Ambarella (AMBA) 10-K27 Mar 202020 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Jan. 31, 2020	Mar. 23, 2020	Jul. 31, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jan. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	AMBA
Entity Registrant Name	AMBARELLA, INC.
Entity Central Index Key	0001280263
Current Fiscal Year End Date	--01-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		34,208,549
Entity Public Float			$ 1.4
Entity File Number	001-35667
Entity Tax Identification Number	98-0459628
Entity Address, Address Line One	3101 Jay Street
Entity Address, City or Town	Santa Clara
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95054
City Area Code	408
Local Phone Number	734-8888
Entity Incorporation, State or Country Code	E9
Title of 12(b) Security	Ordinary Shares, $0.00045 Par Value Per Share
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Certain information is incorporated into Part III of this report by reference to the Proxy Statement for the Registrant’s annual meeting of shareholders to be held on or about June 4, 2020 to be filed with the Securities and Exchange Commission pursuant to Regulation 14A not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Current assets:
Cash and cash equivalents	$ 231,403	$ 194,047
Marketable debt securities	173,345	164,861
Accounts receivable, net	18,487	26,212
Inventories	22,971	18,252
Restricted cash	9	11
Prepaid expenses and other current assets	4,975	6,206
Total current assets	451,190	409,589
Property and equipment, net	5,614	6,728
Deferred tax assets, non-current	10,400	10,587
Intangible assets, net	17,826	10,936
Operating lease right-of-use assets, net	9,935	0
Goodwill	26,601	26,601
Other non-current assets	5,710	2,412
Total assets	527,276	466,853
Current liabilities:
Accounts payable	14,910	12,801
Accrued and other current liabilities	34,970	24,700
Operating lease liabilities, current	2,181	0
Income taxes payable	691	993
Deferred revenue, current	701	529
Total current liabilities	53,453	39,023
Operating lease liabilities, non-current	7,975	0
Other long-term liabilities	17,776	8,341
Total liabilities	79,204	47,364
Commitments and contingencies (Note 14)	0	0
Shareholders' equity:
Preference shares, $0.00045 par value per share, 20,000,000 shares authorized and no shares issued and outstanding at January 31, 2020 and January 31, 2019, respectively	0	0
Ordinary shares, $0.00045 par value per share, 200,000,000 shares authorized at January 31, 2020 and January 31, 2019, respectively; 33,805,609 shares issued and outstanding at January 31, 2020; 32,303,540 shares issued and outstanding at January 31, 2019	15	15
Additional paid-in capital	261,220	188,516
Accumulated other comprehensive income	768	97
Retained earnings	186,069	230,861
Total shareholders’ equity	448,072	419,489
Total liabilities and shareholders' equity	$ 527,276	$ 466,853

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jan. 31, 2020	Jan. 31, 2019
Statement Of Financial Position [Abstract]
Preference shares, par value	$ 0.00045	$ 0.00045
Preference shares, shares authorized	20,000,000	20,000,000
Preference shares, shares issued	0	0
Preference shares, shares outstanding	0	0
Ordinary shares, par value	$ 0.00045	$ 0.00045
Ordinary shares, shares authorized	200,000,000	200,000,000
Ordinary shares, shares issued	33,805,609	32,303,540
Ordinary shares, shares outstanding	33,805,609	32,303,540

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Income Statement [Abstract]
Revenue	$ 228,732	$ 227,768	$ 295,402
Cost of revenue	96,023	89,624	107,669
Gross profit	132,709	138,144	187,733
Operating expenses:
Research and development	129,724	128,084	115,510
Selling, general and administrative	52,634	50,480	47,792
Total operating expenses	182,358	178,564	163,302
Income (loss) from operations	(49,649)	(40,420)	24,431
Other income, net	8,021	5,868	1,298
Income (loss) before income taxes	(41,628)	(34,552)	25,729
Provision (benefit) for income taxes	3,164	(4,105)	6,877
Net income (loss)	$ (44,792)	$ (30,447)	$ 18,852
Net income (loss) per share attributable to ordinary shareholders:
Basic	$ (1.35)	$ (0.93)	$ 0.57
Diluted	$ (1.35)	$ (0.93)	$ 0.55
Weighted-average shares used to compute net income (loss) per share attributable to ordinary shareholders:
Basic	33,083,562	32,713,606	33,224,803
Diluted	33,083,562	32,713,606	34,583,150

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (44,792)	$ (30,447)	$ 18,852
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) on investments	671	376	(209)
Other comprehensive income (loss), net of tax	671	376	(209)
Comprehensive income (loss)	$ (44,121)	$ (30,071)	$ 18,643

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Outstanding Ordinary Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Beginning Balance, Amount at Jan. 31, 2017	$ 454,634	$ 15	$ 212,276	$ (70)	$ 242,413
Beginning Balance, Shares at Jan. 31, 2017		33,369,032
Exercise of stock options, Amount	$ 2,191	$ 0	2,191	0	0
Exercise of stock options, Shares	175,187	175,187
Vesting of restricted stock units, Amount	$ 0	$ 0	0	0	0
Vesting of restricted stock units, Shares		932,454
Employee stock purchase plan, Amount	4,646	$ 0	4,646	0	0
Employee stock purchase plan, Shares		107,736
Stock repurchase, Amount	(54,788)	$ 0	(54,788)	0	0
Stock repurchase, Shares		(1,094,795)
Stock-based compensation expense related to stock awards granted to employees and consultants	56,861	$ 0	56,861	0	0
Net unrealized gains (losses) on investments - net of taxes	(209)	0	0	(209)	0
Net income (loss)	18,852	0	0	0	18,852
Ending Balance, Amount at Jan. 31, 2018	482,187	$ 15	221,186	(279)	261,265
Ending Balance, Shares at Jan. 31, 2018		33,489,614
Cumulative Effect of Change in Accounting Principle	43	$ 0	0	0	43
Exercise of stock options, Amount	$ 1,285	$ 0	1,285	0	0
Exercise of stock options, Shares	232,205	232,205
Vesting of restricted stock units, Amount	$ 0	$ 0	0	0	0
Vesting of restricted stock units, Shares		920,826
Employee stock purchase plan, Amount	5,136	$ 0	5,136	0	0
Employee stock purchase plan, Shares		146,887
Stock repurchase, Amount	(99,903)	$ 0	(99,903)	0	0
Stock repurchase, Shares		(2,485,992)
Stock-based compensation expense related to stock awards granted to employees and consultants	60,812	$ 0	60,812	0	0
Net unrealized gains (losses) on investments - net of taxes	376	0	0	376	0
Net income (loss)	(30,447)	0	0	0	(30,447)
Ending Balance, Amount at Jan. 31, 2019	$ 419,489	$ 15	188,516	97	230,861
Ending Balance, Shares at Jan. 31, 2019	32,303,540	32,303,540
Exercise of stock options, Amount	$ 5,695	$ 0	5,695	0	0
Exercise of stock options, Shares	366,886	366,886
Vesting of restricted stock units, Amount	$ 0	$ 0	0	0	0
Vesting of restricted stock units, Shares		957,319
Employee stock purchase plan, Amount	$ 5,967	$ 0	5,967	0	0
Employee stock purchase plan, Shares		177,864
Stock repurchase, Shares	0
Stock-based compensation expense related to stock awards granted to employees and consultants	$ 61,042	$ 0	61,042	0	0
Net unrealized gains (losses) on investments - net of taxes	671	0	0	671	0
Net income (loss)	(44,792)	0	0	0	(44,792)
Ending Balance, Amount at Jan. 31, 2020	$ 448,072	$ 15	$ 261,220	$ 768	$ 186,069
Ending Balance, Shares at Jan. 31, 2020	33,805,609	33,805,609

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ (44,792)	$ (30,447)	$ 18,852
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	11,631	7,221	4,770
Amortization/accretion of marketable debt securities	(969)	(670)	172
Stock-based compensation	66,871	60,812	56,861
Deferred income taxes	187	(6,945)	2,092
Other non-cash items, net	(71)	350	165
Changes in operating assets and liabilities:
Accounts receivable	7,725	5,082	7,302
Inventories	(4,719)	5,131	(3,238)
Prepaid expenses and other current assets	1,057	(2,202)	379
Other non-current assets	(3,298)	(155)	(33)
Accounts payable	2,109	(7,014)	(140)
Accrued liabilities	5,079	(8,302)	1,430
Income taxes payable	(302)	57	368
Deferred revenue	172	265	(7,026)
Lease liabilities	(2,851)	0	0
Other long-term liabilities	1,585	1,289	3,450
Net cash provided by operating activities	39,414	24,472	85,404
Cash flows from investing activities:
Purchase of investments	(225,913)	(207,841)	(74,863)
Sales of investments	96,363	66,211	10,900
Maturities of investments	122,795	65,428	58,050
Purchase of property and equipment	(1,821)	(2,940)	(3,687)
Net cash used in investing activities	(8,576)	(79,142)	(9,600)
Cash flows from financing activities:
Proceeds from exercise of stock options and employee stock purchase plan	11,960	6,686	7,091
Stock repurchase	0	(99,904)	(54,788)
Payment for intangible assets	(5,444)	(4,735)	(4,306)
Net cash provided by (used in) financing activities	6,516	(97,953)	(52,003)
Net increase (decrease) in cash, cash equivalents and restricted cash	37,354	(152,623)	23,801
Cash, cash equivalents and restricted cash at beginning of period	194,058	346,681	322,880
Cash, cash equivalents and restricted cash at end of period	231,412	194,058	346,681
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1,811	1,409	845
Supplemental disclosure of noncash investing activities:
Unpaid liabilities related to intangible and fixed assets purchases	$ 12,284	$ 933	$ 9,008

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	12 Months Ended
Organization and Summary of Significant Accounting Policies	Jan. 31, 2020
Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	1. Organization and Summary of Significant Accounting Policies Organization Ambarella, Inc. (the “Company”) was incorporated in the Cayman Islands on January 15, 2004. The Company is a leading developer of low-power semiconductor solutions offering high-definition (HD) and Ultra HD compression, image processing, and deep neural network processing. The Company combines its processor design capabilities with its expertise in video and image processing, algorithms and software to provide a technology platform that is designed to be easily scalable across multiple applications and enable rapid and efficient product development. The Company’s system-on-a-chip, or SoC, designs fully integrate high-definition video processing, image processing, artificial intelligence (AI) computer vision algorithms, audio processing and system functions onto a single chip, delivering exceptional video and image quality, differentiated functionality and low power consumption. The Company is currently addressing a broad range of human and computer vision applications, including professional and consumer security cameras, automotive cameras such as advanced driver assistance systems (ADAS), electronic mirrors, drive recorders, driver/cabin monitoring systems, autonomous driving, and industrial and robotic applications. The Company sells its solutions to leading original design manufacturers, or ODMs, and original equipment manufacturers, or OEMs, globally. Basis of Consolidation The Company’s fiscal year ends on January 31. The consolidated financial statements of the Company and its subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”). All intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expense during the reported periods. Actual results could differ from those estimates. On an ongoing basis, management evaluates its estimates and assumptions, including those related to (i) the collectability of accounts receivable; (ii) write down of excess and obsolete inventories; (iii) intangible assets and goodwill; (iv) the estimated useful lives of long-lived assets; (v) impairment of long-lived assets and financial instruments; (vi) warranty obligations; (vii) the valuation of stock-based compensation awards and financial instruments; (viii) the probability of performance objectives achievement; (ix) the realization of tax assets and estimates of tax liabilities, including reserves for uncertain tax positions; and (x) the recognition and disclosure of contingent liabilities. These estimates and assumptions are based on historical experience and on various other factors which the Company believes to be reasonable under the circumstances. The Company may engage third-party valuation specialists to assist with estimates related to the valuation of financial instruments, assets and stock awards associated with various contractual arrangements. Such estimates often require the selection of appropriate valuation methodologies and significant judgment. Actual results could differ from these estimates under different assumptions or circumstances and such differences could be material. Concentration of Risk The Company’s products are manufactured, assembled and tested by third-party contractors located primarily in Asia. The Company does not have long-term agreements with these contractors. A significant disruption in the operations of one or more of these contractors would impact the production of the Company’s products which could have a material adverse effect on its business, financial condition and results of operations. A substantial portion of the Company’s revenue is derived from sales through one of its distributors, Wintech Microelectronics Co., Ltd., or Wintech, which serves as its non-exclusive sales representative in Asia other than Japan, and directly to one ODM customer, Chicony Electronics Co., Ltd., or Chicony. Termination of the relationships with these customers could result in a temporary or permanent loss of revenue. Furthermore, any credit issues from these customers could impair their abilities to make timely payment to the Company. See Note 15 for additional information regarding revenue and credit concentration with these customers. Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable debt securities and accounts receivable. The Company maintains its cash primarily in checking accounts with reputable financial institutions. Cash deposits held with these financial institutions may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses on deposits of its cash. In order to limit the exposure of each investment, the cash equivalents and marketable debt securities consist primarily of money market funds, certificates of deposit, asset-backed securities, commercial paper, U.S. government securities and debt securities of corporations which management assesses to be highly liquid. The Company does not hold or issue financial instruments for trading purposes. The Company performs ongoing credit evaluation of its customers and adjusts credit limits based upon payment history and customers’ credit worthiness. The Company regularly monitors collections and payments from its customers. Foreign Currency Transactions The U.S. dollar is the functional currency for the Company and its subsidiaries. Monetary assets and liabilities denominated in non-U.S. currencies are re-measured to U.S. dollars using current exchange rates in effect at the balance sheet date. Nonmonetary assets and liabilities are re-measured to U.S. dollars using historical exchange rates. Monetary and other accounts are re-measured to U.S. dollars using average exchange rates in effect during each period. Gains or losses from foreign currency re-measurement are included in other income, net in the consolidated statements of operations, and, to date, have not been material. Fair Value of Financial Instruments Fair value accounting is applied to all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed in the financial statements on a recurring basis. The carrying amounts reflected in the consolidated balance sheets for cash equivalents, accounts receivable, accounts payable, accrued liabilities and other current liabilities, approximate fair value due to the short-term nature. Cash Equivalents and Marketable Debt Securities The Company considers all highly liquid debt security investments with original maturities of less than three months at the time of purchase to be cash equivalents. Debt security investments that are highly liquid with original maturities at the time of purchase greater than three months are considered marketable debt securities. The Company classifies these investments as “available-for-sale” securities carried at fair value, based on quoted market prices of similar assets, with the unrealized gains or losses reported, net of tax, as a separate component of shareholders’ equity and included in accumulated other comprehensive income (loss) in the consolidated balance sheets. The amortization of premiums and accretion of discounts and the realized gains and losses are both recorded in other income, net, in the consolidated statements of operations. The Company reviews its investments for possible other-than-temporary impairments on a regular basis. If any loss on investment is believed to be other-than-temporary, a charge will be recorded and a new cost basis in the investment will be established. In evaluating whether a loss on a security is other-than-temporary, the Company considers the following factors: (i) general market conditions, (ii) the duration and extent to which the fair value is less than cost and (iii) the Company’s intent and ability to hold the investment. For securities in an unrealized loss position which is deemed to be other-than-temporary, the difference between the security’s then-current amortized cost basis and fair value is separated into (i) the amount of the impairment related to the credit loss (i.e., the credit loss component) and (ii) the amount of the impairment related to all other factors (i.e., the non-credit loss component). The credit loss component is recognized in earnings. The non-credit loss component is recognized in accumulated other comprehensive loss. Due to the relative short term nature of the investments, there have been no other-than-temporary impairments recorded to date. Restricted Cash Amounts included in restricted cash represent those required to be set aside to secure certain transactions in a foreign entity. As of January 31, 2020 and 2019, the restricted cash was immaterial, respectively. The following table presents cash, cash equivalents and restricted cash reported on the consolidated balance sheets, and the sums are presented on the consolidated statements of cash flows: As of January 31, 2020 2019 2018 (in thousands) Cash and cash equivalents $ 231,403 $ 194,047 $ 346,672 Restricted cash 9 11 9 Total as presented in the consolidated statements of cash flows $ 231,412 $ 194,058 $ 346,681 Trade Accounts Receivable and Allowances for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not include finance charges. The Company performs ongoing credit evaluation of its customers and generally requires no collateral. The Company assesses the need for allowances for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments by considering factors such as historical collection experience, credit quality, aging of the accounts receivable balances and current economic conditions that may affect a customer’s ability to pay. There were no material write-offs of accounts receivable for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. There was no material allowance for doubtful accounts recorded as of January 31, 2020 and 2019, respectively. Inventories The Company records inventories at the lower of cost or net realizable value. The cost includes materials and other production costs and is computed using standard cost on a first-in, first-out basis. Inventory reserves are recorded for estimated obsolescence or unmarketable inventories based on forecast of future demand and market conditions. Any adjustments to reduce the cost of inventories to their net realizable value are recognized in earnings in the current period. Property and Equipment Property and equipment are stated at cost and depreciated using the straight-line method over the estimated useful life for computer equipment, computer software, machinery, equipment and furniture and fixtures. Leasehold improvements are amortized over the shorter of the lease term or their estimated useful lives. Repairs and maintenance are charged to expense as incurred. Noncancelable Internal-Use Software License The Company accounts for a noncancelable on premise internal-use software license as the acquisition of an intangible asset and the incurrence of a liability to the extent that all or a portion of the software licensing fees are not paid on or before the license acquisition date. The intangible asset and related liability are recorded at net present value and interest expense is recorded over the payment term. Leases Effective February 1, 2019, the Company adopted Accounting Standards Codification (“ASC”) Topic 842, Leases, using the alternative transition method with an adjustment to the opening balance in the period of adoption without adjustment of comparative period financial statements. Under this new guidance, the Company recognizes leases as operating lease right-of-use (“ROU”) assets and corresponding lease liabilities at the lease commencement date based on the present value of future lease payments, while recognizing lease expenses under straight-line method through the lease term. The Company also elected the other available practical expedients, and has elected not to recognize ROU assets and lease liabilities that arise from short-term (12 months or less) leases and not to reassess the following for existing leases as of February 1, 2019: (i) whether contracts are or contain leases, (ii) lease classification, and (iii) initial direct costs. The Company does not combine lease components with non-lease components, and as a result, the non-lease components are accounted for separately. In determining the present value of lease payments, the Company uses the implicit interest rate if readily determinable. When the implicit rate is not readily determinable, the Company uses its incremental borrowing rate based on the information available at the lease commencement date. The Company's leases mainly include its worldwide office facilities which are classified as operating leases. Certain leases include renewal options that are under the Company's discretion. The renewal options are included in the ROU assets and liability calculation if it is reasonably certain that the Company will exercise the option. As of February 1, 2019, the Company recognized approximately $8.6 million of operating lease ROU assets, net of previously recognized prepaid rent and accrued liabilities, and corresponding lease liabilities of $8.7 million. The Company's short-term leases and finance leases are immaterial as of January 31, 2020 and February 1, 2019, respectively. Goodwill and In-Process Research and Development The Company does not amortize goodwill. Acquired in-process research and development, or IPR&D, is capitalized at fair value as an intangible asset and amortization commences upon completion of the underlying projects. . Impairment of Long-Lived Assets Including Goodwill and Other Acquired Intangible Assets The Company reviews property and equipment and intangible assets, excluding goodwill, for impairment at least annually in the fourth fiscal quarter or whenever events or changes in circumstances indicate that the carrying amount of an asset, or asset group, may not be recoverable. Determination of recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset, or asset group to estimated undiscounted future cash flows expected to be generated by the asset, or asset group. If the carrying amount of an asset or asset group exceeds its estimated undiscounted future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset or asset group exceeds the estimated fair value of the asset or asset group. Fair value is determined based on the estimated discounted future cash flows expected to be generated by the asset or asset group. Events or changes in circumstances that may indicate that an asset is impaired include significant decreases in the market value of an asset, significant underperformance relative to expected historical or projected future results of operations, a change in the extent or manner in which an asset is utilized, significant declines in the estimated fair value of the overall Company for a sustained period, shifts in technology, loss of key management or personnel, changes in the Company’s operating model or strategy and competitive forces. There has been no occurrence of events to date that would trigger an impairment analysis. As such, no impairment charge has been recognized as of January 31, 2020. The Company tests the goodwill for impairment at least annually in the fourth fiscal quarter, or sooner whenever events or changes in circumstances indicate that the asset may be impaired. The Company has a single reporting unit for goodwill impairment test purposes based on its business and reporting structure. The Company is permitted to first assess qualitative factors to determine whether the two step goodwill impairment test is necessary. Further testing is only required if the Company determines, based on the qualitative assessment, that it is more likely than not that a reporting unit’s fair value is less than its carrying amount. Otherwise, no further impairment testing is required. Qualitative factors include industry and market considerations, overall financial performance, and other relevant events and factors affecting the reporting unit . Equity Investment The Company accounts for its investment in a privately held company as an equity investment and reports the investment in other non-current assets in the consolidated balance sheets. The Company chooses to measure this equity investment that does not have readily determinable fair value at cost minus any recorded impairments, adjusted for observable price changes in transactions for an identical or similar investment of the same issuer. Upon determining that an impairment or observable price change exists, the Company records any adjustment to the fair value of the investment through net income. To date, there have been no identified events or changes in circumstances that may have a significant effect on the fair value of this investment and the Company has not recognized any impairment losses related to this investment nor have there been any observable price changes. Revenue Recognition Effective February 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers. As a result, the Company recognizes revenue when control of its goods and services is transferred to its customers. Revenue recognition is evaluated through the following five steps: (i) identification of the contract, or contracts, with a customer; (ii) identification of the performance obligations in the contract; (iii) determination of the transaction price; (iv) allocation of the transaction price to the performance obligations in the contract; and (v) recognition of revenue when or as a performance obligation is satisfied. The sale of semiconductor products accounts for the substantial majority of the Company’s consolidated revenue. Sales agreements with customers are renewable periodically and contain terms and conditions with respect to payment, delivery, warranty, supply and other rights. The Company considers an accepted customer purchase order, governed by sales agreement, to be the contract with the customer. For each contract, the Company considers the promise to transfer tangible products to be the identified performance obligation. Product sales contracts may include volume-based tiered pricing or rebates that are fulfilled in cash or product. In determining the transaction price, the Company accounts for the right of returns, cash rebates, commissions and other pricing adjustments as variable consideration and estimates these amounts based on the expected amount to be provided to customers and reduces the revenue recognized. The Company estimates sales returns and rebates based on the Company’s historical patterns of return and pricing credits. As the Company’s standard payment terms are 30 days to 60 days, the contracts have no financing component. Under ASC 606, the Company estimates the total consideration to be received by using the expected value method for each contract, computes weighted average selling price for each unit shipped in cases where there is a material right due to the presence of volume-based tiered pricing, allocates the total consideration between the identified performance obligations, and recognizes revenue when control of its goods and services is transferred to its customers. The Company considers product control to be transferred at a point in time upon shipment or delivery because the Company has a present right to payment at that time, the customer has legal title to the asset, the Company has transferred physical possession of the asset, and the customer has significant risk and rewards of ownership of the asset. The Company also enters into fixed-price engineering service agreements with certain customers. These agreements may include multiple performance obligations, such as software development services, licensing of intellectual property and post-contract customer support, or PCS. These multiple performance obligations are highly interdependent, highly interrelated, are typically not sold separately and do not have standalone selling prices. They are all inputs to generate one combined output which is incorporating the Company’s SoC into the customer’s product. Accordingly, the Company determines that they are not separately identifiable and shall be treated as a single performance obligation. Customers usually pay based on milestones achieved. Because payments received do not correspond directly with the value of the Company’s performance to date, for fixed-price engineering services arrangements, revenue is recognized using the time-based straight line method, which best depicts the Company’s performance toward complete satisfaction of the performance obligation based on the nature of such professional services. Revenues from engineering service agreements were not material for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. Timing of revenue recognition may differ from the timing of invoicing to the Company’s customers. The Company records contract assets when revenue is recognized prior to invoicing. The Company’s contract assets are primarily related to satisfied but unbilled performance obligations associated with its engineering service agreements at the reporting date. As of January 31, 2020 and 2019, the contract assets for these unbilled receivables were not material. The Company’s contract liabilities consist of deferred revenue. The deferred revenue is primarily related to the portion of a transaction price that exceeds the weighted average selling price for products sold to date under tiered-pricing contracts which contain material rights. This deferred revenue is expected to be recognized over the course of the contract when products are delivered for future pricing below the weighted average selling price of the contract. For the twelve months ended January 31, 2020 and 2019, the Company did not recognize any material revenue adjustment, respectively, related to performance obligations satisfied in prior periods released from this deferred revenue. As of January 31, 2020 and 2019, the respective deferred revenues were not material. Additionally, the transaction price allocated to unsatisfied, or partially unsatisfied, purchase orders for contracts that are greater than a year was not material as of January 31, 2020 and 2019, respectively. The Company also elects not to disclose the value of unsatisfied or partially unsatisfied performance obligations due to original expected contract duration of one year or less and elects to exclude amounts collected from customers for all sales taxes from the transaction price. Cost of Revenue Cost of revenue includes cost of materials, cost associated with packaging and assembly, testing and shipping, cost of personnel, stock-based compensation, logistics and quality assurance, warranty cost, royalty expense, write-downs of inventories and allocation of overhead. Warranty Costs The Company typically provides warranty on its products. The Company accrues for the estimated warranty costs at the time when revenue is recognized. The warranty accruals are regularly monitored by management based upon historical experience and any specifically identified failures. While the Company engages in extensive product quality assessment, actual product failure rates, material usage or service delivery costs could differ from estimates and revisions to the estimated warranty liability would be required. There was no warranty accrual as of January 31, 2020 and 2019, respectively. Research and Development Research and development costs are expensed as incurred and consist primarily of personnel costs, product development costs, which include engineering services, development software and hardware tools, license fees, costs of fabrication of masks for prototype products, other development materials costs, depreciation of equipment and tools and allocation of facility costs, net of any research and development grants. As of January 31, 2020, there was approximately $1.2 million of grants recorded in prepaid expenses and other current assets and approximately $3.2 million of grants recorded in other non-current assets in the consolidated balance sheets. Selling, General and Administrative Selling, general and administrative expenses consist of personnel costs, travel and trade show costs, legal expenses, other professional services and occupancy costs. Advertising expenses were not material for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. Stock-Based Compensation The Company measures stock-based compensation for equity awards granted to employees and directors based on the estimated fair value on the grant date, and recognizes that compensation as expense using the straight-line attribution method for service condition awards or using the graded-vesting attribution method for awards with performance conditions over the requisite service period, which is typically the vesting period of each award. The Company determines the fair value of restricted stock and restricted stock units with service or performance conditions based on the fair market value of its ordinary shares on the grant date. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options. Determining the fair value of stock options on the grant date requires the input of various assumptions, including stock price of the underlying ordinary share, the exercise price of the stock option, expected volatility, expected term, risk-free interest rate and dividend rate. In prior fiscal years, the expected term was calculated using the simplified method, and the expected volatility was calculated based on the weighted average of historical volatilities of the Company’s stock price and the share prices of similar companies that are publicly available for a period commensurate with the expected term. Starting from fiscal year 2019, the Company calculates expected volatility based on its own historical stock price for a period commensurate with the expected term, which is computed based on its own historical exercise behavior. The risk-free interest rate is derived from an average of the U.S. Treasury constant maturity rates for the respective periods most closely commensurate with the expected term. The expected dividend yield is zero because the Company has not historically paid dividends and has no present intention to pay dividends. The Company uses the Lattice pricing model and Monte Carlo Simulation to evaluate the fair value of awards with market conditions, including assumptions of historical volatility and risk-free interest rate commensurate with the vesting term. Upon adoption of ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting Income Taxes The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in its financial statements or tax returns. In estimating future tax consequences, generally all expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized. The Company applies authoritative guidance for the accounting for uncertainty in income taxes. The guidance requires that tax effects of a position be recognized only if it is “more likely than not” to be sustained based solely on its technical merits as of the reporting date. Upon estimating its tax positions and tax benefits, the Company considers and evaluates numerous factors, which may require periodic adjustments and which may not reflect the final tax liabilities. The Company adjusts its financial statements to reflect only those tax positions that are more likely than not to be sustained under examination . As part of the process of preparing consolidated financial statements, the Company is required to estimate its taxes in each of the jurisdictions in which it operates. The Company estimates actual current tax exposure together with assessing temporary differences resulting from differing treatment of items, such as accruals and allowances not currently deductible for tax purposes. These differences result in deferred tax assets, which are included in the consolidated balance sheets. In general, deferred tax assets represent future tax benefits to be received when certain expenses previously recognized in the consolidated statements of operations become deductible expenses under applicable income tax laws, or loss or credit carryforwards are utilized. In assessing whether deferred tax assets may be realized, the Company considers whether it is more likely than not that some portion or all of deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income. The Company makes estimates and judgments about its future taxable income based on assumptions that are consistent with its plans and estimates. Should the actual amounts differ from estimates, the amount of valuation allowance could be materially impacted. Any adjustment to the deferred tax asset valuation allowance would be recorded in the consolidated income statement for the periods in which the adjustment is determined to be required. Net Income (Loss) Per Ordinary Share Basic earnings (losses) per share is computed by dividing net income (loss) available to ordinary shareholders by the weighted-average number of ordinary shares outstanding during the period. Diluted earnings (losses) per share is computed by dividing net income (loss) available to ordinary shareholders by the weighted-average number of ordinary shares outstanding during the period increased to include the number of additional ordinary shares that would have been outstanding if the potentially dilutive securities had been issued. Potentially dilutive securities include outstanding stock options, shares to be purchased under the Company’s employee stock purchase plan, unvested restricted stock and restricted stock units. The dilutive effect of potentially dilutive securities is reflected in diluted earnings (losses) per share by application of the treasury stock method. Comprehensive Income (Loss) Comprehensive income (loss) includes unrealized gains or losses from available-for-sale securities that are excluded from net income (loss). Recent Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326), to introduce a new impairment model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses (“CECL”). Under the new CECL model, an entity is required to estimate the expected credit losses on available-for-sale (AFS) debt securities only when the fair value is below the amortized cost of the asset and is no longer based on an impairment being “other-than-temporary”. The new model also requires the impairment calculation on an individual security level and requires an entity use present value of cash flows when estimating the expected credit losses. The credit-related losses are required to be recognized through earnings and non-credit related losses are reported in other comprehensive income. In April 2019, the FASB further clarified the scope of the credit losses standard and addressed issues related to accrued interest receivable balances, recoveries, variable interest rates and prepayment. The ASU will be effective for public entities in fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The new guidance will require modified retrospective application to all outstanding instruments, with a cumulative effect adjustment recorded to opening retained earnings as of the beginning of the first period in which the guidance becomes effective. The Company is currently evaluating the impac

Financial Instruments and Fair

Financial Instruments and Fair Value	12 Months Ended
Financial Instruments and Fair Value	Jan. 31, 2020
Investments All Other Investments [Abstract]
Financial Instruments and Fair Value	2. Financial Instruments and Fair Value The Company invests a portion of its cash in debt securities that are denominated in United States dollars. The investment portfolio consists of money market funds, certificates of deposit, asset-backed securities, commercial paper, U.S. government securities and debt securities of corporations. All of the investments are classified as available-for-sale securities and reported at fair value in the consolidated balance sheets as follows: As of January 31, 2020 Amortized Unrealized Unrealized Losses Fair Value (in thousands) Money market funds $ 8,284 $ — $ — $ 8,284 Commercial paper 63,390 — — 63,390 Corporate bonds 95,053 653 — 95,706 Asset-backed securities 23,062 69 (2 ) 23,129 U.S. government securities 20,524 48 — 20,572 Total cash equivalents and marketable debt securities $ 210,313 $ 770 $ (2 ) $ 211,081 As of January 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value (in thousands) Money market funds $ 8,914 $ — $ — $ 8,914 Certificates of Deposit 7,012 — — 7,012 Commercial paper 68,233 — — 68,233 Corporate bonds 87,250 170 (60 ) 87,360 Asset-backed securities 11,607 3 (6 ) 11,604 U.S. government securities 21,993 3 (13 ) 21,983 Total cash equivalents and marketable debt securities $ 205,009 $ 176 $ (79 ) $ 205,106 As of January 31, 2020 January 31, 2019 (in thousands) Included in cash equivalents $ 37,736 $ 40,245 Included in marketable debt securities 173,345 164,861 Total cash equivalents and marketable debt securities $ 211,081 $ 205,106 The contractual maturities of the investments at January 31, 2020 and 2019 were as follows: As of January 31, 2020 January 31, 2019 (in thousands) Due within one year $ 146,267 $ 151,991 Due within one to three years 64,814 53,115 Total cash equivalents and marketable debt securities $ 211,081 $ 205,106 The unrealized losses on the available-for-sale securities were caused by fluctuations in market value and interest rates as a result of the economic environment. As the decline in market value was attributable to changes in market conditions and not credit quality, and because the Company neither intended to sell nor was it more likely than not that it will be required to sell these investments prior to a recovery of par value, the Company did not consider these investments to be other-than temporarily impaired as of January 31, 2020 and 2019, respectively. The following fair value hierarchy is applied for disclosure of the inputs used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows: Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2—Inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the assets or liabilities, either directly or indirectly through market corroboration, for substantially the full term of the financial instruments. Level 3—Unobservable inputs based on the Company’s own assumptions used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. The Company measures the fair value of money market funds and certificates of deposit using quoted prices in active markets for identical assets and classifies them within Level 1. The fair value of the Company’s investments in other debt securities are obtained based on quoted prices for similar assets in active markets and are classified within Level 2. The following tables present the fair value of the financial instruments measured on a recurring basis as of January 31, 2020 and 2019, respectively: As of January 31, 2020 Total Level 1 Level 2 Level 3 (in thousands) Money market funds $ 8,284 $ 8,284 $ — $ — Commercial paper 63,390 — 63,390 — Corporate bonds 95,706 — 95,706 — Asset-backed securities 23,129 — 23,129 — U.S. government securities 20,572 — 20,572 — Total cash equivalents and marketable debt securities $ 211,081 $ 8,284 $ 202,797 $ — As of January 31, 2019 Total Level 1 Level 2 Level 3 (in thousands) Money market funds $ 8,914 $ 8,914 $ — $ — Certificates of Deposit 7,012 7,012 Commercial paper 68,233 — 68,233 — Corporate bonds 87,360 — 87,360 — Asset-backed securities 11,604 — 11,604 — U.S. government securities 21,983 — 21,983 — Total cash equivalents and marketable debt securities $ 205,106 $ 15,926 $ 189,180 $ —

Inventories

Inventories	12 Months Ended
Inventories	Jan. 31, 2020
Inventory Disclosure [Abstract]
Inventories	3. Inventories Inventories at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Work-in-progress $ 10,133 $ 9,430 Finished goods 12,838 8,822 Total $ 22,971 $ 18,252

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
Property and Equipment, Net	Jan. 31, 2020
Property Plant And Equipment [Abstract]
Property and Equipment, Net	4. Property and Equipment, net Depreciation expense was approximately $2.8 million, $2.6 million and $1.8 million for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. Property and equipment at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Computer equipment and software $ 10,282 $ 9,098 Machinery and equipment 6,317 5,659 Furniture and fixtures 969 969 Leasehold improvements 2,356 2,331 Construction in progress 63 330 19,987 18,387 Less: accumulated depreciation and amortization (14,373 ) (11,659 ) Total property and equipment, net $ 5,614 $ 6,728

Intangible Assets

Intangible Assets	12 Months Ended
Intangible Assets	Jan. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	5. Intangible Assets The intangible assets primarily consist of $4.1 million of IPR&D from the acquisition of VisLab S.r.l., or VisLab, The Company enters into certain internal-use noncancelable software license agreements with third parties from time-to-time. The licenses have been capitalized as intangible assets, and the corresponding future payments have been recorded as liabilities at net present value. As of January 31, 2020, $4.4 million was recorded in accrued and other current liabilities and $8.2 million was recorded in other long-term liabilities in the consolidated balance sheets. The carrying amounts of intangible assets as of January 31, 2020 and 2019 were as follows : As of January 31, 2020 As of January 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in thousands) In-process research and development $ 4,100 $ — $ 4,100 $ 4,100 $ — $ 4,100 Internal-use software license 27,203 (13,477 ) 13,726 14,448 (7,612 ) 6,836 Total acquired intangible assets $ 31,303 $ (13,477 ) $ 17,826 $ 18,548 $ (7,612 ) $ 10,936 The amortization expense related to these software licenses was approximately $5.9 million, $4.7 million, and $3.0 million for the fiscal years ended January 31, 2020, 2019, and 2018 respectively. The expected annual amortization expense related to these software licenses as of January 31, 2020 is as follows: As of January 31, 2020 Fiscal Year (in thousands) 2021 $ 5,789 2022 4,519 2023 3,418 2024 — 2025 — Thereafter — Total future amortization expenses: $ 13,726 There were no intangible asset impairments for the fiscal years ended January 31, 2020, 2019 and 2018, respectively.

Goodwill

Goodwill	12 Months Ended
Goodwill	Jan. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	6. Goodwill On June 25, 2015, the Company completed the acquisition of VisLab, a privately-held Italian company that develops computer vision and intelligent control systems for automotive and other commercial applications, including advanced driver assistance systems and several generations of autonomous vehicle driving systems, for $30.0 million in cash. As a result, there was $25.3 million attributed to goodwill, $4.1 million attributed to intangible assets and $0.6 million attributed to net assets acquired. A deferred tax liability of $1.3 million related to the intangible assets was recorded to account for the difference between financial reporting and tax basis at the acquisition date, with an addition to goodwill. The Company does not amortize goodwill. There were no goodwill impairments for the fiscal years ended January 31, 2020, 2019 and 2018, respectively.

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	12 Months Ended
Accrued and Other Current Liabilities	Jan. 31, 2020
Payables And Accruals [Abstract]
Accrued and Other Current Liabilities	7. Accrued and Other Current Liabilities Accrued and other current liabilities at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Accrued employee compensation $ 16,874 $ 10,645 Accrued rebates 54 311 Accrued product development costs 10,885 6,393 Software license liabilities, current 4,388 4,879 Other accrued liabilities 2,769 2,472 Total accrued and other current liabilities $ 34,970 $ 24,700 The increased employee compensation liabilities were primarily due to approximately $5.8 million of stock-based compensation expense associated with the Company’s annual bonus program that will be settled by restricted stock units. The timing of SoC development progress and payments to outside foundries resulted in fluctuation of the accrued product development costs. The current software license liabilities mainly consisted of approximately $3.9 million of short-term liabilities associated with the $12.7 million of license agreements with Cadence Design Systems, Inc. (“Cadence”) that was entered in fiscal year 2020.

Leases

Leases	12 Months Ended
Leases	Jan. 31, 2020
Leases [Abstract]
Leases	8. Leases The Company has entered into various operating leases for its worldwide office buildings and research and development facilities. For the fiscal year ended January 31, 2020, the Company exercised the renewal option to extend its U.S. office lease for a period of 63 months beginning from June 1, 2020 through August 31, 2025 and renewed its Shanghai office lease for another two years beginning from December 1, 2019 to November 30, 2021. The Company accounted these two renewed contracts as lease modifications and recorded an increase to the operating lease right-of-use assets and corresponding operating lease liabilities by approximately $4.0 million, respectively, in the consolidated balance sheets. The Company also signed a separate lease for additional space for its U.S. office for a period of 56 months beginning from January 1, 2021 through August 31, 2025 and will record it in the balance sheet upon commencement date on January 1, 2021. T he total estimated future undiscounted cash payments for this lease are approximately $1.7 million In August 2019, VisLab, a wholly-owned subsidiary, was granted a land lease for 35 years with an obligation to construct a building on the land in Parma, Italy (“Parma lease”). The Company will be responsible for the costs of construction and occupy the building after completion of construction for the remainder of the lease term. which is expected to be two years after The total estimated future undiscounted cash payments are approximately $2.2 million, of which $1.8 million will be paid in the first two years and the remaining balance of $0.4 million will be paid over the remainder of the lease term. For the fiscal year ended January 31, 2020, the Company recorded approximately $3.0 million of operating lease expense under ASC 842. Approximately $4.6 million and $5.3 million of operating lease expense recorded for the fiscal years ended January 31, 2019 and 2018, respectively, under ASC 840. The Company's short-term leases and finance leases are immaterial as of January 31, 2020 . The cumulative effect of the changes made to the consolidated balance sheets as of February 1, 2019 for the adoption of ASC 842 was as follows: Balance as of Opening Balance as of January 31, 2019 Adjustment February 1, (in thousands) Operating lease right-of-use assets $ — $ 8,581 $ 8,581 Prepaid expenses and other current assets $ 6,206 $ (174 ) $ 6,032 Accrued and other current liabilities $ 24,700 $ (279 ) $ 24,421 Operating lease liabilities, current $ — $ 2,534 $ 2,534 Operating lease liabilities, non-current $ — $ 6,152 $ 6,152 Supplemental cash flow information related to leases is as follows: Twelve Months Ended January 31, 2020 (in thousands) Cash paid for operating leases included in operating cash flows $ 2,851 Supplemental non-cash information related to lease liabilities arising from obtaining right-of-use assets $ 299 Leased assets obtained in exchange for operating lease liabilities arising from lease modifications $ 4,021 As of January 31, 2020, the weighted average remaining lease term is 5.02 years, and the weighted average discount rate is 4.43 percent. Future minimum lease payments for the lease liabilities, excluding the additional space for the U.S. office and the Parma lease described above, are as follows : As of January 31, 2020 Fiscal Year (in thousands) 2021 $ 2,522 2022 2,371 2023 1,645 2024 1,694 2025 1,740 Thereafter 1,210 Total future annual minimum lease payments 11,182 Less: interest (1,026 ) Total lease liabilities $ 10,156 Prior to the adoption of the new lease guidance, future minimum undiscounted lease payments as of January 31, 2019 were as follows: As of January 31, 2019 Fiscal Year (in thousands) 2020 $ 2,592 2021 1,040 2022 356 2023 143 2024 147 Thereafter 576 Total future annual minimum lease payments $ 4,854 The increased liabilities, as compared to the minimum lease payments as of January 31, 2019, were primarily attributable to a renewal option exercised and lease modifications during the fiscal year ended January 31, 2020.

Other Long-Term Liabilities

Other Long-Term Liabilities	12 Months Ended
Other Long-Term Liabilities	Jan. 31, 2020
Other Liabilities Disclosure [Abstract]
Other Long-Term Liabilities	9. Other Long-Term Liabilities Other long-term liabilities at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Unrecognized tax benefits, including interest $ 8,261 $ 6,732 Deferred tax liabilities, non-current 1,288 1,293 Software license liabilities, non-current 8,159 310 Other long-term liabilities 68 6 Total other long-term liabilities $ 17,776 $ 8,341 The increased software license liabilities were primarily due to the $12.7 million of license agreements with Cadence entered in fiscal year 2020 that resulted in approximately $8.0 million of long-term liabilities accrued in the other long-term liabilities in the consolidated balance sheets as of January 31, 2020.

Capital Stock

Capital Stock	12 Months Ended
Capital Stock	Jan. 31, 2020
Equity [Abstract]
Capital Stock	10. Capital Stock Preference shares After completion of the Company’s initial public offering, or IPO in 2012, a total of 20,000,000 preference shares, with a $0.00045 par value per share, were authorized. There were no preference shares issued and outstanding as of January 31, 2020 and 2019, respectively. Ordinary shares As of January 31, 2020 and January 31, 2019, the following ordinary shares were reserved for future issuance under the EIP and ESPP: As of January 31, 2020 2019 Shares reserved for options, restricted stock and restricted stock units 6,045,108 5,915,654 Shares reserved for employee stock purchase plan 2,059,504 1,833,574 Shares repurchased On May 29, 2019, the Company’s Board of Directors authorized a program to repurchase up to $50.0 million of the Company’s ordinary shares commencing immediately through June 30, 2020. Since the inception of the repurchase programs in June 2016, a total of $275.0 million has been authorized and a total of 3,985,876 shares have been repurchased for approximately $174.8 million in cash. Repurchases may be made from time-to-time through open market purchases, 10b5-1 plans or privately negotiated transactions subject to market conditions, applicable legal requirements and other relevant factors. The repurchase program does not obligate the Company to acquire any particular amount of ordinary shares, and it may be suspended at any time at the Company’s discretion. The repurchase program is funded using the Company’s working capital and any repurchased shares are recorded as authorized but unissued shares. There were no shares repurchased in fiscal year 2020. As of January 31, 2020, there was $50.0 million available for repurchases under the repurchase program through June 30, 2020.

Employee Benefits and Stock-bas

Employee Benefits and Stock-based Compensation	12 Months Ended
Employee Benefits and Stock-based Compensation	Jan. 31, 2020
Postemployment Benefits [Abstract]
Employee Benefits and Stock-based Compensation	11. Employee Benefits and Stock-based Compensation 401(k) Plan The Company maintains a defined contribution 401(k) plan (the “401(k) Plan”) for all of its eligible U.S. employees. Under the 401(k) Plan, eligible employees may contribute up to the Internal Revenue Service annual contribution limitation. The Company is responsible for administrative costs of the Plan. The Company has not had any matching contributions to date. Stock Option Plans 2004 Stock Plan. The 2004 Stock Plan provides for the grant of incentive stock options (“ISOs”) within the meaning of Section 422 of the Internal Revenue Code of 1986, as amended (the “Code”), nonstatutory stock options (“NSOs”), stock purchase rights to acquire restricted stock and restricted stock units. Upon the completion of the IPO, no additional awards will be granted under the 2004 Plan and the 2004 Plan was terminated. However, all outstanding stock options and other awards previously granted under the 2004 Plan will remain subject to the terms of the 2004 Plan. 2012 Equity Incentive Plan. The 2012 Equity Incentive Plan, or EIP, permits the grant of ISOs, within the meaning of Section 422 of the Code, to employees of the Company and any of the Company’s subsidiary corporations, and the grant of NSOs, stock appreciation rights, restricted stock, restricted stock units, performance units, performance shares, deferred stock units and dividend equivalents to employees, directors and consultants of the Company and any of the Company’s subsidiary corporations’ employees and consultants. The exercise price of ISOs granted to a holder of more than 10% of the voting power of all classes of the Company’s shares shall be no less than 110% of fair market value on the grant date. The exercise price of ISOs granted to other employees and NSOs shall be no less than 100% of fair market value on the grant date. Options granted under the Plan have a term of up to 10 years Restricted stock and restricted stock units granted to new employees generally vest as to 1/4th of the shares on the first anniversary service date of the grant and 1/16th of the shares vest every 3 months thereafter, so as to be 100% vested on the fourth anniversary of the vesting commencement date. Vesting schedules for other service condition, market condition or performance condition awards vary and are subject to approval by the board of directors; provided that the performance condition associated awards shall not vest at all until the performance conditions are achieved and are subject to the award’s holders continuing to provide services to the Company through such vesting dates. The performance condition awards are automatically forfeited in their entirety, without any cost to or action by the Company, if there has been no achievement of the performance. The holders of restricted stock have voting power and other rights with respect to such shares, provided, however, that such shares are held in escrow and subject to forfeiture until the shares vested. In the first quarter of fiscal year 2020 and 2019, the Company added 1,453,659 and 1,507,032 ordinary shares, respectively, to the ordinary shares reserved for issuance, pursuant to an “evergreen” provision contained in the EIP. Pursuant to such provision, on February 1st of each fiscal year, the number of ordinary shares reserved for issuance under the EIP is automatically increased by a number equal to the lesser of (i) 3,500,000 ordinary shares, (ii) four and one half percent (4.5%) of the aggregate number of ordinary shares outstanding on January 31st of the preceding fiscal year, or (iii) a lesser number of shares that may be determined by the Company’s Board of Directors. Amended and Restated The Amended and Restated 2012 Employee Stock Purchase Plan, or ESPP, permits eligible participants to purchase ordinary shares at a discount through contributions up to 15% of their eligible compensation, subject to any IRS limitations. The ESPP provides each offering and purchasing period of six months in duration. The purchase price is 85% of the lower of the closing price of the Company’s ordinary shares on the first trading day of each offering period or on the purchase date. In the first quarter of fiscal year 2020 and 2019, the Company added 403,794 and 418,620 ordinary shares, respectively, to the ordinary shares reserved for issuance, pursuant to an “evergreen” provision contained in the ESPP. Pursuant to such provision, on February 1st of each fiscal year, the number of ordinary shares reserved for issuance under the ESPP is automatically increased by a number equal to the lesser of (i) 1,500,000 ordinary shares, (ii) one and one quarter percent (1.25%) of the aggregate number of ordinary shares outstanding on such date, or (iii) an amount determined by the Company’s Board of Directors or a duly authorized committee of the Board of Directors. Stock-based Compensation The following table presents the classification of stock-based compensation for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands) Stock-based compensation: Cost of revenue $ 1,184 $ 1,261 $ 1,306 Research and development 41,842 37,432 34,575 Selling, general and administrative 23,845 22,119 20,980 Total stock-based compensation $ 66,871 $ 60,812 $ 56,861 For the twelve months ended January 31, 2020, approximately $5.8 million of stock-based compensation expense was accrued in accrued and other current liabilities in the consolidated balance sheets. As of January 31, 2020, total unrecognized compensation cost related to unvested stock options was $3.9 million and is expected to be recognized over a weighted-average period of 2.49 years. Total unrecognized compensation cost related to unvested restricted stock units was $113.8 million and is expected to be recognized over a weighted-average period of 2.49 years. The restricted stock awards were fully vested as of January 31, 2020. The following table sets forth the weighted-average assumptions used to estimate the fair value of the stock options and employee stock purchase plan awards for the periods indicated: Year Ended January 31, 2020 2019 2018 Stock Options: Volatility 52 % 54 % 53 % Risk-free interest rate 1.82 % 2.77 % 2.08 % Expected term (years) 6.01 5.41 6.08 Dividend yield 0 % 0 % 0 % Employee stock purchase plan awards: Volatility 47 % 45 % 44 % Risk-free interest rate 2.23 % 2.15 % 1.03 % Expected term (years) 0.5 0.5 0.5 Dividend yield 0 % 0 % 0 % Starting from fiscal year 2019, the Company calculates expected volatility for stock options based on its own historical stock price for a period commensurate with the expected term. In the prior fiscal year, the Company calculated expected volatility for stock options based on the weighted average of historical volatilities of its own stock price and the stock prices of similar companies that are publicly available for a period commensurate with the expected term. The Company calculates expected volatility for ESPP based on its own historical stock price for a period commensurate with the offering period. The following table summarizes stock option activities for the periods indicated: Option Outstanding Weighted- Total Average Weighted- Value of Remaining Aggregate Weighted- Average options Contractual Intrinsic Average Grant-date Exercised Term Value Shares Exercise Fair Value (in (in years) (in Outstanding at January 31, 2017 1,703,524 $ 21.66 Granted 132,250 54.66 $ 28.28 Exercised (175,187 ) 12.50 $ 7,446 Forfeited (27,721 ) 56.97 Expired (21,522 ) 36.31 Outstanding at January 31, 2018 1,611,344 24.56 Granted 116,600 42.73 $ 21.75 Exercised (232,205 ) 5.54 $ 8,867 Forfeited (20,974 ) 53.50 Expired (15,701 ) 54.35 Outstanding at January 31, 2019 1,459,064 28.31 Granted 66,850 50.56 $ 25.35 Exercised (366,886 ) 15.52 $ 13,263 Forfeited (14,931 ) 46.29 Expired (19,451 ) 64.53 Outstanding at January 31, 2020 1,124,646 $ 32.93 4.35 $ 31,295 Exercisable at January 31, 2020 960,567 $ 30.24 3.65 $ 29,573 The intrinsic value of options outstanding and exercisable is calculated based on the difference between the fair market value of the Company’s ordinary shares on the reporting date and the exercise price. The closing price of the Company’s stock was $59.14 on January 31, 2020, as reported by The NASDAQ Global Market. The intrinsic value of exercised options is calculated based on the difference between the fair market value of the Company’s stock on the exercise date and the exercise price. The following table summarizes restricted stock and restricted stock units activities for the periods indicated: Weighted- Average Grant-Date Shares Fair Value Unvested at January 31, 2017 2,175,673 $ 56.76 Granted 1,052,235 47.11 Vested (1,006,130 ) 47.55 Forfeited (118,497 ) 54.72 Unvested at January 31, 2018 2,103,281 56.45 Granted 1,367,751 40.03 Vested (994,500 ) 53.27 Forfeited (81,016 ) 53.57 Unvested at January 31, 2019 2,395,516 48.49 Granted 1,329,288 54.54 Vested (1,012,581 ) 51.24 Forfeited (94,957 ) 54.26 Unvested at January 31, 2020 2,617,266 $ 50.30 Total fair value as of the respective vesting dates of restricted stock and restricted stock units vested for the fiscal years ended January 31, 2020, 2019 and 2018 was approximately $52.1 million, $42.9 million, and $52.1 million, respectively.

Net Income (Loss) Per Ordinary

Net Income (Loss) Per Ordinary Share	12 Months Ended
Net Income (Loss) Per Ordinary Share	Jan. 31, 2020
Earnings Per Share [Abstract]
Net Income (Loss) Per Ordinary Share	12. Net Income (Loss) Per Ordinary Share The following table sets forth the computation of basic and diluted net income (loss) per ordinary share for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands, except share and per share data) Numerator: Net income (loss) $ (44,792 ) $ (30,447 ) $ 18,852 Denominator: Weighted-average ordinary shares - basic 33,083,562 32,713,606 33,224,803 Effect of dilutive securities: Employee stock options — — 961,797 Restricted stock and restricted stock units — — 390,145 Employee stock purchase plan — — 6,405 Weighted-average ordinary shares - diluted 33,083,562 32,713,606 34,583,150 Net income (loss) per ordinary share: Basic $ (1.35 ) $ (0.93 ) $ 0.57 Diluted $ (1.35 ) $ (0.93 ) $ 0.55 The following weighted-average potentially dilutive securities were excluded from the computation of diluted net income (loss) per ordinary share as their effect would have been antidilutive: Year Ended January 31, 2020 2019 2018 Options to purchase ordinary shares 913,678 1,190,607 280,907 Restricted stock and restricted stock units 1,139,269 1,522,903 907,208 Employee stock purchase plan 8,530 26,831 15,506 2,061,477 2,740,341 1,203,621

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Jan. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes Income (loss) before income taxes consisted of the following for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands) U.S. operations $ 845 $ 1,381 $ 2,683 Non-U.S. operations (42,473 ) (35,933 ) 23,046 Income (loss) before income taxes $ (41,628 ) $ (34,552 ) $ 25,729 Income tax provision (benefit) consisted of the following for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands) Current: U.S. federal tax $ 1,440 $ 1,290 $ 3,321 U.S. state taxes 3 2 4 Non-U.S. foreign taxes 1,540 1,561 1,435 2,983 2,853 4,760 Deferred: U.S. federal tax 182 (7,077 ) 2,185 U.S. state taxes — — — Non-U.S. foreign taxes (1 ) 119 (68 ) 181 (6,958 ) 2,117 Provision (benefit) for income taxes $ 3,164 $ (4,105 ) $ 6,877 The Company consists of a Cayman Islands parent company with various foreign and U.S. Subsidiaries. Moreover, effective from December 31, 2019, the Company has structured its activities to comply with the International Tax Co-Operation (Economic Substance) Law, 2018 in the Cayman Islands. As part of the new structure, the Company is the general partner of a Canadian limited partnership, the ultimate beneficial owner, and is allocated all of the earnings of the partnership. The primary jurisdiction where our foreign earnings are derived is the Cayman Islands, where the Company is domiciled. Under the current laws of the Cayman Islands, the Company is not subject to tax on its income. For purposes of the reconciliation between the provision (benefit) for income taxes at the statutory rate and the effective tax rate, a notional U.S. 21.0%, 21.0% and 33.8% rates are applied to pretax income (loss) as a result of the following for the periods indicated, respectively: Year Ended January 31, 2020 2019 2018 (in thousands) Provision at U.S. notional statutory rate $ (8,742 ) $ (7,256 ) $ 8,699 U.S. state taxes 3 2 2 Non-U.S. foreign tax differential 10,458 9,226 (6,424 ) Stock-based compensation 4,172 4,715 4,645 U.S. R&D credit (3,109 ) (2,770 ) (2,408 ) Valuation allowance — (7,990 ) (1 ) Change in tax rate — — 2,252 Other 382 (32 ) 112 Provision (benefit) for income taxes $ 3,164 $ (4,105 ) $ 6,877 On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted into law in the United States. The tax legislation contains several provisions that impacted the Company, including the reduction of the corporate income tax rate from 35% to 21%, acceleration of business asset expensing, and a reduction in the amount of executive pay that may qualify as a tax deduction, among others. The income tax benefit recorded for the fiscal year ended January 31, 2019 includes the impact of the Tax Act. Temporary differences that gave rise to significant portions of the Company’s deferred tax assets and liabilities at January 31, 2020 and 2019 were as follows: As of January 31, 2020 2019 (in thousands) Deferred tax assets: Federal and state credits $ 21,275 $ 19,426 Expenses not currently deductible 593 575 Operating lease liabilities 2,023 — Stock-based compensation 3,203 3,202 Foreign deferred 132 122 Gross deferred tax assets 27,226 23,325 Valuation allowance (14,670 ) (12,526 ) Total deferred tax assets $ 12,556 $ 10,799 Deferred tax liabilities Property and equipment (1,469 ) (1,505 ) Operating lease assets (1,974 ) — Net deferred tax assets $ 9,113 $ 9,294 Tax valuation allowance for the periods indicated below were as follows: Deductions Additions Charged to Balance at Additional Charged to Expenses Balance at Beginning of Charged to Other or Other End of Period Expenses Account Accounts Period (in thousands) Tax Valuation Allowance Year ended January 31, 2020 $ 12,526 2,144 — — $ 14,670 Year ended January 31, 2019 $ 18,538 1,978 — (7,990 ) $ 12,526 Year ended January 31, 2018 $ 15,061 3,477 — — $ 18,538 The Company conducts its business in several countries and regions and is subject to taxation in those jurisdictions. The Company is incorporated in the Cayman Islands with foreign affiliates in the U.S., Canada, China, Taiwan, Italy and other foreign countries and regions. As such, the Company’s worldwide operating income is subject to varying tax rates and its effective tax rate is highly dependent upon the geographic distribution of its earnings or losses and the tax laws and regulations in each geographical region. Consequently, the Company has experienced lower effective tax rates as a substantial amount of its operations are conducted in lower-tax jurisdictions. If the Company’s operational structure was to change in such a manner that would increase the amount of operating income subject to taxation in higher-tax jurisdictions, or if the Company was to commence operations in jurisdictions assessing relatively higher tax rates, its effective tax rate could fluctuate significantly on a quarterly basis and/or be adversely affected. Dividend distributions received from the Company’s U.S. subsidiary and certain other foreign subsidiaries may be subject to local country withholding taxes when, and if, distributed. Deferred tax liabilities have not been recorded on unremitted earnings of certain subsidiaries because management’s intent is to indefinitely reinvest any undistributed earnings in those subsidiaries. If dividend distributions from those subsidiaries were to occur, the liability as of January 31, 2020 would be $11.9 million. Cumulative undistributed earnings of foreign subsidiaries for which no deferred taxes have been provided approximated $78.5 million at January 31, 2020. As of January 31, 2020 and 2019, the Company had deferred tax assets (net of deferred tax liabilities) before valuation allowance, of $23.8 million and $21.8 million, respectively. The Company assesses whether a valuation allowance should be established against its deferred tax assets based on the consideration of all available evidence, using a “more likely than not” standard. In the fourth quarter of fiscal year 2019, the Company determined that, based on its cumulative profits before taxes and estimates of future forecasts of continued profitability in the United States, sufficient positive evidence existed to conclude that the valuation allowance on the U.S. federal research and development credit carryforwards was no longer needed. Accordingly, the Company realized approximately $8.0 million in deferred tax assets and a corresponding decrease in income tax expense related to the release of the valuation allowance for the U.S. federal research and development credit carryforwards. The Company has $81.3 million and $15.7 million of federal and California net operating loss carryforwards as of January 31, 2020. The federal and California net operating loss carryforwards begin to expire in fiscal year 2035, if not utilized. For financial statement purposes these carry forwards are offset by uncertain tax positions. The Company also has Federal and California state research and development credit carryforwards of approximately $20.4 million and $23.2million, respectively, at January 31, 2020. The Federal credits begin to expire in fiscal year 2033. The California credits can be carried forward indefinitely. The Company reports its U.S. state deferred tax assets and related valuation allowance, net of the U.S federal tax rate of 21%. As of January 31, 2020, the Company has recorded a valuation allowance of $14.7 million against all of its U.S. state deferred tax assets due to uncertainty regarding the future utilization of these deferred tax assets. Utilization of the research credit carryforwards may be subject to an annual limitation due to the ownership percentage change limitations as defined by the U.S. Internal Revenue Code Section 382, as amended, and similar state provisions. The annual limitation may result in the expiration of the U.S. Federal and state research credit carryforwards before utilization. The Company does not expect any tax credit carryforwards to expire as a result of a Section 382 limitation. The Company applies the provisions of FASB’s guidance on accounting for uncertainty in income taxes. As of January 31, 2020, the Company had approximately $42.7 million in unrecognized tax benefits, $36.2 million of which would affect the Company’s effective tax rate if recognized. The remainder of the unrecognized tax benefits would not affect the effective tax rate due to the full valuation recorded for state deferred tax assets. The following table sets forth a reconciliation of the beginning and ending amount of unrecognized tax benefits: Year Ended January 31, 2020 2019 2018 (in thousands) Beginning balance: $ 37,531 $ 34,117 $ 37,977 Additions based on tax positions related to the current year 4,964 3,922 7,892 Additions for tax positions of prior years 252 109 28 Reductions for tax positions in prior years — (552 ) (11,313 ) Settlements for prior periods — — — Lapse of applicable statute of limitations (52 ) (65 ) (467 ) Ending balance: $ 42,695 $ 37,531 $ 34,117 The Company classified $7.5 million and $6.3 million of income tax liabilities as other long term liabilities as of January 31, 2020 and 2019, respectively, because payment of cash or settlement is not anticipated within one year from the balance sheet date. The Company recognizes interest and penalties related to uncertain tax positions as a component of income tax expense. The Company recorded $358,000, $263,000 and $37,000 of interest expense and penalties related to uncertain tax positions for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. The Company recorded noncurrent liabilities of $760,000 and $403,000 related to interest and penalties for uncertain tax positions at January 31, 2020 and 2019, respectively. The primary jurisdiction where our foreign earnings are derived is the Cayman Islands, where the Company is domiciled. The Company files income tax returns in the U.S. federal jurisdiction as well as many U.S. state and foreign jurisdictions. The tax years 2013 to 2019 remain open to examination by U.S. federal tax authorities. The tax years 2009 to 2019 remain open to examination by U.S. state tax authorities. The tax years 2014 to 2019 remain open to examination by foreign tax authorities. Fiscal years outside of the normal statute of limitations remain open to audit by tax authorities due to tax attributes generated in those earlier years, which have been carried forward and may be audited in subsequent years when utilized. The Company believes that an adequate provision has been made for any adjustments that may result from tax examinations. However, the outcome of tax audits cannot be predicted with certainty. If any issues addressed in the Company’s tax audits are resolved in a manner not consistent with management’s expectations, the Company could be required to adjust its provision for income tax in the period such resolution occurs. Although timing of the resolution and/or closure of audits is highly uncertain, the Company does not believe it is reasonably possible that its unrecognized tax benefits would materially change in the next 12 months. As of January 31, 2020, the Company’s long-term income taxes payable, including estimated interest and penalties, was approximately $8.3 million. The Company was unable to make a reasonably reliable estimate of the timing of payments in individual years due to uncertainties in the timing of tax audits, if any, or their outcomes. On July 27, 2015, in Altera Corp. v. Commissioner Altera

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Jan. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. Commitments and Contingencies Contract Manufacturer Commitments The Company’s components and products are procured and built by independent contract manufacturers based on sales forecasts. These forecasts include estimates of future demand, historical trends, analysis of sales and marketing activities, and adjustment of overall market conditions. The Company regularly issues purchase orders to independent contract manufacturers which are cancelable only upon the agreement between the Company and the third-party. As of January 31, 2020 and 2019, total manufacturing purchase commitments were approximately $35.9 million and $28.2 million, respectively. Indemnification The Company, from time to time, in the normal course of business, indemnifies certain vendors with whom it enters into contractual relationships. The Company has agreed to hold the other party harmless against third-party claims in connection with the Company’s future products. The Company also indemnifies certain customers against third-party claims related to certain intellectual property matters. It is not possible to determine the maximum potential amount of liability under these indemnification obligations due to the limited history of prior indemnification claims and the unique facts and circumstances that are likely to be involved in each particular claim. The Company has not made payments under these obligations and no liabilities have been recorded for these obligations on the consolidated balance sheets as of January 31, 2020 and 2019, respectively.

Segment Reporting

Segment Reporting	12 Months Ended
Segment Reporting	Jan. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	15. Segment Reporting The Company operates in one reportable segment related to the development and sales of low-power, high-definition (HD), Ultra HD video compression, image processing and computer vision solutions. The Chief Executive Officer of the Company has been identified as the Chief Operating Decision Maker (the “CODM”) and manages the Company’s operations as a whole. For the purpose of evaluating financial performance and allocating resources, the CODM reviews financial information presented on a consolidated basis accompanied by information by customer and geographic region. Geographic Revenue The following table sets forth the Company’s revenue by geographic region based on bill-to location for the periods indicated. Year Ended January 31, 2020 2019 2018 (in thousands) Taiwan $ 137,946 $ 132,199 $ 174,486 Asia Pacific 66,867 66,981 57,862 Europe 11,134 18,244 45,185 North America other than United States 8,402 7,028 11,110 United States 4,383 3,316 6,759 Total revenue $ 228,732 $ 227,768 $ 295,402 Substantially all of the Company’s property and equipment were located in the United States, Asia Pacific region and Europe. As of January 31, 2020, the net amount of these fixed assets located in these regions was approximate $1.7 million, $2.8 million and $1.1 million, respectively. As of January 31, 2019, the net amount of these fixed assets located in these regions was approximately $2.1 million, $3.2million and $1.4 million, respectively. Major Customers The customers representing 10% or more of revenue and accounts receivable for the fiscal year ended January 31, 2020 were Wintech and Chicony which accounted for approximately 60% and 18% of total revenue, respectively. For the fiscal year ended January 31, 2019, the customers representing 10% or more of revenue and accounts receivables were Wintech and Chicony which accounted for approximately 58% and 16% of total revenue, respectively. For the fiscal year ended January 31, 2018, the customers representing 10% or more of revenue and accounts receivable were Wintech and GoPro Inc., or GoPro, which accounted for approximately 59% and 12% of total revenue, respectively. Accounts receivable from Wintech and Chicony accounted for approximately $3.8 million and $10.8 million as of January 31, 2020, respectively. Accounts receivable from Wintech and Chicony accounted for approximately $14.3 million and $6.9 million as of January 31, 2019, respectively.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
Related-Party Transactions	Jan. 31, 2020
Related Party Transactions [Abstract]
Related-Party Transactions	16. Related-Party Transactions The Company considers an entity to be a related party if it owns more than 10% of the Company’s total voting stock at the end of each reporting period or if an officer or employee of an entity also serves on the Company’s board of directors or if it is a significant shareholder and has material business transactions with the Company. The Company enters into software license agreements with Cadence from time to time. The Chief Executive Officer of Cadence, who is also a Director of Cadence, was a member of the Company’s Board of Directors until June 7, 2017. Starting from fiscal year 2019, Cadence was no longer a related party of the Company. The Company paid $3.6 million of license fee to Cadence for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. License amortization expense related to these agreements included in research and development expense was approximately $4.2 million, $3.4 million and $3.2 million for the fiscal years ended January 31, 2020, 2019 and 2018, respectively.

Subsequent Events

Subsequent Events	12 Months Ended
Subsequent Events	Jan. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent Events From February 1, 2020 to March 26, 2020, the Company repurchased a total of 25,719 shares for approximately $1.0 million in cash. As of March 26, 2020, there was approximately $49.0 million available for repurchases under the Company’s repurchase program through June 30, 2020.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Jan. 31, 2020
Accounting Policies [Abstract]
Organization	Organization Ambarella, Inc. (the “Company”) was incorporated in the Cayman Islands on January 15, 2004. The Company is a leading developer of low-power semiconductor solutions offering high-definition (HD) and Ultra HD compression, image processing, and deep neural network processing. The Company combines its processor design capabilities with its expertise in video and image processing, algorithms and software to provide a technology platform that is designed to be easily scalable across multiple applications and enable rapid and efficient product development. The Company’s system-on-a-chip, or SoC, designs fully integrate high-definition video processing, image processing, artificial intelligence (AI) computer vision algorithms, audio processing and system functions onto a single chip, delivering exceptional video and image quality, differentiated functionality and low power consumption. The Company is currently addressing a broad range of human and computer vision applications, including professional and consumer security cameras, automotive cameras such as advanced driver assistance systems (ADAS), electronic mirrors, drive recorders, driver/cabin monitoring systems, autonomous driving, and industrial and robotic applications. The Company sells its solutions to leading original design manufacturers, or ODMs, and original equipment manufacturers, or OEMs, globally.
Basis of Consolidation	Basis of Consolidation The Company’s fiscal year ends on January 31. The consolidated financial statements of the Company and its subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”). All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expense during the reported periods. Actual results could differ from those estimates. On an ongoing basis, management evaluates its estimates and assumptions, including those related to (i) the collectability of accounts receivable; (ii) write down of excess and obsolete inventories; (iii) intangible assets and goodwill; (iv) the estimated useful lives of long-lived assets; (v) impairment of long-lived assets and financial instruments; (vi) warranty obligations; (vii) the valuation of stock-based compensation awards and financial instruments; (viii) the probability of performance objectives achievement; (ix) the realization of tax assets and estimates of tax liabilities, including reserves for uncertain tax positions; and (x) the recognition and disclosure of contingent liabilities. These estimates and assumptions are based on historical experience and on various other factors which the Company believes to be reasonable under the circumstances. The Company may engage third-party valuation specialists to assist with estimates related to the valuation of financial instruments, assets and stock awards associated with various contractual arrangements. Such estimates often require the selection of appropriate valuation methodologies and significant judgment. Actual results could differ from these estimates under different assumptions or circumstances and such differences could be material.
Concentration of Risk	Concentration of Risk The Company’s products are manufactured, assembled and tested by third-party contractors located primarily in Asia. The Company does not have long-term agreements with these contractors. A significant disruption in the operations of one or more of these contractors would impact the production of the Company’s products which could have a material adverse effect on its business, financial condition and results of operations. A substantial portion of the Company’s revenue is derived from sales through one of its distributors, Wintech Microelectronics Co., Ltd., or Wintech, which serves as its non-exclusive sales representative in Asia other than Japan, and directly to one ODM customer, Chicony Electronics Co., Ltd., or Chicony. Termination of the relationships with these customers could result in a temporary or permanent loss of revenue. Furthermore, any credit issues from these customers could impair their abilities to make timely payment to the Company. See Note 15 for additional information regarding revenue and credit concentration with these customers. Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable debt securities and accounts receivable. The Company maintains its cash primarily in checking accounts with reputable financial institutions. Cash deposits held with these financial institutions may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses on deposits of its cash. In order to limit the exposure of each investment, the cash equivalents and marketable debt securities consist primarily of money market funds, certificates of deposit, asset-backed securities, commercial paper, U.S. government securities and debt securities of corporations which management assesses to be highly liquid. The Company does not hold or issue financial instruments for trading purposes. The Company performs ongoing credit evaluation of its customers and adjusts credit limits based upon payment history and customers’ credit worthiness. The Company regularly monitors collections and payments from its customers.
Foreign Currency Transactions	Foreign Currency Transactions The U.S. dollar is the functional currency for the Company and its subsidiaries. Monetary assets and liabilities denominated in non-U.S. currencies are re-measured to U.S. dollars using current exchange rates in effect at the balance sheet date. Nonmonetary assets and liabilities are re-measured to U.S. dollars using historical exchange rates. Monetary and other accounts are re-measured to U.S. dollars using average exchange rates in effect during each period. Gains or losses from foreign currency re-measurement are included in other income, net in the consolidated statements of operations, and, to date, have not been material.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value accounting is applied to all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed in the financial statements on a recurring basis. The carrying amounts reflected in the consolidated balance sheets for cash equivalents, accounts receivable, accounts payable, accrued liabilities and other current liabilities, approximate fair value due to the short-term nature.
Cash Equivalents and Marketable Debt Securities	Cash Equivalents and Marketable Debt Securities The Company considers all highly liquid debt security investments with original maturities of less than three months at the time of purchase to be cash equivalents. Debt security investments that are highly liquid with original maturities at the time of purchase greater than three months are considered marketable debt securities. The Company classifies these investments as “available-for-sale” securities carried at fair value, based on quoted market prices of similar assets, with the unrealized gains or losses reported, net of tax, as a separate component of shareholders’ equity and included in accumulated other comprehensive income (loss) in the consolidated balance sheets. The amortization of premiums and accretion of discounts and the realized gains and losses are both recorded in other income, net, in the consolidated statements of operations. The Company reviews its investments for possible other-than-temporary impairments on a regular basis. If any loss on investment is believed to be other-than-temporary, a charge will be recorded and a new cost basis in the investment will be established. In evaluating whether a loss on a security is other-than-temporary, the Company considers the following factors: (i) general market conditions, (ii) the duration and extent to which the fair value is less than cost and (iii) the Company’s intent and ability to hold the investment. For securities in an unrealized loss position which is deemed to be other-than-temporary, the difference between the security’s then-current amortized cost basis and fair value is separated into (i) the amount of the impairment related to the credit loss (i.e., the credit loss component) and (ii) the amount of the impairment related to all other factors (i.e., the non-credit loss component). The credit loss component is recognized in earnings. The non-credit loss component is recognized in accumulated other comprehensive loss. Due to the relative short term nature of the investments, there have been no other-than-temporary impairments recorded to date.
Restricted Cash	Restricted Cash Amounts included in restricted cash represent those required to be set aside to secure certain transactions in a foreign entity. As of January 31, 2020 and 2019, the restricted cash was immaterial, respectively. The following table presents cash, cash equivalents and restricted cash reported on the consolidated balance sheets, and the sums are presented on the consolidated statements of cash flows: As of January 31, 2020 2019 2018 (in thousands) Cash and cash equivalents $ 231,403 $ 194,047 $ 346,672 Restricted cash 9 11 9 Total as presented in the consolidated statements of cash flows $ 231,412 $ 194,058 $ 346,681
Trade Accounts Receivable and Allowances for Doubtful Accounts	Trade Accounts Receivable and Allowances for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not include finance charges. The Company performs ongoing credit evaluation of its customers and generally requires no collateral. The Company assesses the need for allowances for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments by considering factors such as historical collection experience, credit quality, aging of the accounts receivable balances and current economic conditions that may affect a customer’s ability to pay. There were no material write-offs of accounts receivable for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. There was no material allowance for doubtful accounts recorded as of January 31, 2020 and 2019, respectively.
Inventories	Inventories The Company records inventories at the lower of cost or net realizable value. The cost includes materials and other production costs and is computed using standard cost on a first-in, first-out basis. Inventory reserves are recorded for estimated obsolescence or unmarketable inventories based on forecast of future demand and market conditions. Any adjustments to reduce the cost of inventories to their net realizable value are recognized in earnings in the current period.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and depreciated using the straight-line method over the estimated useful life for computer equipment, computer software, machinery, equipment and furniture and fixtures. Leasehold improvements are amortized over the shorter of the lease term or their estimated useful lives. Repairs and maintenance are charged to expense as incurred.
Noncancelable Internal-Use Software License	Noncancelable Internal-Use Software License The Company accounts for a noncancelable on premise internal-use software license as the acquisition of an intangible asset and the incurrence of a liability to the extent that all or a portion of the software licensing fees are not paid on or before the license acquisition date. The intangible asset and related liability are recorded at net present value and interest expense is recorded over the payment term.
Leases	Leases Effective February 1, 2019, the Company adopted Accounting Standards Codification (“ASC”) Topic 842, Leases, using the alternative transition method with an adjustment to the opening balance in the period of adoption without adjustment of comparative period financial statements. Under this new guidance, the Company recognizes leases as operating lease right-of-use (“ROU”) assets and corresponding lease liabilities at the lease commencement date based on the present value of future lease payments, while recognizing lease expenses under straight-line method through the lease term. The Company also elected the other available practical expedients, and has elected not to recognize ROU assets and lease liabilities that arise from short-term (12 months or less) leases and not to reassess the following for existing leases as of February 1, 2019: (i) whether contracts are or contain leases, (ii) lease classification, and (iii) initial direct costs. The Company does not combine lease components with non-lease components, and as a result, the non-lease components are accounted for separately. In determining the present value of lease payments, the Company uses the implicit interest rate if readily determinable. When the implicit rate is not readily determinable, the Company uses its incremental borrowing rate based on the information available at the lease commencement date. The Company's leases mainly include its worldwide office facilities which are classified as operating leases. Certain leases include renewal options that are under the Company's discretion. The renewal options are included in the ROU assets and liability calculation if it is reasonably certain that the Company will exercise the option. As of February 1, 2019, the Company recognized approximately $8.6 million of operating lease ROU assets, net of previously recognized prepaid rent and accrued liabilities, and corresponding lease liabilities of $8.7 million. The Company's short-term leases and finance leases are immaterial as of January 31, 2020 and February 1, 2019, respectively.
Goodwill and In-Process Research and Development	Goodwill and In-Process Research and Development The Company does not amortize goodwill. Acquired in-process research and development, or IPR&D, is capitalized at fair value as an intangible asset and amortization commences upon completion of the underlying projects. .
Impairment of Long-Lived Assets Including Goodwill and Other Acquired Intangible Assets	Impairment of Long-Lived Assets Including Goodwill and Other Acquired Intangible Assets The Company reviews property and equipment and intangible assets, excluding goodwill, for impairment at least annually in the fourth fiscal quarter or whenever events or changes in circumstances indicate that the carrying amount of an asset, or asset group, may not be recoverable. Determination of recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset, or asset group to estimated undiscounted future cash flows expected to be generated by the asset, or asset group. If the carrying amount of an asset or asset group exceeds its estimated undiscounted future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset or asset group exceeds the estimated fair value of the asset or asset group. Fair value is determined based on the estimated discounted future cash flows expected to be generated by the asset or asset group. Events or changes in circumstances that may indicate that an asset is impaired include significant decreases in the market value of an asset, significant underperformance relative to expected historical or projected future results of operations, a change in the extent or manner in which an asset is utilized, significant declines in the estimated fair value of the overall Company for a sustained period, shifts in technology, loss of key management or personnel, changes in the Company’s operating model or strategy and competitive forces. There has been no occurrence of events to date that would trigger an impairment analysis. As such, no impairment charge has been recognized as of January 31, 2020. The Company tests the goodwill for impairment at least annually in the fourth fiscal quarter, or sooner whenever events or changes in circumstances indicate that the asset may be impaired. The Company has a single reporting unit for goodwill impairment test purposes based on its business and reporting structure. The Company is permitted to first assess qualitative factors to determine whether the two step goodwill impairment test is necessary. Further testing is only required if the Company determines, based on the qualitative assessment, that it is more likely than not that a reporting unit’s fair value is less than its carrying amount. Otherwise, no further impairment testing is required. Qualitative factors include industry and market considerations, overall financial performance, and other relevant events and factors affecting the reporting unit .
Equity Investment	Equity Investment The Company accounts for its investment in a privately held company as an equity investment and reports the investment in other non-current assets in the consolidated balance sheets. The Company chooses to measure this equity investment that does not have readily determinable fair value at cost minus any recorded impairments, adjusted for observable price changes in transactions for an identical or similar investment of the same issuer. Upon determining that an impairment or observable price change exists, the Company records any adjustment to the fair value of the investment through net income. To date, there have been no identified events or changes in circumstances that may have a significant effect on the fair value of this investment and the Company has not recognized any impairment losses related to this investment nor have there been any observable price changes.
Revenue Recognition	Revenue Recognition Effective February 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers. As a result, the Company recognizes revenue when control of its goods and services is transferred to its customers. Revenue recognition is evaluated through the following five steps: (i) identification of the contract, or contracts, with a customer; (ii) identification of the performance obligations in the contract; (iii) determination of the transaction price; (iv) allocation of the transaction price to the performance obligations in the contract; and (v) recognition of revenue when or as a performance obligation is satisfied. The sale of semiconductor products accounts for the substantial majority of the Company’s consolidated revenue. Sales agreements with customers are renewable periodically and contain terms and conditions with respect to payment, delivery, warranty, supply and other rights. The Company considers an accepted customer purchase order, governed by sales agreement, to be the contract with the customer. For each contract, the Company considers the promise to transfer tangible products to be the identified performance obligation. Product sales contracts may include volume-based tiered pricing or rebates that are fulfilled in cash or product. In determining the transaction price, the Company accounts for the right of returns, cash rebates, commissions and other pricing adjustments as variable consideration and estimates these amounts based on the expected amount to be provided to customers and reduces the revenue recognized. The Company estimates sales returns and rebates based on the Company’s historical patterns of return and pricing credits. As the Company’s standard payment terms are 30 days to 60 days, the contracts have no financing component. Under ASC 606, the Company estimates the total consideration to be received by using the expected value method for each contract, computes weighted average selling price for each unit shipped in cases where there is a material right due to the presence of volume-based tiered pricing, allocates the total consideration between the identified performance obligations, and recognizes revenue when control of its goods and services is transferred to its customers. The Company considers product control to be transferred at a point in time upon shipment or delivery because the Company has a present right to payment at that time, the customer has legal title to the asset, the Company has transferred physical possession of the asset, and the customer has significant risk and rewards of ownership of the asset. The Company also enters into fixed-price engineering service agreements with certain customers. These agreements may include multiple performance obligations, such as software development services, licensing of intellectual property and post-contract customer support, or PCS. These multiple performance obligations are highly interdependent, highly interrelated, are typically not sold separately and do not have standalone selling prices. They are all inputs to generate one combined output which is incorporating the Company’s SoC into the customer’s product. Accordingly, the Company determines that they are not separately identifiable and shall be treated as a single performance obligation. Customers usually pay based on milestones achieved. Because payments received do not correspond directly with the value of the Company’s performance to date, for fixed-price engineering services arrangements, revenue is recognized using the time-based straight line method, which best depicts the Company’s performance toward complete satisfaction of the performance obligation based on the nature of such professional services. Revenues from engineering service agreements were not material for the fiscal years ended January 31, 2020, 2019 and 2018, respectively. Timing of revenue recognition may differ from the timing of invoicing to the Company’s customers. The Company records contract assets when revenue is recognized prior to invoicing. The Company’s contract assets are primarily related to satisfied but unbilled performance obligations associated with its engineering service agreements at the reporting date. As of January 31, 2020 and 2019, the contract assets for these unbilled receivables were not material. The Company’s contract liabilities consist of deferred revenue. The deferred revenue is primarily related to the portion of a transaction price that exceeds the weighted average selling price for products sold to date under tiered-pricing contracts which contain material rights. This deferred revenue is expected to be recognized over the course of the contract when products are delivered for future pricing below the weighted average selling price of the contract. For the twelve months ended January 31, 2020 and 2019, the Company did not recognize any material revenue adjustment, respectively, related to performance obligations satisfied in prior periods released from this deferred revenue. As of January 31, 2020 and 2019, the respective deferred revenues were not material. Additionally, the transaction price allocated to unsatisfied, or partially unsatisfied, purchase orders for contracts that are greater than a year was not material as of January 31, 2020 and 2019, respectively. The Company also elects not to disclose the value of unsatisfied or partially unsatisfied performance obligations due to original expected contract duration of one year or less and elects to exclude amounts collected from customers for all sales taxes from the transaction price.
Cost of Revenue	Cost of Revenue Cost of revenue includes cost of materials, cost associated with packaging and assembly, testing and shipping, cost of personnel, stock-based compensation, logistics and quality assurance, warranty cost, royalty expense, write-downs of inventories and allocation of overhead.
Warranty Costs	Warranty Costs The Company typically provides warranty on its products. The Company accrues for the estimated warranty costs at the time when revenue is recognized. The warranty accruals are regularly monitored by management based upon historical experience and any specifically identified failures. While the Company engages in extensive product quality assessment, actual product failure rates, material usage or service delivery costs could differ from estimates and revisions to the estimated warranty liability would be required. There was no warranty accrual as of January 31, 2020 and 2019, respectively.
Research and Development	Research and Development Research and development costs are expensed as incurred and consist primarily of personnel costs, product development costs, which include engineering services, development software and hardware tools, license fees, costs of fabrication of masks for prototype products, other development materials costs, depreciation of equipment and tools and allocation of facility costs, net of any research and development grants. As of January 31, 2020, there was approximately $1.2 million of grants recorded in prepaid expenses and other current assets and approximately $3.2 million of grants recorded in other non-current assets in the consolidated balance sheets.
Selling, General and Administrative	Selling, General and Administrative Selling, general and administrative expenses consist of personnel costs, travel and trade show costs, legal expenses, other professional services and occupancy costs. Advertising expenses were not material for the fiscal years ended January 31, 2020, 2019 and 2018, respectively.
Stock-Based Compensation	Stock-Based Compensation The Company measures stock-based compensation for equity awards granted to employees and directors based on the estimated fair value on the grant date, and recognizes that compensation as expense using the straight-line attribution method for service condition awards or using the graded-vesting attribution method for awards with performance conditions over the requisite service period, which is typically the vesting period of each award. The Company determines the fair value of restricted stock and restricted stock units with service or performance conditions based on the fair market value of its ordinary shares on the grant date. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options. Determining the fair value of stock options on the grant date requires the input of various assumptions, including stock price of the underlying ordinary share, the exercise price of the stock option, expected volatility, expected term, risk-free interest rate and dividend rate. In prior fiscal years, the expected term was calculated using the simplified method, and the expected volatility was calculated based on the weighted average of historical volatilities of the Company’s stock price and the share prices of similar companies that are publicly available for a period commensurate with the expected term. Starting from fiscal year 2019, the Company calculates expected volatility based on its own historical stock price for a period commensurate with the expected term, which is computed based on its own historical exercise behavior. The risk-free interest rate is derived from an average of the U.S. Treasury constant maturity rates for the respective periods most closely commensurate with the expected term. The expected dividend yield is zero because the Company has not historically paid dividends and has no present intention to pay dividends. The Company uses the Lattice pricing model and Monte Carlo Simulation to evaluate the fair value of awards with market conditions, including assumptions of historical volatility and risk-free interest rate commensurate with the vesting term. Upon adoption of ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting
Income Taxes	Income Taxes The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in its financial statements or tax returns. In estimating future tax consequences, generally all expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized. The Company applies authoritative guidance for the accounting for uncertainty in income taxes. The guidance requires that tax effects of a position be recognized only if it is “more likely than not” to be sustained based solely on its technical merits as of the reporting date. Upon estimating its tax positions and tax benefits, the Company considers and evaluates numerous factors, which may require periodic adjustments and which may not reflect the final tax liabilities. The Company adjusts its financial statements to reflect only those tax positions that are more likely than not to be sustained under examination . As part of the process of preparing consolidated financial statements, the Company is required to estimate its taxes in each of the jurisdictions in which it operates. The Company estimates actual current tax exposure together with assessing temporary differences resulting from differing treatment of items, such as accruals and allowances not currently deductible for tax purposes. These differences result in deferred tax assets, which are included in the consolidated balance sheets. In general, deferred tax assets represent future tax benefits to be received when certain expenses previously recognized in the consolidated statements of operations become deductible expenses under applicable income tax laws, or loss or credit carryforwards are utilized. In assessing whether deferred tax assets may be realized, the Company considers whether it is more likely than not that some portion or all of deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income. The Company makes estimates and judgments about its future taxable income based on assumptions that are consistent with its plans and estimates. Should the actual amounts differ from estimates, the amount of valuation allowance could be materially impacted. Any adjustment to the deferred tax asset valuation allowance would be recorded in the consolidated income statement for the periods in which the adjustment is determined to be required.
Net Income (Loss) Per Ordinary Share	Net Income (Loss) Per Ordinary Share Basic earnings (losses) per share is computed by dividing net income (loss) available to ordinary shareholders by the weighted-average number of ordinary shares outstanding during the period. Diluted earnings (losses) per share is computed by dividing net income (loss) available to ordinary shareholders by the weighted-average number of ordinary shares outstanding during the period increased to include the number of additional ordinary shares that would have been outstanding if the potentially dilutive securities had been issued. Potentially dilutive securities include outstanding stock options, shares to be purchased under the Company’s employee stock purchase plan, unvested restricted stock and restricted stock units. The dilutive effect of potentially dilutive securities is reflected in diluted earnings (losses) per share by application of the treasury stock method.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) includes unrealized gains or losses from available-for-sale securities that are excluded from net income (loss).
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326), to introduce a new impairment model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses (“CECL”). Under the new CECL model, an entity is required to estimate the expected credit losses on available-for-sale (AFS) debt securities only when the fair value is below the amortized cost of the asset and is no longer based on an impairment being “other-than-temporary”. The new model also requires the impairment calculation on an individual security level and requires an entity use present value of cash flows when estimating the expected credit losses. The credit-related losses are required to be recognized through earnings and non-credit related losses are reported in other comprehensive income. In April 2019, the FASB further clarified the scope of the credit losses standard and addressed issues related to accrued interest receivable balances, recoveries, variable interest rates and prepayment. The ASU will be effective for public entities in fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The new guidance will require modified retrospective application to all outstanding instruments, with a cumulative effect adjustment recorded to opening retained earnings as of the beginning of the first period in which the guidance becomes effective. The Company is currently evaluating the impact of adoption of this new guidance but does not expect it will have a material impact on its consolidated financial statements and disclosures. In January 2017, the FASB issued ASU 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test of Goodwill Impairment, to eliminate the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value. This new guidance will be applied prospectively and is effective for annual and interim periods beginning after December 15, 2019. The Company does not believe the adoption of this new guidance will have a material impact on its consolidated financial statements and disclosures . In August 2018, the FASB issued 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. Under this new guidance, the entities will no longer be required to disclose the amount of and the reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, but will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. The guidance is effective for fiscal years beginning after December 15, 2019 and for the interim periods within those fiscal years. Early adoption is permitted. The Company did not early adopt and believes the adoption of this new guidance will not have a material impact on its consolidated financial statements and disclosures. In August 2018, the FASB issued 2018-15, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. Under this new guidance, the entities are required to capitalize implementation costs related to a hosting arrangement that is a service contract and amortize the costs over the term of the hosting arrangement, beginning when the module or component of the hosting arrangement is ready for its intended use. The guidance is effective for fiscal years beginning after December 15, 2019 and for the interim periods within those fiscal years. Early adoption is permitted. The Company did not early adopt and believes the adoption of this new guidance will not have a material impact on its consolidated financial statements and disclosures. In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 25, Financial Instruments. The new guidance further clarifies that equity instruments without readily determinable fair values for which an entity has elected the measurement alternative should be remeasured to fair value as of the date that an observable transaction occurred. The FASB also amended the guidance to clarify that the nonrecurring fair value disclosure is applicable to equity instruments accounted for under the measurement alternative. The ASU will be effective for public entities in fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, with early adoption permitted and requires a prospective method for those related to equity securities without readily determinable fair values that are measured using the measurement alternative. The Company did not early adopt and believes the adoption of this new amendment will not have a material impact on its consolidated financial statements and disclosures. In November 2019, the FASB issued ASU 2019-08, Compensation – Stock Compensation (Topic 718) and Revenue from Contracts with Customers (Topic 606): Codification Improvements – Share-Based Consideration Payable to a Customer. Under this new guidance, a share-based payment award issued to a customer should be measured at the grant date fair value and recorded as a reduction of the transaction price in revenue. Changes in the measurement of the share-based payments after the grant date that are due to the form of the consideration are not included in the transaction price and are recorded elsewhere in the income statement. The award is measured and classified under ASC 718 for its entire life, unless the award is modified after it vests and the grantee is no longer a customer. The new guidance is effective for public entities that have adopted ASU 2018-07 in fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. The Company did not early adopt and believes the adoption of this new guidance will not have a material impact on its consolidated financial statements and disclosures. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in this ASU simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The amendments are effective for public entities in fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. Early adoption is permitted. The Company did not early adopt and believes the adoption of this new guidance will not have a material impact on its consolidated financial statements and disclosures.

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Jan. 31, 2020
Accounting Policies [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table presents cash, cash equivalents and restricted cash reported on the consolidated balance sheets, and the sums are presented on the consolidated statements of cash flows: As of January 31, 2020 2019 2018 (in thousands) Cash and cash equivalents $ 231,403 $ 194,047 $ 346,672 Restricted cash 9 11 9 Total as presented in the consolidated statements of cash flows $ 231,412 $ 194,058 $ 346,681

Financial Instruments and Fai_2

Financial Instruments and Fair Value (Tables)	12 Months Ended
Financial Instruments and Fair Value (Tables)	Jan. 31, 2020
Investments All Other Investments [Abstract]
Schedule of Available-for-Sale Securities at Fair Value	All of the investments are classified as available-for-sale securities and reported at fair value in the consolidated balance sheets as follows: As of January 31, 2020 Amortized Unrealized Unrealized Losses Fair Value (in thousands) Money market funds $ 8,284 $ — $ — $ 8,284 Commercial paper 63,390 — — 63,390 Corporate bonds 95,053 653 — 95,706 Asset-backed securities 23,062 69 (2 ) 23,129 U.S. government securities 20,524 48 — 20,572 Total cash equivalents and marketable debt securities $ 210,313 $ 770 $ (2 ) $ 211,081 As of January 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value (in thousands) Money market funds $ 8,914 $ — $ — $ 8,914 Certificates of Deposit 7,012 — — 7,012 Commercial paper 68,233 — — 68,233 Corporate bonds 87,250 170 (60 ) 87,360 Asset-backed securities 11,607 3 (6 ) 11,604 U.S. government securities 21,993 3 (13 ) 21,983 Total cash equivalents and marketable debt securities $ 205,009 $ 176 $ (79 ) $ 205,106
Schedule of Cash Equivalents and Marketable Debt Securities	As of January 31, 2020 January 31, 2019 (in thousands) Included in cash equivalents $ 37,736 $ 40,245 Included in marketable debt securities 173,345 164,861 Total cash equivalents and marketable debt securities $ 211,081 $ 205,106
Summary of Contractual Maturities of Investments	The contractual maturities of the investments at January 31, 2020 and 2019 were as follows: As of January 31, 2020 January 31, 2019 (in thousands) Due within one year $ 146,267 $ 151,991 Due within one to three years 64,814 53,115 Total cash equivalents and marketable debt securities $ 211,081 $ 205,106
Schedule of Fair Value of Financial Instruments Measured on Recurring Basis	The following tables present the fair value of the financial instruments measured on a recurring basis as of January 31, 2020 and 2019, respectively: As of January 31, 2020 Total Level 1 Level 2 Level 3 (in thousands) Money market funds $ 8,284 $ 8,284 $ — $ — Commercial paper 63,390 — 63,390 — Corporate bonds 95,706 — 95,706 — Asset-backed securities 23,129 — 23,129 — U.S. government securities 20,572 — 20,572 — Total cash equivalents and marketable debt securities $ 211,081 $ 8,284 $ 202,797 $ — As of January 31, 2019 Total Level 1 Level 2 Level 3 (in thousands) Money market funds $ 8,914 $ 8,914 $ — $ — Certificates of Deposit 7,012 7,012 Commercial paper 68,233 — 68,233 — Corporate bonds 87,360 — 87,360 — Asset-backed securities 11,604 — 11,604 — U.S. government securities 21,983 — 21,983 — Total cash equivalents and marketable debt securities $ 205,106 $ 15,926 $ 189,180 $ —

Inventories (Tables)

Inventories (Tables)	12 Months Ended
Inventories (Tables)	Jan. 31, 2020
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventories at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Work-in-progress $ 10,133 $ 9,430 Finished goods 12,838 8,822 Total $ 22,971 $ 18,252

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
Property and Equipment, Net (Tables)	Jan. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Computer equipment and software $ 10,282 $ 9,098 Machinery and equipment 6,317 5,659 Furniture and fixtures 969 969 Leasehold improvements 2,356 2,331 Construction in progress 63 330 19,987 18,387 Less: accumulated depreciation and amortization (14,373 ) (11,659 ) Total property and equipment, net $ 5,614 $ 6,728

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
Intangible Assets (Tables)	Jan. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Carrying Amounts of Intangible Assets	The carrying amounts of intangible assets as of January 31, 2020 and 2019 were as follows : As of January 31, 2020 As of January 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in thousands) In-process research and development $ 4,100 $ — $ 4,100 $ 4,100 $ — $ 4,100 Internal-use software license 27,203 (13,477 ) 13,726 14,448 (7,612 ) 6,836 Total acquired intangible assets $ 31,303 $ (13,477 ) $ 17,826 $ 18,548 $ (7,612 ) $ 10,936
Summary of Expected Annual Amortization Expense Related to Software Licenses	The expected annual amortization expense related to these software licenses as of January 31, 2020 is as follows: As of January 31, 2020 Fiscal Year (in thousands) 2021 $ 5,789 2022 4,519 2023 3,418 2024 — 2025 — Thereafter — Total future amortization expenses: $ 13,726

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	12 Months Ended
Accrued and Other Current Liabilities (Tables)	Jan. 31, 2020
Payables And Accruals [Abstract]
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Accrued employee compensation $ 16,874 $ 10,645 Accrued rebates 54 311 Accrued product development costs 10,885 6,393 Software license liabilities, current 4,388 4,879 Other accrued liabilities 2,769 2,472 Total accrued and other current liabilities $ 34,970 $ 24,700

Leases (Tables)

Leases (Tables)	12 Months Ended
Leases (Tables)	Jan. 31, 2020
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases is as follows: Twelve Months Ended January 31, 2020 (in thousands) Cash paid for operating leases included in operating cash flows $ 2,851 Supplemental non-cash information related to lease liabilities arising from obtaining right-of-use assets $ 299 Leased assets obtained in exchange for operating lease liabilities arising from lease modifications $ 4,021
Schedule of Future Minimum Lease Payments for Lease Liabilities Excluding Additional Space for U.S. Office and Parma Lease	As of January 31, 2020, the weighted average remaining lease term is 5.02 years, and the weighted average discount rate is 4.43 percent. Future minimum lease payments for the lease liabilities, excluding the additional space for the U.S. office and the Parma lease described above, are as follows : As of January 31, 2020 Fiscal Year (in thousands) 2021 $ 2,522 2022 2,371 2023 1,645 2024 1,694 2025 1,740 Thereafter 1,210 Total future annual minimum lease payments 11,182 Less: interest (1,026 ) Total lease liabilities $ 10,156
Schedule of Future Minimum Undiscounted Lease Payments	Prior to the adoption of the new lease guidance, future minimum undiscounted lease payments as of January 31, 2019 were as follows: As of January 31, 2019 Fiscal Year (in thousands) 2020 $ 2,592 2021 1,040 2022 356 2023 143 2024 147 Thereafter 576 Total future annual minimum lease payments $ 4,854
Leases (ASC 842) [Member]
Schedule of Cumulative Effect of the Changes to the Consolidated Balance Sheet	The cumulative effect of the changes made to the consolidated balance sheets as of February 1, 2019 for the adoption of ASC 842 was as follows: Balance as of Opening Balance as of January 31, 2019 Adjustment February 1, (in thousands) Operating lease right-of-use assets $ — $ 8,581 $ 8,581 Prepaid expenses and other current assets $ 6,206 $ (174 ) $ 6,032 Accrued and other current liabilities $ 24,700 $ (279 ) $ 24,421 Operating lease liabilities, current $ — $ 2,534 $ 2,534 Operating lease liabilities, non-current $ — $ 6,152 $ 6,152

Other Long-Term Liabilities (Ta

Other Long-Term Liabilities (Tables)	12 Months Ended
Other Long-Term Liabilities (Tables)	Jan. 31, 2020
Other Liabilities Disclosure [Abstract]
Schedule of Other Long-Term Liabilities	Other long-term liabilities at January 31, 2020 and 2019 consisted of the following: As of January 31, 2020 2019 (in thousands) Unrecognized tax benefits, including interest $ 8,261 $ 6,732 Deferred tax liabilities, non-current 1,288 1,293 Software license liabilities, non-current 8,159 310 Other long-term liabilities 68 6 Total other long-term liabilities $ 17,776 $ 8,341

Capital Stock (Tables)

Capital Stock (Tables)	12 Months Ended
Capital Stock (Tables)	Jan. 31, 2020
Equity [Abstract]
Schedule of Ordinary Shares Reserved for Future Issuance under EIP and ESPP	As of January 31, 2020 and January 31, 2019, the following ordinary shares were reserved for future issuance under the EIP and ESPP: As of January 31, 2020 2019 Shares reserved for options, restricted stock and restricted stock units 6,045,108 5,915,654 Shares reserved for employee stock purchase plan 2,059,504 1,833,574

Employee Benefits and Stock-b_2

Employee Benefits and Stock-based Compensation (Tables)	12 Months Ended
Employee Benefits and Stock-based Compensation (Tables)	Jan. 31, 2020
Postemployment Benefits [Abstract]
Classification of Stock-based Compensation	The following table presents the classification of stock-based compensation for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands) Stock-based compensation: Cost of revenue $ 1,184 $ 1,261 $ 1,306 Research and development 41,842 37,432 34,575 Selling, general and administrative 23,845 22,119 20,980 Total stock-based compensation $ 66,871 $ 60,812 $ 56,861
Weighted-Average Assumptions Used to Estimate Fair Value	The following table sets forth the weighted-average assumptions used to estimate the fair value of the stock options and employee stock purchase plan awards for the periods indicated: Year Ended January 31, 2020 2019 2018 Stock Options: Volatility 52 % 54 % 53 % Risk-free interest rate 1.82 % 2.77 % 2.08 % Expected term (years) 6.01 5.41 6.08 Dividend yield 0 % 0 % 0 % Employee stock purchase plan awards: Volatility 47 % 45 % 44 % Risk-free interest rate 2.23 % 2.15 % 1.03 % Expected term (years) 0.5 0.5 0.5 Dividend yield 0 % 0 % 0 %
Stock Option Activities	The following table summarizes stock option activities for the periods indicated: Option Outstanding Weighted- Total Average Weighted- Value of Remaining Aggregate Weighted- Average options Contractual Intrinsic Average Grant-date Exercised Term Value Shares Exercise Fair Value (in (in years) (in Outstanding at January 31, 2017 1,703,524 $ 21.66 Granted 132,250 54.66 $ 28.28 Exercised (175,187 ) 12.50 $ 7,446 Forfeited (27,721 ) 56.97 Expired (21,522 ) 36.31 Outstanding at January 31, 2018 1,611,344 24.56 Granted 116,600 42.73 $ 21.75 Exercised (232,205 ) 5.54 $ 8,867 Forfeited (20,974 ) 53.50 Expired (15,701 ) 54.35 Outstanding at January 31, 2019 1,459,064 28.31 Granted 66,850 50.56 $ 25.35 Exercised (366,886 ) 15.52 $ 13,263 Forfeited (14,931 ) 46.29 Expired (19,451 ) 64.53 Outstanding at January 31, 2020 1,124,646 $ 32.93 4.35 $ 31,295 Exercisable at January 31, 2020 960,567 $ 30.24 3.65 $ 29,573
Restricted Stock and Restricted Stock Units Activities	The following table summarizes restricted stock and restricted stock units activities for the periods indicated: Weighted- Average Grant-Date Shares Fair Value Unvested at January 31, 2017 2,175,673 $ 56.76 Granted 1,052,235 47.11 Vested (1,006,130 ) 47.55 Forfeited (118,497 ) 54.72 Unvested at January 31, 2018 2,103,281 56.45 Granted 1,367,751 40.03 Vested (994,500 ) 53.27 Forfeited (81,016 ) 53.57 Unvested at January 31, 2019 2,395,516 48.49 Granted 1,329,288 54.54 Vested (1,012,581 ) 51.24 Forfeited (94,957 ) 54.26 Unvested at January 31, 2020 2,617,266 $ 50.30

Net Income (Loss) Per Ordinar_2

Net Income (Loss) Per Ordinary Share (Tables)	12 Months Ended
Net Income (Loss) Per Ordinary Share (Tables)	Jan. 31, 2020
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income (Loss) Per Ordinary Share	The following table sets forth the computation of basic and diluted net income (loss) per ordinary share for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands, except share and per share data) Numerator: Net income (loss) $ (44,792 ) $ (30,447 ) $ 18,852 Denominator: Weighted-average ordinary shares - basic 33,083,562 32,713,606 33,224,803 Effect of dilutive securities: Employee stock options — — 961,797 Restricted stock and restricted stock units — — 390,145 Employee stock purchase plan — — 6,405 Weighted-average ordinary shares - diluted 33,083,562 32,713,606 34,583,150 Net income (loss) per ordinary share: Basic $ (1.35 ) $ (0.93 ) $ 0.57 Diluted $ (1.35 ) $ (0.93 ) $ 0.55
Weighted-Average Potentially Dilutive Securities Excluded from Computation of Diluted Net Income (Loss) Per Ordinary Share	The following weighted-average potentially dilutive securities were excluded from the computation of diluted net income (loss) per ordinary share as their effect would have been antidilutive: Year Ended January 31, 2020 2019 2018 Options to purchase ordinary shares 913,678 1,190,607 280,907 Restricted stock and restricted stock units 1,139,269 1,522,903 907,208 Employee stock purchase plan 8,530 26,831 15,506 2,061,477 2,740,341 1,203,621

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Jan. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Income(Loss) before Income Taxes	Income (loss) before income taxes consisted of the following for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands) U.S. operations $ 845 $ 1,381 $ 2,683 Non-U.S. operations (42,473 ) (35,933 ) 23,046 Income (loss) before income taxes $ (41,628 ) $ (34,552 ) $ 25,729
Schedule of Income Tax Provision (Benefit)	Income tax provision (benefit) consisted of the following for the periods indicated: Year Ended January 31, 2020 2019 2018 (in thousands) Current: U.S. federal tax $ 1,440 $ 1,290 $ 3,321 U.S. state taxes 3 2 4 Non-U.S. foreign taxes 1,540 1,561 1,435 2,983 2,853 4,760 Deferred: U.S. federal tax 182 (7,077 ) 2,185 U.S. state taxes — — — Non-U.S. foreign taxes (1 ) 119 (68 ) 181 (6,958 ) 2,117 Provision (benefit) for income taxes $ 3,164 $ (4,105 ) $ 6,877
Schedule of Reconciliation Between the Provision (Benefit) for Income Taxes at the Statutory Rate and the Effective Tax Rate	For purposes of the reconciliation between the provision (benefit) for income taxes at the statutory rate and the effective tax rate, a notional U.S. 21.0%, 21.0% and 33.8% rates are applied to pretax income (loss) as a result of the following for the periods indicated, respectively: Year Ended January 31, 2020 2019 2018 (in thousands) Provision at U.S. notional statutory rate $ (8,742 ) $ (7,256 ) $ 8,699 U.S. state taxes 3 2 2 Non-U.S. foreign tax differential 10,458 9,226 (6,424 ) Stock-based compensation 4,172 4,715 4,645 U.S. R&D credit (3,109 ) (2,770 ) (2,408 ) Valuation allowance — (7,990 ) (1 ) Change in tax rate — — 2,252 Other 382 (32 ) 112 Provision (benefit) for income taxes $ 3,164 $ (4,105 ) $ 6,877
Schedule of Deferred Tax Assets and Liabilities	On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted into law in the United States. The tax legislation contains several provisions that impacted the Company, including the reduction of the corporate income tax rate from 35% to 21%, acceleration of business asset expensing, and a reduction in the amount of executive pay that may qualify as a tax deduction, among others. The income tax benefit recorded for the fiscal year ended January 31, 2019 includes the impact of the Tax Act. Temporary differences that gave rise to significant portions of the Company’s deferred tax assets and liabilities at January 31, 2020 and 2019 were as follows: As of January 31, 2020 2019 (in thousands) Deferred tax assets: Federal and state credits $ 21,275 $ 19,426 Expenses not currently deductible 593 575 Operating lease liabilities 2,023 — Stock-based compensation 3,203 3,202 Foreign deferred 132 122 Gross deferred tax assets 27,226 23,325 Valuation allowance (14,670 ) (12,526 ) Total deferred tax assets $ 12,556 $ 10,799 Deferred tax liabilities Property and equipment (1,469 ) (1,505 ) Operating lease assets (1,974 ) — Net deferred tax assets $ 9,113 $ 9,294
Summary of Tax Valuation Allowance	Tax valuation allowance for the periods indicated below were as follows: Deductions Additions Charged to Balance at Additional Charged to Expenses Balance at Beginning of Charged to Other or Other End of Period Expenses Account Accounts Period (in thousands) Tax Valuation Allowance Year ended January 31, 2020 $ 12,526 2,144 — — $ 14,670 Year ended January 31, 2019 $ 18,538 1,978 — (7,990 ) $ 12,526 Year ended January 31, 2018 $ 15,061 3,477 — — $ 18,538
Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	The following table sets forth a reconciliation of the beginning and ending amount of unrecognized tax benefits: Year Ended January 31, 2020 2019 2018 (in thousands) Beginning balance: $ 37,531 $ 34,117 $ 37,977 Additions based on tax positions related to the current year 4,964 3,922 7,892 Additions for tax positions of prior years 252 109 28 Reductions for tax positions in prior years — (552 ) (11,313 ) Settlements for prior periods — — — Lapse of applicable statute of limitations (52 ) (65 ) (467 ) Ending balance: $ 42,695 $ 37,531 $ 34,117

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
Segment Reporting (Tables)	Jan. 31, 2020
Segment Reporting [Abstract]
Company's Revenue by Geographic Region Based on Bill-to Location	The following table sets forth the Company’s revenue by geographic region based on bill-to location for the periods indicated. Year Ended January 31, 2020 2019 2018 (in thousands) Taiwan $ 137,946 $ 132,199 $ 174,486 Asia Pacific 66,867 66,981 57,862 Europe 11,134 18,244 45,185 North America other than United States 8,402 7,028 11,110 United States 4,383 3,316 6,759 Total revenue $ 228,732 $ 227,768 $ 295,402

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies - Schedule of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 231,403	$ 194,047	$ 346,672
Restricted cash	9	11	9
Total as presented in the consolidated statements of cash flows	$ 231,412	$ 194,058	$ 346,681	$ 322,880

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Feb. 01, 2019
Summary Of Significant Accounting Policies [Line Items]
Material inventory losses recognized	$ 0	$ 0	$ 0
Operating lease right-of-use assets	9,935,000	0
Operating lease liabilities	10,156,000
Accumulated amortization of intangible asset	13,477,000	7,612,000
Impairment of long-lived assets	0
Goodwill impairment	0	$ 0	$ 0
Impairment losses on investment	0
Accrued warranty	$ 0
Expected dividend yield	0.00%	0.00%	0.00%
Prepaid Expenses and Other Current Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Grants recorded	$ 1,200,000
Other Non-current Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Grants recorded	3,200,000
IPR&D [Member]
Summary Of Significant Accounting Policies [Line Items]
Accumulated amortization of intangible asset	$ 0	$ 0
ASU 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating lease right-of-use assets				$ 8,581,000
Operating lease liabilities				$ 8,700,000

Financial Instruments and Fai_3

Financial Instruments and Fair Value - Schedule of Available-for-Sale Securities at Fair Value (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 210,313	$ 205,009
Unrealized Gains	770	176
Unrealized Losses	(2)	(79)
Fair Value	211,081	205,106
Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,284	8,914
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	8,284	8,914
Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		7,012
Unrealized Gains		0
Unrealized Losses		0
Fair Value		7,012
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	63,390	68,233
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	63,390	68,233
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	95,053	87,250
Unrealized Gains	653	170
Unrealized Losses	0	(60)
Fair Value	95,706	87,360
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,062	11,607
Unrealized Gains	69	3
Unrealized Losses	(2)	(6)
Fair Value	23,129	11,604
U.S. government securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,524	21,993
Unrealized Gains	48	3
Unrealized Losses	0	(13)
Fair Value	$ 20,572	$ 21,983

Financial Instruments and Fai_4

Financial Instruments and Fair Value - Schedule of Cash Equivalents and Marketable Debt Securities (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Total cash equivalents and marketable debt securities	$ 211,081	$ 205,106
Included in cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Total cash equivalents and marketable debt securities	37,736	40,245
Included in marketable debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total cash equivalents and marketable debt securities	$ 173,345	$ 164,861

Financial Instruments and Fai_5

Financial Instruments and Fair Value - Summary of Contractual Maturities of Investments (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Available For Sale Securities Debt Maturities Fair Value [Abstract]
Due within one year	$ 146,267	$ 151,991
Due within one to three years	64,814	53,115
Total cash equivalents and marketable debt securities	$ 211,081	$ 205,106

Financial Instruments and Fai_6

Financial Instruments and Fair Value - Schedule of Fair Value of Financial Instruments Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	$ 211,081	$ 205,106
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	8,284	8,914
Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities		7,012
Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	63,390	68,233
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	95,706	87,360
Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	23,129	11,604
U.S. government securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	20,572	21,983
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	8,284	15,926
Level 1 [Member] \| Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	8,284	8,914
Level 1 [Member] \| Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities		7,012
Level 1 [Member] \| Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 1 [Member] \| Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 1 [Member] \| Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 1 [Member] \| U.S. government securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	202,797	189,180
Level 2 [Member] \| Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 2 [Member] \| Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	63,390	68,233
Level 2 [Member] \| Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	95,706	87,360
Level 2 [Member] \| Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	23,129	11,604
Level 2 [Member] \| U.S. government securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	20,572	21,983
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 3 [Member] \| Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 3 [Member] \| Commercial paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 3 [Member] \| Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 3 [Member] \| Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	0	0
Level 3 [Member] \| U.S. government securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents and marketable debt securities	$ 0	$ 0

Inventories - Schedule of Inven

Inventories - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Inventory Disclosure [Abstract]
Work-in-progress	$ 10,133	$ 9,430
Finished goods	12,838	8,822
Total	$ 22,971	$ 18,252

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation of property and equipment	$ 2.8	$ 2.6	$ 1.8

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 19,987	$ 18,387
Less: accumulated depreciation and amortization	(14,373)	(11,659)
Total property and equipment, net	5,614	6,728
Computer equipment and software [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	10,282	9,098
Machinery and equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	6,317	5,659
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	969	969
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	2,356	2,331
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 63	$ 330

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Jun. 25, 2015
Finite Lived Intangible Assets [Line Items]
Intangible assets, net of amortization expense	$ 17,826,000	$ 10,936,000
Accumulated amortization of intangible asset	13,477,000	7,612,000
Liabilities associated with noncancelable internal-use software license at net present value, current	4,388,000	4,879,000
Liabilities associated with noncancelable internal-use software license at net present value, non-current	8,159,000	310,000
Impairment of intangible assets	0	0	$ 0
Vis Lab SRL [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets acquired				$ 4,100,000
IPR&D [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, net of amortization expense	4,100,000	4,100,000
Accumulated amortization of intangible asset	0	0
IPR&D [Member] \| Vis Lab SRL [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets acquired				$ 4,100,000
Noncancelable software licenses [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, net of amortization expense	13,700,000
Internal-use software licenses [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, net of amortization expense	13,726,000	6,836,000
Accumulated amortization of intangible asset	13,477,000	7,612,000
Amortization expense	$ 5,900,000	$ 4,700,000	$ 3,000,000

Intangible Assets - Summary of

Intangible Assets - Summary of Carrying Amounts of Intangible Assets (Detail) - USD ($)	Jan. 31, 2020	Jan. 31, 2019
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 31,303,000	$ 18,548,000
Accumulated Amortization	(13,477,000)	(7,612,000)
Net Carrying Amount	17,826,000	10,936,000
In-process research and development [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,100,000	4,100,000
Accumulated Amortization	0	0
Net Carrying Amount	4,100,000	4,100,000
Internal-use software license [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	27,203,000	14,448,000
Accumulated Amortization	(13,477,000)	(7,612,000)
Net Carrying Amount	$ 13,726,000	$ 6,836,000

Intangible Assets - Summary o_2

Intangible Assets - Summary of Expected Annual Amortization Expense Related to Software Licenses (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Finite Lived Intangible Assets [Line Items]
Net Carrying Amount	$ 17,826	$ 10,936
Internal-use software license [Member]
Finite Lived Intangible Assets [Line Items]
2021	5,789
2022	4,519
2023	3,418
2024	0
2025	0
Thereafter	0
Net Carrying Amount	$ 13,726	$ 6,836

Goodwill - Additional Informati

Goodwill - Additional Information (Detail) - USD ($)	Jun. 25, 2015	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Finite Lived Intangible Assets [Line Items]
Goodwill		$ 26,601,000	$ 26,601,000
Goodwill impairment		$ 0	$ 0	$ 0
Vis Lab SRL [Member]
Finite Lived Intangible Assets [Line Items]
Business acquisition date	Jun. 25, 2015
Cash paid for business acquisition	$ 30,000,000
Goodwill	25,300,000
Intangible assets acquired	4,100,000
Net assets acquired	600,000
Deferred tax liabilities, intangible assets	$ 1,300,000

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Payables And Accruals [Abstract]
Accrued employee compensation	$ 16,874	$ 10,645
Accrued rebates	54	311
Accrued product development costs	10,885	6,393
Software license liabilities, current	4,388	4,879
Other accrued liabilities	2,769	2,472
Total accrued and other current liabilities	$ 34,970	$ 24,700

Accrued and Other Current Lia_4

Accrued and Other Current Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Schedule of Accrued Liabilities [Line Items]
Total stock-based compensation	$ 5,800
Liabilities associated with noncancelable internal-use software license at net present value, current	4,388	$ 4,879
Cadence Design Systems, Inc. [Member]
Schedule of Accrued Liabilities [Line Items]
Liabilities associated with noncancelable internal-use software license at net present value, current	3,900
License agreement commitment amount	12,700
Restricted stock units [Member]
Schedule of Accrued Liabilities [Line Items]
Total stock-based compensation	$ 5,800

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
Leases - Additional Information (Detail) $ in Thousands	Aug. 31, 2019	Jan. 31, 2020USD ($)Contract	Jan. 31, 2019USD ($)	Jan. 31, 2018USD ($)
Lessee Lease Description [Line Items]
Operating leases, existence of options to extend		true
Future undiscounted cash payments		$ 11,182
Operating lease expense under ASC 842		$ 3,000
Operating lease expense under ASC 840			$ 4,600	$ 5,300
Weighted-average remaining lease term – operating leases		5 years 7 days
Weighted-average discount rate – operating leases		4.43%
Parma Lease [Member]
Lessee Lease Description [Line Items]
Future undiscounted cash payments		$ 2,200
Future undiscounted cash payments in first two years		1,800
Future undiscounted cash payments, paid in remainder of lease term		$ 400
Renewed Contract [Member]
Lessee Lease Description [Line Items]
Operating lease number of renewed contracts \| Contract		2
An increase to operating lease right-of-use assets		$ 4,000
An increase to operating lease liabilities		$ 4,000
U.S. [Member] \| Additional Office Space [Member]
Lessee Lease Description [Line Items]
Lease term		56 months
Commencement date		Jan. 1, 2021
Expiration date		Aug. 31, 2025
Future undiscounted cash payments		$ 1,700
U.S. [Member] \| Renewed Contract [Member]
Lessee Lease Description [Line Items]
Lease term		63 months
Commencement date		Jun. 1, 2020
Expiration date		Aug. 31, 2025
Shanghai [Member] \| Renewed Contract [Member]
Lessee Lease Description [Line Items]
Lease term		2 years
Commencement date		Dec. 1, 2019
Expiration date		Nov. 30, 2021
Italy [Member] \| Building [Member]
Lessee Lease Description [Line Items]
Lease term	35 years
Construction completion period	2 years

Leases - Schedule of Cumulative

Leases - Schedule of Cumulative Effect of Changes to Consolidated Balance Sheet for Adoption of ASC 842 (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Feb. 01, 2019	Jan. 31, 2019
Leases Disclosure [Line Items]
Operating lease right-of-use assets	$ 9,935		$ 0
Prepaid expenses and other current assets	4,975		6,206
Accrued and other current liabilities	34,970		24,700
Operating lease liabilities, current	2,181		0
Operating lease liabilities, non-current	$ 7,975		$ 0
Leases (ASC 842) [Member]
Leases Disclosure [Line Items]
Operating lease right-of-use assets		$ 8,581
Prepaid expenses and other current assets		6,032
Accrued and other current liabilities		24,421
Operating lease liabilities, current		2,534
Operating lease liabilities, non-current		6,152
Leases (ASC 842) [Member] \| Restatement Adjustment [Member]
Leases Disclosure [Line Items]
Operating lease right-of-use assets		8,581
Prepaid expenses and other current assets		(174)
Accrued and other current liabilities		(279)
Operating lease liabilities, current		2,534
Operating lease liabilities, non-current		$ 6,152

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) $ in Thousands	12 Months Ended
	Jan. 31, 2020USD ($)
Leases [Abstract]
Cash paid for operating leases included in operating cash flows	$ 2,851
Supplemental non-cash information related to lease liabilities arising from obtaining right-of-use assets	299
Leased assets obtained in exchange for operating lease liabilities arising from lease modifications	$ 4,021

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Lease Payments for Lease Liabilities Excluding Additional Space for U.S. Office and Parma Lease (Detail) $ in Thousands	Jan. 31, 2020USD ($)
Leases [Abstract]
2021	$ 2,522
2022	2,371
2023	1,645
2024	1,694
2025	1,740
Thereafter	1,210
Total future annual minimum lease payments	11,182
Less: interest	(1,026)
Total lease liabilities	$ 10,156

Leases - Schedule of Future M_2

Leases - Schedule of Future Minimum Undiscounted Lease Payments (Detail) $ in Thousands	Jan. 31, 2019USD ($)
Leases [Abstract]
2020	$ 2,592
2021	1,040
2022	356
2023	143
2024	147
Thereafter	576
Total future annual minimum lease payments	$ 4,854

Other Long-Term Liabilities - S

Other Long-Term Liabilities - Schedule of Other Long-Term Liabilities (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Other Liabilities Disclosure [Abstract]
Unrecognized tax benefits, including interest	$ 8,261	$ 6,732
Deferred tax liabilities, non-current	1,288	1,293
Software license liabilities, non-current	8,159	310
Other long-term liabilities	68	6
Total other long-term liabilities	$ 17,776	$ 8,341

Other Long-Term Liabilities - A

Other Long-Term Liabilities - Additional Information (Detail) - Cadence Design Systems, Inc. [Member] - License Agreements [Member] $ in Millions	Jan. 31, 2020USD ($)
Related Party Transaction [Line Items]
Payable to related party	$ 12.7
Other Long-Term Liabilities [Member]
Related Party Transaction [Line Items]
Long-term liabilities accrued	$ 8

Capital Stock - Additional Info

Capital Stock - Additional Information (Detail) - USD ($)	May 29, 2019	Jun. 30, 2016	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2020
Class Of Stock [Line Items]
Preference shares, shares authorized			20,000,000	20,000,000		20,000,000
Preference shares, par value			$ 0.00045	$ 0.00045		$ 0.00045
Preference shares, shares issued			0	0		0
Preference shares, shares outstanding			0	0		0
Amount authorized under stock repurchase program			$ 275,000,000			$ 275,000,000
Stock repurchase program, inception period		2016-06
Stock repurchase program, expiration date			Jun. 30, 2020
Stock repurchased since the inception of repurchase programs, shares			0			3,985,876
Stock repurchased since the inception of repurchase programs, cash			$ 0	$ 99,904,000	$ 54,788,000	$ 174,800,000
Amount available under stock repurchase program			$ 50,000,000			$ 50,000,000
Stock Repurchase Program $50.0 Million Authorization [Member]
Class Of Stock [Line Items]
Stock repurchase program, authorization date	May 29, 2019
Stock repurchase program, expiration date	Jun. 30, 2020
Stock Repurchase Program $50.0 Million Authorization [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Amount authorized under stock repurchase program	$ 50,000,000

Capital Stock - Schedule of Ord

Capital Stock - Schedule of Ordinary Shares Reserved for Future Issuance under EIP and ESPP (Detail) - shares	Jan. 31, 2020	Jan. 31, 2019
EIP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved	6,045,108	5,915,654
ESPP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved	2,059,504	1,833,574

Employee Benefits and Stock-b_3

Employee Benefits and Stock-based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Accrued share based compensation expense			$ 5.8
Closing price of stock			$ 59.14
2012 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Voting power of all classes of company's shares			10.00%
Additional ordinary shares reserved for issuance	1,453,659	1,507,032
2012 Equity Incentive Plan [Member] \| Scenario, plan automatically increased by the lessor of [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual increase in ordinary shares for available for future issuance	3,500,000	3,500,000
Annual shares increase for future issuance by percentage under 2012 equity incentive plan	4.50%	4.50%
Amended and Restated 2012 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of ordinary shares, percentage			85.00%	85.00%	85.00%
Percentage of salary contribution by employees			15.00%
Additional ordinary shares reserved for issuance	403,794	418,620
Amended and Restated 2012 Employee Stock Purchase Plan [Member] \| Scenario, plan automatically increased by the lessor of [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual increase in ordinary shares for available for future issuance	1,500,000	1,500,000
Annual shares increase for future issuance by percentage under 2012 employee stock purchase plan	1.25%	1.25%
Stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost, stock options			$ 3.9
Weighted average recognition period			2 years 5 months 26 days
Stock options [Member] \| 2012 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option's term of up to 10 years from grant date			10 years	10 years	10 years
Vesting schedule			vest 25% on the first anniversary service date of the grant and remainder vest ratably over the following 36 months.
Stock options [Member] \| Incentive stock options granted to 10% ownership [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of ordinary shares, percentage			110.00%
Stock options [Member] \| Non statutory stock options and incentive stock options granted to less than 10% ownership [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of ordinary shares, percentage			100.00%
Restricted Stock and Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total fair value of vesting dates of restricted stock and restricted stock units vested			$ 52.1	$ 42.9	$ 52.1
Restricted Stock and Restricted Stock Units [Member] \| 2012 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting schedule			1/4th of the shares on the first anniversary service date of the grant and 1/16th of the shares vest every 3 months thereafter, so as to be 100% vested on the fourth anniversary of the vesting commencement date
Restricted stock units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average recognition period			2 years 5 months 26 days
Total unrecognized compensation cost, restricted stock units			$ 113.8
Accrued share based compensation expense			5.8
Aggregate intrinsic value of unvested restricted stock units			$ 154.8

Employee Benefits and Stock-b_4

Employee Benefits and Stock-based Compensation - Classification of Stock-based Compensation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Stock-based compensation:
Total stock-based compensation	$ 66,871	$ 60,812	$ 56,861
Cost of revenue [Member]
Stock-based compensation:
Total stock-based compensation	1,184	1,261	1,306
Research and development [Member]
Stock-based compensation:
Total stock-based compensation	41,842	37,432	34,575
Selling, general and administrative [Member]
Stock-based compensation:
Total stock-based compensation	$ 23,845	$ 22,119	$ 20,980

Employee Benefits and Stock-b_5

Employee Benefits and Stock-based Compensation - Weighted-Average Assumptions Used to Estimate Fair Value (Detail)	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	52.00%	54.00%	53.00%
Risk-free interest rate	1.82%	2.77%	2.08%
Expected term (years)	6 years 3 days	5 years 4 months 28 days	6 years 29 days
Dividend yield	0.00%	0.00%	0.00%
Employee stock purchase plan awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	47.00%	45.00%	44.00%
Risk-free interest rate	2.23%	2.15%	1.03%
Expected term (years)	6 months	6 months	6 months
Dividend yield	0.00%	0.00%	0.00%

Employee Benefits and Stock-b_6

Employee Benefits and Stock-based Compensation - Stock Option Activities (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding	1,459,064	1,611,344	1,703,524
Shares, Granted	66,850	116,600	132,250
Shares, Exercised	(366,886)	(232,205)	(175,187)
Shares, Forfeited	(14,931)	(20,974)	(27,721)
Shares, Expired	(19,451)	(15,701)	(21,522)
Shares, Outstanding	1,124,646	1,459,064	1,611,344
Shares, Exercisable	960,567
Weighted-Average Exercise Price, Outstanding	$ 28.31	$ 24.56	$ 21.66
Weighted-Average Exercise Price, Granted	50.56	42.73	54.66
Weighted-Average Exercise Price, Exercised	15.52	5.54	12.50
Weighted-Average Exercise Price, Forfeited	46.29	53.50	56.97
Weighted-Average Exercise Price, Expired	64.53	54.35	36.31
Weighted-Average Exercise Price, Outstanding	32.93	28.31	24.56
Weighted-Average Exercise Price, Exercisable	30.24
Weighted-Average Grant-date Fair Value, Granted	$ 25.35	$ 21.75	$ 28.28
Total Intrinsic Value of options Exercised	$ 13,263	$ 8,867	$ 7,446
Weighted-Average Remaining Contractual Term, Outstanding	4 years 4 months 6 days
Weighted-Average Remaining Contractual Term, Exercisable	3 years 7 months 24 days
Aggregate Intrinsic Value, Outstanding	$ 31,295
Aggregate Intrinsic Value, Exercisable	$ 29,573

Employee Benefits and Stock-b_7

Employee Benefits and Stock-based Compensation - Restricted Stock and Restricted Stock Units Activities (Detail) - Restricted stock and restricted stock units [Member] - $ / shares	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Unvested, beginning balance	2,395,516	2,103,281	2,175,673
Shares, Granted	1,329,288	1,367,751	1,052,235
Shares, Vested	(1,012,581)	(994,500)	(1,006,130)
Shares, Forfeited	(94,957)	(81,016)	(118,497)
Shares, Unvested, ending balance	2,617,266	2,395,516	2,103,281
Weighted-Average Grant-Date Fair Value, Unvested, beginning balance	$ 48.49	$ 56.45	$ 56.76
Weighted-Average Grant-Date Fair Value, Granted	54.54	40.03	47.11
Weighted-Average Grant-Date Fair Value, Vested	51.24	53.27	47.55
Weighted-Average Grant-Date Fair Value, Forfeited	54.26	53.57	54.72
Weighted-Average Grant-Date Fair Value, Unvested, ending balance	$ 50.30	$ 48.49	$ 56.45

Net Income (Loss) Per Ordinar_3

Net Income (Loss) Per Ordinary Share - Computation of Basic and Diluted Net Income (Loss) Per Ordinary Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Numerator:
Net income (loss)	$ (44,792)	$ (30,447)	$ 18,852
Denominator:
Weighted-average ordinary shares - basic	33,083,562	32,713,606	33,224,803
Effect of dilutive securities:
Employee stock options	0	0	961,797
Restricted stock and restricted stock units	0	0	390,145
Employee stock purchase plan	0	0	6,405
Weighted-average ordinary shares - diluted	33,083,562	32,713,606	34,583,150
Net income (loss) per ordinary share:
Basic	$ (1.35)	$ (0.93)	$ 0.57
Diluted	$ (1.35)	$ (0.93)	$ 0.55

Net Income (Loss) Per Ordinar_4

Net Income (Loss) Per Ordinary Share - Weighted-Average Potentially Dilutive Securities Excluded from Computation of Diluted Net Income (Loss) Per Ordinary Share (Detail) - shares	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share	2,061,477	2,740,341	1,203,621
Options to purchase ordinary shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share	913,678	1,190,607	280,907
Restricted stock and restricted stock units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share	1,139,269	1,522,903	907,208
Employee stock purchase plan awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share	8,530	26,831	15,506

Income Taxes - Summary of Incom

Income Taxes - Summary of Income(Loss) before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Results Of Operations Income Before Income Taxes [Abstract]
U.S. operations	$ 845	$ 1,381	$ 2,683
Non-U.S. operations	(42,473)	(35,933)	23,046
Income (loss) before income taxes	$ (41,628)	$ (34,552)	$ 25,729

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Provision (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Current:
U.S. federal tax	$ 1,440	$ 1,290	$ 3,321
U.S. state taxes	3	2	4
Non-U.S. foreign taxes	1,540	1,561	1,435
Current income tax provision	2,983	2,853	4,760
Deferred:
U.S. federal tax	182	(7,077)	2,185
U.S. state taxes	0	0	0
Non-U.S. foreign taxes	(1)	119	(68)
Deferred income tax provision	181	(6,958)	2,117
Provision (benefit) for income taxes	$ 3,164	$ (4,105)	$ 6,877

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	11 Months Ended	12 Months Ended
Income Taxes - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Income Taxes [Line Items]
Statutory tax rate	35.00%	21.00%	21.00%	33.80%
Deferred tax liabilities, not recognized		$ 11,900,000
Cumulative undistributed earnings of foreign subsidiaries		78,500,000
Gross deferred tax assets, net of deferred tax liabilities before valuation allowance		23,800,000	$ 21,800,000
Deferred tax assets		12,556,000	10,799,000
Valuation allowance		14,670,000	12,526,000
Unrecognized tax benefits		42,695,000	37,531,000	$ 34,117,000	$ 37,977,000
Unrecognized tax benefits that would impact effective tax rate		36,200,000
Interest expense and penalties related to uncertain tax positions		358,000	263,000	$ 37,000
Noncurrent liabilities related to interest and penalties for uncertain tax positions		760,000	403,000
Long term income taxes payable, including estimated interest and penalties		$ 8,300,000
U.S. federal tax authorities [Member] \| Earliest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year		2013
U.S. federal tax authorities [Member] \| Latest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year		2019
U.S. state tax authorities [Member] \| Earliest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year		2009
U.S. state tax authorities [Member] \| Latest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year		2019
Foreign tax authorities [Member] \| Earliest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year		2014
Foreign tax authorities [Member] \| Latest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year		2019
Other Long-Term Liabilities [Member]
Income Taxes [Line Items]
Income tax liabilities considered as other long term liabilities		$ 7,500,000	$ 6,300,000
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 81,300,000
Net operating loss carryforwards begin to expire in fiscal year		2035
Research and development credit carryforwards		$ 20,400,000
Federal credits begin to expire in fiscal year		2033
California state [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 15,700,000
Net operating loss carryforwards begin to expire in fiscal year		2035
Research and development credit carryforwards		$ 23,200,000
Research and Development [Member] \| Federal [Member]
Income Taxes [Line Items]
Deferred tax assets		$ 8,000,000

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation Between the Provision (Benefit) for Income Taxes at the Statutory Rate and the Effective Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Income Tax Disclosure [Abstract]
Provision at U.S. notional statutory rate	$ (8,742)	$ (7,256)	$ 8,699
U.S. state taxes	3	2	2
Non-U.S. foreign tax differential	10,458	9,226	(6,424)
Stock-based compensation	4,172	4,715	4,645
U.S. R&D credit	(3,109)	(2,770)	(2,408)
Valuation allowance	0	(7,990)	(1)
Change in tax rate	0	0	2,252
Other	382	(32)	112
Provision (benefit) for income taxes	$ 3,164	$ (4,105)	$ 6,877

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Deferred tax assets:
Federal and state credits	$ 21,275	$ 19,426
Expenses not currently deductible	593	575
Operating lease liabilities	2,023	0
Stock-based compensation	3,203	3,202
Foreign deferred	132	122
Gross deferred tax assets	27,226	23,325
Valuation allowance	(14,670)	(12,526)
Total deferred tax assets	12,556	10,799
Deferred tax liabilities
Property and equipment	(1,469)	(1,505)
Operating lease assets	(1,974)	0
Net deferred tax assets	$ 9,113	$ 9,294

Income Taxes - Summary of Tax V

Income Taxes - Summary of Tax Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 12,526
Balance at End of Period	14,670	$ 12,526
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	12,526	18,538	$ 15,061
Additional Charged to Expenses	2,144	1,978	3,477
Additions Charged to Other Account	0	0	0
Deductions Charged to Expenses or Other Accounts	0	(7,990)	0
Balance at End of Period	$ 14,670	$ 12,526	$ 18,538

Income Taxes - Schedule of Re_2

Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Income Tax Disclosure [Abstract]
Beginning balance	$ 37,531	$ 34,117	$ 37,977
Additions based on tax positions related to the current year	4,964	3,922	7,892
Additions for tax positions of prior years	252	109	28
Reductions for tax positions in prior years	0	(552)	(11,313)
Settlements for prior periods	0	0	0
Lapse of applicable statute of limitations	(52)	(65)	(467)
Ending balance	$ 42,695	$ 37,531	$ 34,117

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019
Loss Contingencies [Line Items]
Total manufacturing purchase commitments	$ 35,900,000	$ 28,200,000
Indemnification agreement [Member]
Loss Contingencies [Line Items]
Payments under indemnification obligations	0	0
Liabilities recorded under indemnification obligations	$ 0	$ 0

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail) $ in Thousands	12 Months Ended
	Jan. 31, 2020USD ($)Segment	Jan. 31, 2019USD ($)	Jan. 31, 2018
Concentration Risk [Line Items]
Number of reportable segment \| Segment	1
Property and equipment, net	$ 5,614	$ 6,728
Accounts receivable	$ 18,487	$ 26,212
Sales revenue, net [Member] \| Wintech [Member] \| Customer concentration risk [Member]
Concentration Risk [Line Items]
Percentage of revenue	60.00%	58.00%	59.00%
Sales revenue, net [Member] \| Chicony [Member] \| Customer concentration risk [Member]
Concentration Risk [Line Items]
Percentage of revenue	18.00%	16.00%
Sales revenue, net [Member] \| GoPro [Member] \| Customer concentration risk [Member]
Concentration Risk [Line Items]
Percentage of revenue			12.00%
Accounts receivable [Member] \| Wintech [Member] \| Credit concentration risk [Member]
Concentration Risk [Line Items]
Accounts receivable	$ 3,800	$ 14,300
Accounts receivable [Member] \| Chicony [Member] \| Credit concentration risk [Member]
Concentration Risk [Line Items]
Accounts receivable	10,800	6,900
United States [Member]
Concentration Risk [Line Items]
Property and equipment, net	1,700	2,100
Asia Pacific [Member]
Concentration Risk [Line Items]
Property and equipment, net	2,800	3,200
Europe [Member]
Concentration Risk [Line Items]
Property and equipment, net	$ 1,100	$ 1,400

Segment Reporting - Company's R

Segment Reporting - Company's Revenue by Geographic Region Based on Bill-to Location (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Revenue from External Customer [Line Items]
Total revenue	$ 228,732	$ 227,768	$ 295,402
Taiwan [Member]
Revenue from External Customer [Line Items]
Total revenue	137,946	132,199	174,486
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Total revenue	66,867	66,981	57,862
Europe [Member]
Revenue from External Customer [Line Items]
Total revenue	11,134	18,244	45,185
North America other than United States [Member]
Revenue from External Customer [Line Items]
Total revenue	8,402	7,028	11,110
United States [Member]
Revenue from External Customer [Line Items]
Total revenue	$ 4,383	$ 3,316	$ 6,759

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Related Party Transaction [Line Items]
Percentage of entity's voting stock owned by related party	10.00%
Cadence Design Systems, Inc. [Member]
Related Party Transaction [Line Items]
Payment for license fees	$ 3.6	$ 3.6	$ 3.6
License amortization expenses included in research and development expense	$ 4.2	$ 3.4	$ 3.2

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($)	2 Months Ended	12 Months Ended			44 Months Ended
	Mar. 26, 2020	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2020
Subsequent Event [Line Items]
Stock repurchased since the inception of repurchase programs, shares		0			3,985,876
Stock repurchased during period, cash		$ 0	$ 99,904,000	$ 54,788,000	$ 174,800,000
Amount available under stock repurchase program		$ 50,000,000			$ 50,000,000
Stock repurchase program, expiration date		Jun. 30, 2020
Subsequent Event [Member]
Subsequent Event [Line Items]
Stock repurchased since the inception of repurchase programs, shares	25,719
Stock repurchased during period, cash	$ 1,000,000
Amount available under stock repurchase program	$ 49,000,000
Stock repurchase program, expiration date	Jun. 30, 2020