304 $ 16,022 $ 266,720 Income tax expense for 2019 , million million On December 22, 2017, the U.S. enacted the Tax Cuts and Jobs Act of 2017 (the “Tax Reform Act”), making significant changes to the Internal Revenue Code. The Tax Reform Act has significant direct and indirect implications for accounting for income taxes under ASC 740, “Accounting for Income Taxes” some of which could not be calculated with precision until further clarification and guidance was made available from tax authorities, regulatory bodies or the FASB. In light of this uncertainty, on December 22, 2017 the SEC issued Staff Accounting Bulletin (“SAB”) No. 118, “Income Tax Accounting Implications of the Tax Cuts and Jobs Act,” to address uncertainty in the application of U.S. GAAP when the registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Reform Act. In accordance with SAB 118, Teradyne recorded $186.0 million of additional income tax expense in the fourth quarter of 2017 which represented Teradyne’s best estimate of the impact of the Tax Reform Act in accordance with Teradyne’s understanding of the Tax Reform Act and available guidance as of that date. The $186.0 million was primarily composed of expense of $161.0 million related to the one-time , one-time Teradyne has made an accounting policy election to account for GILTI as a component of tax expense in the period in which Teradyne is subject to the rules and therefore did not provide any deferred tax impacts of GILTI in its consolidated financial statements. The increase in the effective tax rate from 2018 to 2019 is primarily attributable to increases in expense associated with GILTI and the transition tax on the mandatory deemed repatriation of foreign earnings. These increases in expense were partially offset by increased benefit from the U.S. foreign derived intangible income deduction, foreign tax credits and a net reduction of reserves for uncertain tax positions. On July 27, 2015, in Altera Corp. (“Altera”) v. Commissioner, the U.S. Tax Court issued an opinion invalidating the regulations relating to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. A final decision was issued by the Tax Court in December 2015. The IRS appealed the decision in June 2016. On July 24, 2018, the U.S. Court of Appeals for the Ninth Circuit (“Ninth Circuit”) issued a decision that was subsequently withdrawn and a reconstituted panel conferred on the appeal. On June 7, 2019, the Ninth Circuit upheld the cost-sharing regulations. On November 12, 2019 the Ninth Circuit denied Altera’s petition for rehearing of its case. As a result, during the fourth quarter of 2019, Teradyne recognized a tax expense of approximately $6.3 million related to the inclusion of stock-based compensation in its intercompany cost-sharing arrangement. The decrease in the effective tax rate from 2017 to 2018 was primarily attributable to the $186.0 million of income tax expense recorded in the fourth quarter of 2017 for one-time non-taxable A reconciliation of the effective tax rate for the years 2019, 2018 and 2017 is as follows: 2019 2018 2017 U.S. statutory federal tax rate 21.0 % 21.0 % 35.0 % U.S. global intangible low-taxed income 6.2 0.3 — U.S. transition tax 1.9 (10.5 ) 28.7 State income taxes, net of federal tax benefit 0.5 0.1 (0.4 ) Foreign tax credits (5.9 ) (2.2 ) (2.2 ) Uncertain tax positions (4.3 ) 1.0 1.7 Foreign taxes (4.0 ) (2.0 ) (16.3 ) U.S. foreign derived intangible income (2.6 ) (1.8 ) — U.S. research and development credit (1.8 ) (2.2 ) (1.6 ) Equity compensation (0.7 ) (1.2 ) (0.8 ) Impact of rate change on deferred taxes — 0.3 6.9 Domestic production activities deduction — — (0.3 ) Other, net 0.8 0.6 0.2 11.1 % 3.4 % 50.9 % Teradyne qualifies for a tax holiday in Singapore by fulfilling the requirements of an agreement with the Singapore Economic Development Board under which certain headcount and spending requirements must be met. The tax savings attributable to the Singapore tax holiday for the years ended December 31, 2019, 2018 and 2017 were $15.1 million or $ 0.08 11.9 December 31, 2020 Significant components of Teradyne’s deferred tax assets (liabilities) as of December 31, 2019 and 2018 were as follows: 2019 2018 (in thousands) Deferred tax assets Tax credits $ 79,480 $ 69,091 Accruals 25,424 23,449 Pension liabilities 24,459 20,826 Inventory valuations 18,572 18,514 Deferred revenue 7,622 9,130 Equity compensation 7,042 7,190 Vacation accrual 4,768 4,772 Investment impairment 3,292 — Net operating loss carryforwards 2,705 3,658 Marketable s — 962 Other 1,472 685 Gross deferred tax assets 174,836 158,277 Less: valuation allowance (77,177 ) (69,852 ) Total deferred tax assets $ 97,659 $ 88,425 Deferred tax liabilities: Depreciation $ (18,238 ) $ (14,028 ) Intangible assets (16,705 ) (24,211 ) Marketable securities (1,601 ) — Total deferred tax liabilities $ (36,544 ) $ (38,239 ) Net deferred assets $ 61,115 $ 50,186 As of December 31, 2019 and 2018, Teradyne evaluated the likelihood that it would realize deferred income taxes to offset future taxable income and concluded that it is more likely than not that a substantial majority of its deferred tax assets will be realized through consideration of both the positive and negative evidence. At December 31, 2019 and 2018, Teradyne maintained a valuation allowance for certain deferred tax assets of $77.2 million and $69.9 million, respectively, primarily related to state net operating losses and state tax credit carryforwards, due to the uncertainty regarding their realization. Adjustments could be required in the future if Teradyne estimates that the amount of deferred tax assets to be realized is more or less than the net amount recorded. At December 31, 2019, Teradyne had operating loss carryforwards that expire in the following years: State Operating Loss Carryforwards Federal Operating Loss Carryforwards Foreign Operating Loss Carryforwards ( in t 2020 $ 269 $ — $ — 2021 2,141 — — 2022 4,934 — — 2023 4,342 — — 2024 1,498 — — 2025-2029 7,673 — — 2030-2034 4,329 — 15 Beyond 2034 2,185 554 74 Non-expiring 1,357 — 4,207 Total $ 28,728 $ 554 $ 4,296 Teradyne has approximately $108.4 million of tax credit carryforwards including federal business tax credits of approximately $2.1 million which expire in 2028 , and state tax credits of $106.3 million, of which $59.7 million do not expire and the remainder expires in the years 2020 through 2039. Teradyne’s gross unrecognized tax benefits for the years ended December 31, 2019, 2018 and 2017 were as follows: 2019 2018 2017 (in thousands) Beginning balance, as of January 1 $ 43,395 $ 36,263 $ 38,958 Additions: Tax positions for current year 1,322 4,716 8,208 Tax positions for prior years 8,043 2,626 199 Reductions: Tax positions for prior years (31,397 ) (153 ) (10,573 ) Expiration of statutes (183 ) (57 ) (325 ) Settlements with tax authorities — — (204 ) Ending balance as of December 31 $ 21,180 $ 43,395 $ 36,263 Current year additions relate to federal and state research credits. Prior year additions primarily relate to stock-based compensation . Prior year reductions are primarily composed of federal and state reserves related to transfer pricing and research credits and resulted from the completion of the 2015 U.S. federal audit in the first quarter of 2019. Of the $21.2 million of unrecognized tax benefits as of December 31, 2019, $12.7 million would impact the consolidated income tax rate if ultimately recognized. The remaining $8.5 million would impact deferred taxes if recognized. Teradyne does not anticipate a material change in the balance of unrecognized tax benefits as of December 31, 2019 in the next twelve months . Teradyne records all interest and penalties related to income taxes as a component of income tax expense. Accrued interest and penalties related to income tax items at December 31, 2019 and 2018 amounted to $1.4 million and $0.3 million, respectively. For the years ended December 31, 2019, 2018 and 2017, expense of $1.1 million, expense of $0.1 million and benefit of $0.1 million, respectively, was recorded for interest and penalties related to income tax items. Teradyne is subject to U.S. federal income tax, as well as income tax in multiple state, local and foreign jurisdictions. As of December 31, 2019, all material state and local income tax matters have been concluded through 2013, all material federal income tax matters have been concluded through 2015 2011 As of December 31, 2019, Teradyne is not permanently reinvested with respect to the unremitted earnings of non-U.S.

Operating Segment, Geographic a

Operating Segment, Geographic and Significant Customer Information	12 Months Ended
	Dec. 31, 2019
Operating Segment, Geographic and Significant Customer Information	T. OPERATING SEGMENT, GEOGRAPHIC AND SIGNIFICANT CUSTOMER INFORMATION Teradyne has four reportable segments (Semiconductor Test, Industrial Automation , System Test and Wireless Test). Each of the Semiconductor Test, System Test, and Wireless Test segments is also an individual operating segment. The Industrial Automation reportable segment consists of operating segments with discrete financial information, which have been combined into one reportable segment as they share similar economic characteristics, types of products, production processes, distribution channels, and currency risks. The Semiconductor Test segment includes operations related to the design, manufacturing and marketing of semiconductor test products and services. The System Test segment includes operations related to the design, manufacturing and marketing of products and services for defense/aerospace instrumentation test, storage test and circuit-board test. The Industrial Automation segment includes operations related to the design, manufacturing and marketing of collaborative robotic arms, autonomous mobile robots and advanced robotic control software. The Wireless Test segment includes operations related to the design, manufacturing and marketing of wireless test products and services. Teradyne evaluates performance based on several factors, of which the primary financial measure is business segment income (loss) before income taxes. The accounting policies of the business segments are the same as those described in Note B: “Accounting Policies.” Segment information for the years ended December 31, 2019, 2018, and 2017 is as follows: Semiconductor Test Industrial Automation System Test Wireless Test Corporate And Other Consolidated (in thousands) 2019 Revenues $ 1,552,571 $ 298,139 $ 287,455 $ 157,315 $ (515 ) $ 2,294,965 Income (loss) before taxes (1)(2) 416,973 (5,916 ) 93,543 35,585 (14,413 ) 525,772 Total assets (3) 784,808 671,559 131,428 97,299 1,101,920 2,787,014 Property additions 112,145 9,076 3,059 10,362 — 134,642 Depreciation and amortization expense 59,197 40,904 5,518 5,365 9,671 120,655 2018 Revenues $ 1,492,417 $ 261,452 $ 216,132 $ 132,006 $ (1,205 ) $ 2,100,802 Income (loss) before taxes (1)(2) 397,645 7,670 48,857 29,052 (15,423 ) 467,801 Total assets (3) 669,452 607,502 88,098 77,570 1,263,984 2,706,606 Property additions 94,496 11,188 3,469 5,226 — 114,379 Depreciation and amortization expense 58,095 36,755 6,430 5,328 6,616 113,224 2017 Revenues $ 1,662,549 $ 170,056 $ 192,135 $ 111,866 $ — $ 2,136,606 Income (loss) before taxes (1)(2) 491,361 8,763 10,305 17,350 (3,368 ) 524,411 Total assets (3) 597,480 368,037 97,018 59,912 1,987,098 3,109,545 Property additions 87,920 7,044 5,976 4,435 — 105,375 Depreciation and amortization expense 58,901 25,711 6,646 5,392 11,425 108,075 (1) Included in Corporate and Other are: contingent consideration adjustments, investment impairment , , property insurance recovery (2) Included in income (loss) before taxes are charges and credits related to restructuring and other, and inventory charges. (3) Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets. Included in each segment are charges and credits in the following line items in the statements of operation s For the Year Ended December 31, 2019 2018 2017 (in thousands) Semiconductor Test: Cost of revenues—inventory charge $ 8,731 $ 6,822 $ 4,606 Restructuring and other—employee severance 1,277 8,429 1,779 Restructuring and other—impairment of fixed assets — — 1,124 Industrial Automation: Restructuring and other—employee severance $ 796 $ — $ 1,414 Restructuring and other—acquisition related expenses and compensation 741 1,163 — Cost of revenues—inventory charge 508 680 — System Test: Cost of revenues—inventory charge $ 2,000 $ 1,175 $ 1,918 Wireless: Cost of revenues—inventory charge $ 4,005 $ 2,565 $ 2,190 Restructuring and other—lease impairment — — 972 Corporate and Other: Restructuring and other—MiR contingent consideration adjustment $ (22,199 ) $ 17,666 $ — Other (income) expense, net—investment impairment charge 15,000 — — Restructuring and other—AutoGuide contingent consideration adjustment 2,976 — — Selling and administrative—equity modification charge 2,108 — — Restructuring and other—acquisition related expenses and compensation 1,765 3,422 — Restructuring and other—Universal Robots contingent consideration adjustment — (16,679 ) 7,820 Restructuring and other—property insurance recovery related to Japan earthquake — — (5,064 ) Information as to Teradyne’s revenues by country is as follows: 2019 2018 2017 (in thousands) Revenues from customers (1): China $ 514,327 $ 348,942 $ 260,451 Taiwan 485,681 516,322 687,031 United States 333,059 282,869 252,516 Korea 239,504 163,224 206,819 Europe 219,015 223,207 163,715 Japan 175,322 158,281 169,093 Thailand 87,503 59,184 29,566 Singapore 84,111 108,618 101,085 Malaysia 58,200 122,797 124,048 Philippines 54,560 77,996 105,850 Rest of the World 43,683 39,362 36,432 $ 2,294,965 $ 2,100,802 $ 2,136,606 (1) Revenues attributable to a country are based on location of customer site. In 2019 and 2018, no single direct Teradyne’ s consolidated revenues. In 2017, revenues from Taiwan Semiconductor Manufacturing Company Ltd. accounted for 13% of its consolidated revenues . Taiwan Semiconductor Manufacturing Company Ltd. is a customer of Ltd. (“Huawei”), combining direct sales to that customer with sales to the customer’s OSATs , its consolidated revenues in 2019 and 2018, respectively. Teradyne estimates consolidated revenues driven by another OEM customer, combining direct sales to that customer with sales to the customer’s OSATs (which include Taiwan Semiconductor Manufacturing Company Ltd.), accounted for approximately %, % and % of its consolidated revenues in 2019, 2018 and 2017, respectively. Long-lived assets by geographic area: United Foreign(1) Total (in thousands) December 31, 2019 $ 252,812 $ 124,943 $ 377,755 December 31, 2018 $ 209,368 $ 70,453 $ 279,821 (1) As of December 31, 2019 and 2018, long-lived assets attributable to Singapore were $35.2

Stock Repurchase Program

Stock Repurchase Program	12 Months Ended
Stock Repurchase Program	Dec. 31, 2019
Stock Repurchase Program	U. STOCK REPURCHASE PROGRAM In December 2016, Teradyne’s Board of Directors approved a $500.0 million share repurchase authorization which commenced on January 1, 2017. The cumulative repurchases as of December 31, 2017 totaled 5.8 million shares of common stock for $200.0 million at an average price per share of $34.30. In January 2018, Teradyne’s Board of Directors cancelled the December 2016 stock repurchase program and authorized a new stock repurchase program for up to $1.5 billion of common stock. In 2019, Teradyne repurchased 10.9 million shares of common stock for $500.0 million at an average price per share of $45.89. In 2018, Teradyne repurchased 21.6 million shares of common stock for $823.5 million at an average price per share of $38.06. The cumulative repurchases as of December 31, 2019 totaled 32.5 million shares of common stock for $1,323.0 million at an average price per share of $40.68. In January 2020, Teradyne’s Board of Directors cancelled the January 2018 repurchase program and approved a new stock repurchase program for up to $1.0 billion of common stock. Teradyne intends to repurchase a minimum of $250.0 million in 2020 .

Subsequent Events

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2019
Subsequent Events	V. SUBSEQUENT EVENTS In January 2020 March 20, 2020 February 21, 2020 While Teradyne declared a quarterly cash dividend and authorized a share repurchase program, it may reduce or eliminate the cash dividend or share repurchase program in the future. Future cash dividends and stock repurchases are subject to the discretion of Teradyne’s Board of Directors which will consider, among other things, Teradyne’s earnings, capital requirements and financial condition. On February 28, 2020, RealWear’s debt holder demanded repayment of its $25.0 million loan to RealWear. As a result, in the fourth quarter of 2019, Teradyne recorded an impairment charge of $15.0 million to reduce its investment in RealWear to zero as of December 31, 2019.

Supplementary Information

Supplementary Information	12 Months Ended
Supplementary Information	Dec. 31, 2019
Supplementary Information	SUPPLEMENTARY INFORMATION (Unaudited) The following sets forth certain unaudited consolidated quarterly statements of operations data for each of Teradyne’s last eight quarters. In management’s opinion, this quarterly information reflects all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement for the periods presented. Such quarterly results are not necessarily indicative of future results of operations and should be read in conjunction with the audited consolidated financial statements of Teradyne and the notes thereto included elsewhere herein. 2019 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter (1) (2) (3) (4)(5) ( 6 (in thousands, except per share amounts) Revenues: Products $ 393,442 $ 457,511 $ 488,170 $ 548,552 Services 100,657 106,667 93,868 106,098 Total revenues 494,099 564,178 582,038 654,650 Cost of revenues: Cost of products 165,368 193,299 197,196 226,184 Cost of services 41,096 46,961 39,804 45,228 Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below) 206,464 240,260 237,000 271,412 Gross profit 287,635 323,918 345,038 383,238 Operating expenses: Selling and administrative 102,013 108,811 109,166 117,092 Engineering and development 76,791 81,434 77,804 86,794 Acquired intangible assets amortization 10,634 10,083 9,647 9,784 Restructuring and other 5,112 (10,404 ) (6,500 ) (2,088 ) Total operating expenses 194,550 189,924 190,117 211,582 Income from operations 93,085 133,994 154,921 171,656 Non-operating Interest income (8,052 ) (5,430 ) (5,159 ) (6,145 ) Interest expense 5,713 5,800 5,682 5,950 Other (income) expense, net 1,445 2,447 2,665 22,965 Income before income taxes 93,979 131,177 151,733 148,886 Income tax (benefit) provision (15,159 ) 33,780 15,873 23,811 Net income $ 109,138 $ 97,397 $ 135,860 $ 125,075 Net income per common share—basic $ 0.63 $ 0.57 $ 0.80 $ 0.75 Net income per common share—diluted $ 0.62 $ 0.55 $ 0.75 $ 0.69 Cash dividend declared per common share $ 0.09 $ 0.09 $ 0.09 $ 0.09 (1) Restructuring and other includes a $3.0 million fair value adjustment to increase the MiR acquisition contingent consideration, $1.3 million of acquisition related expenses and compensation and $0.8 million of employee severance charges. (2) Restructuring and other includes a $11.7 million gain for the decrease in the fair value of the MiR (3) Restructuring and other includes a million gain for the decrease in the fair value of Mi R contingent consideration liability, partially offset by of employee severance charges and of acquisition related expenses an d compensa t (4) Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation (5) Teradyne recorded pension and post retirement net actuarial losses of $7.7 million for the fourth quarter in 2019. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy. (6) Other (income) expense, net includes a $15.0 million charge for the impairment of the investment in RealWear. 2018 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter (1) (2) (3) (4)(5) (in thousands, except per share amounts) Revenues: Products $ 403,925 $ 434,051 $ 470,994 $ 420,652 Services 83,542 92,878 95,854 98,906 Total revenues 487,467 526,929 566,848 519,558 Cost of revenues: Cost of products 180,958 180,777 195,339 170,064 Cost of services 36,677 38,818 37,816 39,959 Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below) 217,635 219,595 233,155 210,023 Gross profit 269,832 307,334 333,693 309,535 Operating expenses: Selling and administrative 90,505 99,410 100,202 100,552 Engineering and development 74,408 75,342 77,049 74,706 Acquired intangible assets amortization 7,698 9,793 11,142 10,558 Restructuring and other (313 ) 2,389 1,710 11,446 Total operating expenses 172,298 186,934 190,103 197,262 Income from operations 97,534 120,400 143,590 112,273 Non-operating Interest income (5,981 ) (5,427 ) (6,213 ) (9,083 ) Interest expense 6,890 5,639 5,557 13,182 Other (income) expense, net 805 176 3,405 (2,954 ) Income before income taxes 95,820 120,012 140,841 111,128 Income tax provision (benefit) 8,846 18,975 20,863 (32,662 ) Net income $ 86,974 $ 101,037 $ 119,978 $ 143,790 Net income per common share—basic $ 0.45 $ 0.53 $ 0.65 $ 0.80 Net income per common share—diluted $ 0.43 $ 0.52 $ 0.63 $ 0.79 Cash dividend declared per common share $ 0.09 $ 0.09 $ 0.09 $ 0.09 (1) Restructuring and other includes a $3.5 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $2.5 million of acquisition related expenses and compensation and $2.4 million of employee severance charges. (2) Restructuring and other includes a $5.0 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $3.9 million of employee severance charges and $0.8 million of acquisition related expenses and compensation. (3) Restructuring and other includes $1.7 million of employee severance charges, $0.8 million of acquisition related expenses and compensation, partially offset by a $0.8 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability. (4) Restructuring and other includes a $17.7 million fair value adjustment to increase the MiR acquisition contingent consideration, $0.8 million of employee severance charges, and $0.5 million acquisition related expenses and compensation, partially offset by a $7.4 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability. (5) Teradyne recorded pension and post retirement net actuarial gains of $3.5 million for the fourth quarter in 2018. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
Valuation and Qualifying Accounts	Dec. 31, 2019
Valuation and Qualifying Accounts	TERADYNE, INC. SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS Column A Column B Column C Column D Column E Column F Description Balance at Beginning of Period Additions Charged to Cost and Expenses Other Deductions Balance at End of Period (in thousands) Valuation reserve deducted in the balance sheet from the asset to which it applies: Accounts receivable: 2019 Allowance for doubtful account $ 1,673 $ 87 $ 28 $ 52 $ 1,736 2018 Allowance for doubtful account $ 2,219 $ — $ 20 $ 566 $ 1,673 2017 Allowance for doubtful accounts $ 2,356 $ 4 $ — $ 141 $ 2,219 Column A Column B Column C Column D Column E Column F Description Balance at Beginning of Period Additions Charged to Cost and Expenses Other Deductions Balance at End of Period (in thousands) Valuation reserve deducted in the balance sheet from the asset to which it applies: Inventory: 2019 Inventory reserve $ 100,779 $ 15,244 $ (85 ) $ 12,382 $ 103,556 2018 Inventory reserve $ 102,896 $ 11,242 $ 368 $ 13,727 $ 100,779 2017 Inventory reserve $ 116,016 $ 8,844 $ (126 ) $ 21,838 $ 102,896 Column A Column B Column C Column D Column E Column F Description Balance at Beginning of Period Additions Charged to Cost and Expenses Other Deductions Balance at End of Period (in thousands) Valuation reserve deducted in the balance sheet from the asset to which it applies: Deferred taxes: 2019 Valuation allowance $ 69,852 $ 7,325 $ — $ — $ 77,177 2018 Valuation allowance $ 63,919 $ 6,333 $ — $ 400 $ 69,852 2017 Valuation allowance $ 48,369 $ 15,571 $ — $ 21 $ 63,919

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
Accounting Policies (Policies)	Dec. 31, 2019
Basis of Presentation	Preparation of Financial Statements and Use of Estimates The preparation of consolidated financial statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent liabilities. On an on-going contingent consideration liabil ities ,
Preparation of Financial Statements and Use of Estimates	Preparation of Financial Statements and Use of Estimates The preparation of consolidated financial statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent liabilities. On an on-going contingent consideration liabil ities ,
Revenue Recognition	Revenue Recognition Revenue from Contracts with Customers Teradyne adopted Accounting Standard Codification (“ASC”) 606 “ Revenue from Contracts with Customers” In accordance with ASC 606, Teradyne recognizes revenues, when or as control is transferred to a customer. Teradyne’s determination of revenue is dependent upon a five step process outlined below. • Teradyne accounts for a contract with a customer when there is written approval, the contract is committed, the rights of the parties, including payment terms, are identified, the contract has commercial substance and consideration is probable of collection. • Teradyne periodically enters into contracts with customers in which a customer may purchase a combination of goods and services, such as products with extended warranty obligations. Teradyne determines performance obligations by assessing whether the products or services are distinct from the other elements of the contract. In order to be distinct, the product or service must perform either on its own or with readily available resources and must be separate within the context of the contract. • Teradyne considers the amount stated on the face of the purchase order to be the transaction price. Teradyne does not have material variable consideration which could impact the stated purchase price agreed to by Teradyne and the customer. • Transaction price is allocated to each individual performance obligation based on the standalone selling price of that performance obligation. Teradyne uses standalone transactions when available to value each performance obligation. If standalone transactions are not available, Teradyne will estimate the standalone selling price through market assessments or cost plus a reasonable margin analysis. Any discounts from standalone selling price are spread proportionally to each performance obligation. • In order to determine the appropriate timing for revenue recognition, Teradyne first determines if the transaction meets any of three criteria for over time recognition. If the transaction meets the criteria for over time recognition, Teradyne recognizes revenue as the good or service is delivered. Teradyne uses input variables such as hours or months utilized or costs incurred to determine the amount of revenue to recognize in a given period. Input variables are used as they best align consumption with benefit to the customer. For transactions that do not meet the criteria for over time recognition, Teradyne will recognize revenue at a point in time based on an assessment of the five criteria for transfer of control. Teradyne has concluded that revenue should be recognized when shipped or delivered based on contractual terms. Typically, acceptance of Teradyne’s products and services is a formality as Teradyne delivers similar systems, instruments and robots to standard specifications. In cases where acceptance is not deemed a formality, Teradyne will defer revenue recognition until customer acceptance. Performance Obligations Products Teradyne products consist primarily of semiconductor test systems and instruments, defense/aerospace test instrumentation and systems, storage test systems and instruments, circuit-board test and inspection systems and instruments, industrial automation products and wireless test systems. Teradyne’s hardware is recognized at a point in time upon transfer of control to the customer. Services Teradyne services consist of extended warranties, training and application support, service agreement, post contract customer support (“PCS”) and replacement parts. Each service is recognized based on relative standalone selling price. Extended warranty, training and support, service agreements and PCS are recognized over time based on the period of service. Replacement parts are recognized at a point in time upon transfer of control to the customer. Teradyne does not allow customer returns or provide refunds to customers for any products or services. Teradyne products include a standard 12-month As of December 31, 2019 and 2018, deferred revenue and customer advances consisted of the following and are included in the short and long-term deferred revenue and customer advances: 2019 2018 (in thousands) Maintenance , service $ 63,815 $ 58,362 Extended warranty 30,677 27,422 Customer advances, undelivered elements and other 56,358 24,677 Total deferred revenue and customer advances $ 150,850 $ 110,461
Product Warranty	Product Warranty Teradyne generally provides a one-year Amount (in thousands) Balance at December 31, 2016 $ 7,203 Accruals for warranties issued during the period 14,223 Accruals related to pre-existing (379 ) Settlements made during the period (12,847 ) Balance at December 31, 2017 8,200 Acquisition 41 Accruals for warranties issued during the period 13,045 Accruals related to pre-existing 921 Settlements made during the period (14,298 ) Balance at December 31, 2018 7,909 Acquisition 14 Accruals for warranties issued during the period 14,106 Accruals related to pre-existing 4,026 Settlements made during the period (17,059 ) Balance at December 31, 2019 $ 8,996 When Teradyne receives revenue for extended warranties, beyond one year, it is deferred and recognized on a straight-line basis over the contract period. Related costs are expensed as incurred. The balance below is included in short and long-term deferred revenue and customer advances: Amount (in thousands) Balance at December 31, 2016 $ 28,200 Deferral of new extended warranty revenue 20,513 Recognition of extended warranty deferred revenue (24,275 ) Balance at December 31, 2017 24,438 Deferral of new extended warranty revenue 23,753 Recognition of extended warranty deferred revenue (20,769 ) Balance at December 31, 2018 27,422 Deferral of new extended warranty revenue 23,271 Recognition of extended warranty deferred revenue (20,016 ) Balance at December 31, 2019 $ 30,677
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The volatility of the industries that Teradyne serves can cause certain of its customers to experience shortages of cash flows, which can impact their ability to make required payments. Teradyne maintains allowances for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments. Estimated allowances for doubtful accounts are reviewed periodically taking into account the customer’s recent payment history, the customer’s current financial statements and other information regarding the customer’s credit worthiness. Account balances are written off against the allowance when it is determined the receivable will not be recovered. Teradyne sells certain trade accounts receivables on a non-recourse are are
Inventories	Inventories Inventories are stated at the lower of cost (first-in, first-out
Investments	Investments Teradyne accounts for its investments in debt and equity securities in accordance with the provisions of ASC 320-10, Investments—Debt and Equity Securities 320-10 available-for-sale held-to-maturity • The length of time and the extent to which the market value has been less than cost; • The financial condition and near-term prospects of the issuer; and • The intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value. Teradyne uses the market and income approach techniques to value its financial instruments and there were no changes in valuation techniques during the twelve months ended December 31, 2019 and 2018. As defined in ASC 820-10, Fair Value Measurements and Disclosures, 820-10 Level 1: Quoted prices in active markets for identical assets as of the reporting date; Level 2: Inputs other than Level 1, that are observable either directly or indirectly as of the reporting date. For example, a common approach for valuing fixed income securities is the use of matrix pricing. Matrix pricing is a mathematical technique used to value securities by relying on the securities’ relationship to other benchmark quoted prices, and is considered a Level 2 input; or Level 3: Unobservable inputs that are not supported by market data. Unobservable inputs are developed based on the best information available, which might include Teradyne’s own data. In accordance with ASC 820-10,
Financial Assets and Financial Liabilities	Financial Assets and Financial Liabilities In January 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities
Investment in Other Company	Investment in Other Company Teradyne holds an investment in a private company that develops and sells advanced wearable technology. Teradyne does not have the ability to exert significant influence over the company. The investment was recorded at cost and is evaluated for impairment or an indication of changes in fair value resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer on a quarterly basis. See Note D: “Acquisitions and Investment in Other Company.”
Prepayments	Prepayments Prepayments consist of the following and are included in prepayments and other current assets on the balance sheet: 2019 2018 (in thousands) Contract manufacturer and supplier prepayments $ 143,392 $ 131,642 Prepaid taxes 8,046 9,646 Prepaid maintenance and other services 8,503 8,487 Other prepayments 16,753 12,744 Total prepayments $ 176,694 $ 162,519
Retirement and Postretirement Plans	Retirement and Postretirement Plans Teradyne recognizes net actuarial gains and losses and the change in the fair value of the plan assets in its operating results in the year in which they occur or upon any interim remeasurement of the plans. Teradyne calculates the expected return on plan assets using the fair value of the plan assets. Actuarial gains and losses are generally measured annually as of December 31 and, accordingly, recorded during the fourth quarter of each year or upon any interim remeasurement of the plans.
Retirement Benefits	Retirement Benefits In March 2017, the FASB issued ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost non-service compensation costs and the non-service components of net benefit costs such as interest cost, expected return on assets, amortization of prior service cost, and actuarial gains or losses are reported within other (income) expense, net. In the twelve months ended December 31, 2017 , million , due to the removal of net actuarial pension gains and increased non-operating (income) expense by the same amount with no impact to net income.
Goodwill, Intangible and Long-Lived Assets	Goodwill, Intangible and Long-Lived Assets Teradyne accounts for goodwill and intangible assets in accordance with ASC 350-10, Intangibles-Goodwill and Other. 350-10, two-step two-step In accordance with ASC 360-10, Impairment or Disposal of Long-Lived Assets, carrying
Business Combination	Business Combination Teradyne recognizes the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The fair value of identifiable intangible assets is based on detailed cash flow valuations that use information and assumptions provided by management. Teradyne estimates the fair value of contingent consideration at the time of the acquisition using all pertinent information known to us at the time to assess the probability of payment of contingent amounts or through the use of a Monte Carlo simulation model. Teradyne allocates any excess purchase price over the fair value of the net tangible and intangible assets acquired and liabilities assumed to goodwill. The assumptions used in the valuations for our acquisitions may differ materially from actual results depending on performance of the acquired businesses and other factors. While Teradyne believes the assumptions used were appropriate, different assumptions in the valuation of assets acquired and liabilities assumed could have a material impact on the timing and extent of impact on our statements of operations. Goodwill is assigned to reporting units as of the date of the related acquisition.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost and depreciated over the estimated useful lives of the assets. Leasehold improvements and major renewals are capitalized and included in property, plant and equipment accounts while expenditures for maintenance and repairs and minor renewals are charged to expense. When assets are retired, the assets and related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in the consolidated statements of operations. Teradyne provides for depreciation of its assets principally on the straight-line method with the cost of the assets being charged to expense over their useful lives as follows: Buildings 40 years Building improvements 5 to 10 years Leasehold improvements Lesser of lease term or 10 years Furniture and fixtures 10 years Test systems manufactured internally 6 years Machinery , and software 3 to 5 years Test systems manufactured internally are used by Teradyne for customer evaluations and manufacturing and support of its customers. Teradyne depreciates the test systems manufactured internally over a six
Leases	Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842)” right-of-use 2018-11, “Leases (Topic 842): Targeted Improvements,” Under ASC 842, a contract is or contains a lease when Teradyne has the right to control the use of an identified asset. Teradyne determines if an arrangement is a lease at inception of the contract, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. Teradyne determines if the lease is an lease For leases commencing after January 1, 2019, the lease liability is measured at the present value of future lease payments, discounted using the discount rate for the lease at the commencement date. As Teradyne is typically unable to determine the implicit rate, Teradyne uses an incremental borrowing rate based on the lease term and economic environment at commencement date. Teradyne initially measures payments based on an index by using the applicable rate at lease commencement. Variable payments that do not depend on an index are not included in the lease liability and are recognized as they are incurred. The ROU asset is initially measured as the amount of lease liability, adjusted for any initial lease costs, prepaid lease payments, and reduced by any lease incentives. Teradyne’s contracts often include non-lease non-lease
Engineering and Development Costs	Engineering and Development Costs Teradyne’s products are highly technical in nature and require a large and continuing engineering and development effort. Software development costs incurred prior to the establishment of technological feasibility non-recurring
Stock Compensation Plans and Employee Stock Purchase Plan	Stock Compensation Plans and Employee Stock Purchase Plan Stock-based compensation expense is based on the grant-date fair value estimated in accordance with the provisions of ASC 718-10, Compensation-Stock Compensation In March 2016, the FASB issued ASU 2016-09, “Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.” Adoption of this ASU required recognition of a cumulative effect adjustment to retained earnings for any prior year excess tax benefits or tax deficiencies not previously recorded. The cumulative effect adjustment of $39 million was recorded in the first quarter of 2017 as an increase to retained earnings and deferred tax assets. This ASU also required a change in how Teradyne recognizes the excess tax benefits or tax deficiencies related to stock-based compensation. Prior to adopting ASU 2016-09, paid-in 2016-09, ASU 2016-09 In addition, under ASU 2016-09, Upon adoption of ASU 2016-09, Under its stock compensation plans, Teradyne has granted stock options, restricted stock units and performance-based restricted stock units, and employees are eligible to purchase Teradyne’s common stock through its Employee Stock Purchase Plan (“ESPP”).
Income Taxes	Income Taxes Deferred tax assets and liabilities are determined based on differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the “Accounting for Income Taxes.” tax-planning
Advertising Costs	Advertising Costs Teradyne expenses all advertising costs as incurred. Advertising costs were $16.6 million, $15.4 million and $9.1 million in 2019, 2018 and 2017, respectively.
Translation of Non-U.S. Currencies	Translation of Non-U.S. The functional currency for all non-U.S. non-monetary Net foreign exchange gains and losses resulting from remeasurement are included in other (income) expense, net. For the years ended December 31, 2019, 2018, and 2017, (gains) losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies were $(1.6) million, $(2.5) million, and $2.9 million, respectively. These amounts do not reflect the corresponding (gains) losses from foreign exchange contracts. See Note H: “Financial Instruments” regarding foreign exchange contracts.
Net Income (Loss) per Common Share	Net Income (Loss) per Common Share Basic net income (loss) per common share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Except where the result would be anti-dilutive, diluted net income (loss) per common share is calculated by dividing net income (loss) by the sum of the weighted average number of common shares plus common stock equivalents, if applicable. With respect to its convertible debt issued in 2016, Teradyne has determined that it has the ability and intent to settle the principal of the convertible debt in cash; accordingly, the principal amount is excluded from the determination of diluted earnings per share. As a result, Teradyne is accounting for the conversion spread using the treasury stock method.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) includes net income, unrealized pension and postretirement prior service costs and benefits, unrealized gains and losses on investments in debt marketable securities and foreign currency translation adjustment. Prior to 2018, comprehensive income (loss) included unrealized gains and losses on investments in equity marketable securities.

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
Accounting Policies (Tables)	Dec. 31, 2019
Deferred Revenue and Customer Advances	As of December 31, 2019 and 2018, deferred revenue and customer advances consisted of the following and are included in the short and long-term deferred revenue and customer advances: 2019 2018 (in thousands) Maintenance , service $ 63,815 $ 58,362 Extended warranty 30,677 27,422 Customer advances, undelivered elements and other 56,358 24,677 Total deferred revenue and customer advances $ 150,850 $ 110,461
Other Accrued Liabilities	The balance below is included in other accrued liabilities: Amount (in thousands) Balance at December 31, 2016 $ 7,203 Accruals for warranties issued during the period 14,223 Accruals related to pre-existing (379 ) Settlements made during the period (12,847 ) Balance at December 31, 2017 8,200 Acquisition 41 Accruals for warranties issued during the period 13,045 Accruals related to pre-existing 921 Settlements made during the period (14,298 ) Balance at December 31, 2018 7,909 Acquisition 14 Accruals for warranties issued during the period 14,106 Accruals related to pre-existing 4,026 Settlements made during the period (17,059 ) Balance at December 31, 2019 $ 8,996
Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances	The balance below is included in short and long-term deferred revenue and customer advances: Amount (in thousands) Balance at December 31, 2016 $ 28,200 Deferral of new extended warranty revenue 20,513 Recognition of extended warranty deferred revenue (24,275 ) Balance at December 31, 2017 24,438 Deferral of new extended warranty revenue 23,753 Recognition of extended warranty deferred revenue (20,769 ) Balance at December 31, 2018 27,422 Deferral of new extended warranty revenue 23,271 Recognition of extended warranty deferred revenue (20,016 ) Balance at December 31, 2019 $ 30,677
Schedule of Prepayments and Other Current Assets	Prepayments consist of the following and are included in prepayments and other current assets on the balance sheet: 2019 2018 (in thousands) Contract manufacturer and supplier prepayments $ 143,392 $ 131,642 Prepaid taxes 8,046 9,646 Prepaid maintenance and other services 8,503 8,487 Other prepayments 16,753 12,744 Total prepayments $ 176,694 $ 162,519
Useful Lives of Assets	Teradyne provides for depreciation of its assets principally on the straight-line method with the cost of the assets being charged to expense over their useful lives as follows: Buildings 40 years Building improvements 5 to 10 years Leasehold improvements Lesser of lease term or 10 years Furniture and fixtures 10 years Test systems manufactured internally 6 years Machinery , and software 3 to 5 years

Acquisitions and Investment I_2

Acquisitions and Investment In Other Company (Tables)	12 Months Ended
Acquisitions and Investment In Other Company (Tables)	Dec. 31, 2019
Autoguide LLC [Member]
Final Allocation of Purchase Price	The following table represents the preliminary allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 41,372 Intangible assets 37,660 Tangible assets acquired and liabilities assumed: Other c 3,661 Non-current 1,227 Accounts payable and current liabilities (1,223 ) Long-term other (949 ) Total purchase price $ 81,748
Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date	Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Developed technology $ 24,590 6.0 Customer relationships 7,360 6.0 Trademarks and tradenames 5,450 7.0 Backlog 260 0.3 Total intangible assets $ 37,660 6.1
Mobile Industrial Robots (MiR)
Final Allocation of Purchase Price	The following table represents the final allocation of the purchase price: Purchase Price Allocation (in thousands) Goodwill $ 135,976 Intangible assets 80,670 Tangible assets acquired and liabilities assumed: Current assets 6,039 Non-current 1,336 Accounts payable and current liabilities (7,336 ) Long-term deferred tax liabilities (18,007 ) Other long-term liabilities (900 ) Total purchase price $ 197,778
Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date	Components of these intangible assets and their estimated useful lives at the acquisition date are as follows: Fair Value Estimated Useful (in thousands) (in years) Developed technology $ 58,900 7.0 Trademarks and tradenames 13,240 11.0 Customer relationships 8,500 2.5 Backlog 30 0.2 Total intangible assets $ 80,670 7.2
Pro Forma Results Under Acquisitions	The unaudited pro forma results are not necessarily indicative of what actually would have occurred had the acquisition been in effect for the periods presented: For the Year Ended December 31, 2019 December 31, 2018 (in thousands, except per share amounts) Revenues $ 2,303,737 $ 2,111,373 Net income $ 464,602 $ 442,082 Net income per common share: Basic $ 2.73 $ 2.36 Diluted $ 2.59 $ 2.30

Revenue (Tables)

Revenue (Tables)	12 Months Ended
Revenue (Tables)	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition	The following table provides information about disaggregated revenue by timing of revenue recognition, primary geographical market, and major product lines. Semiconductor Industrial Automation System Test Wireless Test Corporate and Other Total System on-a-chip Memory Universal Mobile AutoGuide Energid (in thousands) For the Year Ended December 31, 2019 (1) Timing of Revenue Recognition Point in Time $ 1,070,375 $ 247,221 $ 244,515 $ 44,329 $ 1,144 $ — $ 237,686 $ 148,322 $ (515 ) $ 1,993,077 Over Time 216,065 18,910 3,952 74 234 3,891 49,769 8,993 — 301,888 Total $ 1,286,440 $ 266,131 $ 248,467 $ 44,403 $ 1,378 $ 3,891 $ 287,455 $ 157,315 $ (515 ) $ 2,294,965 Geographical Market Asia Pacific $ 1,152,881 $ 238,714 $ 67,806 $ 9,513 $ — $ 221 $ 132,826 $ 126,549 $ — $ 1,728,510 Americas 73,257 23,826 70,165 14,438 1,378 1,761 129,840 24,234 (515 ) 338,384 Europe, Middle East and Africa 60,302 3,591 110,496 20,452 — 1,909 24,789 6,532 — 228,071 Total $ 1,286,440 $ 266,131 $ 248,467 $ 44,403 $ 1,378 $ 3,891 $ 287,455 $ 157,315 $ (515 ) $ 2,294,965 For the Year Ended December 31, 2018 (1) Timing of Revenue Recognition Point in Time $ 1,010,493 $ 259,366 $ 231,895 $ 24,115 $ — $ 553 $ 167,418 $ 122,536 $ (1,205 ) $ 1,815,171 Over Time 208,456 14,102 2,200 — — 2,689 48,714 9,470 — 285,631 Total $ 1,218,949 $ 273,468 $ 234,095 $ 24,115 $ — $ 3,242 $ 216,132 $ 132,006 $ (1,205 ) $ 2,100,802 Geographical Market Asia Pacific $ 1,067,879 $ 245,264 $ 58,381 $ 5,950 $ — $ 111 $ 90,989 $ 107,872 $ — $ 1,576,446 Americas 78,498 17,353 68,938 7,326 — 1,540 96,763 19,166 (1,205 ) 288,379 Europe, Middle East and Africa 72,572 10,851 106,776 10,839 — 1,591 28,380 4,968 — 235,977 Total $ 1,218,949 $ 273,468 $ 234,095 $ 24,115 $ — $ 3,242 $ 216,132 $ 132,006 $ (1,205 ) $ 2,100,802 (1) Includes $8.4 million and $12.0 million in 2019 and 2018, respectively, for leases of Teradyne’s systems recognized outside of ASC 606: “Revenue from Contracts with Customers.”

Inventories (Tables)

Inventories (Tables)	12 Months Ended
Inventories (Tables)	Dec. 31, 2019
Composition of Inventories, Net	Inventories, net consisted of the following at December 31, 2019 and 2018: 2019 2018 (in thousands) Raw material $ 118,595 $ 89,365 Work-in-process 32,695 31,014 Finished g 45,401 33,162 $ 196,691 $ 153,541

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
Property, Plant and Equipment (Tables)	Dec. 31, 2019
Property Plant and Equipment, Net	Property, plant and equipment, net consisted of the following at December 31, 2019 and 2018: 2019 2018 (in thousands) Land $ 16,561 $ 16,561 Buildings 107,282 105,935 Machinery , and s oftware 834,970 752,722 Furniture and fixtures 29,157 27,432 Leasehold improvements 59,378 52,536 Construction in progress 2,537 6,276 1,049,885 961,462 Less: accumulated depreciation 729,669 681,641 $ 320,216 $ 279,821

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
Financial Instruments (Tables)	Dec. 31, 2019
Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis	The following table sets forth by fair value hierarchy Teradyne’s financial assets and liabilities that were measured at fair value on a recurring basis as of December 31, 2019 and 2018: December 31, 2019 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 311,975 $ — $ — $ 311,975 Cash equivalents 410,285 51,664 — 461,949 Available for sale securities: Corporate debt securities — 97,307 — 97,307 Commercial paper — 54,149 — 54,149 U.S. Treasury securities — 42,382 — 42,382 U.S. government agency securities — 9,952 — 9,952 Debt mutual funds 6,888 — — 6,888 Certificates of deposit and time deposits — 4,751 — 4,751 Non-U.S. government securities — 592 — 592 Equity securities: Equity mutual funds 25,772 — — 25,772 Total $ 754,920 $ 260,797 $ — $ 1,015,717 Derivative assets — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Contingent consideration $ — $ — $ 39,705 $ 39,705 Derivative liabilities — 203 — 203 Total $ — $ 203 $ 39,705 $ 39,908 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 722,260 $ 51,664 $ — $ 773,924 Marketable securities — 137,303 — 137,303 Long-term marketable securities 32,660 71,830 — 104,490 Prepayments — 528 — 528 Total $ 754,920 $ 261,325 $ — $ 1,016,245 Liabilities Other current liabilities $ — $ 203 $ — $ 203 Contingent consideration — — 9,106 9,106 Long-term contingent consideration — — 30,599 30,599 Total $ — $ 203 $ 39,705 $ 39,908 December 31, 2018 Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Assets Cash $ 312,512 $ — $ — $ 312,512 Cash equivalents 253,525 360,715 — 614,240 Available for sale securities: U.S. Treasury securities — 109,721 — 109,721 Commercial paper — 86,117 — 86,117 Corporate debt securities — 40,020 — 40,020 U.S. government agency securities — 9,611 — 9,611 Certificates of deposit and time deposits — 7,604 — 7,604 Debt mutual funds 3,187 — — 3,187 Non-U.S. — 376 — 376 Equity securities: Equity mutual funds 21,191 — — 21,191 $ 590,415 $ 614,164 $ — $ 1,204,579 Derivative assets — 79 — 79 Total $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Contingent consideration $ — $ — $ 70,543 $ 70,543 Derivative liabilities — 514 — 514 Total $ — $ 514 $ 70,543 $ 71,057 Reported as follows: (Level 1) (Level 2) (Level 3) Total (in thousands) Assets Cash and cash equivalents $ 566,037 $ 360,715 $ — $ 926,752 Marketable securities — 190,096 — 190,096 Long-term marketable securities 24,378 63,353 — 87,731 Prepayments — 79 — 79 $ 590,415 $ 614,243 $ — $ 1,204,658 Liabilities Other current liabilities $ — $ 514 $ — $ 514 Contingent consideration — — 34,865 34,865 Long-term contingent consideration — — 35,678 35,678 $ — $ 514 $ 70,543 $ 71,057
Schedule of Changes in Fair Value of Level 3 Contingent Consideration	Changes in the fair value of Level 3 contingent consideration for the years ended December 31, 2019 and 2018 were as follows: Contingent Consideration (in thousands) Balance at December 31, 2017 $ 45,102 Acquisition of MiR 52,547 Foreign currency impact (3,540 ) Payments ( 1 (24,553 ) Fair value adjustment ( 2 987 Balance at December 31, 2018 70,543 Acquisition of AutoGuide 23,976 Foreign currency impact (967 ) Payments (3) (34,590 ) Fair value adjustment (4) (19,257 ) Balance at December 31, 2019 $ 39,705 (1) During the year ended December 31, 201 8 24.6 earn-out Un iversal Robots. (2) During the year ended December 31, 2018, the fair value of contingent consideration for the earn-out in connection with the acquisition of MiR was increased by $17.7 million primarily due to an increase in forecasted revenues. During the year ended December 31, 2018, earn-out de 16.7 a de (3) During the year ended December 31, 201 9 30.8 and $3.8 million earn-out s s MiR a d , respectively (4) During the year ended December 31, 201 9 earn-out de 22.2 de partially offset by the impact from modification of the earn-out structure. 9 earn-out Auto G in 3.0 n in c rease revenues
Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument	The following table provides quantitative information associated with the fair value measurement of Teradyne’s Level 3 financial instrument: Liability December 31, 2019 Fair Value Valuation Technique Unobservable Inputs Weighted Average (in thousands) Contingent c (AutoGuide) $ 26,952 Monte Carlo simulation Revenue Volatility 11.5 % Discount Rate 2.6 % Contingent c (MiR) $ 12,753 Monte Carlo simulation Revenue Volatility 14.0 % Discount Rate 0.2 % (1) Contingent consideration related to MiR of $ 9.1 20
Schedule of Carrying Amounts and Fair Values of Financial Instruments	The carrying amounts and fair values of Teradyne’s financial instruments at December 31, 2019 and 2018 were as follows: December 31, 2019 December 31, 2018 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Assets Cash and cash equivalents $ 773,924 $ 773,924 $ 926,752 $ 926,752 Marketable securities 241,793 241,793 277,827 277,827 Derivative assets 528 528 79 79 Liabilities Contingent consideration 39,705 39,705 70,543 70,543 Derivative liabilities 203 203 514 514 Convertible debt (1) 394,687 1,010,275 379,981 547,113 (1) The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note which includes the equity conversion features.
Schedule of Available-for-Sale Marketable Securities	The following tables summarize the composition of available-for-sale December 31, 2019 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Corporate debt securities $ 93,267 $ 4,081 $ (41 ) $ 97,307 $ 2,009 Commercial paper 54,124 26 (1 ) 54,149 1,391 U.S. Treasury securities 42,167 431 (216 ) 42,382 17,556 U.S. government agency securities 9,942 14 (4 ) 9,952 3,043 Debt mutual funds 6,753 135 — 6,888 — Certificates of deposit and time deposits 4,751 — — 4,751 — Non-U.S. government securities 592 — — 592 — $ 211,596 $ 4,687 $ (262 ) $ 216,021 $ 23,999 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 137,144 $ 160 $ (1 ) $ 137,303 $ 2,922 Long-term marketable securities 74,452 4,527 (261 ) 78,718 21,077 $ 211,596 $ 4,687 $ (262 ) $ 216,021 $ 23,999 December 31, 2018 Available-for-Sale Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) U.S. Treasury securities $ 110,969 $ 112 $ (1,360 ) $ 109,721 $ 75,040 Commercial paper 86,130 13 (26 ) 86,117 85,094 Corporate debt securities 41,133 432 (1,545 ) 40,020 24,767 U.S. government agency securities 9,646 1 (36 ) 9,611 7,077 Certificates of deposit and time deposits 7,604 — — 7,604 — Debt mutual funds 3,153 34 — 3,187 — Non-U.S. government securities 376 — — 376 — $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978 Reported as follows: Cost Unrealized Gain Unrealized (Loss) Fair Market Value Fair Market Value of Investments with Unrealized Losses (in thousands) Marketable securities $ 190,100 $ 88 $ (92 ) $ 190,096 $ 140,262 Long-term marketable securities 68,911 504 (2,875 ) 66,540 51,716 $ 259,011 $ 592 $ (2,967 ) $ 256,636 $ 191,978
Contractual Maturities of Investments Held	The contractual available-for-sale Cost Fair Value (in thousands) Due within one year $ 137,144 $ 137,303 Due after 1 year through 5 years 15,264 15,351 Due after 5 years through 10 years 14,436 14,576 Due after 10 years 37,999 41,903 Total $ 204,843 $ 209,133 Contractual maturities of investments in available-for-sale marketable securities held at December 31, 2019 exclude $6.9 million of debt mutual funds as they do not have a contractual maturity date. Derivatives Teradyne conducts business in a number of foreign countries, with certain transactions denominated in local currencies. The purpose of Teradyne’s foreign currency management is to minimize the effect of exchange rate fluctuations on certain foreign currency denominated monetary assets and liabilities. Teradyne does not use derivative financial instruments for trading or speculative purposes. To minimize the effect of exchange rate fluctuations associated with the remeasurement of monetary assets and liabilities denominated in foreign currencies, Teradyne enters into foreign currency forward contracts. The change in fair value of these derivatives is recorded directly in earnings, and is used to offset the change in value of the monetary assets and liabilities denominated in foreign currencies. At December 31, 2019 and 2018, Teradyne had the following contracts to buy and sell non-U.S. non-U.S. December 31, 2019 December 31, 2018 Buy Position Sell Position Net Total Buy Position Sell Position Net Total (in millions) Japanese Yen $ (29.3 ) $ — $ (29.3 ) $ (35.0 ) $ — $ (35.0 ) Taiwan Dollar (18.4 ) — (18.4 ) (11.2 ) — (11.2 ) Korean Won (10.7 ) — (10.7 ) (9.6 ) — (9.6 ) British Pound Sterling (3.8 ) — (3.8 ) (1.4 ) — (1.4 ) Euro — 47.8 47.8 — 82.2 82.2 Singapore Dollar — 25.3 25.3 — 15.7 15.7 Philippine Peso — 5.2 5.2 — 5.2 5.2 Chinese Yuan — 4.4 4.4 — 2.8 2.8 Total $ (62.2 ) $ 82.7 $ 20.5 $ (57.2 ) $ 105.9 $ 48.7
Schedule of Notional Amount of Derivatives	At December 31, 2019 and 2018, Teradyne had the following contracts to buy and sell non-U.S. non-U.S. December 31, 2019 December 31, 2018 Buy Position Sell Position Net Total Buy Position Sell Position Net Total (in millions) Japanese Yen $ (29.3 ) $ — $ (29.3 ) $ (35.0 ) $ — $ (35.0 ) Taiwan Dollar (18.4 ) — (18.4 ) (11.2 ) — (11.2 ) Korean Won (10.7 ) — (10.7 ) (9.6 ) — (9.6 ) British Pound Sterling (3.8 ) — (3.8 ) (1.4 ) — (1.4 ) Euro — 47.8 47.8 — 82.2 82.2 Singapore Dollar — 25.3 25.3 — 15.7 15.7 Philippine Peso — 5.2 5.2 — 5.2 5.2 Chinese Yuan — 4.4 4.4 — 2.8 2.8 Total $ (62.2 ) $ 82.7 $ 20.5 $ (57.2 ) $ 105.9 $ 48.7
Schedule of Derivative Instruments in Statement of Financial Position at Fair Value	The following table summarizes the fair value of derivative instruments as of December 31, 2019 and 2018: December 31, 2019 December 31, 2018 (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Prepayments $ 528 $ 79 Foreign exchange contracts Other current liabilities (203 ) (514 ) Total $ 325 $ (435 )
Schedule of Effect of Derivative Instruments on Statement of Operations Recognized	The following table summarizes the effect of derivative instruments in the statements of operations recognized for the years ended December 31, 2019, 2018, and 2017. Location of (Gains) Losses Recognized in Statement of Operations December 31, 2019 December 31, 2018 December 31, 2017 (in thousands) Derivatives not designated as hedging instruments: Foreign exchange contracts Other (income) expense, net $ 5,960 $ 7,386 $ (1,133 ) (1) The table does not reflect the corresponding gains and losses from the remeasurement of the monetary assets and liabilities denominated in foreign currencies. (2) For the years ended December 31, 2019 and 2018, net gains from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $ 1.6 2.5 (3) For the year ended December 31, 2017, net losses from the remeasurement of monetary assets and liabilities denominated in foreign currencies were $ 2.9

Leases (Tables)

Leases (Tables)	12 Months Ended
Leases (Tables)	Dec. 31, 2019
Supplemental cash flow information related to leases	Supplemental cash flow information related to leases was as follows: For the Year December 31, 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities included in operating cash flows $ 19,400 Right-of-use 26,739
Schedule of operating lease, maturity	Maturities of lease liabilities as of December 31, 2019 were as follows: Operating Lease (in thousands) 2020 $ 21,874 2021 17,638 2022 12,944 2023 6,496 2024 5,106 Thereafter 8,388 Total lease payments 72,446 Less imputed interest (7,121 ) Total lease liabilities $ 65,325
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	As of December 31, 2018, future non-cancelable Operating Lease (in thousands) 2019 $ 19,570 2020 18,293 2021 13,578 2022 9,693 2023 5,449 Thereafter 9,472 Total lease payments $ 76,055

Debt (Tables)

Debt (Tables)	12 Months Ended
Debt (Tables)	Dec. 31, 2019
Components of Convertible Senior Notes	The below tables represents the key components of Teradyne’s convertible senior notes: December 31, December 31, (in thousands) Debt p $ 460,000 $ 460,000 Unamortized discount 65,313 80,019 Net c $ 394,687 $ 379,981 For the year ended December 31, December 31, (in thousands) Contractual interest expense on the coupon $ 5,750 $ 5,750 Amortization of the discount component and debt issue fees recognized as interest expense 14,706 13,995 Total interest expense on the convertible debt $ 20,456 $ 19,745

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
Accumulated Other Comprehensive Income (Loss) (Tables)	Dec. 31, 2019
Changes in Accumulated Other Comprehensive (Loss) Income	Changes in accumulated other comprehensive (loss) income, which is presented net of tax, consist of the following: Foreign Currency Translation Adjustment Unrealized Gain s (Losses) on Marketable Securities Retirement Plans Prior Service Credit Total (in thousands) Balance at December 31, 2017, net of tax of $0, $1,815, $(932) $ 15,919 $ 1,362 $ 1,495 $ 18,776 Other comprehensive loss (28,442 ) (2,110 ) — (30,552 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(21), $(71) — 1,337 (245 ) 1,092 Net current period other comprehensive loss (28,442 ) (773 ) (245 ) (29,460 ) Reclassification of tax effects resulting f rom net of tax of — 691 78 769 Reclassification of unrealized gains on equity securities, net of tax of — (3,125 ) — (3,125 ) Balance at December 31, 2018, net of tax of $0, $(521), $(1,081) (12,523 ) (1,845 ) 1,328 (13,040 ) Other comprehensive (loss) (10,991 ) 6,015 — (4,976 ) Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(192), $(43) — (690 ) (148 ) (838 ) Net current period other comprehensive (loss) (10,991 ) 5,325 (148 ) (5,814 ) Balance at December 31, 2019, net of tax of $0, $946, $(1,124) $ (23,514 ) $ 3,480 $ 1,180 $ (18,854 ) (a) In the year ended December 31, 2018, Teradyne early adopted ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” (b) In the year ended December 31, 2018, Teradyne adopted ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities
Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations	Reclassifications out of accumulated other comprehensive income to the statements of operations for the years ended December 31, 2019, 2018, and 2017, were as follows: Details about Accumulated Other Comprehensive Income Components For the year ended Affected Line Item in the Statements of Operations December 31, 2019 December 31, 2018 December 31, 2017 (in thousands) Available-for-sale Unrealized gains $ 690 $ (1,337 ) $ 441 Interest income (expense) Defined benefit pension and postretirement plans: Amortization of prior service benefit, net of tax of $43, $71, $154 148 245 272 (a) Total reclassifications, net of tax of $235, $92, $451 $ 838 $ (1,092 ) $ 713 Net income (a) The amortization of prior service credit is included in the computation of net periodic pension cost and postretirement benefit; see Note P: “Retirement Plans.”

Goodwill And Intangible Assets

Goodwill And Intangible Assets (Tables)	12 Months Ended
Goodwill And Intangible Assets (Tables)	Dec. 31, 2019
Changes in Carrying Amount of Goodwill by Segment	The changes in the carrying amount of goodwill by reportable segments for the years ended December 31, 2019 and 2018 are as follows: Industrial Automation Wireless Test Semiconductor Test System Test Total (in thousands) Balance at December 31, 2017: Goodwill $ 233,519 $ 361,819 $ 260,540 $ 158,699 $ 1,014,577 Accumulated impairment losses — (353,843 ) (260,540 ) (148,183 ) (762,566 ) 233,519 7,976 — 10,516 252,011 MiR acquisition 135,976 — — — 135,976 Energid acquisition 14,394 — — — 14,394 Foreign currency translation adjustment (20,531 ) — — — (20,531 ) Balance at December 31, 2018: Goodwill 363,358 361,819 260,540 158,699 1,144,416 Accumulated impairment losses — (353,843 ) (260,540 ) (148,183 ) (762,566 ) 363,358 7,976 — 10,516 381,850 Lemsys acquisition — — 1,428 — 1,428 Auto G 41,372 — — — 41,372 Foreign currency translation adjustment (8,247 ) — 28 — (8,219 ) Balance at December 31, 2019: Goodwill 396,483 361,819 261,996 158,699 1,178,997 Accumulated impairment losses — (353,843 ) (260,540 ) (148,183 ) (762,566 ) $ 396,483 $ 7,976 $ 1,456 $ 10,516 $ 416,431
Schedule of Estimated Intangible Assets Amortization Expense	Estimated intangible assets amortization expense for each of the five succeeding fiscal years is as follows: Year Amortization Expense (in thousands) 2020 $ 30,606 2021 20,593 2022 19,700 2023 19,226 2024 18,921 Thereafter 16,434
Wireless Test
Schedule of Amortizable Intangible Assets	Amortizable intangible assets consist of the following and are included in intangible assets, net on the balance sheets: December 31, 2019 Gross Carrying Amount (1 ) Accumulated Amortization (2) Foreign Net Carrying Amount (in thousands) Developed technology $ 361,787 $ (279,000 ) $ (5,709 ) $ 77,078 Customer relationships 75,669 (59,077 ) (455 ) 16,137 Tradenames and trademarks 70,120 (36,671 ) (1,184 ) 32,265 Backlog 260 (260 ) — — Total intangible assets $ 507,836 $ (375,008 ) $ (7,348 ) $ 125,480 December 31, 2018 Gross Carrying Amount Accumulated Amortization Foreign Net Carrying Amount (in thousands) Developed technology $ 336,308 $ (252,080 ) $ (4,079 ) $ 80,149 Customer relationships 97,153 (83,448 ) (340 ) 13,365 Tradenames and trademarks 64,420 (31,653 ) (799 ) 31,968 Non-compete 320 (320 ) — — Backlog 30 (30 ) — — Total intangible assets $ 498,231 $ (367,531 ) $ (5,218 ) $ 125,482

Net Income (Loss) per Common _2

Net Income (Loss) per Common Share (Tables)	12 Months Ended
Net Income (Loss) per Common Share (Tables)	Dec. 31, 2019
Computation of Basic and Diluted Net Income (Loss) Per Common Share	The following table sets forth the computation of basic and diluted net income per common share: 2019 2018 2017 (in thousands, except per share amounts) Net income for basic and diluted net income per share $ 467,468 $ 451,779 $ 257,692 Weighted average common shares-basic 170,425 187,672 198,069 Effect of dilutive potential common shares: Incremental shares from assumed conversion of convertible notes (1) 4,909 2,749 1,298 Convertible note hedge warrant shares (2) 2,698 485 112 Restricted stock units 1,236 1,385 1,800 Stock options 178 278 335 Employee stock purchase rights 13 36 27 Dilutive potential common shares 9,034 4,933 3,572 Weighted average common shares-diluted 179,459 192,605 201,641 Net income per common share-basic $ 2.74 $ 2.41 $ 1.30 Net income per common share-diluted $ 2.60 $ 2.35 $ 1.28 (1) Incremental shares from the assumed conversion of the convertible notes was calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.62, multiplied by 14.5 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period. (2) Convertible notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.68, multiplied by 14.5 million shares. The result of this calculation, representing the total intrinsic value of the warrant, was divided by the average Teradyne stock price for the period.

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
Retirement Plans (Tables)	Dec. 31, 2019
Defined Benefit Pension Plans
Defined Benefit Pension and Postretirement Benefit Plan Assets and Obligations	The December 31 balances of these defined benefit pension plans assets and obligations are shown below: 2019 2018 United States Foreign United States Foreign (in thousands) Assets and Obligations Change in benefit obligation: Projected benefit obligation: Beginning of year $ 178,237 $ 39,146 $ 363,026 $ 39,353 Service cost 1,608 751 2,196 786 Interest cost 7,189 691 8,940 687 Actuarial loss 24,447 4,520 (30,136 ) 773 Benefits paid (7,690 ) (836 ) (14,793 ) (741 ) Retiree annuity purchase — — (151,341 ) — Liability loss due to settlement — — 345 — Non-U.S. — (320 ) — (1,712 ) End of year 203,791 43,952 178,237 39,146 Change in plan assets: Fair value of plan assets: Beginning of year 144,301 1,400 324,506 1,307 Company contributions 2,805 923 2,587 822 Actual return on plan assets 27,516 64 (16,658 ) 50 Benefits paid (7,690 ) (836 ) (14,793 ) (741 ) Retiree annuity purchase — — (151,341 ) — Non-U.S. — 35 — (38 ) End of year 166,932 1,586 144,301 1,400 Funded status $ (36,859 ) $ (42,366 ) $ (33,936 ) $ (37,746 )
Amounts Recorded within Statement of Financial Position	The following table provides amounts recorded within the account line items of the statements of financial position as of December 31: 2019 2018 United States Foreign United States Foreign (in thousands) Retirement plans assets $ 18,457 $ — $ 16,883 $ — Accrued employees’ compensation and withholdings (2,826 ) (922 ) (2,676 ) (852 ) Retirement plans liabilities (52,490 ) (41,444 ) (48,143 ) (36,894 ) Funded status $ (36,859 ) $ (42,366 ) $ (33,936 ) $ (37,746 )
Amounts Recognized in Accumulated Other Comprehensive Income	The following table provides amounts recognized in accumulated other comprehensive income as of December 31: 2019 2018 United States Foreign United States Foreign (in thousands) Deferred taxes related to prior service cost recognized in other comprehensive income $ 560 $ — $ 560 $ —
Pension Plans with Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets	Information for pension plans with an accumulated benefit obligation in excess of plan assets as of December 31: 2019 2018 United States Foreign United States Foreign (in millions) Projected benefit obligation $ 55.3 $ 44.0 $ 50.8 $ 39.1 Accumulated benefit obligation 53.2 39.9 48.6 35.6 Fair value of plan assets — 1.6 — 1.4
Net Periodic Pension and Postretirement Benefit Costs	For the years ended December 31, 2019, 2018, and 2017, Teradyne’s net periodic pension cost 2019 2018 2017 United States Foreign United States Foreign United States Foreign (in thousands) Components of Net Periodic Pension Cost Service cost $ 1,608 $ 751 $ 2,196 $ 786 $ 2,239 $ 818 Interest cost 7,189 691 8,940 687 13,151 852 Expected return on plan assets (6,042 ) (29 ) (9,049 ) (19 ) (12,008 ) (165 ) Amortization of prior service cost — — 58 — 70 — Net actuarial loss 2,973 4,485 (4,429 ) 743 (6,712 ) (310 ) Settlement loss — — 345 — — — Total net periodic pension cost $ 5,728 $ 5,898 $ (1,939 ) $ 2,197 $ (3,260 ) $ 1,195 Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Reversal of amortization items: Prior service cost — — (58 ) — (70 ) — Total recognized in other comprehensive income — — (58 ) — (70 ) — Total recognized in net periodic pension cost and other comprehensive income $ 5,728 $ 5,898 $ (1,997 ) $ 2,197 $ (3,330 ) $ 1,195
Weighted Average Assumptions to Determine Net Periodic Cost and Benefit Obligation	Weighted Average Assumptions to Determine Net Periodic Pension Cost at January 1: 2019 2018 2017 United States Foreign United States Foreign United States Foreign Discount rate 4.1 % 1.8 % 3.4 % 1.8 % 3.9 % 1.8 % Expected return on plan assets 4.3 2.0 4.3 1.5 4.0 2.0 Salary progression rate 2.5 2.5 2.3 2.7 2.6 2.7 Weighted Average Assumptions to Determine Pension Obligations at December 31: 2019 2018 United States Foreign United States Foreign Discount rate 3.0 % 1.1 % 4.1 % 1.8 % Salary progression rate 2.6 2.5 2.5 2.6
Weighted Average Pension Asset Allocations by Category	The following table provides weighted average pension asset allocation by asset category at December 31, 2019 and 2018: 2019 2018 United States Foreign United States Foreign Fixed income securities 94.0 % — % 94.0 % — % Equity securities 5.0 — 5.0 — Other 1.0 100.0 1.0 100.0 100.0 % 100.0 % 100.0 % 100.0 %
Target Asset Allocation and Index for Each Asset Category	The target asset allocation and the index for each asset category for the U.S. Plan, per the investment policy, are as follows: Asset Category: Policy Index: Target Allocation U.S. corporate fixed income Barclays U.S. Corporate A or Better Index 75 % Global equity MSCI World Minimum Volatility Index 5 U.S. government fixed income Barclays U.S. Long Government Bond Index 14 High yield fixed income Barclays U.S. High Yield Index 5 Cash Citigroup Three Month U.S. Treasury Bill Index 1
Changes in Fair Value of Pension Assets	The fair value of pension plan assets by asset category and by level at December 31, 2019 and December 31, 2018 were as follows: December 31, 2019 United States Foreign Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in thousands) Fixed income securities: Corporate debt securities $ — $ 133,792 $ — $ 133,792 $ — $ — $ — $ — U.S. government securities — 23,186 — 23,186 — — — — Global equity — 8,344 — 8,344 — — — — Other — — — — — 1,586 — 1,586 Cash and cash equivalents 1,610 — — 1,610 — — — — Total $ 1,610 $ 165,322 $ — $ 166,932 $ — $ 1,586 $ — $ 1,586 December 31, 2018 United States Foreign Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in thousands) Fixed income securities: Corporate debt securities $ — $ 115,424 $ — $ 115,424 $ — $ — $ — $ — U.S. government securities — 20,176 — 20,176 — — — — Global equity — 7,252 — 7,252 — — — — Other — — — — — 1,400 — 1,400 Cash and cash equivalents 1,449 — — 1,449 — — — — Total $ 1,449 $ 142,852 $ — $ 144,301 $ — $ 1,400 $ — $ 1,400
Expected Future Benefit Payments	Future benefit payments are expected to be paid as follows: United States Foreign (in thousands) 2020 $ 8,027 $ 1,237 2021 8,416 985 2022 9,163 982 2023 9,785 1,258 2024 10,558 1,098 2025-2029 59,665 6,129
Group Annuity Insurance Contracts
Changes in Fair Value of Pension Assets	Changes in the fair value of Level 3 group annuity insurance contracts for the year ended December 31, 2018 were Group Annuity Insurance Contracts (in thousands) Balance at December 31, 2017 $ 3,166 Transfer out of level 3 (2,658 ) Purchase s f insurance ontracts (512 ) Interest and market value adjustments 59 Benefits paid (40 ) Other (15 ) Balance at December 31, 2018 $ —
Postretirement Benefit Plans
Defined Benefit Pension and Postretirement Benefit Plan Assets and Obligations	The December 31 balances of the postretirement assets and obligations are shown below: 2019 2018 (in thousands) Assets and Obligations Change in benefit obligation: Projected benefit obligation: Beginning of year $ 9,256 $ 6,177 Service cost 41 39 Interest cost 347 196 Actuarial loss 717 25 Benefits paid (1,358 ) (889 ) Special termination benefits — 3,708 End of year 9,003 9,256 Change in plan assets: Fair value of plan assets: Beginning of year — — Company contributions 1,358 889 Benefits paid (1,358 ) (889 ) End of year — — Funded status $ (9,003 ) $ (9,256 )
Amounts Recorded within Statement of Financial Position	The following table provides amounts recorded within the account line items of financial position as of December 31: 2019 2018 (in thousands) Accrued employees’ compensation and withholdings $ (1,231 ) $ (1,310 ) Retirement plans liability (7,772 ) (7,946 ) Funded status $ (9,003 ) $ (9,256 )
Amounts Recognized in Accumulated Other Comprehensive Income	The following table provides amounts recognized in accumulated other comprehensive income as of December 31: 2019 2018 (in thousands) Prior service credit, before tax $ (58 ) $ (249 ) Deferred taxes (1,684 ) (1,641 ) Total recognized in other comprehensive income, net of tax $ (1,742 ) $ (1,890 )
Net Periodic Pension and Postretirement Benefit Costs	For the years ended December 31, 2019, 2018, and 2017, Teradyne’s net periodic postretirement benefit cost (income) was comprised of the following: 2019 2018 2017 (in thousands) Components of Net Periodic Postretirement Benefit Cost (income): Service cost $ 41 $ 39 $ 34 Interest cost 347 196 201 Amortization of prior service credit (191 ) (373 ) (496 ) Net actuarial loss 717 25 398 Special termination benefits — 3,708 591 Total net periodic postretirement benefit cost 914 3,595 728 Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Prior service cost — — — Reversal of amortization items: Prior service credit 191 373 496 Total recognized in other comprehensive income 191 373 496 Total recognized in net periodic postretirement cost and other comprehensive income $ 1,105 $ 3,968 $ 1,224
Weighted Average Assumptions to Determine Net Periodic Cost and Benefit Obligation	Weighted Average Assumptions to Determine Net Periodic Postretirement Benefit Income as of January 1: 2019 2018 2017 Discount rate 4.0 % 3.4 % 3.9 % Initial health care cost trend rate 7.5 7.9 7.3 Ultimate health care cost trend rate 4.5 4.5 5.0 Year in which ultimate health care cost trend rate is reached 2026 2026 2023 Weighted Average Assumptions to Determine Postretirement Benefit Obligation as of December 31: 2019 2018 2017 Discount rate 3.0 % 4.0 % 3.4 % Initial medical trend 7.1 7.5 7.9 Ultimate health care trend 4.5 4.5 4.5 Medical cost trend rate decrease to ultimate rate in year 2026 2026 2026
Expected Future Benefit Payments	Future benefit payments are expected to be paid as follows: Benefit Payments (in thousands) 2020 $ 1,231 2021 1,171 2022 958 2023 789 2024 662 2025-2029 1,965
One Percentage Point Change in Assumed Health Care Cost Trend Rates for Year	A one percentage point change in the assumed health care cost trend rates for the year ended December 31, 2019 would have the following effects: 1 Percentage Point Increase 1 Percentage Point Decrease (in thousands) Effect on total service and interest cost components $ 6 $ (6 ) Effect on postretirement benefit obligations 139 (133 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
Stock-Based Compensation (Tables)	Dec. 31, 2019
Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions	The fair value was estimated using the Monte Carlo simulation model with the following assumptions: 2019 2018 2017 Risk-free interest rate 2.6 % 2.2 % 1.5 % Teradyne volatility-historical 31.9 % 26.8 % 26.6 % NYSE Composite Index volatility-historical 11.9 % 12.4 % 13.4 % Dividend yield 1.0 % 0.8 % 1.0 %
Fair Value of Stock Options Using Assumptions	The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions: 2019 2018 2017 Expected life (years) 5.0 5.0 5.0 Risk-free interest rate 2.5 % 2.4 % 2.0 % Volatility-historical 30.1 % 26.4 % 27.8 % Dividend yield 1.00 % 0.80 % 1.00 %
Stock Compensation Plan Activity	Stock compensation plan activity for the years 2019, 2018, and 2017, is as follows: 2019 2018 2017 (in thousands) Restricted Stock Units: Non-vested 2,454 3,174 3,778 Awarded 1,139 790 939 Vested (1,237 ) (1,382 ) (1,434 ) Forfeited (87 ) (128 ) (109 ) Non-vested 2,269 2,454 3,174 Stock Options: Outstanding at January 1 506 531 926 Granted 102 69 111 Exercised (280 ) (94 ) (501 ) Forfeited (7 ) — — Expired (2 ) — (5 ) Outstanding at December 31 319 506 531 Vested and expected to vest at December 31 319 506 531 Exercisable at December 31 85 256 233
Share Based Compensation Total Shares Available	Total shares available for the years 2019, 2018, and 2017: 2019 2018 2017 (in thousands) Shares available: Available for grant at January 1 7,874 8,605 9,546 Options granted (102 ) (69 ) (111 ) Options forfeited 7 — — Restricted stock units awarded (1,139 ) (790 ) (939 ) Restricted stock units forfeited 87 128 109 Available for grant at December 31 6,727 7,874 8,605
Weighted-Average Restricted Stock Unit Award Date Fair Value	Weighted average restricted stock unit award date fair value information for the years 2019, 2018, and 2017 , 2019 2018 2017 Non-vested $ 29.22 $ 21.71 $ 18.27 Awarded 39.08 45.99 28.91 Vested 23.59 20.20 17.90 Forfeited 35.60 24.67 20.35 Non-vested $ 35.58 $ 29.22 $ 21.71
Restricted Stock Unit Awards Aggregate Intrinsic Value	Restricted stock unit awards aggregate intrinsic value information at December 31 for the years 2019, 2018 , 2019 2018 2017 (in thousands) Vested $ 46,110 $ 63,688 $ 40,649 Outstanding 154,752 77,015 132,875 Expected to vest 152,374 77,187 130,594
Restricted Stock Units Weighted Average Remaining Contractual Terms	Restricted stock units weighted average remaining contractual terms (in years) information at December 31 for the years 2019, 2018, and 2019 2018 2017 Outstanding 1.02 0.92 1.00 Expected to vest 1.02 0.91 0.99
Weighted Average Stock Options Exercise Price	Weighted average stock options exercise price information for the year ended December 31, 2019 is as follows: 2019 Outstanding at January 1 $ 19.06 Options granted 37.95 Options exercised 13.20 Options forfeited 36.75 Options cancelled 1.48 Outstanding at December 31 29.91 Exercisable at December 31 14.97
Stock Option Aggregate Intrinsic Value Information	Stock option aggregate intrinsic value information for the years ended December 31, 2019, 2018, and 2017 is as follows: 2019 2018 2017 (in thousands) Exercised $ 9,232 $ 2,960 $ 8,035 Outstanding 12,218 7,359 14,831 Vested and expected to vest 7,701 7,359 14,831 Exercisable 4,517 5,905 9,076
Stock Options Weighted Average Remaining Contractual Terms	Stock options weighted average remaining contractual terms (in years) information at December 31, for the years 2019, 2018, and 2017 is as follows: 2019 2018 2017 Outstanding 4.2 3.6 4.1 Vested and expected to vest 5.0 3.6 4.1 Exercisable 2.1 2.4 2.8
Effect to Income (Loss) from Operations for Recording Stock-Based Compensation	The following table provides the effect to income from operations for recording stock-based compensation for the years ended December 31, 2019, 2018, and 2017: 2019 2018 2017 (in thousands) Cost of revenues $ 3,480 $ 3,129 $ 3,212 Engineering and development 9,913 9,181 9,370 Selling and administrative 24,504 21,267 21,515 Stock-based compensation 37,897 33,577 34,097 Income tax benefit (8,360 ) (12,036 ) (10,462 ) Total stock-based compensation expense after income taxes $ 29,537 $ 21,541 $ 23,635

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2019
Schedule of Income (Loss) Before Income Taxes and Provision (Benefit) for Income Taxes from Operations	The components of income (loss) before income taxes and the provision (benefit) for income taxes as shown in the consolidated statements of operations were as follows: 2019 2018 2017 (in thousands) Income before income taxes U.S. $ 192,442 $ 189,691 $ 76,699 Non-U.S. 333,330 278,110 447,713 $ 525,772 $ 467,801 $ 524,412 Provision (benefit) for income taxes Current: U.S. Federal $ 19,297 $ (59,122 ) $ 162,679 Non-U.S. 52,810 45,083 64,313 State (4,347 ) 1,721 2,623 67,760 (12,318 ) 229,615 Deferred: U.S. Federal (4,522 ) 29,252 43,687 Non-U.S. (8,007 ) (1,243 ) (6,476 ) State 3,073 331 (106 ) (9,456 ) 28,340 37,105 Total provision for income taxes $ 58,304 $ 16,022 $ 266,720
Reconciliation of Effective Tax Rate	A reconciliation of the effective tax rate for the years 2019, 2018 and 2017 is as follows: 2019 2018 2017 U.S. statutory federal tax rate 21.0 % 21.0 % 35.0 % U.S. global intangible low-taxed income 6.2 0.3 — U.S. transition tax 1.9 (10.5 ) 28.7 State income taxes, net of federal tax benefit 0.5 0.1 (0.4 ) Foreign tax credits (5.9 ) (2.2 ) (2.2 ) Uncertain tax positions (4.3 ) 1.0 1.7 Foreign taxes (4.0 ) (2.0 ) (16.3 ) U.S. foreign derived intangible income (2.6 ) (1.8 ) — U.S. research and development credit (1.8 ) (2.2 ) (1.6 ) Equity compensation (0.7 ) (1.2 ) (0.8 ) Impact of rate change on deferred taxes — 0.3 6.9 Domestic production activities deduction — — (0.3 ) Other, net 0.8 0.6 0.2 11.1 % 3.4 % 50.9 %
Deferred Tax Assets (Liabilities)	Significant components of Teradyne’s deferred tax assets (liabilities) as of December 31, 2019 and 2018 were as follows: 2019 2018 (in thousands) Deferred tax assets Tax credits $ 79,480 $ 69,091 Accruals 25,424 23,449 Pension liabilities 24,459 20,826 Inventory valuations 18,572 18,514 Deferred revenue 7,622 9,130 Equity compensation 7,042 7,190 Vacation accrual 4,768 4,772 Investment impairment 3,292 — Net operating loss carryforwards 2,705 3,658 Marketable s — 962 Other 1,472 685 Gross deferred tax assets 174,836 158,277 Less: valuation allowance (77,177 ) (69,852 ) Total deferred tax assets $ 97,659 $ 88,425 Deferred tax liabilities: Depreciation $ (18,238 ) $ (14,028 ) Intangible assets (16,705 ) (24,211 ) Marketable securities (1,601 ) — Total deferred tax liabilities $ (36,544 ) $ (38,239 ) Net deferred assets $ 61,115 $ 50,186
Operating Loss Carryforwards	At December 31, 2019, Teradyne had operating loss carryforwards that expire in the following years: State Operating Loss Carryforwards Federal Operating Loss Carryforwards Foreign Operating Loss Carryforwards ( in t 2020 $ 269 $ — $ — 2021 2,141 — — 2022 4,934 — — 2023 4,342 — — 2024 1,498 — — 2025-2029 7,673 — — 2030-2034 4,329 — 15 Beyond 2034 2,185 554 74 Non-expiring 1,357 — 4,207 Total $ 28,728 $ 554 $ 4,296
Unrecognized Tax Benefits	Teradyne’s gross unrecognized tax benefits for the years ended December 31, 2019, 2018 and 2017 were as follows: 2019 2018 2017 (in thousands) Beginning balance, as of January 1 $ 43,395 $ 36,263 $ 38,958 Additions: Tax positions for current year 1,322 4,716 8,208 Tax positions for prior years 8,043 2,626 199 Reductions: Tax positions for prior years (31,397 ) (153 ) (10,573 ) Expiration of statutes (183 ) (57 ) (325 ) Settlements with tax authorities — — (204 ) Ending balance as of December 31 $ 21,180 $ 43,395 $ 36,263

Operating Segment, Geographic_2

Operating Segment, Geographic and Significant Customer Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Information	Segment information for the years ended December 31, 2019, 2018, and 2017 is as follows: Semiconductor Test Industrial Automation System Test Wireless Test Corporate And Other Consolidated (in thousands) 2019 Revenues $ 1,552,571 $ 298,139 $ 287,455 $ 157,315 $ (515 ) $ 2,294,965 Income (loss) before taxes (1)(2) 416,973 (5,916 ) 93,543 35,585 (14,413 ) 525,772 Total assets (3) 784,808 671,559 131,428 97,299 1,101,920 2,787,014 Property additions 112,145 9,076 3,059 10,362 — 134,642 Depreciation and amortization expense 59,197 40,904 5,518 5,365 9,671 120,655 2018 Revenues $ 1,492,417 $ 261,452 $ 216,132 $ 132,006 $ (1,205 ) $ 2,100,802 Income (loss) before taxes (1)(2) 397,645 7,670 48,857 29,052 (15,423 ) 467,801 Total assets (3) 669,452 607,502 88,098 77,570 1,263,984 2,706,606 Property additions 94,496 11,188 3,469 5,226 — 114,379 Depreciation and amortization expense 58,095 36,755 6,430 5,328 6,616 113,224 2017 Revenues $ 1,662,549 $ 170,056 $ 192,135 $ 111,866 $ — $ 2,136,606 Income (loss) before taxes (1)(2) 491,361 8,763 10,305 17,350 (3,368 ) 524,411 Total assets (3) 597,480 368,037 97,018 59,912 1,987,098 3,109,545 Property additions 87,920 7,044 5,976 4,435 — 105,375 Depreciation and amortization expense 58,901 25,711 6,646 5,392 11,425 108,075 (1) Included in Corporate and Other are: contingent consideration adjustments, investment impairment , , property insurance recovery (2) Included in income (loss) before taxes are charges and credits related to restructuring and other, and inventory charges. (3) Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.
Schedule of Segment Reporting Information by Segment Charges	Included in each segment are charges and credits in the following line items in the statements of operation s For the Year Ended December 31, 2019 2018 2017 (in thousands) Semiconductor Test: Cost of revenues—inventory charge $ 8,731 $ 6,822 $ 4,606 Restructuring and other—employee severance 1,277 8,429 1,779 Restructuring and other—impairment of fixed assets — — 1,124 Industrial Automation: Restructuring and other—employee severance $ 796 $ — $ 1,414 Restructuring and other—acquisition related expenses and compensation 741 1,163 — Cost of revenues—inventory charge 508 680 — System Test: Cost of revenues—inventory charge $ 2,000 $ 1,175 $ 1,918 Wireless: Cost of revenues—inventory charge $ 4,005 $ 2,565 $ 2,190 Restructuring and other—lease impairment — — 972 Corporate and Other: Restructuring and other—MiR contingent consideration adjustment $ (22,199 ) $ 17,666 $ — Other (income) expense, net—investment impairment charge 15,000 — — Restructuring and other—AutoGuide contingent consideration adjustment 2,976 — — Selling and administrative—equity modification charge 2,108 — — Restructuring and other—acquisition related expenses and compensation 1,765 3,422 — Restructuring and other—Universal Robots contingent consideration adjustment — (16,679 ) 7,820 Restructuring and other—property insurance recovery related to Japan earthquake — — (5,064 )
Revenues by Country	Information as to Teradyne’s revenues by country is as follows: 2019 2018 2017 (in thousands) Revenues from customers (1): China $ 514,327 $ 348,942 $ 260,451 Taiwan 485,681 516,322 687,031 United States 333,059 282,869 252,516 Korea 239,504 163,224 206,819 Europe 219,015 223,207 163,715 Japan 175,322 158,281 169,093 Thailand 87,503 59,184 29,566 Singapore 84,111 108,618 101,085 Malaysia 58,200 122,797 124,048 Philippines 54,560 77,996 105,850 Rest of the World 43,683 39,362 36,432 $ 2,294,965 $ 2,100,802 $ 2,136,606 (1) Revenues attributable to a country are based on location of customer site.
Long-Lived Assets by Geographic Area	Long-lived assets by geographic area: United Foreign(1) Total (in thousands) December 31, 2019 $ 252,812 $ 124,943 $ 377,755 December 31, 2018 $ 209,368 $ 70,453 $ 279,821 (1) As of December 31, 2019 and 2018, long-lived assets attributable to Singapore were $35.2

Supplementary Information (Tabl

Supplementary Information (Tables)	12 Months Ended
Supplementary Information (Tables)	Dec. 31, 2019
Consolidated Quarterly Statements of Operations	The following sets forth certain unaudited consolidated quarterly statements of operations data for each of Teradyne’s last eight quarters. In management’s opinion, this quarterly information reflects all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement for the periods presented. Such quarterly results are not necessarily indicative of future results of operations and should be read in conjunction with the audited consolidated financial statements of Teradyne and the notes thereto included elsewhere herein. 2019 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter (1) (2) (3) (4)(5) ( 6 (in thousands, except per share amounts) Revenues: Products $ 393,442 $ 457,511 $ 488,170 $ 548,552 Services 100,657 106,667 93,868 106,098 Total revenues 494,099 564,178 582,038 654,650 Cost of revenues: Cost of products 165,368 193,299 197,196 226,184 Cost of services 41,096 46,961 39,804 45,228 Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below) 206,464 240,260 237,000 271,412 Gross profit 287,635 323,918 345,038 383,238 Operating expenses: Selling and administrative 102,013 108,811 109,166 117,092 Engineering and development 76,791 81,434 77,804 86,794 Acquired intangible assets amortization 10,634 10,083 9,647 9,784 Restructuring and other 5,112 (10,404 ) (6,500 ) (2,088 ) Total operating expenses 194,550 189,924 190,117 211,582 Income from operations 93,085 133,994 154,921 171,656 Non-operating Interest income (8,052 ) (5,430 ) (5,159 ) (6,145 ) Interest expense 5,713 5,800 5,682 5,950 Other (income) expense, net 1,445 2,447 2,665 22,965 Income before income taxes 93,979 131,177 151,733 148,886 Income tax (benefit) provision (15,159 ) 33,780 15,873 23,811 Net income $ 109,138 $ 97,397 $ 135,860 $ 125,075 Net income per common share—basic $ 0.63 $ 0.57 $ 0.80 $ 0.75 Net income per common share—diluted $ 0.62 $ 0.55 $ 0.75 $ 0.69 Cash dividend declared per common share $ 0.09 $ 0.09 $ 0.09 $ 0.09 (1) Restructuring and other includes a $3.0 million fair value adjustment to increase the MiR acquisition contingent consideration, $1.3 million of acquisition related expenses and compensation and $0.8 million of employee severance charges. (2) Restructuring and other includes a $11.7 million gain for the decrease in the fair value of the MiR (3) Restructuring and other includes a million gain for the decrease in the fair value of Mi R contingent consideration liability, partially offset by of employee severance charges and of acquisition related expenses an d compensa t (4) Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation (5) Teradyne recorded pension and post retirement net actuarial losses of $7.7 million for the fourth quarter in 2019. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy. (6) Other (income) expense, net includes a $15.0 million charge for the impairment of the investment in RealWear. 2018 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter (1) (2) (3) (4)(5) (in thousands, except per share amounts) Revenues: Products $ 403,925 $ 434,051 $ 470,994 $ 420,652 Services 83,542 92,878 95,854 98,906 Total revenues 487,467 526,929 566,848 519,558 Cost of revenues: Cost of products 180,958 180,777 195,339 170,064 Cost of services 36,677 38,818 37,816 39,959 Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below) 217,635 219,595 233,155 210,023 Gross profit 269,832 307,334 333,693 309,535 Operating expenses: Selling and administrative 90,505 99,410 100,202 100,552 Engineering and development 74,408 75,342 77,049 74,706 Acquired intangible assets amortization 7,698 9,793 11,142 10,558 Restructuring and other (313 ) 2,389 1,710 11,446 Total operating expenses 172,298 186,934 190,103 197,262 Income from operations 97,534 120,400 143,590 112,273 Non-operating Interest income (5,981 ) (5,427 ) (6,213 ) (9,083 ) Interest expense 6,890 5,639 5,557 13,182 Other (income) expense, net 805 176 3,405 (2,954 ) Income before income taxes 95,820 120,012 140,841 111,128 Income tax provision (benefit) 8,846 18,975 20,863 (32,662 ) Net income $ 86,974 $ 101,037 $ 119,978 $ 143,790 Net income per common share—basic $ 0.45 $ 0.53 $ 0.65 $ 0.80 Net income per common share—diluted $ 0.43 $ 0.52 $ 0.63 $ 0.79 Cash dividend declared per common share $ 0.09 $ 0.09 $ 0.09 $ 0.09 (1) Restructuring and other includes a $3.5 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $2.5 million of acquisition related expenses and compensation and $2.4 million of employee severance charges. (2) Restructuring and other includes a $5.0 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $3.9 million of employee severance charges and $0.8 million of acquisition related expenses and compensation. (3) Restructuring and other includes $1.7 million of employee severance charges, $0.8 million of acquisition related expenses and compensation, partially offset by a $0.8 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability. (4) Restructuring and other includes a $17.7 million fair value adjustment to increase the MiR acquisition contingent consideration, $0.8 million of employee severance charges, and $0.5 million acquisition related expenses and compensation, partially offset by a $7.4 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability. (5) Teradyne recorded pension and post retirement net actuarial gains of $3.5 million for the fourth quarter in 2018. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.

The Company - Additional inform

The Company - Additional information (Detail)	Nov. 14, 2019	Nov. 13, 2019USD ($)	Apr. 25, 2018USD ($)	Apr. 25, 2018USD ($)	Feb. 26, 2018USD ($)	Jan. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Feb. 28, 2020USD ($)	Jun. 03, 2019USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Contingent consideration		$ 24,000,000	$ 30,800,000	$ 30,800,000			$ 9,100,000	$ 9,100,000
Investment impairment							15,000,000	15,000,000
Real War In [Member]
Business Acquisition [Line Items]
Equity Method Investments							0	0		$ 15,000,000
Real War In [Member] \| Subsequent Event [Member]
Business Acquisition [Line Items]
Repayment of debt demanded									$ 25,000,000
Industrial Automation [Member]
Business Acquisition [Line Items]
Total preliminary purchase price		81,700,000
Energid Technologies Corporation
Business Acquisition [Line Items]
Total preliminary purchase price					$ 27,600,000
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Cash paid to acquire outstanding common and preferred stock			145,200,000	145,200,000
Total preliminary purchase price				197,680,000
Contingent consideration			$ 52,600,000	$ 52,600,000			9,100,000	9,100,000			$ 31,000,000
Arrangement range of outcomes value high							63,200,000	63,200,000
Lemsys
Business Acquisition [Line Items]
Total preliminary purchase price						$ 9,100,000
Autoguide LLC [Member]
Business Acquisition [Line Items]
Arrangement range of outcomes value high		106,900,000					$ 106,900,000	$ 106,900,000
Autoguide LLC [Member] \| Industrial Automation [Member]
Business Acquisition [Line Items]
Cash paid to acquire outstanding common and preferred stock		57,800,000
Contingent consideration		$ 24,000,000
Business acquisition percentage of equity	100.00%	100.00%
Arrangement range of outcomes value high		$ 106,900,000
Quantity of material to be transported	4,500	4,500

Accounting Policies - Additiona

Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 29, 2019

[3]

Jun. 30, 2019

[4]

Mar. 31, 2019

[5]

Dec. 31, 2018

Sep. 30, 2018

[8]

Jul. 01, 2018

[9]

Apr. 01, 2018

[10]

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Jan. 01, 2019

Jan. 01, 2018

Mar. 31, 2017

Feb. 28, 2016

Summary Of Significant Accounting Policies [Line Items]

Standard warranty period

12 months

Depreciation over life to cost of revenues and selling and administrative expenses, years

6 years

Net book value of internally manufactured test systems sold

$ 5,000

$ 3,800

$ 3,600

Cumulative effect adjustment to increase retained earnings and deferred tax assets

$ 12,679

12,679

Income tax provision (benefit)

$ 23,811

[1],[2]

$ 15,873

$ 33,780

$ (15,159)

(32,662)

[6],[7]

$ 20,863

$ 18,975

$ 8,846

58,304

16,022

266,720

Advertising costs

16,600

15,400

9,100

Losses (gains) on foreign currency transactions

(1,600)

(2,500)

2,900

Trade Accounts Receivable

143,600

52,200

143,600

52,200

Lease right-of-use assets

57,539

$ 50,100

Operating Lease, Liability

$ 65,325

65,325

$ 54,300

ASU 2016-09

Summary Of Significant Accounting Policies [Line Items]

Cumulative effect adjustment to increase retained earnings and deferred tax assets

$ 39,000

Income tax provision (benefit)

$ 4,900

7,600

6,300

ASU 2017-07

Summary Of Significant Accounting Policies [Line Items]

Increase (decrease) in income from operations

$ (5,000)

Retained Earnings

Summary Of Significant Accounting Policies [Line Items]

Cumulative effect adjustment to increase retained earnings and deferred tax assets

$ 12,679

Retained Earnings | ASU 2016-01

Summary Of Significant Accounting Policies [Line Items]

Increase (decrease) in adoption of new accounting guidance amount

$ 3,100

Accumulated Other Comprehensive Income (Loss) | ASU 2016-01

Summary Of Significant Accounting Policies [Line Items]

Increase (decrease) in adoption of new accounting guidance amount

$ (3,100)

[1]

Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.

[2]

Teradyne recorded pension and post retirement net actuarial losses of $7.7 million for the fourth quarter in 2019. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.

[3]

Restructuring and other includes a $7.8 million gain for the decrease in the fair value of MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.

[4]

Restructuring and other includes a $11.7 million gain for the decrease in the fair value of the MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.

[5]

Restructuring and other includes a $3.0 million fair value adjustment to increase the MiR acquisition contingent consideration, $1.3 million of acquisition related expenses and compensation and $0.8 million of employee severance charges.

[6]

Restructuring and other includes a $17.7 million fair value adjustment to increase the MiR acquisition contingent consideration, $0.8 million of employee severance charges, and $0.5 million acquisition related expenses and compensation, partially offset by a $7.4 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.

[7]

Teradyne recorded pension and post retirement net actuarial gains of $3.5 million for the fourth quarter in 2018. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.

[8]

Restructuring and other includes $1.7 million of employee severance charges, $0.8 million of acquisition related expenses and compensation, partially offset by a $0.8 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.

[9]

Restructuring and other includes a $5.0 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $3.9 million of employee severance charges and $0.8 million of acquisition related expenses and compensation.

[10]

Restructuring and other includes a $3.5 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $2.5 million of acquisition related expenses and compensation and $2.4 million of employee severance charges.

Deferred Revenue and Customer A

Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred Revenue Arrangement
Maintenance, service and training	$ 63,815	$ 58,362
Extended warranty	30,677	27,422	$ 24,438	$ 28,200
Customer advances, undelivered elements and other	56,358	24,677
Total deferred revenue and customer advances	$ 150,850	$ 110,461

Warranty Accrual Included in Ot

Warranty Accrual Included in Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 7,909	$ 8,200	$ 7,203
Acquisition	14	41
Accruals for warranties issued during the period	14,106	13,045	14,223
Accruals related to pre-existing warranties	4,026	921	(379)
Settlements made during the period	(17,059)	(14,298)	(12,847)
Balance at end of period	$ 8,996	$ 7,909	$ 8,200

Extended Product Warranty of Sh

Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Product Warranty Liability [Line Items]
Balance at beginning of period	$ 27,422	$ 24,438	$ 28,200
Deferral of new extended warranty revenue	23,271	23,753	20,513
Recognition of extended warranty deferred revenue	(20,016)	(20,769)	(24,275)
Balance at end of period	$ 30,677	$ 27,422	$ 24,438

Schedule of Prepayments and Oth

Schedule of Prepayments and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Prepaid And Other Current Assets [Line Items]
Contract manufacturer and supplier prepayments	$ 143,392	$ 131,642
Prepaid taxes	8,046	9,646
Prepaid maintenance and other services	8,503	8,487
Other prepayments	16,753	12,744
Total prepayments	$ 176,694	$ 162,519

Useful Lives of Assets (Detail)

Useful Lives of Assets (Detail)	12 Months Ended
Useful Lives of Assets (Detail)	Dec. 31, 2019
Buildings
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	40 years
Building Improvements \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	5 years
Building Improvements \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	10 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Useful lives, description	Lesser of lease term or 10 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	10 years
Test Systems Manufactured Internally
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	6 years
Machinery Equipment And Software \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	3 years
Machinery Equipment And Software \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	5 years

Acquisitions and Investment I_3

Acquisitions and Investment In Other Company - Additional Information (Detail)	Nov. 14, 2019USD ($)	Nov. 13, 2019USD ($)	Apr. 25, 2018USD ($)	Apr. 25, 2018USD ($)	Feb. 26, 2018USD ($)	Jan. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Feb. 28, 2020USD ($)	Jun. 03, 2019USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Business acquisiton consideration through earnouts		$ 24,000,000	$ 30,800,000	$ 30,800,000			$ 9,100,000	$ 9,100,000		$ 9,100,000
Goodwill							416,431,000	416,431,000	$ 381,850,000	416,431,000	$ 381,850,000			$ 252,011,000
Investment impairment								15,000,000		15,000,000
Industrial Automation
Business Acquisition [Line Items]
Total preliminary purchase price		81,700,000
Goodwill							396,483,000	396,483,000	363,358,000	396,483,000	363,358,000			$ 233,519,000
Estimate of Fair Value Measurement [Member]
Business Acquisition [Line Items]
Business acquisiton consideration through earnouts							39,705,000	39,705,000	70,543,000	39,705,000	70,543,000
Real War In [Member]
Business Acquisition [Line Items]
Equity Method Investments							0	0		0			$ 15,000,000
Subsequent Event [Member] \| Real War In [Member]
Business Acquisition [Line Items]
Repayment of debt demanded												$ 25,000,000
Autoguide LLC [Member]
Business Acquisition [Line Items]
Total preliminary purchase price	$ 81,748,000
Arrangement range of outcomes value high		106,900,000					106,900,000	106,900,000		106,900,000
Goodwill, not deductible for tax purposes	41,400,000
Revenues							1,400,000
Business combination earnings or loss of acquiree since acquisition date							(900,000)
Goodwill	$ 41,372,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 1 month 6 days
Autoguide LLC [Member] \| Industrial Automation
Business Acquisition [Line Items]
Total preliminary purchase price		81,700,000
Cash paid to acquire outstanding common and preferred stock		57,800,000
Business acquisiton consideration through earnouts		24,000,000
Arrangement range of outcomes value high		$ 106,900,000
Quantity of material to be transported	4,500	4,500
Business acquisition percentage of equity	100.00%	100.00%
Autoguide LLC [Member] \| Estimate of Fair Value Measurement [Member]
Business Acquisition [Line Items]
Revenues										100,000	400,000
Autoguide LLC [Member] \| Acquisition Related Costs
Business Acquisition [Line Items]
Net income										1,200,000	1,200,000
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total preliminary purchase price			197,778,000	197,778,000
Cash paid to acquire outstanding common and preferred stock			145,200,000	145,200,000
Business acquisiton consideration through earnouts			52,600,000	52,600,000			9,100,000	9,100,000	31,000,000	9,100,000	31,000,000
Arrangement range of outcomes value high							$ 63,200,000	$ 63,200,000		63,200,000
Goodwill, not deductible for tax purposes			136,000,000	136,000,000
Revenues									24,100,000
Business combination earnings or loss of acquiree since acquisition date									$ (7,600,000)
Net income										$ 464,602,000	442,082,000
Total preliminary purchase price				197,680,000
Goodwill			$ 135,976,000	$ 135,976,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			7 years 2 months 12 days
Mobile Industrial Robots (MiR) \| Estimate of Fair Value Measurement [Member]
Business Acquisition [Line Items]
Revenues											400,000
Mobile Industrial Robots (MiR) \| Acquisition Related Costs
Business Acquisition [Line Items]
Net income											$ 2,900,000
Energid Technologies Corporation
Business Acquisition [Line Items]
Total preliminary purchase price					$ 27,600,000
Goodwill					14,400,000
Acquired value of intangible assets					$ 12,300,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life					7 years 8 months 12 days
Net tangible assets					$ 1,000,000
Lemsys [Member]
Business Acquisition [Line Items]
Total preliminary purchase price						$ 1.4
Total preliminary purchase price						9,100,000
Acquired value of intangible assets						$ 4,600,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life						5 years 2 months 12 days
Net tangible assets						$ 3,100,000

Final Allocation of Purchase Pr

Final Allocation of Purchase Price (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Nov. 14, 2019	Dec. 31, 2018	Apr. 25, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 416,431		$ 381,850		$ 252,011
Autoguide LLC [Member]
Business Acquisition [Line Items]
Goodwill		$ 41,372
Intangible assets		37,660
Other current assets		3,661
Non-current assets		1,227
Accounts payable and current liabilities		(1,223)
Long-term deferred tax liabilities		(949)
Total purchase price		$ 81,748
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Goodwill				$ 135,976
Intangible assets				80,670
Other current assets				6,039
Non-current assets				1,336
Accounts payable and current liabilities				(7,336)
Long-term deferred tax liabilities				(18,007)
Other long-term liabilities				(900)
Total purchase price				$ 197,778

Components of Intangible Assets

Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date (Detail) - USD ($) $ in Thousands	Nov. 14, 2019	Apr. 25, 2018	Dec. 31, 2019
Autoguide LLC [Member]
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 37,660
Total intangible assets, estimated useful life, years	6 years 1 month 6 days
Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 80,670	$ 37,700
Total intangible assets, estimated useful life, years		7 years 2 months 12 days
Developed technology \| Autoguide LLC [Member]
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 24,590
Total intangible assets, estimated useful life, years	6 years
Developed technology \| Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 58,900
Total intangible assets, estimated useful life, years		7 years
Trademarks and tradenames \| Autoguide LLC [Member]
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 7,360
Total intangible assets, estimated useful life, years	6 years
Trademarks and tradenames \| Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 13,240
Total intangible assets, estimated useful life, years		11 years
Customer Relationships \| Autoguide LLC [Member]
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 5,450
Total intangible assets, estimated useful life, years	7 years
Customer Relationships \| Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 8,500
Total intangible assets, estimated useful life, years		2 years 6 months
Customer backlog \| Autoguide LLC [Member]
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 260
Total intangible assets, estimated useful life, years	3 months 18 days
Customer backlog \| Mobile Industrial Robots (MiR)
Business Acquisition [Line Items]
Total intangible assets, fair value		$ 30
Total intangible assets, estimated useful life, years		2 months 12 days

Pro Forma Results Under Acquisi

Pro Forma Results Under Acquisition (Detail) - Mobile Industrial Robots (MiR) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Revenue	$ 2,303,737	$ 2,111,373
Net income	$ 464,602	$ 442,082
Net income per common share, basic	$ 2.73	$ 2.36
Net income per common share, diluted	$ 2.59	$ 2.30

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Deferred Revenue And Customer Advances	$ 65.6	$ 69.9
Short-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	70.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period	12 months
Long-term Contract with Customer [Member]
Revenue, Remaining Performance Obligation, Percentage	26.00%
Long-term Contract with Customer [Member] \| Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period	3 years
Long-term Contract with Customer [Member] \| Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Period	1 year

Disaggregated Revenue by Primar

Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total	[2]	$ 2,294,965	[1]	$ 2,100,802	[1]	$ 2,136,606
Semiconductor Test
Disaggregation of Revenue [Line Items]
Total		1,552,571		1,492,417		1,662,549
System Test
Disaggregation of Revenue [Line Items]
Total		287,455	[1]	216,132	[1]	192,135
Industrial Automation
Disaggregation of Revenue [Line Items]
Total		298,139		261,452		170,056
Wireless Test
Disaggregation of Revenue [Line Items]
Total		157,315	[1]	132,006	[1]	$ 111,866
Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]	(515)		(1,205)
Point in Time
Disaggregation of Revenue [Line Items]
Total	[1]	1,993,077		1,815,171
Point in Time \| System Test
Disaggregation of Revenue [Line Items]
Total	[1]	237,686		167,418
Point in Time \| Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	148,322		122,536
Point in Time \| Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]	(515)		(1,205)
Over Time
Disaggregation of Revenue [Line Items]
Total	[1]	301,888		285,631
Over Time \| System Test
Disaggregation of Revenue [Line Items]
Total	[1]	49,769		48,714
Over Time \| Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	8,993		9,470
Americas
Disaggregation of Revenue [Line Items]
Total	[1]	338,384		288,379
Americas \| System Test
Disaggregation of Revenue [Line Items]
Total	[1]	129,840		96,763
Americas \| Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	24,234		19,166
Americas \| Corporate and Other
Disaggregation of Revenue [Line Items]
Total	[1]	(515)		(1,205)
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total	[1]	228,071		235,977
Europe, Middle East and Africa \| System Test
Disaggregation of Revenue [Line Items]
Total	[1]	24,789		28,380
Europe, Middle East and Africa \| Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	6,532		4,968
Asia Pacific
Disaggregation of Revenue [Line Items]
Total	[1]	1,728,510		1,576,446
Asia Pacific \| System Test
Disaggregation of Revenue [Line Items]
Total	[1]	132,826		90,989
Asia Pacific \| Wireless Test
Disaggregation of Revenue [Line Items]
Total	[1]	126,549		107,872
SOC \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	1,286,440		1,218,949
SOC \| Point in Time \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	1,070,375		1,010,493
SOC \| Over Time \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	216,065		208,456
SOC \| Americas \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	73,257		78,498
SOC \| Europe, Middle East and Africa \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	60,302		72,572
SOC \| Asia Pacific \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	1,152,881		1,067,879
Memory \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	266,131		273,468
Memory \| Point in Time \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	247,221		259,366
Memory \| Over Time \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	18,910		14,102
Memory \| Americas \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	23,826		17,353
Memory \| Europe, Middle East and Africa \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	3,591		10,851
Memory \| Asia Pacific \| Semiconductor Test
Disaggregation of Revenue [Line Items]
Total	[1]	238,714		245,264
Universal Robots (UR) \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	248,467		234,095
Universal Robots (UR) \| Point in Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	244,515		231,895
Universal Robots (UR) \| Over Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	3,952		2,200
Universal Robots (UR) \| Americas \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	70,165		68,938
Universal Robots (UR) \| Europe, Middle East and Africa \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	110,496		106,776
Universal Robots (UR) \| Asia Pacific \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	67,806		58,381
MiR \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	44,403		24,115
MiR \| Point in Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	44,329		24,115
MiR \| Over Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	74
MiR \| Americas \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	14,438		7,326
MiR \| Europe, Middle East and Africa \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	20,452		10,839
MiR \| Asia Pacific \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	9,513		5,950
AutoGuide \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,378
AutoGuide \| Point in Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,144
AutoGuide \| Over Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	234
AutoGuide \| Americas \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,378
AutoGuide \| Europe, Middle East and Africa \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	0
Energid \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	3,891		3,242
Energid \| Point in Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]			553
Energid \| Over Time \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	3,891		2,689
Energid \| Americas \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,761		1,540
Energid \| Europe, Middle East and Africa \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	1,909		1,591
Energid \| Asia Pacific \| Industrial Automation
Disaggregation of Revenue [Line Items]
Total	[1]	$ 221		$ 111

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Revenues attributable to a country are based on location of customer site.

Disaggregated Revenue by Prim_2

Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Revenue on leases	$ 8.4	$ 12

Composition of Inventories, Net

Composition of Inventories, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory [Line Items]
Raw material	$ 118,595	$ 89,365
Work-in-process	32,695	31,014
Finished goods	45,401	33,162
Inventories, net	$ 196,691	$ 153,541

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Inventory [Line Items]
Inventory reserves	$ 103.6	$ 100.8

Property Plant and Equipment, N

Property Plant and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Land	$ 16,561	$ 16,561
Buildings	107,282	105,935
Machinery, equipment and software	834,970	752,722
Furniture and fixtures	29,157	27,432
Leasehold improvements	59,378	52,536
Construction in progress	2,537	6,276
Property, Plant and Equipment, Gross, Total	1,049,885	961,462
Less: accumulated depreciation	729,669	681,641
Property, plant and equipment, net	$ 320,216	$ 279,821

Property, Plant and Equipment -

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation of property, plant and equipment	$ 70,834	$ 67,415	$ 66,122
Accumulated depreciation	729,669	681,641
Test Systems Leased By Customers
Property, Plant and Equipment [Line Items]
Machinery and equipment	5,400	5,500
Accumulated depreciation	$ 5,100	$ 5,200

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Nov. 13, 2019
Financial Instruments and Fair Value [Line Items]
Available-for-sale securities, realized gain	$ 1,300,000	$ 4,000,000	$ 1,100,000
Available-for-sale securities, realized loss	200,000	1,600,000	300,000
Available-for-sale marketable securities, Fair Market Value of Investments in debt securities with Unrealized Losses	23,999,000	191,978,000
Fair market value of investments with unrealized losses greater than one year		28,500,000
Aggregate loss of investments with unrealized losses greater than one year		1,600,000
Fair market value of investments with unrealized losses less than one year		163,500,000
Aggregate loss of investments with unrealized losses less than one year	23,600,000	1,400,000
Unrealized Gain (loss) on contracts	1,600,000	2,500,000	$ (2,900,000)
Equity securities unrealized gain	5,300,000	1,400,000
Equity securities unrealized loss	$ 400,000	$ 7,400,000
Accounts Receivable \| Customer 1 \| Minimum
Financial Instruments and Fair Value [Line Items]
Concentration risk, percentage	10.00%
Accounts Receivable \| Customer 2 \| Minimum
Financial Instruments and Fair Value [Line Items]
Concentration risk, percentage		10.00%
Debt Mutual Funds
Financial Instruments and Fair Value [Line Items]
Available for sale securities with out contractual maturity date	$ 6,900
Mobile Industrial Robots (MiR)
Financial Instruments and Fair Value [Line Items]
Maximum amount of contingent consideration paid for acquisition	63,200,000
Autoguide LLC [Member]
Financial Instruments and Fair Value [Line Items]
Maximum amount of contingent consideration paid for acquisition	106,900,000			$ 106,900,000
Foreign Exchange Contracts
Financial Instruments and Fair Value [Line Items]
Unrealized Gain (loss) on contracts	$ 300,000	$ 400,000

Schedule of Fair Value of Finan

Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Nov. 13, 2019	Dec. 31, 2018	Apr. 25, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	$ 216,021		$ 256,636
Contingent consideration	9,100	$ 24,000		$ 30,800
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	97,307		40,020
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	54,149		86,117
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	42,382		109,721
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	9,952		9,611
Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	6,888		3,187
Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	4,751		7,604
Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	592		376
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	1,015,717		1,204,579
Derivative assets	528		79
Total	1,016,245		1,204,658
Contingent consideration	39,705		70,543
Derivative liabilities	203		514
Total	39,908		71,057
Fair Value, Measurements, Recurring \| Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	311,975		312,512
Fair Value, Measurements, Recurring \| Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	461,949		614,240
Fair Value, Measurements, Recurring \| Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	97,307		40,020
Fair Value, Measurements, Recurring \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	54,149		86,117
Fair Value, Measurements, Recurring \| U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	42,382		109,721
Fair Value, Measurements, Recurring \| U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	9,952		9,611
Fair Value, Measurements, Recurring \| Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	6,888		3,187
Fair Value, Measurements, Recurring \| Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	4,751		7,604
Fair Value, Measurements, Recurring \| Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	592		376
Fair Value, Measurements, Recurring \| Equity Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale equity securities	25,772		21,191
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	754,920		590,415
Total	754,920		590,415
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring \| Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	311,975		312,512
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring \| Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	410,285		253,525
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring \| Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	6,888		3,187
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring \| Equity Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale equity securities	25,772		21,191
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	260,797		614,164
Derivative assets	528		79
Total	261,325		614,243
Derivative liabilities	203		514
Total	203		514
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	51,664		360,715
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	97,307		40,020
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	54,149		86,117
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	42,382		109,721
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	9,952		9,611
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	4,751		7,604
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	592		376
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration	39,705		70,543
Total	$ 39,705		$ 70,543

Schedule of Reported Financial

Schedule of Reported Financial Assets and Liabilities (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 1,016,245	$ 1,204,658
Liabilities	39,908	71,057
Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	203	514
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	773,924	926,752
Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	137,303	190,096
Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	104,490	87,731
Prepayments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	528	79
Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	9,106	34,865
Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	30,599	35,678
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	754,920	590,415
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	722,260	566,037
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	32,660	24,378
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	261,325	614,243
Liabilities	203	514
Significant Other Observable Inputs (Level 2) \| Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	203	514
Significant Other Observable Inputs (Level 2) \| Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	51,664	360,715
Significant Other Observable Inputs (Level 2) \| Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	137,303	190,096
Significant Other Observable Inputs (Level 2) \| Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	71,830	63,353
Significant Other Observable Inputs (Level 2) \| Prepayments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	528	79
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	39,705	70,543
Significant Unobservable Inputs (Level 3) \| Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	9,106	34,865
Significant Unobservable Inputs (Level 3) \| Long Term Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	$ 30,599	$ 35,678

Schedule of Changes in Fair Val

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period		$ 70,543	$ 45,102
Acquisition of MiR		23,976	52,547
Foreign currency impact		(967)	(3,540)
Payments	[1]	(34,590)	(24,553)
Fair value adjustment	[2]	(19,257)	987
Balance at end of period		$ 39,705	$ 70,543

[1]	During the year ended December 31, 2018, Teradyne paid $24.6 million of contingent consideration for the earn-out in connection with the acquisition of Universal Robots.
[2]	During the year ended December 31, 2018, the fair value of contingent consideration for the earn-out in connection with the acquisition of MiR was increased by $17.7 million primarily due to an increase in forecasted revenues. During the year ended December 31, 2018, the fair value of contingent consideration for the earn-out in connection with the acquisition of Universal Robots was decreased by $16.7 million primarily due to a decrease in forecasted revenues.

Schedule of Changes in Fair V_2

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended						12 Months Ended
	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration							$ 27,615	$ 13,571	$ 1,050
Increase (decrease) in contingent consideration							(19,257)	987	$ 7,820
Universal Robots (UR)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration							30,800
Increase (decrease) in contingent consideration		$ 11,700	$ 3,000	$ 7,400	$ 5,000	$ 3,500	3,800	16,700
Avionics Interface Technologies, LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration								24,600
MiR
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Increase (decrease) in contingent consideration							(22,200)	$ 17,700
Autoguide LLC [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Increase (decrease) in contingent consideration	$ 3,000						$ 3,000

Quantitative Information Associ

Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Nov. 13, 2019	Dec. 31, 2018	Apr. 25, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration		$ 9,100	$ 24,000		$ 30,800
Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration		$ 9,100		$ 31,000	$ 52,600
Monte Carlo Simulation \| Revenue for the period July 1, 2015-December 31, 2018 \| Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Target achievement, volatility		11.50%
Discount rate		2.60%
Monte Carlo Simulation \| Revenue for the period July 1, 2015-December 31, 2018 \| Significant Unobservable Inputs (Level 3) \| Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration	[1]	$ 26,952
Monte Carlo Simulation \| Revenue for the period July 1, 2018-December 31, 2018 \| Universal Robots (UR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Target achievement, volatility		14.00%
Discount rate		0.20%
Monte Carlo Simulation \| Revenue for the period July 1, 2018-December 31, 2018 \| Significant Unobservable Inputs (Level 3) \| Universal Robots (UR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration	[1]	$ 12,753

[1]	Contingent consideration related to MiR and Universal Robots acquisitions of $31.0 million and $3.9 million, respectively, is expected to be paid in March 2019.

Quantitative Information Asso_2

Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument (Parenthetical) (Detail) $ in Millions	1 Months Ended
	Mar. 31, 2019USD ($)
Mobile Industrial Robots (MiR)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Payment for contingent consideration	$ 9.1

Schedule of Carrying Amounts an

Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands		Dec. 31, 2019	Nov. 13, 2019	Dec. 31, 2018	Apr. 25, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Marketable securities		$ 216,021		$ 256,636
Contingent consideration		9,100	$ 24,000		$ 30,800
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents		773,924		926,752
Marketable securities		241,793		277,827
Derivative assets		528		79
Contingent consideration		39,705		70,543
Derivative liabilities		203		514
Convertible debt	[1]	394,687		379,981
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents		773,924		926,752
Marketable securities		241,793		277,827
Derivative assets		528		79
Contingent consideration		39,705		70,543
Derivative liabilities		203		514
Convertible debt	[1]	$ 1,010,275		$ 547,113

[1]	The carrying value represents the bifurcated debt component only, while the fair value is based on quoted market prices for the convertible note which includes the equity conversion features.

Schedule of Available for Sale

Schedule of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 211,596	$ 259,011
Available-for-sale marketable securities, Unrealized Gain	4,687	592
Available-for-sale marketable securities, Unrealized (Loss)	(262)	(2,967)
Available-for-sale marketable securities, Fair Market Value	216,021	256,636
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	23,999	191,978
Corporate Debt Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	93,267	41,133
Available-for-sale marketable securities, Unrealized Gain	4,081	432
Available-for-sale marketable securities, Unrealized (Loss)	(41)	(1,545)
Available-for-sale marketable securities, Fair Market Value	97,307	40,020
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	2,009	24,767
Commercial Paper
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	54,124	86,130
Available-for-sale marketable securities, Unrealized Gain	26	13
Available-for-sale marketable securities, Unrealized (Loss)	(1)	(26)
Available-for-sale marketable securities, Fair Market Value	54,149	86,117
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	1,391	85,094
U.S. Treasury Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	42,167	110,969
Available-for-sale marketable securities, Unrealized Gain	431	112
Available-for-sale marketable securities, Unrealized (Loss)	(216)	(1,360)
Available-for-sale marketable securities, Fair Market Value	42,382	109,721
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	17,556	75,040
U.S. Government Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	9,942	9,646
Available-for-sale marketable securities, Unrealized Gain	14	1
Available-for-sale marketable securities, Unrealized (Loss)	(4)	(36)
Available-for-sale marketable securities, Fair Market Value	9,952	9,611
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	3,043	7,077
Debt Mutual Funds
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	6,753	3,153
Available-for-sale marketable securities, Unrealized Gain	135	34
Available-for-sale marketable securities, Fair Market Value	6,888	3,187
Certificates of Deposit and Time Deposits
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	4,751	7,604
Available-for-sale marketable securities, Unrealized Gain	0
Available-for-sale marketable securities, Fair Market Value	4,751	7,604
Non-U.S. Government Securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	592	376
Available-for-sale marketable securities, Fair Market Value	$ 592	$ 376

Schedule of Reported Available

Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 211,596	$ 259,011
Available-for-sale marketable securities, Unrealized Gain	4,687	592
Available-for-sale marketable securities, Unrealized (Loss)	(262)	(2,967)
Available-for-sale marketable securities, Fair Market Value	216,021	256,636
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	23,999	191,978
Marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	137,144	190,100
Available-for-sale marketable securities, Unrealized Gain	160	88
Available-for-sale marketable securities, Unrealized (Loss)	(1)	(92)
Available-for-sale marketable securities, Fair Market Value	137,303	190,096
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	2,922	140,262
Long-term marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	74,452	68,911
Available-for-sale marketable securities, Unrealized Gain	4,527	504
Available-for-sale marketable securities, Unrealized (Loss)	(261)	(2,875)
Available-for-sale marketable securities, Fair Market Value	78,718	66,540
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$ 21,077	$ 51,716

Contractual Maturities of Inves

Contractual Maturities of Investments in Debt Securities Held (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Schedule of Available-for-sale Securities
Due within one year, cost	$ 137,144
Due after 1 year through 5 years, cost	15,264
Due after 5 years through 10 years, cost	14,436
Due after 10 years, cost	37,999
Total, cost	204,843
Due within one year, fair market value	137,303
Due after 1 year through 5 years, fair market value	15,351
Due after 5 years through 10 years, fair market value	14,576
Due after 10 years, fair maket value	41,903
Total, fair market value	$ 209,133

Schedule of Notional Amount of

Schedule of Notional Amount of Derivatives (Detail) - Foreign Exchange Contracts - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	$ 20.5	$ 48.7
Buy Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(62.2)	(57.2)
Sell Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	82.7	105.9
Japanese Yen
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(29.3)	(35)
Japanese Yen \| Buy Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(29.3)	(35)
Taiwan Dollar
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(18.4)	(11.2)
Taiwan Dollar \| Buy Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(18.4)	(11.2)
Korean Won
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(10.7)	(9.6)
Korean Won \| Buy Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(10.7)	(9.6)
British Pound Sterling
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(3.8)	(1.4)
British Pound Sterling \| Buy Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Liability, Notional amounts	(3.8)	(1.4)
Euro
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	47.8	82.2
Euro \| Sell Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	47.8	82.2
Singapore Dollar
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	25.3	15.7
Singapore Dollar \| Sell Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	25.3	15.7
Philippines, Pesos
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	5.2	5.2
Philippines, Pesos \| Sell Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	5.2	5.2
China, Yuan Renminbi
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	4.4	2.8
China, Yuan Renminbi \| Sell Position
Intercompany Foreign Currency Balance [Line Items]
Derivative Asset, Notional amounts	$ 4.4	$ 2.8

Schedule of Derivative Instrume

Schedule of Derivative Instruments in Statement of Financial Position at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets (liabilities), net	$ 325	$ (435)
Not Designated as Hedging Instrument \| Foreign currency forward contracts \| Prepayments
Derivatives, Fair Value [Line Items]
Derivative assets	528	79
Not Designated as Hedging Instrument \| Foreign currency forward contracts \| Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ (203)	$ (514)

Schedule of Effect of Derivativ

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Losses (Gains) on derivatives recognized in statements of operations	$ 5,960	$ 7,386	$ (1,133)

Schedule of Effect of Derivat_2

Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on foreign currency transactions	$ 1.6	$ 2.5	$ (2.9)

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Feb. 28, 2016
Total lease expense	$ 35,600
Variable lease costs	11,100
Lease right-of-use assets	57,539	$ 50,100	$ 50,100
Operating Lease, Liability	$ 65,325	$ 54,300	$ 54,300
Operating Lease, Weighted Average Remaining Lease Term	4 years 6 months
Operating Lease, Weighted Average Discount Rate, Percent	5.00%
Short-term Lease, Cost	$ 2,600

Supplemental Cash Flow Informat

Supplemental Cash Flow Information Related to Leases (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Cash paid for amounts included in the measurement of lease liabilities included in operating cash flows	$ 19,400
Right-of-use assets obtained in exchange for new lease obligations	$ 26,739

Schedule of Operating Lease, Ma

Schedule of Operating Lease, Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Feb. 28, 2016
2020	$ 21,874
2021	17,638
2022	12,944
2023	6,496
2024	5,106
Thereafter	8,388
Total lease payments	72,446
Less imputed interest	(7,121)
Total lease liabilities	$ 65,325	$ 54,300		$ 54,300
2019			$ 19,570
2020			18,293
2021			13,578
2022			9,693
2023			5,449
Thereafter			9,472
Total lease payments			$ 76,055

Debt - Additional Information (

Debt - Additional Information (Detail) $ / shares in Units, $ in Thousands, shares in Millions	Dec. 12, 2016USD ($)Customershares	Apr. 27, 2015USD ($)	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)$ / shares
Debt Instrument
Repurchase of common stock			$ 500,000	$ 823,478	$ 200,304
Term of loan, years		5 years
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Aggregate principal amount	$ 460,000		460,000	460,000
Debt instrument, interest rate, stated percentage	1.25%
Debt instrument, net proceeds after issuance costs	$ 450,800
Payment for net cost of convertible note hedges net of warrant proceeds	33,000		$ 33,000
Repurchase of common stock	$ 50,100
Repurchase of stock, shares \| shares	2
Senior notes maturity date	Dec. 15, 2023
Debt instrument, frequency of periodic payment	payable semiannually in arrears on June 15 and December 15 of each year
Debt instrument, conversion option expiration date	Sep. 15, 2023
Debt instrument conversion price \| $ / shares			$ 31.62			$ 31.62
Shares that would be issued upon conversion \| shares			14.5
Strike price per share of warrant \| $ / shares			$ 39.68
Debt instrument, convertible, carrying amount of equity component			$ 100,800
Debt instrument, effective annual interest rate			5.00%
Financing cost			$ 4,300			$ 7,200
Debt issuance costs, amortization period			7 years
Unamortized discount			$ 65,300
Debt Instrument, convertible, remaining discount amortization period			4 years
Value of notes converted			$ 992,000
Debt Instrument, Face Amount	$ 460,000		$ 460,000	$ 460,000
1.25% Convertible Senior Unsecured Notes Due December 15, 2023 \| Conversion option one
Debt Instrument
Trading days measurement period \| Customer	20
Consecutive trading days measurement period \| Customer	30
Percentage of conversion price	130.00%
1.25% Convertible Senior Unsecured Notes Due December 15, 2023 \| Conversion option two
Debt Instrument
Aggregate principal amount	$ 1,000
Trading days measurement period \| Customer	5
Consecutive trading days measurement period \| Customer	5
Percentage of closing sale price of common stock and conversion rate product	98.00%
Debt Instrument, Face Amount	$ 1,000
Revolving Credit Facility \| Maximum
Debt Instrument
Credit facility, borrowing capacity		$ 350,000

Components of Convertible Senio

Components of Convertible Senior Notes (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 12, 2016
Debt Instrument
Net carrying amount of convertible debt	$ 394,687	$ 379,981
1.25% Convertible Senior Unsecured Notes Due December 15, 2023
Debt Instrument
Debt principal	460,000	460,000	$ 460,000
Unamortized discount	65,313	80,019
Net carrying amount of convertible debt	$ 394,687	$ 379,981

Interest Expense on Convertible

Interest Expense on Convertible Senior Notes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument
Contractual interest expense on the coupon	$ 5,750	$ 5,750
Amortization of the discount component and debt issue fees recognized as interest expense	14,706	13,995
Total interest expense on the convertible debt	$ 20,456	$ 19,745

Changes in Accumulated Other Co

Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		$ 1,522,354	$ 1,953,646	$ 1,828,659
Other comprehensive income (loss) before reclassifications, net of tax		(4,976)	(30,552)
Amounts reclassified from accumulated other comprehensive income, net of tax		(838)	1,092
Other comprehensive (loss) income		(5,814)	(29,460)	38,990
Reclassification of tax effects resulting from the Tax Reform Act	[1]		769
Reclassification of unrealized gains on equity securities,net of tax		(690)	1,337	(441)
Balance		1,480,158	1,522,354	1,953,646
ASU 2016-01
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of unrealized gains on equity securities,net of tax	[2]		(3,125)
Foreign Currency Translation Reclassification Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(12,523)	15,919
Other comprehensive income (loss) before reclassifications, net of tax		(10,991)	(28,442)
Other comprehensive (loss) income		(10,991)	(28,442)
Balance		(23,514)	(12,523)	15,919
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(1,845)	1,362
Other comprehensive income (loss) before reclassifications, net of tax		6,015	(2,110)
Amounts reclassified from accumulated other comprehensive income, net of tax		(690)	1,337
Other comprehensive (loss) income		5,325	(773)
Reclassification of tax effects resulting from the Tax Reform Act	[1]		691
Balance		3,480	(1,845)	1,362
Unrealized Gains (Losses) on Marketable Securities \| ASU 2016-01
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of unrealized gains on equity securities,net of tax	[2]		(3,125)
Amortization of Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		1,328	1,495
Amounts reclassified from accumulated other comprehensive income, net of tax		(148)	(245)	(272)
Other comprehensive (loss) income		(148)	(245)
Reclassification of tax effects resulting from the Tax Reform Act	[1]		78
Balance		1,180	1,328	1,495
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(13,040)	18,776	(20,214)
Amounts reclassified from accumulated other comprehensive income, net of tax		(838)	1,092	(713)
Other comprehensive (loss) income		(5,814)	(29,460)	38,990
Reclassification of tax effects resulting from the Tax Reform Act			769
Balance		$ (18,854)	$ (13,040)	$ 18,776

[1]	In the year ended December 31, 2018, Teradyne early adopted ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” As a result, the stranded tax effects resulting from the Tax Reform Act enacted in December 2017 were reclassified from accumulated other comprehensive income to retained earnings.
[2]	In the year ended December 31, 2018, Teradyne adopted ASU 2016-01, “Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” See Note B: “Accounting Policies.”

Changes in Accumulated Other _2

Changes in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss), tax	$ (235)	$ (92)	$ (451)
Reclassification of unrealized gains on equity securities, net of tax	(192)	(21)	(297)
Foreign currency translation adjustments, tax	0	0	0
Unrealized (losses) gains on marketable securities, tax	946	(521)	1,815
Retirement plans prior service benefit, tax	(1,124)	(1,081)	(932)
Foreign Currency Translation Reclassification Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	0	0
Amounts reclassified from accumulated other comprehensive income (loss), tax	0	0
Other comprehensive income (loss), tax	0	0
Reclassification of income tax effects from the Tax Reform Act, net of tax		0
Unrealized (Losses) Gains on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	1,659	(722)
Amounts reclassified from accumulated other comprehensive income (loss), tax	(192)	(21)	(297)
Other comprehensive income (loss), tax	1,467	(743)
Reclassification of income tax effects from the Tax Reform Act, net of tax		(691)
Amortization of Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, tax	0	0
Amounts reclassified from accumulated other comprehensive income (loss), tax	(43)	(71)	$ (154)
Other comprehensive income (loss), tax	$ (43)	(71)
Reclassification of income tax effects from the Tax Reform Act, net of tax		(78)
ASU 2016-01 \| Foreign Currency Translation Reclassification Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of unrealized gains on equity securities, net of tax		0
ASU 2016-01 \| Unrealized (Losses) Gains on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of unrealized gains on equity securities, net of tax		(902)
ASU 2016-01 \| Amortization of Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of unrealized gains on equity securities, net of tax		$ 0

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income (expense)	$ 690	$ (1,337)	$ 441
Reclassifications, net of tax	838	(1,092)
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	148	245	272
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	$ 838	$ (1,092)	$ 713

Reclassifications Out of Accu_2

Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ 235	$ 92	$ 451
Unrealized (Losses) Gains on Marketable Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	192	21	297
Amortization of Prior Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, tax	$ 43	$ 71	$ 154

Goodwill and Acquired Intangibl

Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 29, 2019

[3]

Jun. 30, 2019

[4]

Mar. 31, 2019

[5]

Dec. 31, 2018

[6],[7]

Sep. 30, 2018

[8]

Jul. 01, 2018

[9]

Apr. 01, 2018

[10]

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Line Items]

Acquired intangible assets amortization

$ 9,784

[1],[2]

$ 9,647

$ 10,083

$ 10,634

$ 10,558

$ 11,142

$ 9,793

$ 7,698

$ 40,147

$ 39,191

$ 30,530

MiR Reporting Unit Percentage

14.00%

MiR Goodwill Amount

$ 123,600

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

Changes in Carrying Amount of G

Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Nov. 14, 2019	Apr. 25, 2018	Feb. 26, 2018
Goodwill [Line Items]
Goodwill acquisition	$ 1,428
Foreign currency translation adjustment		$ (20,531)
Goodwill	1,144,416	1,014,577	$ 1,178,997
Accumulated impairment losses	(762,566)	(762,566)	(762,566)
Goodwill	381,850	252,011	416,431
Mobile Industrial Robots (MiR)
Goodwill [Line Items]
Goodwill acquisition		135,976
Goodwill					$ 135,976
Energid Technologies Corporation
Goodwill [Line Items]
Goodwill acquisition		14,394
Goodwill						$ 14,400
Lemsys
Goodwill [Line Items]
Goodwill acquisition	41,372
Autoguide LLC
Goodwill [Line Items]
Foreign currency translation adjustment	(8,219)
Goodwill				$ 41,372
Industrial Automation
Goodwill [Line Items]
Foreign currency translation adjustment		(20,531)
Goodwill	363,358	233,519	396,483
Accumulated impairment losses	0	0	0
Goodwill	363,358	233,519	396,483
Industrial Automation \| Mobile Industrial Robots (MiR)
Goodwill [Line Items]
Goodwill acquisition		135,976
Industrial Automation \| Energid Technologies Corporation
Goodwill [Line Items]
Goodwill acquisition		14,394
Industrial Automation \| Lemsys
Goodwill [Line Items]
Goodwill acquisition	41,372
Industrial Automation \| Autoguide LLC
Goodwill [Line Items]
Foreign currency translation adjustment	(8,247)
Wireless Test
Goodwill [Line Items]
Goodwill	361,819	361,819	361,819
Accumulated impairment losses	(353,843)	(353,843)	(353,843)
Goodwill	7,976	7,976	7,976
Semiconductor Test
Goodwill [Line Items]
Goodwill acquisition	1,428
Goodwill	260,540	260,540	261,996
Accumulated impairment losses	(260,540)	(260,540)	(260,540)
Goodwill			1,456
Semiconductor Test \| Autoguide LLC
Goodwill [Line Items]
Foreign currency translation adjustment	28
System Test
Goodwill [Line Items]
Goodwill	158,699	158,699	158,699
Accumulated impairment losses	(148,183)	(148,183)	(148,183)
Goodwill	$ 10,516	$ 10,516	$ 10,516

Schedule of Amortizable Intangi

Schedule of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 507,836	$ 498,231
Accumulated Amortization	(375,008)	(367,531)
Foreign Currency Translation Adjustment	(7,348)	(5,218)
Net Carrying Amount	125,480	125,482
Developed technology
Finite-Lived Intangible Assets
Gross Carrying Amount	361,787	336,308
Accumulated Amortization	(279,000)	(252,080)
Foreign Currency Translation Adjustment	(5,709)	(4,079)
Net Carrying Amount	77,078	80,149
Customer Relationships
Finite-Lived Intangible Assets
Gross Carrying Amount	75,669	97,153
Accumulated Amortization	(59,077)	(83,448)
Foreign Currency Translation Adjustment	(455)	(340)
Net Carrying Amount	16,137	13,365
Trademarks and tradenames
Finite-Lived Intangible Assets
Gross Carrying Amount	70,120	64,420
Accumulated Amortization	(36,671)	(31,653)
Foreign Currency Translation Adjustment	(1,184)	(799)
Net Carrying Amount	32,265	31,968
Non-compete Agreements
Finite-Lived Intangible Assets
Gross Carrying Amount		320
Accumulated Amortization		(320)
Backlog
Finite-Lived Intangible Assets
Gross Carrying Amount	260	30
Accumulated Amortization	$ (260)	$ (30)

Schedule of Amortizable Intan_2

Schedule of Amortizable Intangible Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	Apr. 25, 2018	Dec. 31, 2019
Intangible Assets [Member]
Finite-Lived Intangible Assets
Impairment of intangible assets		$ 32,700
Mobile Industrial Robots (MiR)
Finite-Lived Intangible Assets
Intangible assets acquired	$ 80,670	37,700
Energid Technologies Corporation
Finite-Lived Intangible Assets
Intangible assets acquired		$ 4,600

Schedule of Estimated Intangibl

Schedule of Estimated Intangible Asset Amortization Expense (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Finite-Lived Intangible Assets
2020	$ 30,606
2021	20,593
2022	19,700
2023	19,226
2024	18,921
Thereafter	$ 16,434

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Purchase Commitment, Excluding Long-term Commitment
Aggregate purchase commitments	$ 415.6
Purchase commitments less than one year	$ 412.9
Warranty period	1 year
Product warranty accrual	$ 9	$ 7.9
Revenue deferrals related to extended warranties	$ 30.7	$ 27.4

Computation of Basic and Dilute

Computation of Basic and Diluted Net (Loss) Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2019	[1],[2]	Sep. 29, 2019	[3]	Jun. 30, 2019	[4]	Mar. 31, 2019	[5]	Dec. 31, 2018	[6],[7]	Sep. 30, 2018	[8]	Jul. 01, 2018	[9]	Apr. 01, 2018	[10]	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income Loss Per Common Share
Net income for basic and diluted net income per share		$ 125,075		$ 135,860		$ 97,397		$ 109,138		$ 143,790		$ 119,978		$ 101,037		$ 86,974		$ 467,468	$ 451,779	$ 257,692
Weighted average common shares-basic																		170,425	187,672	198,069
Incremental shares from assumed conversion of convertible notes	[11]																	4,909	2,749	1,298
Convertible note hedge warrant shares	[12]																	2,698	485	112
Employee stock purchase plan																		13	36	27
Dilutive potential common shares																		9,034	4,933	3,572
Weighted average common shares-diluted																		179,459	192,605	201,641
Net income per common share-basic		$ 0.75		$ 0.80		$ 0.57		$ 0.63		$ 0.80		$ 0.65		$ 0.53		$ 0.45		$ 2.74	$ 2.41	$ 1.30
Net income per common share-diluted		$ 0.69		$ 0.75		$ 0.55		$ 0.62		$ 0.79		$ 0.63		$ 0.52		$ 0.43		$ 2.60	$ 2.35	$ 1.28
Restricted Stock Units
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements																		1,236	1,385	1,800
Stock Options
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements																		178	278	335

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Teradyne recorded pension and post retirement net actuarial losses of $7.7 million for the fourth quarter in 2019. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[3]	Restructuring and other includes a $7.8 million gain for the decrease in the fair value of MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[4]	Restructuring and other includes a $11.7 million gain for the decrease in the fair value of the MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[5]	Restructuring and other includes a $3.0 million fair value adjustment to increase the MiR acquisition contingent consideration, $1.3 million of acquisition related expenses and compensation and $0.8 million of employee severance charges.
[6]	Restructuring and other includes a $17.7 million fair value adjustment to increase the MiR acquisition contingent consideration, $0.8 million of employee severance charges, and $0.5 million acquisition related expenses and compensation, partially offset by a $7.4 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[7]	Teradyne recorded pension and post retirement net actuarial gains of $3.5 million for the fourth quarter in 2018. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[8]	Restructuring and other includes $1.7 million of employee severance charges, $0.8 million of acquisition related expenses and compensation, partially offset by a $0.8 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[9]	Restructuring and other includes a $5.0 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $3.9 million of employee severance charges and $0.8 million of acquisition related expenses and compensation.
[10]	Restructuring and other includes a $3.5 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $2.5 million of acquisition related expenses and compensation and $2.4 million of employee severance charges.
[11]	Incremental shares from the assumed conversion of the convertible notes was calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.70, multiplied by 14.5 million shares. The result of this calculation, representing the total intrinsic value of the convertible debt, was divided by the average Teradyne stock price for the period.
[12]	Convertible notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price of $39.78, multiplied by 14.5 million shares. The result of this calculation, representing the total intrinsic value of the warrant, was divided by the average Teradyne stock price for the period.

Computation of Basic and Dilu_2

Computation of Basic and Diluted Net (Loss) Income Per Common Share (Parenthetical) (Detail) shares in Millions	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Convertible Notes
Net Income Loss Per Common Share
Initial debt conversion price \| $ / shares	$ 31.62
Shares that would be issued upon conversion \| shares	14.5
Convertible Notes Hedge Warrant
Net Income Loss Per Common Share
Initial debt conversion price \| $ / shares	$ 39.68
Shares that would be issued upon conversion \| shares	14.5

Net Income per Common Share - A

Net Income per Common Share - Additional Information (Detail) - shares shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Employee Stock Option [Member]
Net Income Loss Per Common Share
Exercise of stock options	0.1	0.1
Restricted Stock Units (RSUs) [Member]
Net Income Loss Per Common Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.5

Restructuring and Other - Addit

Restructuring and Other - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve
Contingent consideration adjustment										$ (19,257)	$ 987	$ 7,820
Severance benefit and charges	$ 500		$ 7,800	$ 800	$ 800	$ 800		$ 3,900	$ 2,400
Acquisition related costs	200		800	500	1,300	500	$ 800	800	2,500
Wireless Test
Restructuring Cost and Reserve
Lease impairment												1,000
Semiconductor Test
Restructuring Cost and Reserve
Acquisition related costs										2,500	4,500
Semiconductor Test \| Property, Plant and Equipment
Restructuring Cost and Reserve
Impairment charges fixed assets												1,100
AutoGuide
Restructuring Cost and Reserve
Contingent consideration adjustment										3,000
Impairment of Fixed Assets and Expenses Related to the Japan Earthquake
Restructuring Cost and Reserve
Property insurance recovery												5,100
Impairment of Fixed Assets and Expenses Related to the Japan Earthquake \| Earthquake Related Expenses
Restructuring Cost and Reserve
Impairment charges fixed assets												800
Universal Robots (UR)
Restructuring Cost and Reserve
Contingent consideration adjustment				$ 11,700	$ 3,000	7,400		$ 5,000	$ 3,500	3,800	16,700
Severance benefit and charges		$ 1,700	$ 500				$ 800
Mobile Industrial Robots (MiR)
Restructuring Cost and Reserve
Contingent consideration adjustment	$ 5,800					$ 17,700					17,700
Semiconductor Test and Wireless Test \| Universal Robots (UR)
Restructuring Cost and Reserve
Contingent consideration adjustment												7,800
System Test and Semiconductor Test
Restructuring Cost and Reserve
Severance benefit and charges											$ 8,700
Semiconductor Test, Industrial Automation and Corporate
Restructuring Cost and Reserve
Severance benefit and charges										2,900		$ 3,800
Semiconductor Test, Industrial Automation and Corporate \| Mobile Industrial Robots (MiR)
Restructuring Cost and Reserve
Contingent consideration adjustment										$ 22,200

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)Participant	Dec. 31, 2017USD ($)
Defined Benefit Plan Disclosure
Number of retiree participants \| Participant		1,700
Defined Benefit Plan, decrease in benefit obligation		$ 151,300
Defined Benefit Plan, decrease in plan assets		(151,300)
Gain (Loss) Due to Settlement		(300)
Fair value of pension plans assets totaled	$ 168,500
Transfer out of level 3		$ 2,700
United States Plans
Defined Benefit Plan Disclosure
Percentage of expected return on plan assets assumption	4.25%
Discount rate utilized to determine future pension obligations	3.10%	4.15%
Fair value of pension plans assets totaled	$ 166,900
U.S. Supplemental Executive Defined Benefit Pension Plan
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans	900	$ 2,600
Contribution to defined benefit pension plans in 2018	2,800
Non-United States Subsidiaries
Defined Benefit Plan Disclosure
Contribution to defined benefit pension plans		800
Contribution to defined benefit pension plans in 2018	1,000
Taiwan Defined Benefit Pension Plan
Defined Benefit Plan Disclosure
Fair value of pension plans assets totaled	1,600
UNITED STATES
Defined Benefit Plan Disclosure
Accumulated benefit obligation for defined benefit pension plans	$ 198,200	$ 172,800
Percentage of expected return on plan assets assumption	4.30%	4.30%	4.00%
Discount rate utilized to determine future pension obligations	3.00%	4.10%
Fair value of pension plans assets totaled	$ 166,932	$ 144,301	$ 324,506
Contribution to defined benefit pension plans	2,805	2,587
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Accumulated benefit obligation for defined benefit pension plans	$ 39,900	$ 35,600
Percentage of expected return on plan assets assumption	2.00%	1.50%	2.00%
Discount rate utilized to determine future pension obligations	1.10%	1.80%
Fair value of pension plans assets totaled	$ 1,586	$ 1,400	$ 1,307
Contribution to defined benefit pension plans	$ 923	$ 822

Schedule of Defined Benefit Pen

Schedule of Defined Benefit Pension and Postretirement Benefit Plan Assets and Obligation (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure
Actuarial (gain) loss	$ 7,700	$ (3,500)
Ending Balance	168,500		$ 168,500
UNITED STATES
Defined Benefit Plan Disclosure
Projected benefit obligation, Beginning of year			178,237	$ 363,026
Service cost			1,608	2,196	$ 2,239
Interest cost			7,189	8,940	13,151
Actuarial (gain) loss			24,447	(30,136)
Benefits paid			(7,690)	(14,793)
Retiree annuity purchase				(151,341)
Liability loss due to settlement				345
Projected benefit obligation, End of year	203,791	178,237	203,791	178,237	363,026
Beginning Balance			144,301	324,506
Company contributions			2,805	2,587
Actual return on plan assets			27,516	(16,658)
Benefits paid			(7,690)	(14,793)
Retiree annuity purchase				(151,341)
Ending Balance	166,932	144,301	166,932	144,301	324,506
Funded status	(36,859)	(33,936)	(36,859)	(33,936)
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Projected benefit obligation, Beginning of year			39,146	39,353
Service cost			751	786	818
Interest cost			691	687	852
Actuarial (gain) loss			4,520	773
Benefits paid			(836)	(741)
Non-U.S. currency movement			(320)	(1,712)
Projected benefit obligation, End of year	43,952	39,146	43,952	39,146	39,353
Beginning Balance			1,400	1,307
Company contributions			923	822
Actual return on plan assets			64	50
Benefits paid			(836)	(741)
Non-U.S. currency movement			35	(38)
Ending Balance	1,586	1,400	1,586	1,400	1,307
Funded status	(42,366)	(37,746)	(42,366)	(37,746)
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Projected benefit obligation, Beginning of year			9,256	6,177
Service cost			41	39	34
Interest cost			347	196	201
Actuarial (gain) loss			717	25
Benefits paid			(1,358)	(889)
Special termination benefits				3,708	591
Projected benefit obligation, End of year	9,003	9,256	9,003	9,256	$ 6,177
Company contributions			1,358	889
Benefits paid			(1,358)	(889)
Funded status	$ (9,003)	$ (9,256)	$ (9,003)	$ (9,256)

Schedule of Amounts Recorded wi

Schedule of Amounts Recorded within Statements of Financial Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure
Retirement plans assets	$ 18,457	$ 16,883
UNITED STATES
Defined Benefit Plan Disclosure
Retirement plans assets	18,457	16,883
Accrued employees' compensation and withholdings	(2,826)	(2,676)
Retirement plans liabilities	(52,490)	(48,143)
Funded status	(36,859)	(33,936)
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Accrued employees' compensation and withholdings	(922)	(852)
Retirement plans liabilities	(41,444)	(36,894)
Funded status	(42,366)	(37,746)
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Accrued employees' compensation and withholdings	(1,231)	(1,310)
Retirement plans liabilities	(7,772)	(7,946)
Funded status	$ (9,003)	$ (9,256)

Schedule of Amounts Recognized

Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
UNITED STATES
Defined Benefit Plan Disclosure
Deferred taxes related to prior service cost recognized in other comprehensive income	$ 560	$ 560
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Prior service cost, before tax	(58)	(249)
Deferred taxes	(1,684)	(1,641)
Deferred taxes related to prior service cost recognized in other comprehensive income	$ (1,742)	$ (1,890)

Schedule of Pension Plans with

Schedule of Pension Plans with Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
UNITED STATES
Defined Benefit Plan Disclosure
Projected benefit obligation	$ 55.3	$ 50.8
Accumulated benefit obligation	53.2	48.6
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Projected benefit obligation	44	39.1
Accumulated benefit obligation	39.9	35.6
Fair value of plan assets	$ 1.6	$ 1.4

Schedule of Net Periodic Pensio

Schedule of Net Periodic Pension and Postretirement (income) Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure
Net actuarial (gain) loss	$ 8,176	$ (3,316)	$ (6,624)
UNITED STATES
Defined Benefit Plan Disclosure
Service cost	1,608	2,196	2,239
Interest cost	7,189	8,940	13,151
Expected return on plan assets	(6,042)	(9,049)	(12,008)
Amortization of prior service cost		58	70
Net actuarial (gain) loss	2,973	(4,429)	(6,712)
Settlement loss		345
Total net periodic pension cost	5,728	(1,939)	(3,260)
Prior service cost		(58)	(70)
Total recognized in other comprehensive income		(58)	(70)
Total recognized in net periodic pension (income) cost and other comprehensive income	5,728	(1,997)	(3,330)
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Service cost	751	786	818
Interest cost	691	687	852
Expected return on plan assets	(29)	(19)	(165)
Net actuarial (gain) loss	4,485	743	(310)
Total net periodic pension cost	5,898	2,197	1,195
Total recognized in net periodic pension (income) cost and other comprehensive income	5,898	2,197	1,195
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	41	39	34
Interest cost	347	196	201
Amortization of prior service cost	(191)	(373)	(496)
Net actuarial (gain) loss	717	25	398
Special termination benefits		3,708	591
Total net periodic pension cost	914	3,595	728
Prior service cost	191	373	496
Total recognized in other comprehensive income	191	373	496
Total recognized in net periodic pension (income) cost and other comprehensive income	$ 1,105	$ 3,968	$ 1,224

Schedule of Weighted Average -

Schedule of Weighted Average - Assumptions to Determine Net Periodic Pension Cost (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017
UNITED STATES
Defined Benefit Plan Disclosure
Discount rate	4.10%	3.40%	3.90%
Expected return on plan assets	4.30%	4.30%	4.00%
Salary progression rate	2.50%	2.30%	2.60%
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Discount rate	1.80%	1.80%	1.80%
Expected return on plan assets	2.00%	1.50%	2.00%
Salary progression rate	2.50%	2.70%	2.70%
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Discount rate	4.00%	3.40%	3.90%
Initial health care cost trend rate				7.50%	7.90%	7.30%
Ultimate health care cost trend rate	4.50%	4.50%	4.50%	4.50%	4.50%	5.00%
Year in which ultimate health care cost trend rate is reached	2026	2026	2023

Schedule of Weighted Average As

Schedule of Weighted Average Assumptions to Determine Pension Obligations (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Discount rate	3.00%	4.00%	3.40%
Initial medical trend	7.10%	7.50%	7.90%
Ultimate health care trend	4.50%	4.50%	4.50%	4.50%	4.50%	5.00%
Medical cost trend rate decrease to ultimate rate in year	2026	2026	2026
UNITED STATES
Defined Benefit Plan Disclosure
Discount rate	3.00%	4.10%
Salary progression rate	2.60%	2.50%
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Discount rate	1.10%	1.80%
Salary progression rate	2.50%	2.60%

Schedule of Weighted Average Pe

Schedule of Weighted Average Pension Assets Allocations by Category (Detail)	Dec. 31, 2019	Dec. 31, 2018
UNITED STATES
Defined Benefit Plan Disclosure
Total	100.00%	100.00%
UNITED STATES \| Fixed income securities
Defined Benefit Plan Disclosure
Total	94.00%	94.00%
UNITED STATES \| Equity securities
Defined Benefit Plan Disclosure
Total	5.00%	5.00%
UNITED STATES \| Other than Securities Investment
Defined Benefit Plan Disclosure
Total	1.00%	1.00%
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Total	100.00%	100.00%
Foreign Pension Plans, Defined Benefit \| Other than Securities Investment
Defined Benefit Plan Disclosure
Total	100.00%	100.00%

Schedule of Target Assets Alloc

Schedule of Target Assets Allocation (Detail)	Dec. 31, 2019
Barclays Corporate or Better Index \| U.S. corporate fixed income
Defined Benefit Plan Disclosure
Target assets allocation percentage	75.00%
MSCI World Minimum Volatility Index \| Global equity Securities
Defined Benefit Plan Disclosure
Target assets allocation percentage	5.00%
Barclays Long Government Bond Index \| U.S. government fixed income
Defined Benefit Plan Disclosure
Target assets allocation percentage	14.00%
Barclays High Yield Index \| High yield fixed income
Defined Benefit Plan Disclosure
Target assets allocation percentage	5.00%
Citigroup Three Month Treasury Bill Index \| Cash
Defined Benefit Plan Disclosure
Target assets allocation percentage	1.00%

Schedule of Fair Value of Pensi

Schedule of Fair Value of Pensions Plan Assets by Asset Category (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure
Total	$ 168,500
UNITED STATES
Defined Benefit Plan Disclosure
Total	166,932	$ 144,301	$ 324,506
UNITED STATES \| Quoted Prices in Active Markets for Identical Instruments (Level 1)
Defined Benefit Plan Disclosure
Total	1,610	1,449
UNITED STATES \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure
Total	165,322	142,852
UNITED STATES \| Corporate Debt Securities
Defined Benefit Plan Disclosure
Total	133,792	115,424
UNITED STATES \| Corporate Debt Securities \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure
Total	133,792	115,424
UNITED STATES \| US Government Debt Securities
Defined Benefit Plan Disclosure
Total	23,186	20,176
UNITED STATES \| US Government Debt Securities \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure
Total	23,186	20,176
UNITED STATES \| Global equity Securities
Defined Benefit Plan Disclosure
Total	8,344	7,252
UNITED STATES \| Global equity Securities \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure
Total	8,344	7,252
UNITED STATES \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure
Total	1,610	1,449
UNITED STATES \| Cash and Cash Equivalents \| Quoted Prices in Active Markets for Identical Instruments (Level 1)
Defined Benefit Plan Disclosure
Total	1,610	1,449
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
Total	1,586	1,400	$ 1,307
Foreign Pension Plans, Defined Benefit \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure
Total	1,586	1,400
Foreign Pension Plans, Defined Benefit \| Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure
Total	1,586	1,400
Foreign Pension Plans, Defined Benefit \| Other \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure
Total	1,586	1,400
Foreign Pension Plans, Defined Benefit \| Other \| Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure
Total	$ 1,586	$ 1,400

Schedule of Defined Benefit Pla

Schedule of Defined Benefit Plans Disclosures (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure
Transfer out of Level 3		$ 2,700
Ending Balance	$ 168,500
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure
Interest and market value adjustments		59
Benefits paid		(40)
Other		(15)
Significant Unobservable Inputs (Level 3) \| Group Annuity Insurance Contracts
Defined Benefit Plan Disclosure
Beginning Balance	$ 0	3,166
Transfer out of Level 3		(2,658)
Purchases of retiree annuity insurance contracts		(512)
Ending Balance		$ 0

Schedule of Expected Future Ben

Schedule of Expected Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2019USD ($)
UNITED STATES
Defined Benefit Plan Disclosure
2020	$ 8,027
2021	8,416
2022	9,163
2023	9,785
2024	10,558
2025-2029	59,665
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure
2020	1,237
2021	985
2022	982
2023	1,258
2024	1,098
2025-2029	6,129
Postretirement Benefit Plans
Defined Benefit Plan Disclosure
2020	1,231
2021	1,171
2022	958
2023	789
2024	662
2025-2029	$ 1,965

Schedule of One Percent Point C

Schedule of One Percent Point Change in assumed Health Care Cost Trends Rate (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Defined Benefit Plan Disclosure
Effect of one percentage point increase on total service and interest cost components	$ 6
Effect of one percentage point increase on postretirement benefit obligations	139
Effect of one percentage point decrease on total service and interest cost components	(6)
Effect of one percentage point decrease on postretirement benefit obligations	$ (133)

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	1 Months Ended					12 Months Ended
	Jan. 31, 2020	Jul. 31, 2019	Jul. 31, 2018	Jan. 31, 2018	Jul. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award
Total shareholder return performance measurement period						3 years
Restricted stock unit awards granted						1,139,000	790,000	939,000
Weighted average grant date fair value of restricted stock units granted						$ 39.08	$ 45.99	$ 28.91
Stock price						$ 37.95	$ 47.70	$ 28.56
Tax benefit from compensation expense						$ 8,360,000	$ 12,036,000	$ 10,462,000
Total unrecognized expense related to non-vested restricted stock unit awards and stock options						$ 45,000,000
Unrecognized expense related to non-vested restricted stock unit awards and stock options expected to be recognized over weighted average period, in years						1 year 9 months 18 days
Maximum percent of shares allowed to purchase						10.00%
Fair market value						$ 25,000
Maximum number of shares allowed to purchase						6,000
Percentage of common stock price paid						85.00%
Common stock issued to employees		300,000	300,000	300,000	300,000	400,000
Value of common stock issued to employees per share		$ 40.72	$ 32.36	$ 35.59	$ 25.53	$ 57.96	$ 26.67
Number of shares available for grant						6,727,000	7,874,000	8,605,000	9,546,000
Stock Based Compensation Relating To Retirement Agreement						$ 37,897,000	$ 33,577,000	$ 34,097,000
Retirement Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Stock Based Compensation Relating To Retirement Agreement						2,100,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Cash received from employees, employee stock options exercises						3,700,000	1,000,000	6,800,000
Tax benefit from compensation expense						$ 2,000,000	$ 400,000	$ 2,500,000
Percentage of common stock price paid						100.00%
Stock Options \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Period of stock granted to employees and executive officers vest in equal installments						4 years
Stock Options \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Period of stock granted to employees and executive officers vest in equal installments						7 years
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted						1,139,000	790,000	939,000
Restricted Stock Units \| Employees
Share-based Compensation Arrangement by Share-based Payment Award
Period of stock granted to employees and executive officers vest in equal installments						4 years
Restricted Stock Units \| Director
Share-based Compensation Arrangement by Share-based Payment Award
Period of stock granted to employees and executive officers vest in equal installments						1 year
Percentage of awards vesting on the first anniversary of grant date						100.00%
TSR Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Total shareholder return performance measurement period						3 years
Share-based compensation arrangement by share-based payment award, description						capped at four times the grant date value for grants prior to 2019
Minimum age of retirement to be eligible for PRSUs						60 years
Minimum years of service for retirement to be eligible for PRSUs						10 years
Restricted stock unit awards granted						100,000	100,000	100,000
Weighted average grant date fair value of restricted stock units granted						$ 51.51	$ 54.85	$ 35.66
Stock price						37.95	47.70	28.56
TSR Performance-Based Restricted Stock Units \| Measurement Input, Expected Dividend Payment [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Estimated annual dividend amount per share						$ 0.36	$ 0.36	$ 0.28
TSR Performance-Based Restricted Stock Units \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of vesting of target shares upon performance achieved						200.00%
TSR Performance-Based Restricted Stock Units \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of vesting of target shares upon performance achieved						0.00%
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares available for grant						1,800,000
PBIT Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted						100,000	100,000	100,000
Weighted average grant date fair value of restricted stock units granted						$ 36.88	$ 46.62	$ 27.72
Service-Based Restricted Stock Units \| Employees
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted						800,000	600,000	800,000
Weighted average grant date fair value of restricted stock units granted						$ 37.65	$ 45.92	$ 28.19
Service-Based Restricted Stock Units \| Non Employee Directors And Certain Employees
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted						100,000	100,000	100,000
Weighted average grant date fair value of restricted stock units granted						$ 48.03	$ 35.81	$ 34.48
Service-Based Restricted Stock Units \| Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award
Restricted stock unit awards granted						100,000	100,000	100,000
Weighted average grant date fair value of restricted stock units granted						$ 10.64	$ 12.17	$ 7.13
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award
Common stock issued to employees	200,000

Schedule of Estimated Fair Valu

Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions (Detail) - TSR Performance-Based Restricted Stock Units	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Risk-free interest rate	2.60%	2.20%	1.50%
Expected historical volatility	31.90%	26.80%	26.60%
Dividend yield	1.00%	0.80%	1.00%
New York Stock Exchange Composite Index
Share-based Compensation Arrangement by Share-based Payment Award
Expected historical volatility	11.90%	12.40%	13.40%

Schedule of Estimated Fair Va_2

Schedule of Estimated Fair Value of Stock Options Grant Using Black Scholes Option Pricing Model (Detail) - Stock Options	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Expected life (years)	5 years	5 years	5 years
Risk-free interest rate	2.50%	2.40%	2.00%
Volatility-historical	30.10%	26.40%	27.80%
Dividend yield	1.00%	0.80%	1.00%

Schedule of Stock Compensation

Schedule of Stock Compensation Plan Activity (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Awarded	1,139	790	939
Forfeited	(87)	(128)	(109)
Outstanding at January 1	506	531	926
Granted	102	69	111
Exercised	(280)	(94)	(501)
Forfeited	(7)
Expired	(2)		(5)
Outstanding at December 31	319	506	531
Vested and expected to vest at December 31	319	506	531
Exercisable at December 31	85	256	233
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Non-vested at January 1	2,454	3,174	3,778
Awarded	1,139	790	939
Vested	(1,237)	(1,382)	(1,434)
Forfeited	(87)	(128)	(109)
Non-vested at December 31	2,269	2,454	3,174

Schedule of Share Based Compens

Schedule of Share Based Compensation Total Shares Available (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Available for grant at January 1	7,874	8,605	9,546
Options granted	(102)	(69)	(111)
Options forfeited	7
Restricted stock units awarded	(1,139)	(790)	(939)
Restricted stock units forfeited	87	128	109
Available for grant at December 31	6,727	7,874	8,605

Schedule of Weighted-Average Re

Schedule of Weighted-Average Restricted Stock Unit Award Fair Value (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Non-vested at January 1	$ 29.22	$ 21.71	$ 18.27
Awarded	39.08	45.99	28.91
Vested	23.59	20.20	17.90
Forfeited	35.60	24.67	20.35
Non-vested at December 31	$ 35.58	$ 29.22	$ 21.71

Schedule of Restricted Stock Un

Schedule of Restricted Stock Unit Awards Aggregate Intrinsic Value (Detail) - Restricted Stock Units - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Vested	$ 46,110	$ 63,688	$ 40,649
Outstanding	$ 154,752	$ 77,015	$ 132,875
Expected to vest	$ 152,374	$ 77,187	$ 130,594

Schedule of Restricted Stock _2

Schedule of Restricted Stock Units Weighted Average Remaining Contractual Terms (Detail) - Restricted Stock Units	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Outstanding	1 year 7 days	11 months 1 day	1 year
Expected to vest	1 year 7 days	10 months 28 days	11 months 26 days

Schedule of Weighted Average St

Schedule of Weighted Average Stock Options Exercise Price (Detail)	12 Months Ended
	Dec. 31, 2019$ / shares
Share-based Compensation Arrangement by Share-based Payment Award
Outstanding at January 1	$ 19.06
Options granted	37.95
Options exercised	13.20
Option forfeited	36.75
Option cancelled	1.48
Outstanding at December 31	29.91
Exercisable at December 31	$ 14.97

Schedule of Stock Option Aggreg

Schedule of Stock Option Aggregated Intrinsic Value Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Exercised	$ 9,232	$ 2,960	$ 8,035
Outstanding	12,218	7,359	14,831
Vested and expected to vest	7,701	7,359	14,831
Exercisable	$ 4,517	$ 5,905	$ 9,076

Schedule of Stock Options Weigh

Schedule of Stock Options Weighted Average Remaining Contractual Terms (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Outstanding	4 years 2 months 12 days	3 years 7 months 6 days	4 years 1 month 6 days
Vested and expected to vest	5 years	3 years 7 months 6 days	4 years 1 month 6 days
Exercisable	2 years 1 month 6 days	2 years 4 months 24 days	2 years 9 months 18 days

Stock Based Compensation (Detai

Stock Based Compensation (Detail) - USD ($) $ in Thousands	12 Months Ended
Stock Based Compensation (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 37,897	$ 33,577	$ 34,097
Income tax benefit	(8,360)	(12,036)	(10,462)
Total stock-based compensation expense after income taxes	29,537	21,541	23,635
Cost Of Revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	3,480	3,129	3,212
Engineering And Development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	9,913	9,181	9,370
Selling and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 24,504	$ 21,267	$ 21,515

Savings Plan - Additional Infor

Savings Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Savings Plan [Line Items]
Savings plan maximum percentage of employees contribution allowable	20.00%
Percentage of employer contributions vested per year	25.00%
Maximum employment period considered for vesting of employers' contribution, in years	4 years
Liability, Retirement and Postemployment Benefits	$ 32.7	$ 24.4
U.S. Qualified Pension Plan
Savings Plan [Line Items]
Maximum percentage of matching contributions made by the employer	100.00%	100.00%	100.00%
Percentage of employer match on employee contribution	4.00%	4.00%	4.00%
Savings Plan
Savings Plan [Line Items]
Amounts charged to statements of operations	$ 20.9	$ 19.4	$ 16.8

Schedule of Income (Loss) Befor

Schedule of Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

[1],[2]

Sep. 29, 2019

[3]

Jun. 30, 2019

[4]

Mar. 31, 2019

[5]

Dec. 31, 2018

[6],[7]

Sep. 30, 2018

[8]

Jul. 01, 2018

[9]

Apr. 01, 2018

[10]

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Income Tax Disclosure [Line Items]

U.S.

$ 192,442

$ 189,691

$ 76,699

Non-U.S.

333,330

278,110

447,713

Income before income taxes

$ 148,886

$ 151,733

$ 131,177

$ 93,979

$ 111,128

$ 140,841

$ 120,012

$ 95,820

$ 525,772

$ 467,801

$ 524,412

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

Schedule of Provision (Benefit)

Schedule of Provision (Benefit) for Income Taxes from Operations (Detail) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019	[1],[2]	Sep. 29, 2019	[3]	Jun. 30, 2019	[4]	Mar. 31, 2019	[5]	Dec. 31, 2018	[6],[7]	Sep. 30, 2018	[8]	Jul. 01, 2018	[9]	Apr. 01, 2018	[10]	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
Current, U.S. Federal																	$ 19,297	$ (59,122)	$ 162,679
Current, Non-U.S.																	52,810	45,083	64,313
Current, State																	(4,347)	1,721	2,623
Current, Total																	67,760	(12,318)	229,615
Deferred, U.S. Federal																	(4,522)	29,252	43,687
Deferred, Non-U.S.																	(8,007)	(1,243)	(6,476)
Deferred, State																	3,073	331	(106)
Deferred, Total																	(9,456)	28,340	37,105
Total provision (benefit) for income taxes	$ 23,811		$ 15,873		$ 33,780		$ (15,159)		$ (32,662)		$ 20,863		$ 18,975		$ 8,846		$ 58,304	$ 16,022	$ 266,720

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Teradyne recorded pension and post retirement net actuarial losses of $7.7 million for the fourth quarter in 2019. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[3]	Restructuring and other includes a $7.8 million gain for the decrease in the fair value of MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[4]	Restructuring and other includes a $11.7 million gain for the decrease in the fair value of the MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[5]	Restructuring and other includes a $3.0 million fair value adjustment to increase the MiR acquisition contingent consideration, $1.3 million of acquisition related expenses and compensation and $0.8 million of employee severance charges.
[6]	Restructuring and other includes a $17.7 million fair value adjustment to increase the MiR acquisition contingent consideration, $0.8 million of employee severance charges, and $0.5 million acquisition related expenses and compensation, partially offset by a $7.4 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[7]	Teradyne recorded pension and post retirement net actuarial gains of $3.5 million for the fourth quarter in 2018. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[8]	Restructuring and other includes $1.7 million of employee severance charges, $0.8 million of acquisition related expenses and compensation, partially offset by a $0.8 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[9]	Restructuring and other includes a $5.0 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $3.9 million of employee severance charges and $0.8 million of acquisition related expenses and compensation.
[10]	Restructuring and other includes a $3.5 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $2.5 million of acquisition related expenses and compensation and $2.4 million of employee severance charges.

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																	12 Months Ended
	Dec. 31, 2019		Sep. 29, 2019	[3]	Jun. 30, 2019	[4]	Mar. 31, 2019	[5]	Dec. 31, 2018		Sep. 30, 2018	[8]	Jul. 01, 2018	[9]	Apr. 01, 2018	[10]	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Total (benefit) provision for income taxes	$ 23,811	[1],[2]	$ 15,873		$ 33,780		$ (15,159)		$ (32,662)	[6],[7]	$ 20,863		$ 18,975		$ 8,846			$ 58,304	$ 16,022	$ 266,720
Effective tax rate																		11.10%	3.40%	50.90%
Provisional amount of additional income tax expense									49,500								$ 186,000
Transition tax on mandatory deemed repatriation of foreign earnings																			$ 51,700	$ 161,000
Expense related to remeasurement of deferred tax assets and liabilities																				33,600
Expense (benefit) associated with impact of correlative adjustments on tax positions																			2,200
Tax savings due to the tax holiday																		$ 15,100	$ 11,900	$ 24,800
Tax savings due to the tax holiday, per share																		$ 0.08	$ 0.06	$ 0.12
Tax holiday expiration date																		December 31, 2020
Valuation allowance includes net deferred tax assets	77,177								69,852									$ 77,177	$ 69,852
Tax credit carryforwards, approximately																	108,400			$ 108,400
Tax credits carryforwards	79,480								69,091									79,480	69,091
Reduction in un recognized tax benefits	21,180								43,395								36,263	21,180	43,395	36,263	$ 38,958
Unrecognized tax benefits, if recognized would impact effective tax rate	12,700																	12,700
Unrecognized tax benefits, if recognized would impact deferred taxes	8,500																	8,500
Accrued interest and penalties	1,400								300									1,400	300
Interest and penalties related to income tax, expense (benefit)																		1,100	$ 100	100
Intercompany Cost Sharing Arrangement [Member]
Income Taxes [Line Items]
Total (benefit) provision for income taxes																		6,300
United States
Income Taxes [Line Items]
Tax credits carryforwards, business																	2,100			$ 2,100
Tax credit carryforward, expiration date																				2028
State and Local Jurisdiction
Income Taxes [Line Items]
Provisional amount of additional income tax expense																	186,000
Transition tax on mandatory deemed repatriation of foreign earnings									$ 51,700
Expense (benefit) associated with impact of correlative adjustments on tax positions																				$ 10,300
Tax credits carryforwards																	106,300			$ 106,300
Reduction in un recognized tax benefits	$ 21,200																	$ 21,200
State and Local Jurisdiction \| Earliest Tax Year
Income Taxes [Line Items]
Tax credit carryforward, expiration date																				2020
State and Local Jurisdiction \| Latest Tax Year
Income Taxes [Line Items]
Tax credit carryforward, expiration date																				2039
State and Local Jurisdiction \| Do Not Expire
Income Taxes [Line Items]
Tax credits carryforwards																	$ 59,700			$ 59,700

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Teradyne recorded pension and post retirement net actuarial losses of $7.7 million for the fourth quarter in 2019. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[3]	Restructuring and other includes a $7.8 million gain for the decrease in the fair value of MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[4]	Restructuring and other includes a $11.7 million gain for the decrease in the fair value of the MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[5]	Restructuring and other includes a $3.0 million fair value adjustment to increase the MiR acquisition contingent consideration, $1.3 million of acquisition related expenses and compensation and $0.8 million of employee severance charges.
[6]	Restructuring and other includes a $17.7 million fair value adjustment to increase the MiR acquisition contingent consideration, $0.8 million of employee severance charges, and $0.5 million acquisition related expenses and compensation, partially offset by a $7.4 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[7]	Teradyne recorded pension and post retirement net actuarial gains of $3.5 million for the fourth quarter in 2018. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[8]	Restructuring and other includes $1.7 million of employee severance charges, $0.8 million of acquisition related expenses and compensation, partially offset by a $0.8 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[9]	Restructuring and other includes a $5.0 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $3.9 million of employee severance charges and $0.8 million of acquisition related expenses and compensation.
[10]	Restructuring and other includes a $3.5 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $2.5 million of acquisition related expenses and compensation and $2.4 million of employee severance charges.

Schedule of Reconciliation of E

Schedule of Reconciliation of Effective Tax Rate (Detail)	12 Months Ended
Schedule of Reconciliation of Effective Tax Rate (Detail)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
U.S. statutory federal tax rate	21.00%	21.00%	35.00%
U.S. global intangible low-taxed income	6.20%	0.30%
U.S. transition tax	1.90%	(10.50%)	28.70%
State income taxes, net of federal tax benefit	0.50%	0.10%	(0.40%)
Foreign tax credits	(5.90%)	(2.20%)	(2.20%)
Uncertain tax positions	(4.30%)	1.00%	1.70%
Foreign taxes	(4.00%)	(2.00%)	(16.30%)
U.S, foreign derived intangible income	(2.60%)	(1.80%)
U.S. research and development credit	(1.80%)	(2.20%)	(1.60%)
Equity compensation	(0.70%)	(1.20%)	(0.80%)
Impact of rate change on deferred taxs		0.30%	6.90%
Domestic production activities deduction			(0.30%)
Other, net	0.80%	0.60%	0.20%
Effective tax rate, Total	11.10%	3.40%	50.90%

Schedule of Components of Defer

Schedule of Components of Deferred Tax Assets Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Line Items]
Tax credits	$ 79,480	$ 69,091
Accruals	18,572	18,514
Pension liabilities	25,424	23,449
Inventory valuations	24,459	20,826
Deferred revenue	7,622	9,130
Equity compensation	7,042	7,190
Vacation accrual	4,768	4,772
Investment impairment	3,292
Net operating loss carryforwards	2,705	3,658
Marketable securities		962
Other	1,472	685
Gross deferred tax assets	174,836	158,277
Less: valuation allowance	(77,177)	(69,852)
Total deferred tax assets	97,659	88,425
Intangible assets	(18,238)	(14,028)
Depreciation	(16,705)	(24,211)
Marketable securities	(1,601)
Total deferred tax liabilities	(36,544)	(38,239)
Net deferred assets	$ 61,115	$ 50,186

Summary of Operating Loss Carry

Summary of Operating Loss Carryforwards (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
U.S. Federal Operating Loss Carryforwards	$ 554
State Operating Loss Carryforwards	28,728
Foreign Operating Loss Carryforwards		$ 4,296
2020
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	269
2021
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	2,141
2022
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	4,934
2023
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	4,342
2024
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	1,498
2025-2029
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	7,673
2030-2034
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	4,329
Foreign Operating Loss Carryforwards		15
Beyond 2034
Operating Loss Carryforwards [Line Items]
U.S. Federal Operating Loss Carryforwards	554
State Operating Loss Carryforwards	2,185
Foreign Operating Loss Carryforwards		74
Non-Expiring
Operating Loss Carryforwards [Line Items]
State Operating Loss Carryforwards	$ 1,357
Foreign Operating Loss Carryforwards		$ 4,207

Schedule of Unrecognized Tax Be

Schedule of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
Beginning balance, as of January 1	$ 43,395	$ 36,263	$ 38,958
Tax positions for current year, Additions	1,322	4,716	8,208
Tax positions for prior years, Additions	8,043	2,626	199
Tax positions for prior years, Reductions	(31,397)	(153)	(10,573)
Expiration of statutes, Reductions	(183)	(57)	(325)
Settlements with tax authorities, Reductions			(204)
Ending balance as of December 31	$ 21,180	$ 43,395	$ 36,263

Operating Segment, Geographic_3

Operating Segment, Geographic and Significant Customer Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019CustomerSegment	Dec. 31, 2018Customer	Dec. 31, 2017
Segment Reporting Information [Line Items]
Operating segments \| Segment	4
Number of customer accounted for more than ten percent of consolidated revenue \| Customer	0	0
Consolidated Revenue
Segment Reporting Information [Line Items]
Concentration risk, percentage	10.00%	10.00%
Semiconductor Test \| Consolidated Revenue \| Customer Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	10.00%	13.00%	22.00%
Semiconductor Test \| Customer 1 \| Consolidated Revenue \| Revenue from Rights Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage	11.00%	4.00%
Semiconductor Test \| Customer 2 \| Consolidated Revenue \| Revenue from Rights Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, percentage			13.00%

Schedule of Segment Information

Schedule of Segment Information (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	[2]	$ 2,294,965	[1]	$ 2,100,802	[1]	$ 2,136,606
Income (loss) before taxes	[3],[4]	525,772		467,801		524,411
Total assets	[5]	2,787,014		2,706,606		3,109,545
Property additions		134,642		114,379		105,375
Depreciation and amortization expense		120,655		113,224		108,075
Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		1,552,571		1,492,417		1,662,549
Income (loss) before taxes	[3],[4]	416,973		397,645		491,361
Total assets	[5]	784,808		669,452		597,480
Property additions		112,145		94,496		87,920
Depreciation and amortization expense		59,197		58,095		58,901
System Test
Segment Reporting Information [Line Items]
Revenues		287,455	[1]	216,132	[1]	192,135
Income (loss) before taxes	[3],[4]	93,543		48,857		10,305
Total assets	[5]	131,428		88,098		97,018
Property additions		3,059		3,469		5,976
Depreciation and amortization expense		5,518		6,430		6,646
Industrial Automation
Segment Reporting Information [Line Items]
Revenues		298,139		261,452		170,056
Income (loss) before taxes	[3],[4]	(5,916)		7,670		8,763
Total assets	[5]	671,559		607,502		368,037
Property additions		9,076		11,188		7,044
Depreciation and amortization expense		40,904		36,755		25,711
Wireless Test
Segment Reporting Information [Line Items]
Revenues		157,315	[1]	132,006	[1]	111,866
Income (loss) before taxes	[3],[4]	35,585		29,052		17,350
Total assets	[5]	97,299		77,570		59,912
Property additions		10,362		5,226		4,435
Depreciation and amortization expense		5,365		5,328		5,392
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues		(515)		(1,205)
Income (loss) before taxes	[3],[4]	(14,413)		(15,423)		(3,368)
Total assets	[5]	1,101,920		1,263,984		1,987,098
Depreciation and amortization expense		$ 9,671		$ 6,616		$ 11,425

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Revenues attributable to a country are based on location of customer site.
[3]	Included in Corporate and Other are: contingent consideration adjustments, investment impairment, pension and postretirement plans actuarial gains (losses), severance charges, property insurance recovery related to the Japan earthquake, interest income, interest expense, net foreign exchange gains (losses), intercompany eliminations and acquisition related charges.
[4]	Included in income (loss) before taxes are charges and credits related to restructuring and other, and inventory charges. In 2016, loss before income taxes in Wireless Test also included charges related to goodwill and acquired intangible assets impairment.
[5]	Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.

Schedule of Segment Reporting I

Schedule of Segment Reporting Information by Segment Charges (Detail) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Acquisition related costs	$ 200		$ 800	$ 500	$ 1,300	$ 500	$ 800	$ 800	$ 2,500
Restructuring and other-employee severance	(2,088)	$ (6,500)		(10,404)	5,112	11,446	$ 1,710	2,389	(313)	$ (13,880)	$ 15,232	$ 9,362
Contingent consideration adjustment										(19,257)	987	7,820
Investment of impairment charge	15,000									15,000
Universal Robots (UR)
Segment Reporting Information [Line Items]
Contingent consideration adjustment				$ 11,700	$ 3,000	7,400		$ 5,000	$ 3,500	3,800	16,700
Mobile Industrial Robots (MiR)
Segment Reporting Information [Line Items]
Contingent consideration adjustment	5,800					$ 17,700					17,700
Autoguide LLC [Member]
Segment Reporting Information [Line Items]
Contingent consideration adjustment	$ 3,000									3,000
Semiconductor Test
Segment Reporting Information [Line Items]
Acquisition related costs										2,500	4,500
Cost of revenues-inventory charge										1,277	8,429	1,779
Restructuring and other-employee severance										8,731
Semiconductor Test \| Fixed Assets [Member]
Segment Reporting Information [Line Items]
Restructuring and other-employee severance												1,124
Semiconductor Test \| Severance And Benefits
Segment Reporting Information [Line Items]
Restructuring and other-employee severance											6,822	4,606
System Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge										2,000	1,175	1,918
Industrial Automation
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge										508	680
Restructuring and other-employee severance										796	0	1,414
Industrial Automation \| Restructuring and other
Segment Reporting Information [Line Items]
Acquisition related costs										741	1,163
Industrial Automation \| Severance And Benefits
Segment Reporting Information [Line Items]
Restructuring and other-employee severance												0
Wireless Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge										4,005	2,565	2,190
Restructuring and other-lease impairment												972
Corporate And Eliminations
Segment Reporting Information [Line Items]
Selling and administrative – equity modification charge										2,108
Corporate And Eliminations \| Restructuring and other
Segment Reporting Information [Line Items]
Acquisition related costs										1,765	3,422
Property insurance recovery												(5,064)
Investment of impairment charge										15,000
Corporate And Eliminations \| Universal Robots (UR) \| Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment											(16,679)	$ 7,820
Corporate And Eliminations \| Mobile Industrial Robots (MiR) \| Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment										(22,199)	$ 17,666
Corporate And Eliminations \| Autoguide LLC [Member] \| Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment										$ 2,976

Schedule of Revenues by Country

Schedule of Revenues by Country (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	$ 2,294,965	[1]	$ 2,100,802	[1]	$ 2,136,606
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	514,327		348,942		260,451
TAIWAN
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	485,681		516,322		687,031
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	333,059		282,869		252,516
KOREA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	239,504		163,224		206,819
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	219,015		223,207		163,715
JAPAN
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	175,322		158,281		169,093
THAILAND
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	87,503		59,184		29,566
SINGAPORE
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	84,111		108,618		101,085
MALAYSIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	58,200		122,797		124,048
PHILIPPINES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	54,560		77,996		105,850
Rest Of The World
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from unaffiliated customers	[2]	$ 43,683		$ 39,362		$ 36,432

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Revenues attributable to a country are based on location of customer site.

Schedule of Long-Lived Assets b

Schedule of Long-Lived Assets by Geographic Area (Detail) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets		$ 377,755	$ 279,821
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets		252,812	209,368
Foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	[1]	$ 124,943	$ 70,453

[1]	As of December 31, 2019 and 2018, long-lived assets attributable to Singapore were $__ million and $19.4 million, respectively.

Schedule of Long-Lived Assets_2

Schedule of Long-Lived Assets by Geographic Area (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 377,755	$ 279,821
SINGAPORE
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 35,200	$ 19,400

Stock Repurchase Program - Addi

Stock Repurchase Program - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2020	Jan. 31, 2019	Jan. 31, 2018
Stock Repurchase Programs [Line Items]
Stock repurchase program, authorized amount				$ 500,000,000
Cumulative repurchases, value	$ 491,202,000	$ 832,356,000	$ 200,304,000
Cumulative repurchases, shares	32.5	21.6	5.8		1	10.9
Cumulative repurchases, value	$ 1,323,000,000	$ 823,500,000	$ 200,000,000		$ 250,000,000
Common stock average price	$ 40.68	$ 38.06	$ 34.30	$ 45.89
Maximum [Member] \| Scenario, Plan [Member]
Stock Repurchase Programs [Line Items]
Stock repurchase program, authorized amount							$ 1,500,000,000
Cumulative repurchases, value	$ 500,000,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2019	Dec. 31, 2019	Dec. 31, 2019	Feb. 28, 2020	Jun. 03, 2019
Subsequent Event [Line Items]
Cash Dividends payable, amount per share	$ 0.10
Cash Dividends payable, date to be paid	Mar. 20, 2020
Cash Dividends payable, record date	Feb. 21, 2020
Investment impairment		$ 15,000,000	$ 15,000,000
Real War In [Member]
Subsequent Event [Line Items]
Equity method investments		$ 0	$ 0		$ 15,000,000
Subsequent Event \| Real War In [Member]
Subsequent Event [Line Items]
Repayment of debt demanded				$ 25,000,000

Consolidated Quarterly Statemen

Consolidated Quarterly Statements of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																	12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019	Sep. 29, 2019	[3]	Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018		Jul. 01, 2018		Apr. 01, 2018		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information [Line Items]
Total revenues	$ 654,650	[1],[2]		$ 582,038		$ 564,178	[4]	$ 494,099	[5]	$ 519,558	[6],[7]	$ 566,848	[8]	$ 526,929	[9]	$ 487,467	[10]
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	271,412	[1],[2]		237,000		240,260	[4]	206,464	[5]	210,023	[6],[7]	233,155	[8]	219,595	[9]	217,635	[10]	$ 955,136	$ 880,408	$ 915,153
Gross profit	383,238	[1],[2]		345,038		323,918	[4]	287,635	[5]	309,535	[6],[7]	333,693	[8]	307,334	[9]	269,832	[10]	1,339,829	1,220,394	1,221,453
Selling and administrative	117,092	[1],[2]		109,166		108,811	[4]	102,013	[5]	100,552	[6],[7]	100,202	[8]	99,410	[9]	90,505	[10]	437,084	390,669	348,913
Engineering and development	86,794	[1],[2]		77,804		81,434	[4]	76,791	[5]	74,706	[6],[7]	77,049	[8]	75,342	[9]	74,408	[10]	322,824	301,505	307,305
Acquired intangible assets amortization	9,784	[1],[2]		9,647		10,083	[4]	10,634	[5]	10,558	[6],[7]	11,142	[8]	9,793	[9]	7,698	[10]	40,147	39,191	30,530
Restructuring and other	(2,088)		$ (6,500)			(10,404)		5,112		11,446		1,710		2,389		(313)		(13,880)	15,232	9,362
Total operating expenses	211,582	[1],[2]		190,117		189,924	[4]	194,550	[5]	197,262	[6],[7]	190,103	[8]	186,934	[9]	172,298	[10]	786,175	746,597	696,110
Income from operations	171,656	[1],[2]		154,921		133,994	[4]	93,085	[5]	112,273	[6],[7]	143,590	[8]	120,400	[9]	97,534	[10]	553,654	473,797	525,343
Interest income	(6,145)	[1],[2]		(5,159)		(5,430)	[4]	(8,052)	[5]	(9,083)	[6],[7]	(6,213)	[8]	(5,427)	[9]	(5,981)	[10]	(24,785)	(26,704)	(17,805)
Interest expense	5,950	[1],[2]		5,682		5,800	[4]	5,713	[5]	13,182	[6],[7]	5,557	[8]	5,639	[9]	6,890	[10]	23,145	31,269	21,663
Other (income) expense, net	22,965	[1],[2]		2,665		2,447	[4]	1,445	[5]	(2,954)	[6],[7]	3,405	[8]	176	[9]	805	[10]	29,522	1,431	(2,927)
Income before income taxes	148,886	[1],[2]		151,733		131,177	[4]	93,979	[5]	111,128	[6],[7]	140,841	[8]	120,012	[9]	95,820	[10]	525,772	467,801	524,412
Income tax (benefit) provision	23,811	[1],[2]		15,873		33,780	[4]	(15,159)	[5]	(32,662)	[6],[7]	20,863	[8]	18,975	[9]	8,846	[10]	58,304	16,022	266,720
Net income	$ 125,075	[1],[2]		$ 135,860		$ 97,397	[4]	$ 109,138	[5]	$ 143,790	[6],[7]	$ 119,978	[8]	$ 101,037	[9]	$ 86,974	[10]	$ 467,468	$ 451,779	$ 257,692
Net income per common share—basic	$ 0.75	[1],[2]		$ 0.80		$ 0.57	[4]	$ 0.63	[5]	$ 0.80	[6],[7]	$ 0.65	[8]	$ 0.53	[9]	$ 0.45	[10]	$ 2.74	$ 2.41	$ 1.30
Net income per common share—diluted	0.69	[1],[2]		0.75		0.55	[4]	0.62	[5]	0.79	[6],[7]	0.63	[8]	0.52	[9]	0.43	[10]	2.60	2.35	1.28
Cash dividend declared per common share	$ 0.09	[1],[2]		$ 0.09		$ 0.09	[4]	$ 0.09	[5]	$ 0.09	[6],[7]	$ 0.09	[8]	$ 0.09	[9]	$ 0.09	[10]	$ 0.36	$ 0.36	$ 0.28
Product [Member]
Quarterly Financial Information [Line Items]
Total revenues	$ 548,552	[1],[2]		$ 488,170		$ 457,511	[4]	$ 393,442	[5]	$ 420,652	[6],[7]	$ 470,994	[8]	$ 434,051	[9]	$ 403,925	[10]
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	226,184	[1],[2]		197,196		193,299	[4]	165,368	[5]	170,064	[6],[7]	195,339	[8]	180,777	[9]	180,958	[10]	$ 782,047	$ 727,138	$ 760,967
Service [Member]
Quarterly Financial Information [Line Items]
Total revenues	106,098	[1],[2]		93,868		106,667	[4]	100,657	[5]	98,906	[6],[7]	95,854	[8]	92,878	[9]	83,542	[10]
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)	$ 45,228	[1],[2]		$ 39,804		$ 46,961	[4]	$ 41,096	[5]	$ 39,959	[6],[7]	$ 37,816	[8]	$ 38,818	[9]	$ 36,677	[10]	$ 173,089	$ 153,270	$ 154,186

[1]	Restructuring and other includes a $5.8 million gain for the decrease in the fair value adjustment to the MiR acquisition contingent consideration, partially offset by a $3.0 million fair value adjustment to increase the AutoGuide acquisition contingent consideration, $0.5 million of employee severance charges and $0.2 million of acquisition related expenses and compensation.
[2]	Teradyne recorded pension and post retirement net actuarial losses of $7.7 million for the fourth quarter in 2019. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[3]	Restructuring and other includes a $7.8 million gain for the decrease in the fair value of MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[4]	Restructuring and other includes a $11.7 million gain for the decrease in the fair value of the MiR contingent consideration liability, partially offset by $0.8 million of employee severance charges and $0.5 million of acquisition related expenses and compensation.
[5]	Restructuring and other includes a $3.0 million fair value adjustment to increase the MiR acquisition contingent consideration, $1.3 million of acquisition related expenses and compensation and $0.8 million of employee severance charges.
[6]	Restructuring and other includes a $17.7 million fair value adjustment to increase the MiR acquisition contingent consideration, $0.8 million of employee severance charges, and $0.5 million acquisition related expenses and compensation, partially offset by a $7.4 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[7]	Teradyne recorded pension and post retirement net actuarial gains of $3.5 million for the fourth quarter in 2018. See Note B: “Accounting Policies” for a discussion of Teradyne’s accounting policy.
[8]	Restructuring and other includes $1.7 million of employee severance charges, $0.8 million of acquisition related expenses and compensation, partially offset by a $0.8 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability.
[9]	Restructuring and other includes a $5.0 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $3.9 million of employee severance charges and $0.8 million of acquisition related expenses and compensation.
[10]	Restructuring and other includes a $3.5 million gain for the decrease in the fair value of the Universal Robots contingent consideration liability, partially offset by $2.5 million of acquisition related expenses and compensation and $2.4 million of employee severance charges.

Consolidated Quarterly Statem_2

Consolidated Quarterly Statements of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information [Line Items]
Contingent consideration fair value adjustment										$ (19,257)	$ 987	$ 7,820
Severance benefit and charges	$ 500		$ 7,800	$ 800	$ 800	$ 800		$ 3,900	$ 2,400
Acquisition related expense and compensation	200		800	500	1,300	500	$ 800	800	2,500
Pension and post retirement net actuarial gains (losses)	(7,700)					3,500
Investment impairment	15,000									15,000
Universal Robots (UR)
Quarterly Financial Information [Line Items]
Contingent consideration fair value adjustment				$ 11,700	$ 3,000	7,400		$ 5,000	$ 3,500	3,800	16,700
Severance benefit and charges		$ 1,700	$ 500				$ 800
Mobile Industrial Robots (MiR)
Quarterly Financial Information [Line Items]
Contingent consideration fair value adjustment	5,800					$ 17,700					$ 17,700
Autoguide LLC [Member]
Quarterly Financial Information [Line Items]
Contingent consideration fair value adjustment	$ 3,000									$ 3,000

Valuation and Qualifying Acco_2

Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 1,673	$ 2,219	$ 2,356
Additions Charged to Cost and Expenses		87		4
Other		28	20
Deductions		52	566	141
Balance at End of Period	$ 1,673	1,736	1,673	2,219
Inventory Reserve
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		100,779	102,896	116,016
Additions Charged to Cost and Expenses		15,244	11,242	8,844
Other		(85)	368	(126)
Deductions			13,727	21,838
Balance at End of Period	100,779	103,556	100,779	102,896
Valuation Allowance of Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	63,919	69,852	63,919	48,369
Additions Charged to Cost and Expenses		7,325	6,333	15,571
Deductions	400			21
Balance at End of Period	$ 69,852	$ 77,177	$ 69,852	$ 63,919