The Trade Desk, Inc. (TTD) 10-Q8 Nov 212021 Q3 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2021	Oct. 31, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Trading Symbol	TTD
Entity Registrant Name	TRADE DESK, INC.
Entity Central Index Key	0001671933
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity File Number	001-37879
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-1887399
Entity Address, Address Line One	42 N. Chestnut Street
Entity Address, City or Town	Ventura
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	93001
City Area Code	805
Local Phone Number	585-3434
Title of 12(b) Security	Class A Common Stock, par value $0.000001 per share
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		436,076,902
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		44,556,450

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 576,916	$ 437,353
Short-term investments, net	221,685	186,685
Accounts receivable, net of allowance for credit losses of $7,245 and $7,253 as of September 30, 2021 and December 31, 2020, respectively	1,624,759	1,584,109
Prepaid expenses and other current assets	92,557	102,170
TOTAL CURRENT ASSETS	2,515,917	2,310,317
Property and equipment, net	137,416	115,863
Operating lease assets	242,436	248,143
Deferred income taxes	46,405	50,168
Other assets, non-current	46,581	29,154
TOTAL ASSETS	2,988,755	2,753,645
Current liabilities:
Accounts payable	1,304,971	1,348,480
Accrued expenses and other current liabilities	77,323	88,335
Operating lease liabilities	45,603	37,868
TOTAL CURRENT LIABILITIES	1,427,897	1,474,683
Operating lease liabilities, non-current	247,923	254,562
Other liabilities, non-current	10,121	11,255
TOTAL LIABILITIES	1,685,941	1,740,500
Commitments and contingencies (Note 10)
STOCKHOLDERS’ EQUITY
Preferred stock, par value $0.000001; 100,000 shares authorized, zero shares issued and outstanding as of September 30, 2021 and December 31, 2020
Common stock, par value $0.000001 Class A, 1,000,000 shares authorized; 436,033 and 423,383 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively Class B, 95,000 shares authorized; 44,556 and 50,018 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively	0	0
Additional paid-in capital	698,724	538,778
Retained earnings	604,090	474,367
TOTAL STOCKHOLDERS’ EQUITY	1,302,814	1,013,145
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 2,988,755	$ 2,753,645

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts receivable, allowance for credit losses	$ 7,245	$ 7,253
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Preferred stock, authorized shares	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock
Common stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Class A common stock
Common stock
Common stock, authorized shares	1,000,000,000	1,000,000,000
Common stock, shares issued	436,033,000	423,383,000
Common stock, shares outstanding	436,033,000	423,383,000
Class B common stock
Common stock
Common stock, authorized shares	95,000,000	95,000,000
Common stock, shares issued	44,556,000	50,018,000
Common stock, shares outstanding	44,556,000	50,018,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 301,091	$ 216,113	$ 800,869	$ 516,128
Type of Revenue [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember
Operating expenses:
Platform operations	$ 53,400	$ 44,826	$ 154,709	$ 127,167
Type of Cost, Good or Service [Extensible List]	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember	us-gaap:ServiceMember
Sales and marketing	$ 59,278	$ 44,637	$ 176,797	$ 116,002
Technology and development	55,847	41,079	163,301	117,931
General and administrative	52,120	42,789	155,884	117,252
Total operating expenses	220,645	173,331	650,691	478,352
Income from operations	80,446	42,782	150,178	37,776
Other expense (income):
Interest expense (income), net	317	235	556	(740)
Foreign currency exchange loss (gain), net	1,153	(12)	1,004	1,574
Total other expense, net	1,470	223	1,560	834
Income before income taxes	78,976	42,559	148,618	36,942
Provision for (benefit from) income taxes	19,592	1,312	18,895	(53,473)
Net income	$ 59,384	$ 41,247	$ 129,723	$ 90,415
Earnings per share:
Basic	$ 0.12	$ 0.09	$ 0.27	$ 0.20
Diluted	$ 0.12	$ 0.08	$ 0.26	$ 0.19
Weighted average shares outstanding:
Basic	478,101	465,819	475,496	460,747
Diluted	498,912	492,207	497,942	487,309

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment
Balance at beginning of period at Dec. 31, 2019	$ 612,517	$ (388)		$ 380,079	$ 232,438	$ (388)
Balance at beginning of period (in shares) at Dec. 31, 2019			454,755
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Exercise of common stock options	$ 19,478			19,478
Exercise of common stock options (in shares)			5,393
Issuance of restricted stock, net of forfeitures and shares withheld for taxes	(4,893)			(4,893)
Issuance of restricted stock, net of forfeitures and shares withheld for taxes (in shares)			197
Stock-based compensation	23,263			23,263
Net income	24,057				24,057
Balance at end of period at Mar. 31, 2020	674,034			417,927	256,107
Balance at end of period (in shares) at Mar. 31, 2020			460,346
Balance at beginning of period at Dec. 31, 2019	612,517	$ (388)		380,079	232,438	$ (388)
Balance at beginning of period (in shares) at Dec. 31, 2019			454,755
Net income	90,415
Balance at end of period at Sep. 30, 2020	832,627			510,162	322,465
Balance at end of period (in shares) at Sep. 30, 2020			469,452
Balance at beginning of period at Mar. 31, 2020	674,034			417,927	256,107
Balance at beginning of period (in shares) at Mar. 31, 2020			460,346
Exercise of common stock options	22,491			22,491
Exercise of common stock options (in shares)			4,306
Issuance of restricted stock, net of forfeitures and shares withheld for taxes	(2,836)			(2,836)
Issuance of restricted stock, net of forfeitures and shares withheld for taxes (in shares)			613
Stock-based compensation	24,516			24,516
Issuance of common stock under employee stock purchase plan	15,035			15,035
Issuance of common stock under employee stock purchase plan (in shares)			2,026
Net income	25,111				25,111
Balance at end of period at Jun. 30, 2020	758,351			477,133	281,218
Balance at end of period (in shares) at Jun. 30, 2020			467,291
Exercise of common stock options	12,118			12,118
Exercise of common stock options (in shares)			2,245
Issuance of restricted stock, net of forfeitures and shares withheld for taxes	(6,455)			(6,455)
Issuance of restricted stock, net of forfeitures and shares withheld for taxes (in shares)			(84)
Stock-based compensation	27,366			27,366
Net income	41,247				41,247
Balance at end of period at Sep. 30, 2020	832,627			510,162	322,465
Balance at end of period (in shares) at Sep. 30, 2020			469,452
Balance at beginning of period at Dec. 31, 2020	1,013,145			538,778	474,367
Balance at beginning of period (in shares) at Dec. 31, 2020			473,401
Exercise of common stock options	12,621			12,621
Exercise of common stock options (in shares)			1,794
Issuance of restricted stock, net of forfeitures and shares withheld for taxes	(17,080)			(17,080)
Issuance of restricted stock, net of forfeitures and shares withheld for taxes (in shares)			110
Stock-based compensation	52,985			52,985
Net income	22,642				22,642
Balance at end of period at Mar. 31, 2021	1,084,313			587,304	497,009
Balance at end of period (in shares) at Mar. 31, 2021			475,305
Balance at beginning of period at Dec. 31, 2020	1,013,145			538,778	474,367
Balance at beginning of period (in shares) at Dec. 31, 2020			473,401
Net income	129,723
Balance at end of period at Sep. 30, 2021	1,302,814			698,724	604,090
Balance at end of period (in shares) at Sep. 30, 2021			480,589
Balance at beginning of period at Mar. 31, 2021	1,084,313			587,304	497,009
Balance at beginning of period (in shares) at Mar. 31, 2021			475,305
Exercise of common stock options	13,718			13,718
Exercise of common stock options (in shares)			1,401
Issuance of restricted stock, net of forfeitures and shares withheld for taxes	(12,155)			(12,155)
Issuance of restricted stock, net of forfeitures and shares withheld for taxes (in shares)			409
Stock-based compensation	46,015			46,015
Issuance of common stock under employee stock purchase plan	22,758			22,758
Issuance of common stock under employee stock purchase plan (in shares)			1,334
Net income	47,697				47,697
Balance at end of period at Jun. 30, 2021	1,202,346			657,640	544,706
Balance at end of period (in shares) at Jun. 30, 2021			478,449
Exercise of common stock options	13,220			13,220
Exercise of common stock options (in shares)			1,808
Issuance of restricted stock, net of forfeitures and shares withheld for taxes	(9,038)			(9,038)
Issuance of restricted stock, net of forfeitures and shares withheld for taxes (in shares)			307
Stock-based compensation	35,086			35,086
Issuance of common stock related to acquisition	1,816			1,816
Issuance of common stock related to acquisition (in shares)			25
Net income	59,384				59,384
Balance at end of period at Sep. 30, 2021	$ 1,302,814			$ 698,724	$ 604,090
Balance at end of period (in shares) at Sep. 30, 2021			480,589

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
OPERATING ACTIVITIES:
Net income	$ 129,723	$ 90,415
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	29,969	20,777
Stock-based compensation	132,010	73,751
Allowance for credit losses on accounts receivable	520	2,722
Noncash lease expense	29,914	24,052
Deferred income taxes	5,044	(20,978)
Other	6,730	1,242
Changes in operating assets and liabilities:
Accounts receivable	(48,637)	21,063
Prepaid expenses and other assets	20,627	(23,919)
Accounts payable	(44,105)	47,728
Accrued expenses and other liabilities	(14,790)	11,047
Operating lease liabilities	(31,886)	(10,388)
Net cash provided by operating activities	215,119	237,512
INVESTING ACTIVITIES:
Purchases of investments	(233,427)	(127,254)
Sales of investments	4,539
Maturities of investments	192,077	128,315
Purchases of property and equipment	(43,920)	(57,721)
Capitalized software development costs	(3,684)	(4,246)
Business acquisition	(13,261)
Net cash used in investing activities	(97,676)	(60,906)
FINANCING ACTIVITIES:
Proceeds from line of credit		143,000
Repayment on line of credit		(71,000)
Payment of debt financing costs	(1,924)
Proceeds from exercise of stock options	39,559	54,038
Proceeds from employee stock purchase plan	22,758	15,035
Taxes paid related to net settlement of restricted stock awards	(38,273)	(14,184)
Net cash provided by financing activities	22,120	126,889
Increase in cash and cash equivalents	139,563	303,495
Cash and cash equivalents—Beginning of period	437,353	130,876
Cash and cash equivalents—End of period	576,916	434,371
SUPPLEMENTAL CASH FLOW INFORMATION:
Capitalized assets financed by accounts payable	8,934	12,842
Cash paid for amounts included in the measurement of lease liabilities included in operating cash flows	39,006	17,702
Right-of-use assets obtained in exchange for operating lease liabilities	23,293	52,238
Asset retirement obligation	1,609	1,601
Stock-based compensation included in capitalized software development costs	$ 2,076	$ 1,394

Nature of Operations

Nature of Operations	9 Months Ended
Nature of Operations	Sep. 30, 2021
Accounting Policies [Abstract]
Nature of Operations	Note 1—Nature of Operations The Trade Desk, Inc. (the “Company”) was formed in November 2009 as a Delaware corporation. The Company is headquartered in Ventura, California and has offices in various cities in North America, Europe, Asia and Australia. The Company is a technology company that empowers buyers of advertising by providing a self-service cloud-based platform on which ad buyers can create, manage, and optimize more expressive data-driven digital advertising campaigns across ad formats, including display, video, audio, native and social, on a multitude of devices, such as computers, mobile devices, and connected TV.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Note 2—Basis of Presentation and Summary of Significant Accounting Policies The accompanying condensed consolidated financial statements were prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and are unaudited. Certain information and disclosures normally included in consolidated financial statements prepared in accordance with GAAP have been condensed or omitted. The condensed consolidated balance sheet as of December 31, 2020 was derived from audited financial statements but does not include all disclosures required by GAAP. There have been no material changes to the Company’s accounting policies from those disclosed in its Annual Report on Form 10-K for the year ended December 31, 2020, and these unaudited interim condensed consolidated financial statements have been prepared on a basis consistent with that used to prepare the Company’s audited annual consolidated financial statements for the year ended December 31, 2020, and include, in the opinion of management, all adjustments, consisting of normal recurring items, necessary for the fair statement of the condensed consolidated financial statements. The results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results expected for the full year ending December 31, 2021. On June 16, 2021, the Company effected a ten-for-one Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ materially from these estimates. As of September 30, 2021, the impact of the Coronavirus pandemic (“COVID-19”) on the Company’s business continued to evolve. As a result, many of the Company’s estimates and assumptions, including the allowance for credit losses, consider macro-economic factors in the market, which require increased judgment and carry a higher degree of variability and volatility. As events continue to evolve and additional information becomes available, the Company’s estimates may change materially in future periods. For the three and nine months ended September 30, 2021, the Company’s assessment of credit losses considered business and market disruptions caused by COVID-19 and estimates of defaults by industry. The Company reviews the allowance for credit losses and financial implications of COVID-19 on expected credit losses on a quarterly basis. Account balances are charged off against the allowance when the Company believes it is probable the receivable will not be recovered. Business Combinations The results of a business combination are included in the Company’s condensed consolidated financial statements from the date of the acquisition. Purchase accounting results in assets and liabilities of an acquired business are generally recorded at their estimated fair values on the acquisition date, which may require management to use significant judgment and estimates, including the selection of valuation methodologies, estimates of future revenue, costs and cash flows, discount rates, and selection of comparable companies. The Company engages valuation specialists to assist in determining the fair values of these acquired assets and liabilities. Any excess consideration over the fair value of these acquired assets and liabilities assumed is recognized as goodwill. In July 2021, the Company acquired all of the equity interests of a technology company for a GAAP purchase price of $17.8 million, subject to purchase price adjustments. The purchase consideration was primarily attributable to non-deductible goodwill of $11.4 million, with the remainder allocated to acquired technology and other assets Recent Accounting Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848)

Earnings Per Share

Earnings Per Share	9 Months Ended
Earnings Per Share	Sep. 30, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Note 3—Earnings Per Share The Company has two classes of common stock, Class A and Class B. Basic and diluted earnings per share (“EPS”) attributable to common stockholders for Class A and Class B common stock were the same because they were entitled to the same liquidation and dividend rights. The computation of basic and diluted EPS after giving retroactive effect to the Stock Split is as follows (in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Numerator: Net income $ 59,384 $ 41,247 $ 129,723 $ 90,415 Denominator: Weighted-average shares outstanding—basic 478,101 465,819 475,496 460,747 Effect of dilutive securities: Options to purchase common stock 17,623 22,230 18,772 22,819 Employee stock purchase plan shares 278 454 533 815 Restricted stock 2,910 3,704 3,141 2,928 Weighted-average shares outstanding—diluted 498,912 492,207 497,942 487,309 Basic EPS $ 0.12 $ 0.09 $ 0.27 $ 0.20 Diluted EPS $ 0.12 $ 0.08 $ 0.26 $ 0.19 Anti-dilutive equity awards under stock-based award plans excluded from the determination of diluted EPS 1,439 1,880 1,439 1,880

Cash, Cash Equivalents and Shor

Cash, Cash Equivalents and Short-Term Investments	9 Months Ended
Cash, Cash Equivalents and Short-Term Investments	Sep. 30, 2021
Cash Cash Equivalents And Short Term Investments [Abstract]
Cash, Cash Equivalents and Short-Term Investments	Note 4—Cash, Cash Equivalents and Short-Term Investments Cash, cash equivalents and short-term investments in marketable securities were as follows (in thousands): As of September 30, 2021 Cash and Cash Short-Term Equivalents Investments Total Cash $ 141,689 $ — $ 141,689 Level 1: Money market funds 403,952 — 403,952 Level 2: Commercial paper 31,275 84,253 115,528 Corporate debt securities — 94,080 94,080 U.S. government and agency securities — 43,352 43,352 Total $ 576,916 $ 221,685 $ 798,601 As of December 31, 2020 Cash and Cash Short-Term Equivalents Investments Total Cash $ 132,372 $ — $ 132,372 Level 1: Money market funds 259,434 — 259,434 Level 2: Commercial paper 45,547 63,372 108,919 Corporate debt securities — 79,342 79,342 U.S. government and agency securities — 43,971 43,971 Total $ 437,353 $ 186,685 $ 624,038 The Company’s gross unrealized gains or losses from its short-term investments, recorded at fair value, for the three and nine months ended September 30, 2021 and 2020, were immaterial. The contractual maturities of the Company’s short-term investments are as follows (in thousands): September 30, 2021 Due in one year $ 195,238 Due in one to two years 26,447 Total $ 221,685

Leases

Leases	9 Months Ended
Leases	Sep. 30, 2021
Leases [Abstract]
Leases	Note 5—Leases The components of lease expense recorded in the condensed consolidated statements of income were as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Operating lease cost $ 12,402 $ 10,768 $ 38,288 $ 30,848 Short-term lease cost 229 228 592 723 Variable lease cost 1,891 1,688 4,848 4,251 Sublease income (751 ) (936 ) (2,114 ) (2,789 ) Total lease cost $ 13,771 $ 11,748 $ 41,614 $ 33,033

Debt

Debt	9 Months Ended
Debt	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	Note 6—Debt Credit Facility On June 15, 2021, the Company and a syndicate of banks, led by JPMorgan Chase Bank, N.A., as agent, entered into a Loan and Security Agreement Loans under the credit facility bear interest through maturity at a variable rate based upon, at the Company’s option, an annual rate of either a Base Rate or an adjusted LIBOR rate, plus an applicable margin (“Base Rate Borrowings” and “LIBOR Rate Borrowings”). The Base Rate is defined as a rate per annum for any day equal to the greatest of (1) the rate of interest last quoted by The Wall Street Journal as the “Prime Rate” in the United States, (2) the NYFRB Rate in effect on such day plus half of 1%, and (3) the adjusted LIBOR rate for a one month interest period on such day plus 1%. The applicable margin is between 0.25% to 1.25% for Base Rate Borrowings and between 1.25% and 2.25% for LIBOR Rate Borrowings based on the Company maintaining certain leverage ratios. The fee for undrawn amounts under the credit facility ranges, based on the applicable leverage, from 0.200% to 0.350%. The Company is also required to pay customary letter of credit fees, as necessary. As of September 30, 2021, the Company did not have an outstanding debt balance under the credit facility. Availability under the credit facility was $443.9 million as of September 30, 2021, which is net of outstanding letters of credit of $6.1 million. The credit facility matures, and all outstanding amounts become due and payable, on June 15, 2026. The credit facility contains customary conditions to borrowings, events of default and covenants, including covenants that restrict the Company’s ability to sell assets, make changes to the nature of the Company’s business, engage in mergers or acquisitions, incur, assume or permit to exist additional indebtedness and guarantees, create or permit to exist liens, pay dividends, issue equity instruments, make distributions or redeem or repurchase capital stock or make other investments, engage in transactions with affiliates and make payments in respect of subordinated debt. The credit facility also requires the Company to maintain compliance with a maximum ratio of consolidated funded debt to consolidated EBITDA of 3.50 to 1.00. As of September 30, 2021, the Company was in compliance with all covenants.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
Stock-Based Compensation	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note 7—Stock-Based Compensation Stock-Based Compensation Expense Stock-based compensation expense recorded in the condensed consolidated statements of income was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Platform operations $ 2,518 $ 1,639 $ 11,624 $ 5,459 Sales and marketing 9,099 6,916 37,362 18,549 Technology and development 11,269 7,911 41,337 24,345 General and administrative 11,573 10,386 41,687 25,398 Total $ 34,459 $ 26,852 $ 132,010 $ 73,751 Stock Options The following summarizes stock option activity: Shares Under Option (in thousands) Weighted- Average Exercise Price Outstanding as of December 31, 2020 26,481 $ 10.73 Granted 1,171 74.52 Exercised (5,004 ) 7.91 Cancelled (1,186 ) 18.20 Outstanding as of September 30, 2021 21,462 $ 14.45 Exercisable as of September 30, 2021 13,962 $ 7.97 Restricted Stock The following summarizes restricted stock activity: RSU (in thousands) Weighted- Average Grant Date Fair Value Unvested as of December 31, 2020 5,698 $ 26.10 Granted 2,166 73.70 Vested (1,494 ) 22.41 Forfeited (575 ) 28.72 Unvested as of September 30, 2021 5,795 $ 44.58 Employee Stock Purchase Plan (“ESPP”) Stock-based compensation expense related to the ESPP totaled $4.1 million and $3.7 million for the three months ended September 30, 2021 and 2020, respectively. Stock-based compensation expense related to the ESPP totaled $46.1 million and $17.8 million for the nine months ended September 30, 2021 and 2020, respectively.

Income Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 8—Income Taxes In determining the interim income tax provision for the nine months ended September 30, 2021, the Company utilized the annual estimated effective tax rate applied to the actual year-to-date income and added the tax effects of any discrete items in the reporting period in which they occur. In determining the interim benefit from income taxes for the nine months ended September 30, 2020, the Company utilized the discrete effective tax rate method, as allowed by Accounting Standards Codification (“ASC”) 740-270-30-18, “Income Taxes – Interim Reporting”. For the three months ended September 30, 2021 and 2020, the income tax provision included benefits associated with stock-based awards in the amounts of $21.9 million and $25.6 million, respectively. For the nine months ended September 30, 2021 and 2020, the provision for (benefit from) income taxes included benefits associated with stock-based awards in the amounts of $58.2 million and $98.7 million, respectively. For the nine months ended September 30, 2021, and 2020, the Company’s effective tax rate differed from the United States federal statutory tax rate of 21% primarily due to the impact of tax benefits associated with stock-based awards, nondeductible stock-based compensation, state and foreign taxes, and research and development tax credits. On June 10, 2021, the UK Finance Act 2021 was enacted, increasing the corporate tax rate from 19% to 25%. Accordingly, the Company increased its net UK deferred tax assets by $76.4 million, which was fully offset by a valuation allowance. There were no material changes to the Company’s unrecognized tax benefits during the nine months ended September 30, 2021, and the Company does not expect to have any significant changes to unrecognized tax benefits through the end of the fiscal year.

Geographic Information

Geographic Information	9 Months Ended
Geographic Information	Sep. 30, 2021
Segments Geographical Areas [Abstract]
Geographic Information	Note 9—Geographic Information The Company reports revenue net of amounts it pays suppliers for the cost of advertising inventory, third-party data and other add-on features (collectively, “Supplier Features”). The Company generally bills clients for the gross amount of Supplier Features they purchase through its platform and the platform fees, net of allowances (“Gross Billings”). The Company’s accounts receivable are recorded at the amount of Gross Billings for the amounts it is responsible to collect, and accounts payable are recorded at the net amount payable to suppliers. Accordingly, both accounts receivable and accounts payable appear large in relation to revenue reported on a net basis. Gross Billings, set forth as a percentage, based on the billing address of the clients or client affiliates, were as follows: Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 U.S. 87 % 86 % 86 % 86 % International 13 % 14 % 14 % 14 % Total 100 % 100 % 100 % 100 %

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 10— Commitments and Contingencies Guarantees and Indemnification In the ordinary course of business, the Company may provide indemnifications of varying scope and terms to clients, vendors, lessors, business partners, and other parties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements, services to be provided by the Company or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with directors and certain officers and employees that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors, officers or employees. No demands have been made upon the Company to provide indemnification under such agreements, and thus, there are no claims that the Company is aware of that could have a material effect on its balance sheet, statement of income or statement of cash flows. Accordingly, no amounts for any obligation have been recorded at September 30, 2021. Litigation From time to time, the Company is subject to various legal proceedings and claims, either asserted or unasserted, that arise in the ordinary course of business. Although the outcome of the various legal proceedings and claims cannot be predicted with certainty, management does not believe that any of these proceedings or other claims will have a material adverse effect on the Company’s business, financial condition, results of operations or cash flows. On June 28, 2021, a class action lawsuit was filed against the Company, the members of the Company’s board of directors, and one of the Company’s executive officers (collectively, the “Defendants”) in the Court of Chancery of the State of Delaware. The complaint alleges generally that the Defendants breached their fiduciary duties to the Company’s stockholders in connection with the negotiation and approval of the amendments to the Company’s certificate of incorporation and related matters voted on at the Special Meeting of Stockholders held on December 22, 2020 (the “Amendments”). Plaintiff seeks a court order rescinding the Amendments, as well as monetary damages. On August 27, 2021, the Defendants moved to dismiss the complaint. On October 8, 2021, the plaintiff filed an opposition to Defendants’ motion to dismiss the complaint. The Company believes that all of the claims asserted in the complaint are without merit and intends to defend against them vigorously. However, litigation is inherently uncertain and there can be no assurance regarding the likelihood that the Defendants’ defense of the action will be successful. Employment Contracts The Company has entered into agreements with severance terms with certain employees and officers, all of whom are employed on an at-will basis, subject to certain severance obligations in the event of certain involuntary terminations. The Company may be required to accelerate the vesting of certain stock-based awards in the event of changes in control, as defined, and involuntary terminations.

Subsequent Event

Subsequent Event	9 Months Ended
Subsequent Event	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Event	Note 11— Subsequent Event On October 6, 2021, the Company granted a market-based performance award (the “Performance Option”) to the Company’s Chief Executive Officer (the “CEO”) under the Company’s 2016 Incentive Award Plan. If specified target goals for the per share price of the Company’s Class A common stock (ranging

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ materially from these estimates. As of September 30, 2021, the impact of the Coronavirus pandemic (“COVID-19”) on the Company’s business continued to evolve. As a result, many of the Company’s estimates and assumptions, including the allowance for credit losses, consider macro-economic factors in the market, which require increased judgment and carry a higher degree of variability and volatility. As events continue to evolve and additional information becomes available, the Company’s estimates may change materially in future periods. For the three and nine months ended September 30, 2021, the Company’s assessment of credit losses considered business and market disruptions caused by COVID-19 and estimates of defaults by industry. The Company reviews the allowance for credit losses and financial implications of COVID-19 on expected credit losses on a quarterly basis. Account balances are charged off against the allowance when the Company believes it is probable the receivable will not be recovered.
Business Combinations	Business Combinations The results of a business combination are included in the Company’s condensed consolidated financial statements from the date of the acquisition. Purchase accounting results in assets and liabilities of an acquired business are generally recorded at their estimated fair values on the acquisition date, which may require management to use significant judgment and estimates, including the selection of valuation methodologies, estimates of future revenue, costs and cash flows, discount rates, and selection of comparable companies. The Company engages valuation specialists to assist in determining the fair values of these acquired assets and liabilities. Any excess consideration over the fair value of these acquired assets and liabilities assumed is recognized as goodwill. In July 2021, the Company acquired all of the equity interests of a technology company for a GAAP purchase price of $17.8 million, subject to purchase price adjustments. The purchase consideration was primarily attributable to non-deductible goodwill of $11.4 million, with the remainder allocated to acquired technology and other assets
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
Earnings Per Share (Tables)	Sep. 30, 2021
Earnings Per Share [Abstract]
Computation of Basic and Diluted EPS	The computation of basic and diluted EPS after giving retroactive effect to the Stock Split is as follows (in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Numerator: Net income $ 59,384 $ 41,247 $ 129,723 $ 90,415 Denominator: Weighted-average shares outstanding—basic 478,101 465,819 475,496 460,747 Effect of dilutive securities: Options to purchase common stock 17,623 22,230 18,772 22,819 Employee stock purchase plan shares 278 454 533 815 Restricted stock 2,910 3,704 3,141 2,928 Weighted-average shares outstanding—diluted 498,912 492,207 497,942 487,309 Basic EPS $ 0.12 $ 0.09 $ 0.27 $ 0.20 Diluted EPS $ 0.12 $ 0.08 $ 0.26 $ 0.19 Anti-dilutive equity awards under stock-based award plans excluded from the determination of diluted EPS 1,439 1,880 1,439 1,880

Cash, Cash Equivalents and Sh_2

Cash, Cash Equivalents and Short-Term Investments (Tables)	9 Months Ended
Cash, Cash Equivalents and Short-Term Investments (Tables)	Sep. 30, 2021
Cash Cash Equivalents And Short Term Investments [Abstract]
Schedule of Cash, Cash Equivalents and Short-term Investments in Marketable Securities	Cash, cash equivalents and short-term investments in marketable securities were as follows (in thousands): As of September 30, 2021 Cash and Cash Short-Term Equivalents Investments Total Cash $ 141,689 $ — $ 141,689 Level 1: Money market funds 403,952 — 403,952 Level 2: Commercial paper 31,275 84,253 115,528 Corporate debt securities — 94,080 94,080 U.S. government and agency securities — 43,352 43,352 Total $ 576,916 $ 221,685 $ 798,601 As of December 31, 2020 Cash and Cash Short-Term Equivalents Investments Total Cash $ 132,372 $ — $ 132,372 Level 1: Money market funds 259,434 — 259,434 Level 2: Commercial paper 45,547 63,372 108,919 Corporate debt securities — 79,342 79,342 U.S. government and agency securities — 43,971 43,971 Total $ 437,353 $ 186,685 $ 624,038
Schedule of Contractual Maturities of Short-Term Investments	The contractual maturities of the Company’s short-term investments are as follows (in thousands): September 30, 2021 Due in one year $ 195,238 Due in one to two years 26,447 Total $ 221,685

Leases (Tables)

Leases (Tables)	9 Months Ended
Leases (Tables)	Sep. 30, 2021
Leases [Abstract]
Summary of Components of Lease Expense	The components of lease expense recorded in the condensed consolidated statements of income were as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Operating lease cost $ 12,402 $ 10,768 $ 38,288 $ 30,848 Short-term lease cost 229 228 592 723 Variable lease cost 1,891 1,688 4,848 4,251 Sublease income (751 ) (936 ) (2,114 ) (2,789 ) Total lease cost $ 13,771 $ 11,748 $ 41,614 $ 33,033

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
Stock-Based Compensation (Tables)	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock-Based Compensation Expense	Stock-based compensation expense recorded in the condensed consolidated statements of income was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Platform operations $ 2,518 $ 1,639 $ 11,624 $ 5,459 Sales and marketing 9,099 6,916 37,362 18,549 Technology and development 11,269 7,911 41,337 24,345 General and administrative 11,573 10,386 41,687 25,398 Total $ 34,459 $ 26,852 $ 132,010 $ 73,751
Summary of Stock Option Activity	The following summarizes stock option activity: Shares Under Option (in thousands) Weighted- Average Exercise Price Outstanding as of December 31, 2020 26,481 $ 10.73 Granted 1,171 74.52 Exercised (5,004 ) 7.91 Cancelled (1,186 ) 18.20 Outstanding as of September 30, 2021 21,462 $ 14.45 Exercisable as of September 30, 2021 13,962 $ 7.97
Summary of Restricted Stock Activity	The following summarizes restricted stock activity: RSU (in thousands) Weighted- Average Grant Date Fair Value Unvested as of December 31, 2020 5,698 $ 26.10 Granted 2,166 73.70 Vested (1,494 ) 22.41 Forfeited (575 ) 28.72 Unvested as of September 30, 2021 5,795 $ 44.58

Geographic Information (Tables)

Geographic Information (Tables)	9 Months Ended
Geographic Information (Tables)	Sep. 30, 2021
Segments Geographical Areas [Abstract]
Gross Billings Percentage, Based on Billing Address of Clients or Client Affiliates	Gross Billings, set forth as a percentage, based on the billing address of the clients or client affiliates, were as follows: Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 U.S. 87 % 86 % 86 % 86 % International 13 % 14 % 14 % 14 % Total 100 % 100 % 100 % 100 %

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) $ in Millions	Jun. 16, 2021	Jul. 31, 2021USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Stock split ratio	0.1
Technology Company
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Business combination, purchase price		$ 17.8
Non-deductible goodwill		$ 11.4

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail)	Sep. 30, 2021Class
Earnings Per Shares [Abstract]
Number of classes of common stock	2

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income	$ 59,384	$ 47,697	$ 22,642	$ 41,247	$ 25,111	$ 24,057	$ 129,723	$ 90,415
Denominator:
Weighted-average shares outstanding—basic	478,101			465,819			475,496	460,747
Effect of dilutive securities:
Options to purchase common stock	17,623			22,230			18,772	22,819
Employee stock purchase plan shares	278			454			533	815
Restricted stock	2,910			3,704			3,141	2,928
Weighted-average shares outstanding—diluted	498,912			492,207			497,942	487,309
Basic EPS	$ 0.12			$ 0.09			$ 0.27	$ 0.20
Diluted EPS	$ 0.12			$ 0.08			$ 0.26	$ 0.19
Anti-dilutive equity awards under stock-based award plans excluded from the determination of diluted EPS	1,439			1,880			1,439	1,880

Cash, Cash Equivalents and Sh_3

Cash, Cash Equivalents and Short -Term Investments - Schedule of Cash, Cash Equivalents and Short-term Investments in Marketable Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	$ 576,916	$ 437,353
Short-Term Investments	221,685	186,685
Available For Sale
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	576,916	437,353
Short-Term Investments	221,685	186,685
Total	798,601	624,038
Available For Sale \| Cash
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	141,689	132,372
Total	141,689	132,372
Available For Sale \| Level 1 \| Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	403,952	259,434
Total	403,952	259,434
Available For Sale \| Level 2 \| Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	31,275	45,547
Short-Term Investments	84,253	63,372
Total	115,528	108,919
Available For Sale \| Level 2 \| Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Short-Term Investments	94,080	79,342
Total	94,080	79,342
Available For Sale \| Level 2 \| U.S. Government and Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Short-Term Investments	43,352	43,971
Total	$ 43,352	$ 43,971

Cash, Cash Equivalents and Sh_4

Cash, Cash Equivalents and Short - Schedule of Contractual Maturities of Short-Term Investments (Detail) $ in Thousands	Sep. 30, 2021USD ($)
Available For Sale Securities Debt Maturities Fair Value [Abstract]
Due in one year	$ 195,238
Due in one to two years	26,447
Total	$ 221,685

Leases - Summary of Components

Leases - Summary of Components of Lease Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lease Cost [Abstract]
Operating lease cost	$ 12,402	$ 10,768	$ 38,288	$ 30,848
Short-term lease cost	229	228	592	723
Variable lease cost	1,891	1,688	4,848	4,251
Sublease income	(751)	(936)	(2,114)	(2,789)
Total lease cost	$ 13,771	$ 11,748	$ 41,614	$ 33,033

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Jun. 15, 2021	Sep. 30, 2021
Loan and Security Agreement
Long-term debt:
Line of credit maximum amount right to increase	$ 300,000,000
Interest rate description		The Base Rate is defined as a rate per annum for any day equal to the greatest of (1) the rate of interest last quoted by The Wall Street Journal as the “Prime Rate” in the United States, (2) the NYFRB Rate in effect on such day plus half of 1%, and (3) the adjusted LIBOR rate for a one month interest period on such day plus 1%. The applicable margin is between 0.25% to 1.25% for Base Rate Borrowings and between 1.25% and 2.25% for LIBOR Rate Borrowings based on the Company maintaining certain leverage ratios.
Outstanding debt balance		$ 0
Availability under the credit facility		$ 443,900,000
Credit facility, maturity		Jun. 15, 2026
Maximum ratio of consolidated funded debt to consolidated EBITDA		350.00%
Loan and Security Agreement \| Minimum
Long-term debt:
Fee percentage for undrawn amounts		0.20%
Loan and Security Agreement \| Maximum
Long-term debt:
Fee percentage for undrawn amounts		0.35%
Loan and Security Agreement \| LIBOR Rate
Long-term debt:
Description of variable rate basis		one month interest period on such day plus 1%
Basis spread on variable rate		1.00%
Loan and Security Agreement \| LIBOR Rate \| Minimum
Long-term debt:
Basis spread on variable rate		1.25%
Loan and Security Agreement \| LIBOR Rate \| Maximum
Long-term debt:
Basis spread on variable rate		2.25%
Loan and Security Agreement \| NYFRB Rate
Long-term debt:
Description of variable rate basis		day plus half of 1%
Basis spread on variable rate		1.00%
Loan and Security Agreement \| Base Rate \| Minimum
Long-term debt:
Basis spread on variable rate		0.25%
Loan and Security Agreement \| Base Rate \| Maximum
Long-term debt:
Basis spread on variable rate		1.25%
Loan and Security Agreement Revolving Loan Facility
Long-term debt:
Line of credit facility	450,000,000
Loan and Security Agreement Revolving Loan Facility Swingline Borrowings
Long-term debt:
Line of credit facility	20,000,000
Loan and Security Agreement Revolving Loan Facility Letter of Credit
Long-term debt:
Line of credit facility	$ 15,000,000
Outstanding letters of credit		$ 6,100,000

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Stock-based compensation expense, by operating expense category
Stock-based compensation expense	$ 34,459	$ 26,852	$ 132,010	$ 73,751
Platform operations
Stock-based compensation expense, by operating expense category
Stock-based compensation expense	2,518	1,639	11,624	5,459
Sales and marketing
Stock-based compensation expense, by operating expense category
Stock-based compensation expense	9,099	6,916	37,362	18,549
Technology and development
Stock-based compensation expense, by operating expense category
Stock-based compensation expense	11,269	7,911	41,337	24,345
General and administrative
Stock-based compensation expense, by operating expense category
Stock-based compensation expense	$ 11,573	$ 10,386	$ 41,687	$ 25,398

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - Stock Options - $ / shares shares in Thousands	9 Months Ended
	Sep. 30, 2021
Shares Under Option
Outstanding at the beginning of the period (in shares)	26,481
Granted (in shares)	1,171
Exercised (in shares)	(5,004)
Cancelled (in shares)	(1,186)
Outstanding at the end of the period (in shares)	21,462
Exercisable as of September 30, 2021	13,962
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 10.73
Granted (in dollars per share)	74.52
Exercised (in dollars per share)	7.91
Cancelled (in dollars per share)	18.20
Outstanding at the end of the period (in dollars per share)	14.45
Exercisable as of September 30, 2021	$ 7.97

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Restricted Stock Activity (Detail) shares in Thousands	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Unvested, RSU, beginning balance \| shares	5,698
Granted, RSU \| shares	2,166
Vested, RSU \| shares	(1,494)
Forfeited, RSU \| shares	(575)
Unvested, RSU, ending balance \| shares	5,795
Unvested, Weighted-Average Grant Date Fair Value Per Share, beginning balance \| $ / shares	$ 26.10
Granted, Weighted-Average Grant Date Fair Value Per Share \| $ / shares	73.70
Vested, Weighted-Average Grant Date Fair Value Per Share \| $ / shares	22.41
Forfeited, Weighted-Average Grant Date Fair Value Per Share \| $ / shares	28.72
Unvested, Weighted-Average Grant Date Fair Value Per Share, ending balance \| $ / shares	$ 44.58

Stock-Based Compensation - ESPP

Stock-Based Compensation - ESPP - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Stock-Based Compensation
Stock-based compensation expense	$ 34,459	$ 26,852	$ 132,010	$ 73,751
ESPP
Stock-Based Compensation
Stock-based compensation expense	$ 4,100	$ 3,700	$ 46,100	$ 17,800

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	Jun. 10, 2021	Jun. 09, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Provision for (benefit from) income taxes, benefits associated with stock-based awards			$ 21.9	$ 25.6	$ 58.2	$ 98.7
Federal tax at statutory rate (as a percent)					21.00%	21.00%
Corporate tax rate	25.00%	19.00%
Deferred tax assets			$ 76.4		$ 76.4

Geographic Information - Gross

Geographic Information - Gross Billings Percentage, Based on Billing Address of Clients or Client Affiliates (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues From External Customers And Long Lived Assets [Line Items]
Gross Billings	100.00%	100.00%	100.00%	100.00%
U.S.
Revenues From External Customers And Long Lived Assets [Line Items]
Gross Billings	87.00%	86.00%	86.00%	86.00%
International
Revenues From External Customers And Long Lived Assets [Line Items]
Gross Billings	13.00%	14.00%	14.00%	14.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Sep. 30, 2021USD ($)
Indemnifications
Commitments and Contingencies
Recorded obligation	$ 0

Subsequent Event - Additional I

Subsequent Event - Additional Information (Details) - Subsequent Event - Performance Option - 2016 Incentive Award Plan - Class A common stock - Chief Executive Officer $ / shares in Units, $ in Millions	Oct. 06, 2021USD ($)Tranche$ / sharesshares
Subsequent Event [Line Items]
Maximum number of shares that can be purchased \| shares	16,000,000
Number of tranches \| Tranche	8
Increase/decrease of shares to be purchased based on relative shareholder return	20.00%
Exercise price	$ 68.29
Grant-date fair value \| $	$ 819
Vesting period	5 years
Weighted-average period for recognition of stock based expense	2 years 10 months 24 days
Maximum
Subsequent Event [Line Items]
Share price	$ 340
Minimum
Subsequent Event [Line Items]
Share price	$ 90