Twitter (TWTR) 10-Q 27 Oct 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 22, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-36164
Entity Registrant Name	Twitter, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8913779
Entity Address, Address Line One	1355 Market Street
Entity Address, Address Line Two	Suite 900
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94103
City Area Code	415
Local Phone Number	222-9670
Title of 12(b) Security	Common Stock, par value $0.000005 per share
Trading Symbol	TWTR
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		799,609,869
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001418091
Current Fiscal Year End Date	--12-31

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 3,473,865	$ 1,988,429
Short-term investments	3,937,447	5,483,873
Accounts receivable, net of allowance for doubtful accounts of $14,815 and $16,946	1,014,208	1,041,743
Prepaid expenses and other current assets	194,914	123,063
Assets held for sale	28,800	0
Total current assets	8,649,234	8,637,108
Property and equipment, net	2,053,480	1,493,794
Operating lease right-of-use assets	1,115,929	930,139
Intangible assets, net	46,702	58,338
Goodwill	1,293,826	1,312,346
Deferred tax assets, net	1,133,816	796,326
Other assets	296,358	151,039
Total assets	14,589,345	13,379,090
Current liabilities:
Accounts payable	207,912	194,281
Accrued and other current liabilities	1,688,768	663,532
Convertible notes, short-term	0	917,866
Operating lease liabilities, short-term	218,301	177,147
Total current liabilities	2,114,981	1,952,826
Convertible notes, long-term	3,556,934	1,875,878
Senior notes, long-term	693,744	692,994
Operating lease liabilities, long-term	980,764	819,748
Deferred and other long-term tax liabilities, net	40,009	31,463
Other long-term liabilities	30,282	36,099
Total liabilities	7,416,714	5,409,008
Commitments and contingencies (Note 15)
Stockholders' equity:
Preferred stock, $0.000005 par value-- 200,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.000005 par value-- 5,000,000 shares authorized; 799,612 and 796,000 shares issued and outstanding	4	4
Additional paid-in capital	8,468,708	9,167,138
Treasury stock, at cost-- 87 and 98 shares	(5,291)	(5,297)
Accumulated other comprehensive loss	(106,794)	(66,094)
Accumulated deficit	(1,183,996)	(1,125,669)
Total stockholders' equity	7,172,631	7,970,082
Total liabilities and stockholders' equity	$ 14,589,345	$ 13,379,090

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 14,815	$ 16,946
Preferred stock, par value (USD per share)	$ 0.000005	$ 0.000005
Preferred stock, shares authorized (shares)	200,000,000	200,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (USD per share)	$ 0.000005	$ 0.000005
Common stock, shares authorized (share)	5,000,000,000	5,000,000,000
Common stock, shares issued (shares)	799,612,000	796,000,000
Common stock, shares outstanding (shares)	799,612,000	796,000,000
Treasury stock (shares)	87,000	98,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - 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	$ 1,283,817	$ 936,233	$ 3,510,262	$ 2,427,308
Costs and expenses
Cost of revenue	484,479	361,388	1,282,419	933,464
Research and development	324,252	208,877	874,820	625,071
Sales and marketing	301,078	215,285	837,572	643,858
General and administrative	150,855	94,576	409,864	450,181
Litigation settlement, net	765,701	0	765,701	0
Total costs and expenses	2,026,365	880,126	4,170,376	2,652,574
Income (loss) from operations	(742,548)	56,107	(660,114)	(225,266)
Interest expense	(13,284)	(39,614)	(40,362)	(112,712)
Interest income	8,125	17,167	28,328	75,077
Other income (expense), net	20,625	(3,977)	76,370	(12,057)
Income (loss) before income taxes	(727,082)	29,683	(595,778)	(274,958)
Provision (benefit) for income taxes	(190,325)	1,024	(192,675)	1,082,784
Net income (loss)	$ (536,757)	$ 28,659	$ (403,103)	$ (1,357,742)
Net income (loss) per share attributable to common stockholders:
Basic (USD per share)	$ (0.67)	$ 0.04	$ (0.51)	$ (1.73)
Diluted (USD per share)	$ (0.67)	$ 0.04	$ (0.51)	$ (1.73)
Weighted-average shares used to compute net income (loss) per share attributable to common stockholders:
Basic (shares)	797,985	790,827	796,775	785,788
Diluted (shares)	797,985	806,383	796,775	785,788

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (536,757)	$ 28,659	$ (403,103)	$ (1,357,742)
Other comprehensive income (loss), net of tax:
Change in unrealized gain (loss) on investments in available-for-sale securities	(3,288)	(2,154)	(18,096)	20,037
Change in foreign currency translation adjustment	(14,450)	5,067	(22,604)	(39,590)
Net change in accumulated other comprehensive income (loss)	(17,738)	2,913	(40,700)	(19,553)
Comprehensive income (loss)	$ (554,495)	$ 31,572	$ (443,803)	$ (1,377,295)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Additional paid-in capitalCumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Accumulated other comprehensive loss	Retained earnings (Accumulated deficit)	Retained earnings (Accumulated deficit)Cumulative Effect, Period of Adoption, Adjustment
Balance, beginning of period (shares) at Dec. 31, 2019		779,619,000
Balance, beginning of period at Dec. 31, 2019		$ 4	$ 8,763,330			$ (70,534)	$ 11,586	$ (1,629)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with RSU vesting (shares)		12,256,000
Issuance of common stock in connection with acquisitions (in shares)		33,000
Issuance of restricted stock in connection with acquisitions accounted for as stock-based compensation (shares)		1,381,000
Exercise of stock options (shares)		301,000
Issuance of common stock upon purchases under employee stock purchase plan (shares)	1,400,000	1,395,000
Shares withheld related to net share settlement of equity awards (shares)		(538,000)
Issuance of common stock in connection with acquisitions			1,312
Exercise of stock options			454
Issuance of common stock upon purchases under employee stock purchase plan			34,395
Shares withheld related to net share settlement of equity awards			(18,344)
Stock-based compensation			376,600
Equity component of the convertible note issuance, net			92,209
Purchases of convertible note hedges	$ 0
Other comprehensive income (loss)	(19,553)					(19,553)
Net income (loss)	$ (1,357,742)						(1,357,742)
Balance, end of period (shares) at Sep. 30, 2020	794,447,000	794,447,000
Balance, end of period at Sep. 30, 2020	$ 7,812,088	$ 4	9,249,956			(90,087)	(1,347,785)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other activities (shares)		0
Balance, beginning of period (shares) at Jun. 30, 2020		790,426,000
Balance, beginning of period at Jun. 30, 2020		$ 4	9,127,495			(93,000)	(1,376,444)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with RSU vesting (shares)		4,085,000
Issuance of restricted stock in connection with acquisitions accounted for as stock-based compensation (shares)		0
Exercise of stock options (shares)		37,000
Issuance of common stock upon purchases under employee stock purchase plan (shares)		0
Shares withheld related to net share settlement of equity awards (shares)		(101,000)
Exercise of stock options			31
Issuance of common stock upon purchases under employee stock purchase plan			0
Shares withheld related to net share settlement of equity awards			(3,726)
Stock-based compensation			126,156
Other comprehensive income (loss)	2,913					2,913
Net income (loss)	$ 28,659						28,659
Balance, end of period (shares) at Sep. 30, 2020	794,447,000	794,447,000
Balance, end of period at Sep. 30, 2020	$ 7,812,088	$ 4	9,249,956			(90,087)	(1,347,785)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other activities (shares)		0
Balance, beginning of period (shares) at Dec. 31, 2020		796,000,000
Balance, beginning of period at Dec. 31, 2020	$ 7,970,082	$ 4	9,167,138	$ (567,547)	$ (5,297)	(66,094)	(1,125,669)	$ 344,776
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with RSU vesting (shares)		13,030,000
Issuance of restricted stock in connection with acquisitions accounted for as stock-based compensation (shares)		69,000
Exercise of stock options (shares)		531,000
Issuance of common stock upon purchases under employee stock purchase plan (shares)	1,500,000	1,539,000
Shares withheld related to net share settlement of equity awards (shares)		(334,000)
Repurchased of common stock (in shares)	(11,200,000)	(11,169,000)
Exercise of stock options			2,037
Issuance of common stock upon purchases under employee stock purchase plan			39,531
Shares withheld related to net share settlement of equity awards			(21,712)
Stock-based compensation			517,145
Purchases of convertible note hedges	$ 213,469		(213,469)
Tax related to purchase of convertible note hedge			49,262
Issuance of warrants			161,144
Retirement of treasury stock (in shares)					15,892
Repurchases of common stock	(664,800)		(664,821)		(15,886)
Other comprehensive income (loss)	(40,700)					(40,700)
Net income (loss)	$ (403,103)						(403,103)
Balance, end of period (shares) at Sep. 30, 2021	799,612,000	799,612,000
Balance, end of period at Sep. 30, 2021	$ 7,172,631	$ 4	8,468,708		(5,291)	(106,794)	(1,183,996)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other activities (shares)		(54,000)
Balance, beginning of period (shares) at Jun. 30, 2021		797,941,000
Balance, beginning of period at Jun. 30, 2021		$ 4	8,457,717		(5,298)	(89,056)	(647,239)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with RSU vesting (shares)		4,383,000
Issuance of restricted stock in connection with acquisitions accounted for as stock-based compensation (shares)		0
Exercise of stock options (shares)		7,000
Issuance of common stock upon purchases under employee stock purchase plan (shares)		0
Shares withheld related to net share settlement of equity awards (shares)		(91,000)
Repurchased of common stock (in shares)	(2,600,000)	(2,574,000)
Exercise of stock options			51
Issuance of common stock upon purchases under employee stock purchase plan			0
Shares withheld related to net share settlement of equity awards			(6,215)
Stock-based compensation			186,612
Retirement of treasury stock (in shares)					5,298
Repurchases of common stock	$ (169,400)		(169,457)		(5,291)
Other comprehensive income (loss)	(17,738)					(17,738)
Net income (loss)	$ (536,757)						(536,757)
Balance, end of period (shares) at Sep. 30, 2021	799,612,000	799,612,000
Balance, end of period at Sep. 30, 2021	$ 7,172,631	$ 4	$ 8,468,708		$ (5,291)	$ (106,794)	$ (1,183,996)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other activities (shares)		(54,000)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (403,103)	$ (1,357,742)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization expense	399,312	366,469
Stock-based compensation expense	453,370	346,748
Amortization of discount on convertible notes	0	74,733
Bad debt expense	2,434	16,861
Deferred income taxes	(222,789)	(32,382)
Deferred tax assets valuation allowance establishment	0	1,101,374
Impairment (gain) on investments in privately-held companies	(76,794)	8,842
Other adjustments	1,521	(7,756)
Changes in assets and liabilities, net of assets acquired and liabilities assumed from acquisitions:
Accounts receivable	19,830	97,812
Prepaid expenses and other assets	(78,394)	(24,765)
Operating lease right-of-use assets	159,891	121,712
Accounts payable	20,701	(5,722)
Accrued and other liabilities	1,029,091	76,497
Operating lease liabilities	(143,939)	(120,111)
Net cash provided by operating activities	1,161,131	662,570
Cash flows from investing activities
Purchases of property and equipment	(871,603)	(577,829)
Proceeds from sales of property and equipment	6,913	5,815
Purchases of marketable securities	(2,785,014)	(5,103,983)
Proceeds from maturities of marketable securities	3,188,254	3,566,895
Proceeds from sales of marketable securities	1,141,614	925,387
Purchases of investments in privately-held companies	(33,189)	(3,839)
Investments in Finance Justice Fund	(52,000)	0
Business combinations, net of cash acquired	(22,937)	(34,285)
Other investing activities	(8,385)	(11,050)
Net cash provided by (used in) investing activities	563,653	(1,232,889)
Cash flows from financing activities
Proceeds from issuance of convertible notes	1,437,500	1,000,000
Purchases of convertible note hedges	(213,469)	0
Proceeds from issuance of warrants concurrent with note hedges	161,144	0
Debt issuance costs	(16,769)	(14,662)
Repayment of convertible notes	(954,000)	0
Repurchases of common stock	(664,821)	0
Taxes paid related to net share settlement of equity awards	(21,712)	(18,344)
Payments of finance lease obligations	(565)	(20,573)
Proceeds from exercise of stock options	2,037	454
Proceeds from issuances of common stock under employee stock purchase plan	39,531	34,395
Net cash provided by (used in) financing activities	(231,124)	981,270
Net increase in cash, cash equivalents and restricted cash	1,493,660	410,951
Foreign exchange effect on cash, cash equivalents and restricted cash	(8,391)	(14,854)
Cash, cash equivalents and restricted cash at beginning of period	2,011,276	1,827,666
Cash, cash equivalents and restricted cash at end of period	3,496,545	2,223,763
Supplemental disclosures of non-cash investing and financing activities
Common stock issued in connection with acquisitions	0	1,312
Changes in accrued property and equipment purchases	(6,293)	103,649
Reconciliation of cash, cash equivalents and restricted cash as shown in the consolidated statements of cash flows
Cash and cash equivalents	3,473,865	2,201,073
Restricted cash included in prepaid expenses and other current assets	3,156	2,251
Restricted cash included in other assets	19,524	20,439
Total cash, cash equivalents and restricted cash	$ 3,496,545	$ 2,223,763

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements include the accounts of Twitter, Inc. and its wholly-owned subsidiaries (collectively, “Twitter” or the “Company”). All intercompany accounts and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (GAAP). The unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and reflect, in management’s opinion, all adjustments of a normal, recurring nature that are necessary for the fair statement of the Company’s financial position, results of operations and cash flows for the interim periods, but are not necessarily indicative of the results expected for the full fiscal year or any other period. The accompanying interim consolidated financial statements and these related notes should be read in conjunction with the consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. Prior Period Reclassifications Certain prior period amounts have been reclassified to conform to the current period presentation. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, as well as related disclosure of contingent assets and liabilities. Actual results could differ materially from the Company’s estimates due to risks and uncertainties, including uncertainty in the current economic environment due to the global impact of the COVID-19 pandemic. To the extent that there are material differences between these estimates and actual results, the Company’s financial condition or operating results will be affected. The Company bases its estimates on past experience and other assumptions that the Company believes are reasonable under the circumstances, and the Company evaluates these estimates on an ongoing basis. Recent Accounting Pronouncements Recently adopted accounting pronouncements In August 2020, the Financial Accounting Standards Board (FASB) issued a new accounting standard update to simplify the accounting for convertible debt and other equity-linked instruments. The new guidance simplifies the accounting for convertible instruments by eliminating the cash conversion and beneficial conversion feature models used to separately account for embedded conversion features as a component of equity. Instead, the entity will account for the convertible debt or convertible preferred stock securities as a single unit of account, unless the conversion feature requires bifurcation and recognition as derivatives. Additionally, the guidance requires entities to use the if-converted method for all convertible instruments in the diluted earnings per share calculation and include the effect of potential share settlement for instruments that may be settled in cash or shares. The Company early adopted this new guidance using the modified retrospective method as of January 1, 2021. The adoption of this new guidance resulted in an increase of $254.6 million and $34.7 million to "Convertible notes, long-term" and "Convertible notes, short-term", respectively, to reflect the full principal amount of the Convertible Notes (as defined below) outstanding, net of issuance costs, a reduction of $567.5 million to additional paid-in capital, net of estimated income tax effects, to remove the equity component separately recorded for the conversion features associated with the Convertible Notes, an increase to deferred tax assets, net of $66.6 million, and a cumulative-effect adjustment of $344.8 million, net of estimated income tax effects, reducing the beginning balance of accumulated deficit as of January 1, 2021. The adoption of this new guidance reduced interest expense by $26.9 million and $83.0 million in the three and nine months ended September 30, 2021. In addition, the adoption requires the use of the if-converted method for all convertible notes in the diluted net income (loss) per share calculation and the inclusion of the effect of potential share settlement of the convertible notes, if the effect is more dilutive. There was no impact to the number of potentially dilutive shares in each of the periods presented. With the exception of the standards discussed above, there have been no other recent accounting pronouncements or changes in accounting pronouncements during the nine months ended September 30, 2021, as compared to the recent accounting pronouncements described in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, that are of significance or potential significance to the Company.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Revenue Recognition Revenue is recognized when the control of promised goods or services is transferred to customers at an amount that reflects the consideration to which the Company expects to be entitled to in exchange for those goods or services. The Company identifies its contracts with customers and all performance obligations within those contracts. The Company then determines the transaction price and allocates the transaction price to the performance obligations within the Company's contracts with customers, recognizing revenue when, or as the Company satisfies its performance obligations. While the majority of the Company's revenue transactions are based on standard business terms and conditions, the Company also enters into sales agreements with advertisers and data partners that sometimes involve multiple performance obligations and occasionally include non-standard terms or conditions. Revenue by geography is based on the billing address of the customers. The following tables set forth revenue by services and revenue by geographic area (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Revenue by services: Advertising services $ 1,140,504 $ 808,449 $ 3,092,755 $ 2,052,635 Data licensing and other 143,313 127,784 417,507 374,673 Total revenue $ 1,283,817 $ 936,233 $ 3,510,262 $ 2,427,308 Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Revenue by geographic area: United States $ 741,879 $ 512,637 $ 1,951,174 $ 1,345,948 Japan 159,151 132,392 480,558 371,763 Rest of World 382,787 291,204 1,078,530 709,597 Total revenue $ 1,283,817 $ 936,233 $ 3,510,262 $ 2,427,308 Contract Balances The Company enters into contracts with its customers, which may give rise to contract liabilities (deferred revenue) and contract assets (unbilled revenue). The payment terms and conditions within the Company’s contracts vary by the type and location of its customer and products or services purchased, the substantial majority of which are due in less than one year. When the timing of revenue recognition differs from the timing of payments made by customers, the Company recognizes either unbilled revenue (its performance precedes the billing date) or deferred revenue (customer payment is received in advance of performance). Unbilled Revenue (Contract Assets) The Company presents unbilled revenue in the consolidated balance sheets within prepaid expenses and other current assets and within other assets. The Company’s contracts do not contain material financing components. The Company's unbilled revenue primarily consists of amounts that have yet to be billed under contracts with escalating fee structures. Specifically, because the Company generally recognizes revenue on a straight-line basis for data licensing arrangements with escalating fee structures, revenue recognized represents amounts to which the Company is contractually entitled; however, the revenue recognized exceeds the amounts the Company has a right to bill as of the period end, thus resulting in unbilled revenue. As of September 30, 2021, the Company recorded an immaterial amount of allowance for credit losses on unbilled revenue. Deferred Revenue (Contract Liabilities) The Company presents deferred revenue primarily within accrued and other current liabilities in the consolidated balance sheets and there is not expected to be any material non-current contract liabilities given the Company's contracting provisions. The Company's deferred revenue balance primarily consists of cash payments due in advance of satisfying its performance obligations relating to data licensing contracts and performance obligations given to customers based on their spend relating to advertising contracts, for which the Company defers, as they represent material rights. The Company recognizes deferred revenue relating to its data licensing contracts on a straight-line basis over the period in which the Company provides data. The Company recognizes deferred revenue relating to its advertising contracts based on the amount of customer spend and the relative standalone selling price of the material rights. The following table presents contract balances (in thousands): September 30, December 31, Unbilled revenue $ 41,089 $ 44,063 Deferred revenue $ 92,871 $ 62,191 The amount of revenue recognized in the three months ended September 30, 2021 that was included in the deferred revenue balance as of June 30, 2021 was $51.3 million. The amount of revenue recognized in the nine months ended September 30, 2021 that was included in the deferred revenue balance as of December 31, 2020 was $61.8 million. This revenue consists primarily of revenue recognized as a result of the utilization of bonus ads inventory earned by and material rights provided to customers in prior periods and the satisfaction of the Company’s performance obligations relating to data licensing contracts with advance cash payments or material rights. The amount of revenue recognized from obligations satisfied (or partially satisfied) in prior periods was not material. The decrease in the unbilled revenue balance from December 31, 2020 to September 30, 2021 was primarily attributable to differences between revenue recognized and amounts billed in the Company's data licensing arrangements with escalating fee structures due to recognizing such fees as revenue on a straight-line basis. The increase in the deferred revenue balance from December 31, 2020 to September 30, 2021 was primarily due to cash payments received or due in advance of satisfying the Company’s performance obligations for data licensing contracts and bonus ads inventory offered to customers during the period, offset by the delivery of performance obligations and bonus ads inventory. Remaining Performance Obligations As of September 30, 2021, the aggregate amount of the transaction price allocated to remaining performance obligations in contracts with an original expected duration exceeding one year is $578.2 million. This total amount primarily consists of long-term data licensing contracts and excludes deferred revenue related to the Company’s short-term advertising service arrangements. The Company expects to recognize this amount as revenue over the following time periods (in thousands): Remaining Performance Obligations Total Remainder of 2021 2022 2023 and Thereafter Revenue expected to be recognized on remaining performance obligations $ 578,182 $ 75,661 $ 211,907 $ 290,614

Cash, Cash Equivalents and Shor

Cash, Cash Equivalents and Short-term Investments	9 Months Ended
	Sep. 30, 2021
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Short-term Investments	Cash, Cash Equivalents and Short-term Investments Cash, cash equivalents and short-term investments consist of the following (in thousands): September 30, December 31, Cash and cash equivalents: Cash $ 271,236 $ 285,002 Money market funds 3,038,524 1,158,927 Corporate notes, commercial paper and certificates of deposit 164,105 544,500 Total cash and cash equivalents $ 3,473,865 $ 1,988,429 Short-term investments: U.S. government and agency securities $ 450,275 $ 910,259 Corporate notes, commercial paper and certificates of deposit 3,466,012 4,572,394 Marketable equity securities 21,160 1,220 Total short-term investments $ 3,937,447 $ 5,483,873 The contractual maturities of debt securities classified as available-for-sale as of September 30, 2021 were as follows (in thousands): September 30, Due within one year $ 1,798,169 Due after one year through five years 2,118,118 Total $ 3,916,287 The following tables summarize unrealized gains and losses related to available-for-sale debt securities classified as short-term investments on the Company’s consolidated balance sheets (in thousands): September 30, 2021 Gross Gross Gross Aggregated U.S. government and agency securities $ 450,361 $ 138 $ (224) $ 450,275 Corporate notes, commercial paper and certificates of deposit 3,456,150 11,078 (1,216) 3,466,012 Total available-for-sale debt securities classified as short-term investments $ 3,906,511 $ 11,216 $ (1,440) $ 3,916,287 December 31, 2020 Gross Gross Gross Aggregated U.S. government and agency securities $ 909,092 $ 1,177 $ (10) $ 910,259 Corporate notes, commercial paper and certificates of deposit 4,545,687 26,939 (232) 4,572,394 Total available-for-sale debt securities classified as short-term investments $ 5,454,779 $ 28,116 $ (242) $ 5,482,653 The gross unrealized loss on available-for-sale debt securities in a continuous loss position for 12 months or longer was not material as of September 30, 2021 and December 31, 2020.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company measures its cash equivalents, short-term investments and derivative financial instruments at fair value. The Company classifies its cash equivalents, short-term investments and derivative financial instruments within Level 1 or Level 2 because the Company values these investments using quoted market prices or alternative pricing sources and models utilizing market observable inputs. The fair value of the Company’s Level 1 financial assets is based on quoted market prices of the identical underlying security. The fair value of the Company’s Level 2 financial assets is based on inputs that are directly or indirectly observable in the market, including the readily-available pricing sources for the identical underlying security that may not be actively traded. The following tables set forth the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2021 and December 31, 2020 based on the three-tier fair value hierarchy (in thousands): September 30, 2021 Level 1 Level 2 Total Assets Cash equivalents: Money market funds $ 3,038,524 $ — $ 3,038,524 Commercial paper — 164,105 164,105 Short-term investments: U.S. government and agency securities — 450,275 450,275 Corporate notes — 2,586,251 2,586,251 Commercial paper — 593,297 593,297 Certificates of deposit — 286,464 286,464 Marketable equity securities 21,160 — 21,160 Other current assets: Foreign currency contracts — 1,025 1,025 Total $ 3,059,684 $ 4,081,417 $ 7,141,101 Liabilities Other current liabilities: Foreign currency contracts $ — $ 3,015 $ 3,015 Total $ — $ 3,015 $ 3,015 December 31, 2020 Level 1 Level 2 Total Assets Cash equivalents: Money market funds $ 1,158,927 $ — $ 1,158,927 Corporate notes — 1,347 1,347 Commercial paper — 543,153 543,153 Short-term investments: U.S. government and agency securities — 910,259 910,259 Corporate notes — 2,829,521 2,829,521 Commercial paper — 1,240,670 1,240,670 Certificates of deposit — 502,203 502,203 Marketable equity securities 1,220 — 1,220 Other current assets: Foreign currency contracts — 5,529 5,529 Total $ 1,160,147 $ 6,032,682 $ 7,192,829 Liabilities Other current liabilities: Foreign currency contracts $ — $ 1,028 $ 1,028 Total $ — $ 1,028 $ 1,028 The following table sets forth the estimated fair value of the Company's convertible and senior notes outstanding as of September 30, 2021 based on the three-tier fair value hierarchy (in thousands): September 30, 2021 Level 2 Level 3 Total $1.15 billion in aggregate principal amount of 0.25% convertible senior notes due in 2024 (the 2024 Notes) 1,444,285 — 1,444,285 $1.0 billion in aggregate principal amount of 0.375% convertible senior notes due in 2025 (the 2025 Notes) — 1,509,620 1,509,620 $1.44 billion in aggregate principal amount of 0% convertible senior notes due in 2026 (the 2026 Notes) 1,341,763 — 1,341,763 $700.0 million in aggregate principal amount of 3.875% senior notes due in 2027 (the 2027 Notes) 743,750 — 743,750 Total 3,529,798 1,509,620 5,039,418 The estimated fair value of the 2024 Notes, the 2026 Notes, and the 2027 Notes is determined based on a market approach, using the estimated or actual bids and offers of the respective notes in an over-the-counter market on the last business day of the period. The estimated fair value of the 2025 Notes is determined based on a binomial model, using inputs including risk free rate, volatility and discount yield. Refer to Note 11 – Convertible Notes and Senior Notes for further details on the Notes. Derivative Financial Instruments The Company enters into foreign currency forward contracts with financial institutions to reduce the risk that its earnings may be adversely affected by the impact of exchange rate fluctuations on monetary assets or liabilities denominated in currencies other than the functional currency of a subsidiary. These contracts do not subject the Company to material balance sheet risk due to exchange rate movements because gains and losses on these derivatives are intended to offset gains and losses on the hedged foreign currency denominated assets and liabilities. These foreign currency forward contracts are not designated as hedging instruments. The Company recognizes these derivative instruments as either assets or liabilities in the consolidated balance sheets at fair value based on a Level 2 valuation. The Company records changes in the fair value (i.e., gains or losses) of the derivatives in other income (expense), net in the consolidated statements of operations. The notional principal of foreign currency contracts outstanding was equivalent to $524.4 million and $729.8 million as of September 30, 2021 and December 31, 2020, respectively. The fair values of outstanding derivative instruments for the periods presented on a gross basis are as follows (in thousands): Balance Sheet Location September 30, December 31, Assets Foreign currency contracts not designated as hedging instruments Other current assets $ 1,025 $ 5,529 Liabilities Foreign currency contracts not designated as hedging instruments Other current liabilities $ 3,015 $ 1,028 The Company recognized $3.7 million and $0.5 million of net losses on its foreign currency contracts in the three and nine months ended September 30, 2021, respectively. The Company recognized $7.1 million and $18.3 million of net losses on its foreign currency contracts in the three and nine months ended September 30, 2020, respectively.

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Property and Equipment, Net The following tables set forth property and equipment, net by type and by geographic area for the periods presented (in thousands): September 30, December 31, Property and equipment, net Equipment $ 2,171,491 $ 1,830,459 Furniture and leasehold improvements 393,950 362,766 Capitalized software 892,829 811,371 Construction in progress 707,041 349,935 Total 4,165,311 3,354,531 Less: Accumulated depreciation and amortization (2,111,831) (1,860,737) Property and equipment, net $ 2,053,480 $ 1,493,794 September 30, December 31, Property and equipment, net: United States $ 2,018,861 $ 1,460,163 International 34,619 33,631 Total property and equipment, net $ 2,053,480 $ 1,493,794

Operating Leases

Operating Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Operating Leases	Operating Leases The Company has operating leases primarily for office space and data center facilities. The Company subleases certain leased office space to third parties when it determines there is excess leased capacity. Operating lease right-of-use assets obtained in exchange for operating lease obligations were $352.5 million and $253.9 million in the nine months ended September 30, 2021 and 2020, respectively. Future lease payments under operating leases and sublease income as of September 30, 2021 were as follows (in thousands): Operating Sublease Year Ending December 31, Remainder of 2021 $ 54,407 $ (2,833) 2022 279,750 (3,888) 2023 236,335 (2,616) 2024 235,587 (1,629) 2025 230,852 (120) Thereafter 895,980 — Total future lease payments (receipts) 1,932,911 $ (11,086) Less: leases not yet commenced (576,997) Less: imputed interest (156,849) Total operating lease liabilities $ 1,199,065 Reconciliation of operating lease liabilities as shown in the consolidated balance sheets Operating lease liabilities, short-term $ 218,301 Operating lease liabilities, long-term 980,764 Total operating lease liabilities $ 1,199,065 There were no other material changes in the Company's operating leases in the three and nine months ended September 30, 2021, as compared to the disclosure in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets The following table presents the goodwill activities for the periods presented (in thousands): Goodwill Balance as of December 31, 2020 $ 1,312,346 Acquisitions 13,893 Reclassified to assets held for sale (1) (28,800) Other (3,613) Balance as of September 30, 2021 $ 1,293,826 (1) On October 6, 2021 the Company announced that it entered into a definitive agreement to sell its MoPub business. The Company reclassified $28.8 million of goodwill to assets held for sale on the consolidated balance sheets as of September 30, 2021. Refer to Note 10 - Assets Held for Sale for further details on the transaction. For each of the periods presented, gross goodwill balance equaled the net balance since no impairment charges have been recorded. The following table presents the detail of intangible assets for the periods presented (in thousands): Gross Carrying Accumulated Net Carrying September 30, 2021: Patents and developed technologies $ 119,862 $ (74,209) $ 45,653 Other 10,769 (9,720) 1,049 Total $ 130,631 $ (83,929) $ 46,702 December 31, 2020: Patents and developed technologies $ 110,153 $ (53,265) $ 56,888 Other 1,800 (350) 1,450 Total $ 111,953 $ (53,615) $ 58,338 Amortization expense associated with intangible assets was $10.8 million and $5.4 million for the three months ended September 30, 2021 and 2020, respectively, and $30.6 million and $18.0 million for the nine months ended September 30, 2021 and 2020, respectively. Estimated future amortization expense as of September 30, 2021 is as follows (in thousands): Remainder of 2021 $ 7,105 2022 17,369 2023 7,843 2024 6,026 2025 1,863 Thereafter 6,496 Total $ 46,702

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Accrued and Other Current Liabilities	Accrued and Other Current Liabilities The following table presents the detail of accrued and other current liabilities for the periods presented (in thousands): September 30, December 31, Litigation settlement accrual (see Note 15) $ 809,500 $ — Accrued compensation 290,088 171,681 Federal Trade Commission accrual (see Note 15) 150,000 150,000 Deferred revenue 92,826 58,976 Accrued professional services 55,116 27,404 Accrued publisher, content and ad network costs 43,379 42,541 Accrued tax liabilities 41,875 40,384 Accrued other 205,984 172,546 Total $ 1,688,768 $ 663,532

Acquisitions and Other Investme

Acquisitions and Other Investments	9 Months Ended
	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Acquisitions and Other Investments	Acquisitions and Other Investments 2021 Acquisitions During the nine months ended September 30, 2021, the Company made a number of acquisitions, which were accounted for as business combinations. The total purchase price for these acquisitions was $24.1 million, which was allocated as follows: $9.7 million to developed technologies, $0.5 million to net assets assumed based on their estimated fair value on the acquisition date, and the excess $13.9 million of the purchase price over the fair value of net assets acquired to goodwill. The goodwill from the acquisitions is mainly attributable to assembled workforce, expected synergies and other benefits. $2.1 million of the goodwill is tax deductible. Developed technologies will be amortized on a straight-line basis over their estimated useful lives of up to one year. The results of operations for these acquisitions have been included in the Company’s consolidated statements of operations since the date of each respective acquisition. Actual and pro forma revenue and results of operations for these acquisitions have not been presented because they do not have a material impact on the consolidated results of operations. Investments in Privately-Held Companies The Company makes strategic investments in privately-held companies. The Company evaluates each investee to determine if the investee is a variable interest entity and, if so, whether the Company is the primary beneficiary of the variable interest entity. The Company has determined, as of September 30, 2021, there were no variable interest entities required to be consolidated in the Company’s consolidated financial statements. The Company’s investments in privately-held companies are primarily non-marketable equity securities without readily determinable fair values. The Company accounts for its investments in privately-held companies either under equity method accounting or by adjusting the carrying value of its non-marketable equity securities to fair value upon observable transactions for identical or similar investments of the same issuer or upon impairment (referred to as the measurement alternative). All gains and losses on non-marketable equity securities, realized and unrealized, are recognized in other income (expense), net. The maximum loss the Company can incur for its investments is their carrying value. These investments in privately-held companies are included within other assets on the consolidated balance sheets. The Company’s non-marketable equity securities had a combined carrying value of $179.5 million and $85.8 million as of September 30, 2021 and December 31, 2020, respectively. In the three months ended March 31, 2021, the Company funded $60.0 million of bridge financing in the form of convertible loans to a privately-held company in which it had an existing investment. In April 2021, the Company converted $30.0 million of the $60.0 million of the convertible loans into preferred stock, and sold the remaining $30.0 million of the convertible loans at face value to an unaffiliated third party. As of September 30, 2021, the $30.0 million of the preferred stock is included within other assets on the consolidated balance sheets. In the three and nine months ended September 30, 2021, the Company recorded upward adjustments (unrealized gain) of $24.9 million and $60.9 million, respectively, on its investment in this privately-held company in other income (expense), net in the consolidated statements of operations. The upward adjustments represent the difference between fair value and carrying value of the preferred stock, resulting from observable price changes in orderly transactions for similar investments related to subsequent rounds of financing completed by the privately-held company. The estimated fair value of the preferred stock is determined based on an option pricing model, which represents a Level 3 valuation. The option pricing model allocates equity value to individual securities within the investees’ capital structure based on contractual rights and preferences. The inputs in the option pricing model are transaction price per share of those similar securities along with time to liquidity and volatility. No upward adjustment was recorded in the three and nine months ended September 30, 2020. The Company periodically evaluates the carrying value of its investments in privately-held companies when events and circumstances indicate that the carrying amount of the investment may not be recovered. The Company estimates the fair value of the investments to assess whether impairment losses shall be recorded using Level 3 inputs. These investments include the Company’s holdings in privately-held companies that are not exchange traded and therefore not supported with observable market prices; hence, the Company may determine the fair value by reviewing equity valuation reports, current financial results, long-term plans of the privately-held companies, the amount of cash that the privately-held companies have on-hand, the ability to obtain additional financing and overall market conditions in which the privately-held companies operate or based on the price observed from the most recent completed financing. No impairment charge was recorded in the three and nine months ended September 30, 2021. The Company recorded impairment charges of $0.3 million and $8.8 million in the three and nine months ended September 30, 2020, respectively, within other income (expense), net in the consolidated statements of operations.

Assets Held for Sale

Assets Held for Sale	9 Months Ended
	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Assets Held for Sale	Assets Held for SaleOn October 6, 2021 the Company entered into a definitive agreement to sell its MoPub business to AppLovin Corporation for $1.05 billion in cash. The sale of MoPub enables the Company to concentrate more of its efforts on the significant opportunity for performance-based advertising, SMB offerings, and commerce initiatives on Twitter. The transaction is expected to close in the first quarter of 2022, subject to customary closing conditions, including receipt of regulatory approval. The Company is currently assessing the impact of the transaction on its consolidated financial statements. The Company expects to record a pre-tax gain of approximately $1.0 billion in the consolidated statements of operations in the period the transaction closes. The sale does not represent a strategic shift that would have a major effect on the Company's operations and financial results, and therefore does not qualify for reporting as a discontinued operation for financial statement purposes. The Company concluded that the sale of the MoPub business meets the criteria to be classified as assets held for sale as of September 30, 2021. The held for sale assets on the consolidated balance sheet as of September 30, 2021 consist only of goodwill. No liabilities will be transferred in the transaction. No impairment charges were required for the held for sale assets in the three months ended September 30, 2021.

Convertible Notes and Senior No

Convertible Notes and Senior Notes	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Convertible Notes and Senior Notes	Convertible Notes and Senior Notes Convertible Notes 2026 Notes In March 2021, the Company issued $1.44 billion in aggregate principal amount of 0% convertible senior notes due 2026 (or the 2026 Notes) in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended. The total net proceeds from this offering, after deducting debt issuance costs, were approximately $1.42 billion. The 2026 Notes represent senior unsecured obligations of the Company. The 2026 Notes do not bear interest except in special circumstances described below, and the principal amount of the 2026 Notes does not accrete. The 2026 Notes mature on March 15, 2026. Each $1,000 of principal of the notes will initially be convertible into 7.6905 shares of the Company’s common stock, which is equivalent to an initial conversion price of approximately $130.03 per share, subject to adjustment upon the occurrence of certain specified events set forth in the indenture governing the 2026 Notes. Holders of the 2026 Notes may convert their 2026 Notes at their option at any time on or after December 15, 2025 until close of business on the second scheduled trading day immediately preceding the maturity date of March 15, 2026. Further, holders of the 2026 Notes may convert all or any portion of their 2026 Notes at their option prior to the close of business on the business day immediately preceding December 15, 2025, only under the following circumstances: 1) during any calendar quarter commencing after June 30, 2021 (and only during such calendar quarter), if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; 2) during the five business day period after any five consecutive trading day period (the measurement period) in which the trading price (as defined in the indenture governing the 2026 Notes) per $1,000 principal amount of the 2026 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; or 3) upon the occurrence of certain specified corporate events. Upon conversion of the 2026 Notes, the Company will pay or deliver, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at the Company’s election. If the Company satisfies its conversion obligation solely in cash or through payment and delivery, as the case may be, of a combination of cash and shares of its common stock, the amount of cash and shares of common stock, if any, due upon conversion will be based on a daily conversion value (as set forth in the indenture governing the 2026 Notes) calculated on a proportionate basis for each trading day in a 30 trading day observation period. The Company may not redeem the 2026 Notes prior to the maturity date and no sinking fund is provided for the 2026 Notes. If a fundamental change (as defined in the indenture governing the 2026 Notes) occurs prior to the maturity date, holders of the 2026 Notes may require the Company to repurchase all or a portion of their notes for cash at a repurchase price equal to 100% of the principal amount of the 2026 Notes, plus any accrued and unpaid interest to, but excluding, the repurchase date. In addition, if specific corporate events occur prior to the maturity date of the 2026 Notes, the Company will be required to increase the conversion rate for holders who elect to convert their 2026 Notes in connection with such corporate events. Concurrent with the offering of the 2026 Notes, the Company entered into convertible note hedge transactions with certain bank counterparties whereby the Company has the option to purchase initially (subject to adjustment for certain specified events) a total of approximately 11.1 million shares of its common stock at a price of approximately $130.03 per share. The total cost of such convertible note hedge transactions was $213.5 million. In addition, the Company sold warrants to certain bank counterparties whereby the holders of the warrants have the option to purchase initially (subject to adjustment for certain specified events) a total of approximately 11.1 million shares of the Company’s common stock at a price of $163.02 per share. The Company received $161.1 million in cash proceeds from the sale of these warrants. Taken together, the purchase of such convertible note hedges and the sale of such warrants are intended to offset any actual dilution from the conversion of the 2026 Notes and to effectively increase the overall conversion price from $130.03 to $163.02 per share. As these transactions meet certain accounting criteria, such convertible note hedges and warrants are recorded in stockholders’ equity and are not accounted for as derivatives. The net cost incurred in connection with such convertible note hedge and warrant transactions was recorded as a reduction to additional paid-in capital in the consolidated balance sheets as of September 30, 2021. 2021 Notes, 2024 Notes, and 2025 Notes In 2014, the Company issued $954.0 million in aggregate principal amount of the 1.00% convertible senior notes due 2021, or the 2021 Notes, in a private placement to qualified institutional buyers pursuant to Rule 144A of the Securities Act of 1933, as amended. The total net proceeds from this offering were approximately $939.5 million, after deducting $14.3 million of debt discount and $0.2 million of debt issuance costs in connection with the issuance of the 2021 Notes. On September 15, 2021, the Company repaid at maturity the $954.0 million of aggregate principal amount associated with its 2021 Notes. In 2018, the Company issued $1.15 billion aggregate principal amount of the 0.25% convertible senior notes due 2024, or the 2024 Notes, in a private placement to qualified institutional buyers pursuant to Rule144A under the Securities Act of 1933, as amended. The total net proceeds from this offering were approximately $1.14 billion, after deducting $12.3 million of debt issuance costs in connection with the 2024 Notes. In 2020, the Company entered into an investment agreement (the Investment Agreement) with Silver Lake Partners V DE (AIV), L.P. (Silver Lake) relating to the issuance and sale to Silver Lake of $1.0 billion in aggregate principal amount of the Company's 0.375% convertible senior notes due 2025, or the 2025 Notes. The total net proceeds from this offering were approximately $985.3 million, after deducting $14.7 million of debt issuance costs in connection with the 2025 Notes. The 2024 Notes and 2025 Notes are senior unsecured obligations of the Company. The interest rate of the 2024 Notes is fixed at 0.25% per annum and interest is payable semi-annually in arrears on June 15 and December 15 of each year. The interest rate of the 2025 Notes is fixed at 0.375% per annum and interest is payable semi-annually in arrears on March 15 and September 15 of each year. The 2024 Notes and 2025 Notes mature on June 15, 2024 and March 15, 2025, respectively. Each $1,000 of principal of the 2024 Notes and 2025 Notes will initially be convertible into 17.5001 and 24.0964 shares, respectively, of the Company’s common stock, which is equivalent to an initial conversion price of approximately $57.14, and $41.50 per share, respectively, in each case, subject to adjustment upon the occurrence of specified events set forth in the indenture governing such series of Convertible Notes. Holders of the 2024 Notes may convert their 2024 Notes at their option at any time on or after March 15, 2024 until close of business on the second scheduled trading day immediately preceding the maturity date of June 15, 2024. Further, holders of the 2024 Notes may convert all or any portion of the notes at the option of such holder prior to March 15, 2024 only under the following circumstances: 1) during any calendar quarter, if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price for the applicable series of Convertible Notes on each applicable trading day; 2) during the five business day period after any five consecutive trading day period (the measurement period) in which the trading price (as defined in the indenture governing the applicable series of Convertible Notes) per $1,000 principal amount of such series of Convertible Notes for each trading day of the applicable measurement period was less than 98% of the product of the last reported sale price of Twitter’s common stock and the conversion rate for the applicable series of Convertible Notes on each such trading day; or 3) upon the occurrence of certain specified corporate events. Upon conversion of the 2024 Notes and 2025 Notes, the Company will pay or deliver, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at the Company’s election. If the Company satisfies its conversion obligation solely in cash or through payment and delivery of a combination of cash and shares of its common stock, the amount of cash and shares of common stock, if any, due upon conversion, will be based on a daily conversion value (as defined in the indenture governing the applicable series of Convertible Notes) calculated on a proportionate basis for each trading day in the applicable 30 trading day observation period. If a fundamental change (as defined in the indenture governing the applicable series of Convertible Notes) occurs prior to the applicable maturity date, holders of the 2024 Notes or 2025 Notes, as applicable, may require the Company to repurchase all or a portion of their notes for cash at a repurchase price equal to 100% of the principal amount of such notes, plus any accrued and unpaid interest to, but excluding, the repurchase date of such series of notes. In addition, if specific corporate events occur prior to the applicable maturity date of the 2024 Notes or 2025 Notes, the Company will be required to increase the conversion rate for holders who elect to convert their notes in connection with such corporate events. On or after March 20, 2022, the 2025 Notes will be redeemable by the Company in the event that the closing sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides the redemption notice at a redemption price of 100% of the principal amount of such 2025 Notes, plus accrued and unpaid interest to, but excluding, the redemption date. The 2025 Notes are convertible at the option of the holder at any time until the scheduled trading day prior to the maturity date, including in connection with a redemption by the Company. Pursuant to the Investment Agreement related to the 2025 Notes, and subject to certain exceptions, Silver Lake will be restricted from transferring or entering into an agreement that transfers the economic consequences of ownership of the 2025 Notes or converting the 2025 Notes prior to the earlier of (i) the two year anniversary of the original issue date of the 2025 Notes or (ii) immediately prior to the consummation of a change of control of the Company. Exceptions to such restrictions on transfer include, among others: a) transfers to affiliates of Silver Lake, b) transfers to the Company or any of its subsidiaries, c) transfers to a third party where the net proceeds of such sale are solely used to satisfy a margin call or repay a permitted loan or d) transfers in connection with certain merger and acquisition events. Concurrent with the offering of the 2021 Notes and the 2024 Notes, the Company entered into convertible note hedge transactions with certain bank counterparties whereby the Company has the option to purchase initially (subject to adjustment for certain specified events) a total of approximately 12.3 million and 20.1 million shares, respectively, of its common stock at a price of approximately $77.64 and $57.14 per share. The note hedge transactions in connection with the 2021 Notes expired on September 15, 2021. The total cost of the convertible note hedge transactions associated with the 2024 Notes was $268.0 million. In addition, the Company sold warrants to certain bank counterparties whereby the holders of the warrants have the option to purchase initially (subject to adjustment for certain specified events) a total of approximately 12.3 million and 20.1 million shares, respectively, of the Company’s common stock at an initial strike price of $105.28 and $80.20 per share, respectively. The Company received $172.9 million and $186.8 million in cash proceeds from the sale of these warrants, respectively. The warrant transactions in connection with the 2021 Notes expire over a 60 trading day settlement period scheduled to end on March 11, 2022. Taken together, the purchase of the convertible note hedges and the sale of warrants are intended to offset any actual dilution from the conversion of the 2024 Notes and to effectively increase the overall conversion price from $57.14 to $80.20 per share. As these transactions meet certain accounting criteria, the convertible note hedges and warrants are recorded in stockholders’ equity and are not accounted for as derivatives. The net cost incurred in connection with the convertible note hedge and warrant transactions was recorded as a reduction to additional paid-in capital in the consolidated balance sheets as of September 30, 2021. Senior Notes 2027 Notes In 2019, the Company issued $700.0 million aggregate principal amount of the 3.875% senior notes due 2027, or the 2027 Notes, in a private placement to qualified institutional buyers pursuant to Rule144A under the Securities Act of 1933, as amended, and outside the United States pursuant to Regulation S under the Securities Act of 1933, as amended. The total net proceeds from this offering were approximately $691.9 million, after deducting $8.1 million of debt issuance costs in connection with the issuance of the 2027 Notes. The 2027 Notes represent senior unsecured obligations of the Company. The interest rate is fixed at 3.875% per annum and interest is payable semi-annually in arrears on June 15 and December 15 of each year, which commenced on June 15, 2020. The 2027 Notes mature on December 15, 2027. Convertible Notes and Senior Notes The Notes consisted of the following (in thousands): September 30, 2021 2024 Notes 2025 Notes 2026 Notes 2027 Notes Principal amounts: Principal $ 1,150,000 $ 1,000,000 $ 1,437,500 $ 700,000 Unamortized debt discount and issuance costs (1) (5,569) (10,134) (14,863) (6,256) Net carrying amount $ 1,144,431 $ 989,866 $ 1,422,637 $ 693,744 Carrying amount of the equity component (2) $ — $ — $ — $ — December 31, 2020 2021 Notes 2024 Notes 2025 Notes 2027 Notes Principal amounts: Principal $ 954,000 $ 1,150,000 $ 1,000,000 $ 700,000 Unamortized debt discount and issuance costs (1) (36,134) (160,297) (113,825) (7,006) Net carrying amount $ 917,866 $ 989,703 $ 886,175 $ 692,994 Carrying amount of the equity component (2) $ 283,283 $ 254,981 $ 121,413 $ — (1) Included in the consolidated balance sheets within "convertible notes, short-term"; "convertible notes, long-term"; and "senior notes, long-term", and amortized over the remaining lives of the Notes. The decrease of unamortized debt discount and issuance costs balance as of September 30, 2021 compared to December 31, 2020 was mainly due to the adoption of the new convertible debt standard on January 1, 2021. (2) The Company adopted the new accounting standard update which simplifies the accounting for convertible debt instruments on January 1, 2021 using the modified retrospective method. The adoption eliminates the cash conversion and beneficial conversion feature models used to separately account for embedded conversion features as a component of equity. As of December 31, 2020, these amounts were included in the consolidated balance sheets within additional paid-in capital. In the three and nine months ended September 30, 2021, the effective interest rate for the 2024 Notes, 2025 Notes, and 2027 Notes was 0.25%, 0.375%, and 3.875%, respectively. The 2026 Notes do not bear regular interest. In the three and nine months ended September 30, 2020 the effective interest rate for the 2024 Notes, 2025 Notes, and 2027 Notes was 4.46%, 2.99%, and 3.875%, respectively. During the three months ended September 30, 2021 and 2020, the Company recognized $2.7 million and $29.6 million, respectively, of interest expense related to the amortization of debt discount and issuance costs prior to capitalization of interest. During the nine months ended September 30, 2021 and 2020, the Company recognized $7.8 million and $82.4 million, respectively, of interest expense related to the amortization of debt discount and issuance costs prior to capitalization of interest. The decreases in the effective interest rate and interest expense are due to the elimination of interest expense related to the conversion features of the Convertible Notes as a result of the adoption of the new accounting standard update to simplify the accounting for convertible debt on January 1, 2021. Refer to Note 1 - Summary of Significant Accounting Policies for more detail. During the three months ended September 30, 2021 and 2020, the Company recognized $10.5 million and $10.9 million, respectively, of coupon interest expense. During the nine months ended September 30, 2021 and 2020, the Company recognized $32.1 million and $31.7 million, respectively, of coupon interest expense. As of September 30, 2021, the remaining life of the 2024 Notes, the 2025 Notes, the 2026 Notes, and the 2027 Notes is approximately 32 months, 41 months, 53 months, and 74 months, respectively.

Net Income (Loss) per Share

Net Income (Loss) per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Net Income (Loss) per Share Basic net income (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted-average common shares outstanding during the period. The weighted-average common shares outstanding is adjusted for shares subject to repurchase such as unvested restricted stock granted to employees in connection with acquisitions, contingently returnable shares and escrowed shares supporting indemnification obligations that are issued in connection with acquisitions and unvested stock options exercised. Diluted net income (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period, including potential dilutive securities. When the convertible notes are dilutive, interest expense, net of tax, is added back to net income attributable to common stockholders to calculate diluted net income per share. The following table presents the calculation of basic and diluted net income (loss) per share for periods presented (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Basic net income (loss) per share: Numerator Net income (loss) $ (536,757) $ 28,659 $ (403,103) $ (1,357,742) Denominator Weighted-average common shares outstanding 799,537 793,065 798,559 787,831 Weighted-average restricted stock subject to repurchase (1,552) (2,238) (1,784) (2,043) Weighted-average shares used to compute basic net income (loss) per share 797,985 790,827 796,775 785,788 Basic net income (loss) per share attributable to common stockholders $ (0.67) $ 0.04 $ (0.51) $ (1.73) Diluted net income (loss) per share: Numerator Net income (loss) $ (536,757) $ 28,659 $ (403,103) $ (1,357,742) Denominator Number of shares used in basic computation 797,985 790,827 796,775 785,788 Weighted-average effect of dilutive securities: Convertible notes — — — — RSUs — 12,194 — — Stock options — 2,221 — — Other — 1,141 — — Weighted-average shares used to compute diluted net income (loss) per share 797,985 806,383 796,775 785,788 Diluted net income (loss) per share attributable to common stockholders $ (0.67) $ 0.04 $ (0.51) $ (1.73) The following numbers of potential common shares at the end of each period were excluded from the calculation of diluted net income (loss) per share attributable to common stockholders because their effect would have been anti-dilutive for the periods presented (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Warrants 43,467 32,412 43,467 32,412 Convertible notes 55,277 — 55,277 — RSUs 39,192 2,549 39,192 38,932 Shares subject to repurchase and others 8,348 3,317 8,348 7,930 Stock options 907 26 907 2,917 Prior to January 1, 2021, the Company used the treasury stock method for calculating any potential dilutive effect of the conversion spread on diluted net income (loss) per share, if applicable. In the three months ended September 30, 2020 since the average market price of the common stock was below the conversion price of each of the Convertible Notes outstanding and the exercise price of each of the warrants in the period, the Convertible Notes and warrants were anti-dilutive. In the nine months ended September 30, 2020, the Company’s potential common stock instruments such as stock options, RSUs, shares to be purchased under the 2013 Employee Stock Purchase Plan, shares subject to repurchases, the Convertible Notes and the warrants were not included in the computation of diluted net loss per share as the effect of including these shares in the calculation would have been anti-dilutive. On January 1, 2021, the Company adopted the accounting standard update to simplify the accounting for convertible debt instruments. The Company now uses the if-converted method for all Convertible Notes in the diluted net income (loss) per share calculation and includes the effect of potential share settlement for the Convertible Notes, if the effect is more dilutive. In the three and nine months ended September 30, 2021, the Convertible Notes were not included in the computation of diluted net loss per share as the effect of including these shares in the calculation would have been anti-dilutive. The use of the if-converted method had no impact on the diluted net income (loss) per share amount in any of the periods presented. If the average market price of the common stock exceeds the exercise price of the warrants, $105.28 for the 2021 Notes, $80.20 for the 2024 Notes, and $163.02 for the 2026 Notes, the warrants will have a dilutive effect on the earnings per share assuming that the Company is profitable. Since the average market price of the common stock is below $80.20 for all periods presented, the warrants are anti-dilutive.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2021
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity Equity Incentive Plans The Company’s 2013 Equity Incentive Plan serves as the successor to the 2007 Equity Incentive Plan. The number of shares of the Company’s common stock available for issuance under the 2013 Equity Incentive Plan have been and will be increased on the first day of each fiscal year beginning with the 2014 fiscal year, in an amount equal to the least of (i) 60,000,000 shares, (ii) 5% of the outstanding shares on the last day of the immediately preceding fiscal year, or (iii) such number of shares determined by the Company’s Board of Directors. Share Repurchases In March 2020, the Company's Board of Directors authorized a program to repurchase up to $2.0 billion of the Company's common stock over time. Repurchases may be made from time to time through open market purchases or through 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 its common stock, and may be suspended at any time at the Company’s discretion. In the three and nine months ended September 30, 2021, the Company repurchased 2.6 million and 11.2 million shares for an aggregate amount of $169.4 million and $664.8 million, respectively. The repurchases include 87,000 shares for $5.3 million that were not settled as of September 30, 2021 and that are presented as treasury stock on the consolidated balance sheets as of such date. Employee Stock Purchase Plan The number of shares available for sale under the Employee Stock Purchase Plan (ESPP) has been and will be increased on the first day of each fiscal year beginning with the 2014 fiscal year, in an amount equal to the least of (i) 11.3 million shares; (ii) 1% of the outstanding shares of the Company’s common stock as of the last day of the immediately preceding fiscal year; or (iii) such other amount as determined by the Company's Board of Directors. During the nine months ended September 30, 2021, employees purchased an aggregate of 1.5 million shares under the ESPP at a weighted-average price of $25.69 per share. During the nine months ended September 30, 2020, employees purchased an aggregate of 1.4 million shares under the ESPP at a weighted-average price of $24.65 per share. Restricted Common Stock The Company has granted restricted common stock to certain continuing employees in connection with certain of its acquisitions. Vesting of this stock is dependent on the respective employee’s continued employment at the Company during the requisite service period, which is generally up to four years from the issuance date, and the Company has the right to repurchase the unvested shares upon termination of employment. The fair value of the restricted common stock issued to employees is recorded as compensation expense on a straight-line basis over the requisite service period. The Company had 1.4 million and 2.0 million shares of unvested restricted common stock as of September 30, 2021 and December 31, 2020, respectively. The Company's restricted common stock activity was not material during the nine months ended September 30, 2021. Stock Option Activity The Company had 0.9 million and 1.4 million shares of stock options outstanding as of September 30, 2021 and December 31, 2020, respectively. The Company’s stock option activity was not material during the nine months ended September 30, 2021. Performance Restricted Stock Units Activity The Company grants restricted stock units to certain of its executive officers periodically that vest based on the Company’s attainment of the annual financial performance goals and the executives’ continued employment through the vesting date (PRSUs). These PRSUs are granted when the annual performance targets are set and the awards are approved by the Compensation Committee of the Board of Directors, generally in the first half of each financial year. The Company granted PRSUs with a vesting period of one year prior to 2020, and three years since 2020. The following table summarizes the activity related to the Company’s PRSUs for the nine months ended September 30, 2021 (in thousands, except per share data): PRSUs Outstanding Shares Weighted- Unvested and outstanding at December 31, 2020 729 $ 27.77 Granted (100% target level) 348 $ 71.22 Unearned performance shares canceled related to 2020 grants (365) $ 27.77 Vested (50% target level for 2020 performance period) (121) $ 27.77 Forfeited or cancelled (57) $ 52.76 Unvested and outstanding at September 30, 2021 534 $ 53.40 The total fair value of PRSUs vested during the nine months ended September 30, 2021 and 2020 was $9.4 million and $22.7 million, respectively. The Company grants market-based restricted stock units to certain of its executive officers that vest based on Twitter stock price performance relative to a broad-market index or upon achievement of certain Twitter stock price targets over a performance period of up to five years and the executives’ continued employment through the vesting date. The Company granted market-based RSUs with a vesting period of two The following table summarizes the activity related to the Company’s market-based restricted stock units for the nine months ended September 30, 2021 (in thousands, except per share data): Market-based RSUs Outstanding Shares Weighted- Unvested and outstanding at December 31, 2020 917 $ 30.90 Granted (100% target level) 2,888 $ 36.32 Unearned performance shares canceled related to 2019 grants (207) $ 30.60 Vested (52% target level for 2019-2020 performance period) (224) $ 30.60 Forfeited or cancelled (70) $ 52.03 Unvested and outstanding at September 30, 2021 3,304 $ 35.23 The total fair value of market-based RSUs vested during the nine months ended September 30, 2021 and 2020 was $17.2 million and $13.4 million, respectively. RSU Activity The following table summarizes the activity related to the Company’s RSUs, excluding PRSUs and market-based RSUs, for the nine months ended September 30, 2021. For purposes of this table, vested RSUs represent the shares for which the service condition had been fulfilled as of each respective date (in thousands, except per share data): RSUs Outstanding Shares Weighted- Unvested and outstanding at December 31, 2020 36,611 $ 32.28 Granted 19,790 $ 64.54 Vested (12,685) $ 35.16 Canceled (4,524) $ 38.35 Unvested and outstanding at September 30, 2021 39,192 $ 46.94 The total fair value of RSUs vested during the three months ended September 30, 2021 and 2020 was $301.8 million and $147.7 million, respectively. The total fair value of RSUs vested during the nine months ended September 30, 2021 and 2020 was $764.4 million and $363.6 million, respectively. Stock-Based Compensation Expense Stock-based compensation expense is allocated based on the cost center to which the award holder belongs. Total stock-based compensation expense by function is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Cost of revenue $ 11,627 $ 8,581 $ 33,479 $ 23,333 Research and development 101,515 66,111 269,983 204,686 Sales and marketing 27,105 25,550 84,647 73,572 General and administrative 24,048 15,727 65,261 45,157 Total stock-based compensation expense $ 164,295 $ 115,969 $ 453,370 $ 346,748 The Company capitalized $22.3 million and $10.2 million of stock-based compensation expense associated with the cost for developing software for internal use in the three months ended September 30, 2021 and 2020, respectively, and $63.8 million and $29.1 million in the nine months ended September 30, 2021 and 2020, respectively. As of September 30, 2021, there was $1.88 billion of gross unamortized stock-based compensation expense related to unvested awards which is expected to be recognized over a weighted-average period of 3.0 years. The Company accounts for forfeitures as they occur.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s tax provision or benefit for income taxes for interim periods has generally been determined using an estimate of its annual effective tax rate, adjusted for discrete items, if any. Under certain circumstances where the Company is unable to make a reliable estimate of the annual effective tax rate, the accounting guidance permits the use of the actual effective tax rate for the year-to-date period. In the three and nine months ended September 30, 2021, the Company used this approach because it was unable to reasonably estimate its annual effective tax rate due to the variability of the rate as a result of fluctuations in forecasted income and the effects of being taxed in multiple tax jurisdictions. The Company recorded a benefit from income taxes of $190.3 million and $192.7 million for the three and nine months ended September 30, 2021, respectively. The Company recorded a provision for income taxes of $1.0 million and $1.08 billion for the three and nine months ended September 30, 2020, respectively. For the nine months ended September 30, 2020, the provision for income taxes consisted of the establishment of a valuation allowance against deferred tax assets of $1.10 billion of a foreign subsidiary, which was partially offset by an income tax benefit of $18.6 million. The primary difference between the effective tax rate and the federal statutory tax rate relates to the valuation allowance establishment in 2020, the accrual related to the ongoing Federal Trade Commission matter described in Note 15 - Commitments and Contingencies that is not expected to be tax-deductible if and when paid, research and development credits, stock-based compensation, and foreign tax rate differences. The Company reassessed the ability to realize deferred tax assets by considering the available positive and negative evidence. As of June 30, 2020, the Company concluded that the deferred tax assets in a foreign subsidiary were not more-likely-than-not to be realized and recorded a full valuation allowance against such deferred tax assets in the approximate amount of $1.10 billion. As of September 30, 2021, there have been no changes to the Company's conclusion. As of September 30, 2021, the Company had $1.13 billion of deferred tax assets for which it has not established a valuation allowance, related to the U.S. federal, states other than Massachusetts and California, and certain international subsidiaries. The Company completed its reassessment of the ability to realize these assets and concluded that a valuation allowance was not required. As of September 30, 2021, the Company had $383.3 million of unrecognized tax benefits, of which $295.9 million could result in a reduction of 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 allowance recorded for California and Massachusetts deferred tax assets. The Company is subject to taxation in the United States and various foreign jurisdictions. Earnings from non-U.S. activities are subject to local country income tax. The material jurisdictions where the Company is subject to potential examination by tax authorities include the United States, California and Ireland. The Company believes that it has reserved adequate amounts for these jurisdictions.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Credit Facility The Company has a revolving credit agreement with certain lenders, which provides for a $500.0 million unsecured revolving credit facility maturing on August 7, 2023. The Company is obligated to pay interest on loans under the credit facility and other customary fees for a credit facility of this size and type, including an upfront fee and an unused commitment fee. The interest rate for the credit facility is determined based on calculations using certain market rates as set forth in the credit agreement. In addition, the credit facility contains restrictions on payments including cash payments of dividends. In March 2021, the Company entered into an amendment to the revolving credit agreement to increase the amount of indebtedness the Company may incur from $4.5 billion to $6.0 billion and to permit the convertible note issuance and hedge transactions associated with the 2026 Notes. As of September 30, 2021, no amounts had been drawn under the credit facility. Contractual Obligations The Company's principal commitments consist of obligations under the Notes (including principal and coupon interest), operating and finance leases for equipment, office space and co-located data center facilities, as well as non-cancellable contractual commitments. During the nine months ended September 30, 2021, the Company issued $1.44 billion in aggregate principal amount of the 2026 Notes. As of September 30, 2021, the Company's contractual obligation to settle commitments related to the 2026 Notes is $1.44 billion for the year ended December 31, 2026. On September 15, 2021, the Company repaid at maturity the $954.0 million of principal balance associated with its 2021 Notes. Other than as described above, there were no material changes outside the Company's normal course of business in its commitments under contractual obligations from those disclosed in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020. Legal Proceedings Beginning in September 2016, multiple putative class actions and derivative actions were filed in state and federal courts in the United States against the Company and the Company’s directors and/or certain former officers alleging that false and misleading statements, made in 2015, are in violation of securities laws and breached fiduciary duty. The putative class actions were consolidated in the U.S. District Court for the Northern District of California. On October 16, 2017, the court granted in part and denied in part the Company’s motion to dismiss. On July 17, 2018, the court granted plaintiffs' motion for class certification in the consolidated securities action. In January 2021, the Company entered into a binding agreement to settle the shareholder derivative lawsuits. The derivative settlement resolves all claims asserted against the Company and the other named defendants in the derivative lawsuits without any liability or wrongdoing attributed to them personally or the Company. Under the terms of the settlement, the Company's board of directors will adopt and implement certain corporate governance modifications. On July 27, 2021, the Court of Chancery of the State of Delaware approved the settlement agreement, and in the three months ended September 30, 2021, the Company received $38.0 million of insurance proceeds to be used for general corporate purposes. The settlement does not require the Company to make any payment, aside from covering certain administrative costs related to the settlement. The shareholder class action lawsuit was scheduled for trial on September 20, 2021. In September 2021, prior to the start of the trial, the Company negotiated and entered into a binding agreement to settle the shareholder class action lawsuit. The proposed class action settlement resolves all claims asserted against the Company and the other named defendants in the shareholder class action lawsuit without any liability or wrongdoing attributed to them personally or to the Company. Under the terms of the proposed settlement, the Company will pay $809.5 million. The settlement agreement is subject to final approval by the U.S. District Court for the Northern District of California. The Company recorded an accrual of $809.5 million for the proposed settlement, which is included in accrued and other current liabilities on the consolidated balance sheet as of September 30, 2021 and in litigation settlement, net in the consolidated statements of operations in the three and nine months ended September 30, 2021. In October 2021, the Company paid the settlement amount to escrow from cash on hand. Following the agreements to settle the class action and derivative lawsuits, no other matters related to the aforementioned putative class actions and derivative actions remain outstanding. Beginning in October 2019, putative class actions were filed in the U.S. District Court for the Northern District of California against the Company and certain of the Company’s officers alleging violations of securities laws in connection with the Company’s announcements that it had discovered and taken steps to remediate issues related to certain user settings designed to target advertising that were not working as expected and seeking unspecified damages. The Company disputes the claims and intends to defend the lawsuit vigorously. In December 2020, the district court dismissed the plaintiffs’ claims. The case is currently on appeal to the United States Court of Appeal for the Ninth Circuit. From time to time the Company notifies the Irish Data Protection Commission, its designated European privacy regulator under the European Union General Data Protection Regulation, or GDPR, and other regulators, of certain personal data breaches and privacy issues, and is subject to inquiries and investigations regarding various aspects of our regulatory compliance. The Company is currently the subject of inquiries by the Irish Data Protection Commission with respect to its compliance with the GDPR. On July 28, 2020, the Company received a draft complaint from the Federal Trade Commission (FTC) alleging violations of the Company’s 2011 consent order with the FTC and the Federal Trade Commission Act. The allegations relate to the Company’s use of phone number and/or email address data provided for safety and security purposes for targeted advertising during periods between 2013 and 2019. The Company estimates that the range of probable loss in this matter is $150.0 million to $250.0 million and recorded an accrual of $150.0 million in the three months ended June 30, 2020. The accrual is included in accrued and other current liabilities in the consolidated balance sheets as of September 30, 2021. The matter remains unresolved, and there can be no assurance as to the timing or the terms of any final outcome. On January 15, 2021, a derivative action was filed in the Delaware Chancery Court against certain directors of the Company alleging that the directors violated their fiduciary duties in deciding to enter into the Cooperation Agreement with certain affiliates of Elliott Management Corporation, to enter into the Investment Agreement with an affiliate of Silver Lake Partners, and to authorize a program to repurchase up to $2.0 billion of the Company's common stock. The Company and the directors dispute the claims and intend to defend the lawsuit vigorously. The defendants moved to dismiss the complaint on March 19, 2021 and on September 10, 2021, the Court denied defendants’ motion to dismiss. Defendants’ answer to the complaint is currently due October 29, 2021. On February 22, 2021, a derivative action was filed in the Delaware Chancery Court against Jack Dorsey alleging that Mr. Dorsey violated his fiduciary duties relating to various alleged privacy and cybersecurity issues. The parties have agreed to a stay of this action pending the outcome of the Company's board of directors' investigation of the claims. The Company and Mr. Dorsey dispute the claims and intend to defend the lawsuit vigorously. The Company is also currently involved in, and may in the future be involved in, legal proceedings, claims, investigations, and government inquiries and investigations arising in the ordinary course of business. These proceedings, which include both individual and class action litigation and administrative proceedings, have included, but are not limited to matters involving content on the platform or the Company's actions related thereto, intellectual property, privacy, data protection, consumer protection, securities, employment, and contractual rights. Legal fees and other costs associated with such actions are expensed as incurred. The Company assesses, in conjunction with its legal counsel, the need to record a liability for litigation and contingencies. With respect to the cases, actions, and inquiries described above, the Company evaluates the associated developments on a regular basis and will accrue a liability when it believes a loss is probable and the amount can be reasonably estimated. In addition, the Company believes there is a reasonable possibility that it may incur a loss in some of these matters and the loss may be material or exceed its estimated ranges of possible loss. With respect to the matters described above that do not include an estimate of the amount of loss or range of possible loss, such losses or range of possible losses either are not material or may be material but cannot be estimated. The outcomes of the matters described in this section, such as whether the likelihood of loss is remote, reasonably possible, or probable, or if and when the reasonably possible range of loss is estimable, are inherently uncertain. If one or more of these matters were resolved against the Company for amounts above management’s estimates, the Company’s financial condition and results of operations, including in a particular reporting period in which any such outcome becomes probable and estimable, could be materially adversely affected. Non-Income Taxes The Company is under various non-income tax audits by domestic and foreign tax authorities. These audits primarily revolve around routine inquiries, refund requests, and employee benefits. The Company accrues non-income taxes that may result from these audits when they are probable and can be reasonably estimated. Due to the complexity and uncertainty of some of these matters, however, as well as the judicial process in certain jurisdictions, the final outcome of these audits may be materially different from the Company's expectations. Indemnification In the ordinary course of business, the Company often includes standard indemnification provisions in its arrangements with its customers, partners, suppliers and vendors. Pursuant to these provisions, the Company may be obligated to indemnify such parties for losses or claims suffered or incurred in connection with its service, breach of representations or covenants, intellectual property infringement or other claims made against such parties. These provisions may limit the time within which an indemnification claim can be made. It is not possible to determine the maximum potential amount under these indemnification obligations due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. The Company has never incurred significant expense defending its licensees against third-party claims, nor has it ever incurred significant expense under its standard service warranties or arrangements with its customers, partners, suppliers and vendors. Accordingly, the Company had no liabilities recorded for these provisions as of September 30, 2021 and December 31, 2020.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Twitter, Inc. and its wholly-owned subsidiaries (collectively, “Twitter” or the “Company”). All intercompany accounts and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (GAAP). The unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and reflect, in management’s opinion, all adjustments of a normal, recurring nature that are necessary for the fair statement of the Company’s financial position, results of operations and cash flows for the interim periods, but are not necessarily indicative of the results expected for the full fiscal year or any other period. The accompanying interim consolidated financial statements and these related notes should be read in conjunction with the consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020.
Prior Period Reclassifications	Prior Period Reclassifications Certain prior period amounts have been reclassified to conform to the current period presentation.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, as well as related disclosure of contingent assets and liabilities. Actual results could differ materially from the Company’s estimates due to risks and uncertainties, including uncertainty in the current economic environment due to the global impact of the COVID-19 pandemic. To the extent that there are material differences between these estimates and actual results, the Company’s financial condition or operating results will be affected. The Company bases its estimates on past experience and other assumptions that the Company believes are reasonable under the circumstances, and the Company evaluates these estimates on an ongoing basis.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently adopted accounting pronouncements In August 2020, the Financial Accounting Standards Board (FASB) issued a new accounting standard update to simplify the accounting for convertible debt and other equity-linked instruments. The new guidance simplifies the accounting for convertible instruments by eliminating the cash conversion and beneficial conversion feature models used to separately account for embedded conversion features as a component of equity. Instead, the entity will account for the convertible debt or convertible preferred stock securities as a single unit of account, unless the conversion feature requires bifurcation and recognition as derivatives. Additionally, the guidance requires entities to use the if-converted method for all convertible instruments in the diluted earnings per share calculation and include the effect of potential share settlement for instruments that may be settled in cash or shares. The Company early adopted this new guidance using the modified retrospective method as of January 1, 2021. The adoption of this new guidance resulted in an increase of $254.6 million and $34.7 million to "Convertible notes, long-term" and "Convertible notes, short-term", respectively, to reflect the full principal amount of the Convertible Notes (as defined below) outstanding, net of issuance costs, a reduction of $567.5 million to additional paid-in capital, net of estimated income tax effects, to remove the equity component separately recorded for the conversion features associated with the Convertible Notes, an increase to deferred tax assets, net of $66.6 million, and a cumulative-effect adjustment of $344.8 million, net of estimated income tax effects, reducing the beginning balance of accumulated deficit as of January 1, 2021. The adoption of this new guidance reduced interest expense by $26.9 million and $83.0 million in the three and nine months ended September 30, 2021. In addition, the adoption requires the use of the if-converted method for all convertible notes in the diluted net income (loss) per share calculation and the inclusion of the effect of potential share settlement of the convertible notes, if the effect is more dilutive. There was no impact to the number of potentially dilutive shares in each of the periods presented. With the exception of the standards discussed above, there have been no other recent accounting pronouncements or changes in accounting pronouncements during the nine months ended September 30, 2021, as compared to the recent accounting pronouncements described in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, that are of significance or potential significance to the Company.
Revenue Recognition	Revenue Recognition Revenue is recognized when the control of promised goods or services is transferred to customers at an amount that reflects the consideration to which the Company expects to be entitled to in exchange for those goods or services. The Company identifies its contracts with customers and all performance obligations within those contracts. The Company then determines the transaction price and allocates the transaction price to the performance obligations within the Company's contracts with customers, recognizing revenue when, or as the Company satisfies its performance obligations. While the majority of the Company's revenue transactions are based on standard business terms and conditions, the Company also enters into sales agreements with advertisers and data partners that sometimes involve multiple performance obligations and occasionally include non-standard terms or conditions. Contract Balances The Company enters into contracts with its customers, which may give rise to contract liabilities (deferred revenue) and contract assets (unbilled revenue). The payment terms and conditions within the Company’s contracts vary by the type and location of its customer and products or services purchased, the substantial majority of which are due in less than one year. When the timing of revenue recognition differs from the timing of payments made by customers, the Company recognizes either unbilled revenue (its performance precedes the billing date) or deferred revenue (customer payment is received in advance of performance). Unbilled Revenue (Contract Assets) The Company presents unbilled revenue in the consolidated balance sheets within prepaid expenses and other current assets and within other assets. The Company’s contracts do not contain material financing components. The Company's unbilled revenue primarily consists of amounts that have yet to be billed under contracts with escalating fee structures. Specifically, because the Company generally recognizes revenue on a straight-line basis for data licensing arrangements with escalating fee structures, revenue recognized represents amounts to which the Company is contractually entitled; however, the revenue recognized exceeds the amounts the Company has a right to bill as of the period end, thus resulting in unbilled revenue. As of September 30, 2021, the Company recorded an immaterial amount of allowance for credit losses on unbilled revenue. Deferred Revenue (Contract Liabilities) The Company presents deferred revenue primarily within accrued and other current liabilities in the consolidated balance sheets and there is not expected to be any material non-current contract liabilities given the Company's contracting provisions. The Company's deferred revenue balance primarily consists of cash payments due in advance of satisfying its performance obligations relating to data licensing contracts and performance obligations given to customers based on their spend relating to advertising contracts, for which the Company defers, as they represent material rights. The Company recognizes deferred revenue relating to its data licensing contracts on a straight-line basis over the period in which the Company provides data. The Company recognizes deferred revenue relating to its advertising contracts based on the amount of customer spend and the relative standalone selling price of the material rights.
Fair Value Measurements	The Company measures its cash equivalents, short-term investments and derivative financial instruments at fair value. The Company classifies its cash equivalents, short-term investments and derivative financial instruments within Level 1 or Level 2 because the Company values these investments using quoted market prices or alternative pricing sources and models utilizing market observable inputs. The fair value of the Company’s Level 1 financial assets is based on quoted market prices of the identical underlying security. The fair value of the Company’s Level 2 financial assets is based on inputs that are directly or indirectly observable in the market, including the readily-available pricing sources for the identical underlying security that may not be actively traded.
Investments in Privately-Held Companies	Investments in Privately-Held Companies The Company makes strategic investments in privately-held companies. The Company evaluates each investee to determine if the investee is a variable interest entity and, if so, whether the Company is the primary beneficiary of the variable interest entity. The Company has determined, as of September 30, 2021, there were no variable interest entities required to be consolidated in the Company’s consolidated financial statements. The Company’s investments in privately-held companies are primarily non-marketable equity securities without readily determinable fair values. The Company accounts for its investments in privately-held companies either under equity method accounting or by adjusting the carrying value of its non-marketable equity securities to fair value upon observable transactions for identical or similar investments of the same issuer or upon impairment (referred to as the measurement alternative). All gains and losses on non-marketable equity securities, realized and unrealized, are recognized in other income (expense), net. The maximum loss the Company can incur for its investments is their carrying value. These investments in privately-held companies are included within other assets on the consolidated balance sheets.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue from External Customers by Products and Services	Revenue by geography is based on the billing address of the customers. The following tables set forth revenue by services and revenue by geographic area (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Revenue by services: Advertising services $ 1,140,504 $ 808,449 $ 3,092,755 $ 2,052,635 Data licensing and other 143,313 127,784 417,507 374,673 Total revenue $ 1,283,817 $ 936,233 $ 3,510,262 $ 2,427,308
Revenue from External Customers by Geographic Areas	Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Revenue by geographic area: United States $ 741,879 $ 512,637 $ 1,951,174 $ 1,345,948 Japan 159,151 132,392 480,558 371,763 Rest of World 382,787 291,204 1,078,530 709,597 Total revenue $ 1,283,817 $ 936,233 $ 3,510,262 $ 2,427,308
Summary of Contract Balances	The following table presents contract balances (in thousands): September 30, December 31, Unbilled revenue $ 41,089 $ 44,063 Deferred revenue $ 92,871 $ 62,191
Summary of Revenue Expected to Recognize on Remaining Performance Obligations Over the Time Periods	The Company expects to recognize this amount as revenue over the following time periods (in thousands): Remaining Performance Obligations Total Remainder of 2021 2022 2023 and Thereafter Revenue expected to be recognized on remaining performance obligations $ 578,182 $ 75,661 $ 211,907 $ 290,614

Cash, Cash Equivalents and Sh_2

Cash, Cash Equivalents and Short-term Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Cash and Cash Equivalents [Abstract]
Cash, Cash and Equivalents and Short-term Investments	Cash, cash equivalents and short-term investments consist of the following (in thousands): September 30, December 31, Cash and cash equivalents: Cash $ 271,236 $ 285,002 Money market funds 3,038,524 1,158,927 Corporate notes, commercial paper and certificates of deposit 164,105 544,500 Total cash and cash equivalents $ 3,473,865 $ 1,988,429 Short-term investments: U.S. government and agency securities $ 450,275 $ 910,259 Corporate notes, commercial paper and certificates of deposit 3,466,012 4,572,394 Marketable equity securities 21,160 1,220 Total short-term investments $ 3,937,447 $ 5,483,873
Contractual Maturities of Securities Classified as Available-for-Sale	The contractual maturities of debt securities classified as available-for-sale as of September 30, 2021 were as follows (in thousands): September 30, Due within one year $ 1,798,169 Due after one year through five years 2,118,118 Total $ 3,916,287
Summary of Unrealized Gains and Losses Related to Available-for-Sale Securities Classified as Short-term Investments	The following tables summarize unrealized gains and losses related to available-for-sale debt securities classified as short-term investments on the Company’s consolidated balance sheets (in thousands): September 30, 2021 Gross Gross Gross Aggregated U.S. government and agency securities $ 450,361 $ 138 $ (224) $ 450,275 Corporate notes, commercial paper and certificates of deposit 3,456,150 11,078 (1,216) 3,466,012 Total available-for-sale debt securities classified as short-term investments $ 3,906,511 $ 11,216 $ (1,440) $ 3,916,287 December 31, 2020 Gross Gross Gross Aggregated U.S. government and agency securities $ 909,092 $ 1,177 $ (10) $ 910,259 Corporate notes, commercial paper and certificates of deposit 4,545,687 26,939 (232) 4,572,394 Total available-for-sale debt securities classified as short-term investments $ 5,454,779 $ 28,116 $ (242) $ 5,482,653

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables set forth the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2021 and December 31, 2020 based on the three-tier fair value hierarchy (in thousands): September 30, 2021 Level 1 Level 2 Total Assets Cash equivalents: Money market funds $ 3,038,524 $ — $ 3,038,524 Commercial paper — 164,105 164,105 Short-term investments: U.S. government and agency securities — 450,275 450,275 Corporate notes — 2,586,251 2,586,251 Commercial paper — 593,297 593,297 Certificates of deposit — 286,464 286,464 Marketable equity securities 21,160 — 21,160 Other current assets: Foreign currency contracts — 1,025 1,025 Total $ 3,059,684 $ 4,081,417 $ 7,141,101 Liabilities Other current liabilities: Foreign currency contracts $ — $ 3,015 $ 3,015 Total $ — $ 3,015 $ 3,015 December 31, 2020 Level 1 Level 2 Total Assets Cash equivalents: Money market funds $ 1,158,927 $ — $ 1,158,927 Corporate notes — 1,347 1,347 Commercial paper — 543,153 543,153 Short-term investments: U.S. government and agency securities — 910,259 910,259 Corporate notes — 2,829,521 2,829,521 Commercial paper — 1,240,670 1,240,670 Certificates of deposit — 502,203 502,203 Marketable equity securities 1,220 — 1,220 Other current assets: Foreign currency contracts — 5,529 5,529 Total $ 1,160,147 $ 6,032,682 $ 7,192,829 Liabilities Other current liabilities: Foreign currency contracts $ — $ 1,028 $ 1,028 Total $ — $ 1,028 $ 1,028
Schedule of Convertible and Senior Notes Measured at Fair Value	The following table sets forth the estimated fair value of the Company's convertible and senior notes outstanding as of September 30, 2021 based on the three-tier fair value hierarchy (in thousands): September 30, 2021 Level 2 Level 3 Total $1.15 billion in aggregate principal amount of 0.25% convertible senior notes due in 2024 (the 2024 Notes) 1,444,285 — 1,444,285 $1.0 billion in aggregate principal amount of 0.375% convertible senior notes due in 2025 (the 2025 Notes) — 1,509,620 1,509,620 $1.44 billion in aggregate principal amount of 0% convertible senior notes due in 2026 (the 2026 Notes) 1,341,763 — 1,341,763 $700.0 million in aggregate principal amount of 3.875% senior notes due in 2027 (the 2027 Notes) 743,750 — 743,750 Total 3,529,798 1,509,620 5,039,418
Schedule of Fair Values of Outstanding Derivative Instruments	The fair values of outstanding derivative instruments for the periods presented on a gross basis are as follows (in thousands): Balance Sheet Location September 30, December 31, Assets Foreign currency contracts not designated as hedging instruments Other current assets $ 1,025 $ 5,529 Liabilities Foreign currency contracts not designated as hedging instruments Other current liabilities $ 3,015 $ 1,028

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	The following tables set forth property and equipment, net by type and by geographic area for the periods presented (in thousands): September 30, December 31, Property and equipment, net Equipment $ 2,171,491 $ 1,830,459 Furniture and leasehold improvements 393,950 362,766 Capitalized software 892,829 811,371 Construction in progress 707,041 349,935 Total 4,165,311 3,354,531 Less: Accumulated depreciation and amortization (2,111,831) (1,860,737) Property and equipment, net $ 2,053,480 $ 1,493,794
Property and Equipment Net by Geographic Area	September 30, December 31, Property and equipment, net: United States $ 2,018,861 $ 1,460,163 International 34,619 33,631 Total property and equipment, net $ 2,053,480 $ 1,493,794

Operating Leases (Tables)

Operating Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Summary of Future Operating Lease Payments Under Leases and Sublease Income	Future lease payments under operating leases and sublease income as of September 30, 2021 were as follows (in thousands): Operating Sublease Year Ending December 31, Remainder of 2021 $ 54,407 $ (2,833) 2022 279,750 (3,888) 2023 236,335 (2,616) 2024 235,587 (1,629) 2025 230,852 (120) Thereafter 895,980 — Total future lease payments (receipts) 1,932,911 $ (11,086) Less: leases not yet commenced (576,997) Less: imputed interest (156,849) Total operating lease liabilities $ 1,199,065 Reconciliation of operating lease liabilities as shown in the consolidated balance sheets Operating lease liabilities, short-term $ 218,301 Operating lease liabilities, long-term 980,764 Total operating lease liabilities $ 1,199,065
Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity	Future lease payments under operating leases and sublease income as of September 30, 2021 were as follows (in thousands): Operating Sublease Year Ending December 31, Remainder of 2021 $ 54,407 $ (2,833) 2022 279,750 (3,888) 2023 236,335 (2,616) 2024 235,587 (1,629) 2025 230,852 (120) Thereafter 895,980 — Total future lease payments (receipts) 1,932,911 $ (11,086) Less: leases not yet commenced (576,997) Less: imputed interest (156,849) Total operating lease liabilities $ 1,199,065 Reconciliation of operating lease liabilities as shown in the consolidated balance sheets Operating lease liabilities, short-term $ 218,301 Operating lease liabilities, long-term 980,764 Total operating lease liabilities $ 1,199,065

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill Activities	The following table presents the goodwill activities for the periods presented (in thousands): Goodwill Balance as of December 31, 2020 $ 1,312,346 Acquisitions 13,893 Reclassified to assets held for sale (1) (28,800) Other (3,613) Balance as of September 30, 2021 $ 1,293,826 (1) On October 6, 2021 the Company announced that it entered into a definitive agreement to sell its MoPub business. The Company reclassified $28.8 million of goodwill to assets held for sale on the consolidated balance sheets as of September 30, 2021. Refer to Note 10 - Assets Held for Sale for further details on the transaction.
Schedule of Intangible Assets	The following table presents the detail of intangible assets for the periods presented (in thousands): Gross Carrying Accumulated Net Carrying September 30, 2021: Patents and developed technologies $ 119,862 $ (74,209) $ 45,653 Other 10,769 (9,720) 1,049 Total $ 130,631 $ (83,929) $ 46,702 December 31, 2020: Patents and developed technologies $ 110,153 $ (53,265) $ 56,888 Other 1,800 (350) 1,450 Total $ 111,953 $ (53,615) $ 58,338
Schedule of Estimated Future Amortization Expenses	Estimated future amortization expense as of September 30, 2021 is as follows (in thousands): Remainder of 2021 $ 7,105 2022 17,369 2023 7,843 2024 6,026 2025 1,863 Thereafter 6,496 Total $ 46,702

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	The following table presents the detail of accrued and other current liabilities for the periods presented (in thousands): September 30, December 31, Litigation settlement accrual (see Note 15) $ 809,500 $ — Accrued compensation 290,088 171,681 Federal Trade Commission accrual (see Note 15) 150,000 150,000 Deferred revenue 92,826 58,976 Accrued professional services 55,116 27,404 Accrued publisher, content and ad network costs 43,379 42,541 Accrued tax liabilities 41,875 40,384 Accrued other 205,984 172,546 Total $ 1,688,768 $ 663,532

Convertible Notes and Senior _2

Convertible Notes and Senior Notes (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Components of Notes	The Notes consisted of the following (in thousands): September 30, 2021 2024 Notes 2025 Notes 2026 Notes 2027 Notes Principal amounts: Principal $ 1,150,000 $ 1,000,000 $ 1,437,500 $ 700,000 Unamortized debt discount and issuance costs (1) (5,569) (10,134) (14,863) (6,256) Net carrying amount $ 1,144,431 $ 989,866 $ 1,422,637 $ 693,744 Carrying amount of the equity component (2) $ — $ — $ — $ — December 31, 2020 2021 Notes 2024 Notes 2025 Notes 2027 Notes Principal amounts: Principal $ 954,000 $ 1,150,000 $ 1,000,000 $ 700,000 Unamortized debt discount and issuance costs (1) (36,134) (160,297) (113,825) (7,006) Net carrying amount $ 917,866 $ 989,703 $ 886,175 $ 692,994 Carrying amount of the equity component (2) $ 283,283 $ 254,981 $ 121,413 $ — (1) Included in the consolidated balance sheets within "convertible notes, short-term"; "convertible notes, long-term"; and "senior notes, long-term", and amortized over the remaining lives of the Notes. The decrease of unamortized debt discount and issuance costs balance as of September 30, 2021 compared to December 31, 2020 was mainly due to the adoption of the new convertible debt standard on January 1, 2021. (2) The Company adopted the new accounting standard update which simplifies the accounting for convertible debt instruments on January 1, 2021 using the modified retrospective method. The adoption eliminates the cash conversion and beneficial conversion feature models used to separately account for embedded conversion features as a component of equity. As of December 31, 2020, these amounts were included in the consolidated balance sheets within additional paid-in capital.

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Basic and Diluted Net Income (Loss) Per Share	The following table presents the calculation of basic and diluted net income (loss) per share for periods presented (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Basic net income (loss) per share: Numerator Net income (loss) $ (536,757) $ 28,659 $ (403,103) $ (1,357,742) Denominator Weighted-average common shares outstanding 799,537 793,065 798,559 787,831 Weighted-average restricted stock subject to repurchase (1,552) (2,238) (1,784) (2,043) Weighted-average shares used to compute basic net income (loss) per share 797,985 790,827 796,775 785,788 Basic net income (loss) per share attributable to common stockholders $ (0.67) $ 0.04 $ (0.51) $ (1.73) Diluted net income (loss) per share: Numerator Net income (loss) $ (536,757) $ 28,659 $ (403,103) $ (1,357,742) Denominator Number of shares used in basic computation 797,985 790,827 796,775 785,788 Weighted-average effect of dilutive securities: Convertible notes — — — — RSUs — 12,194 — — Stock options — 2,221 — — Other — 1,141 — — Weighted-average shares used to compute diluted net income (loss) per share 797,985 806,383 796,775 785,788 Diluted net income (loss) per share attributable to common stockholders $ (0.67) $ 0.04 $ (0.51) $ (1.73)
Summary of Potential Common Shares Excluded from Calculation of Diluted Net Income Per Share Attributable to Common Stockholders	The following numbers of potential common shares at the end of each period were excluded from the calculation of diluted net income (loss) per share attributable to common stockholders because their effect would have been anti-dilutive for the periods presented (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Warrants 43,467 32,412 43,467 32,412 Convertible notes 55,277 — 55,277 — RSUs 39,192 2,549 39,192 38,932 Shares subject to repurchase and others 8,348 3,317 8,348 7,930 Stock options 907 26 907 2,917

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense Allocated	Stock-based compensation expense is allocated based on the cost center to which the award holder belongs. Total stock-based compensation expense by function is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Cost of revenue $ 11,627 $ 8,581 $ 33,479 $ 23,333 Research and development 101,515 66,111 269,983 204,686 Sales and marketing 27,105 25,550 84,647 73,572 General and administrative 24,048 15,727 65,261 45,157 Total stock-based compensation expense $ 164,295 $ 115,969 $ 453,370 $ 346,748
PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of RSU Activity	The following table summarizes the activity related to the Company’s PRSUs for the nine months ended September 30, 2021 (in thousands, except per share data): PRSUs Outstanding Shares Weighted- Unvested and outstanding at December 31, 2020 729 $ 27.77 Granted (100% target level) 348 $ 71.22 Unearned performance shares canceled related to 2020 grants (365) $ 27.77 Vested (50% target level for 2020 performance period) (121) $ 27.77 Forfeited or cancelled (57) $ 52.76 Unvested and outstanding at September 30, 2021 534 $ 53.40
Market-based RSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of RSU Activity	The following table summarizes the activity related to the Company’s market-based restricted stock units for the nine months ended September 30, 2021 (in thousands, except per share data): Market-based RSUs Outstanding Shares Weighted- Unvested and outstanding at December 31, 2020 917 $ 30.90 Granted (100% target level) 2,888 $ 36.32 Unearned performance shares canceled related to 2019 grants (207) $ 30.60 Vested (52% target level for 2019-2020 performance period) (224) $ 30.60 Forfeited or cancelled (70) $ 52.03 Unvested and outstanding at September 30, 2021 3,304 $ 35.23
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of RSU Activity	The following table summarizes the activity related to the Company’s RSUs, excluding PRSUs and market-based RSUs, for the nine months ended September 30, 2021. For purposes of this table, vested RSUs represent the shares for which the service condition had been fulfilled as of each respective date (in thousands, except per share data): RSUs Outstanding Shares Weighted- Unvested and outstanding at December 31, 2020 36,611 $ 32.28 Granted 19,790 $ 64.54 Vested (12,685) $ 35.16 Canceled (4,524) $ 38.35 Unvested and outstanding at September 30, 2021 39,192 $ 46.94

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jan. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Convertible notes, long-term		$ 3,556,934		$ 3,556,934			$ 1,875,878
Convertible notes, short-term		0		0			917,866
Cumulative-effect adjustment on stockholders' equity attributable to parent		7,172,631	$ 7,812,088	7,172,631	$ 7,812,088		7,970,082
Accumulated deficit		(1,183,996)		(1,183,996)			(1,125,669)
Interest expense		13,284	39,614	40,362	112,712
Accounting Standards Update 2020-06
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Interest expense		26,900		83,000
Cumulative Effect, Period of Adoption, Adjustment
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Convertible notes, long-term	$ 254,600
Convertible notes, short-term	34,700
Deferred tax asset, increase (decrease), amount	66,600
Accumulated deficit	$ 344,800
Additional paid-in capital
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cumulative-effect adjustment on stockholders' equity attributable to parent		$ 8,468,708	$ 9,249,956	$ 8,468,708	$ 9,249,956	$ 8,457,717	9,167,138	$ 9,127,495	$ 8,763,330
Additional paid-in capital | Cumulative Effect, Period of Adoption, Adjustment
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cumulative-effect adjustment on stockholders' equity attributable to parent							$ (567,547)

Revenue - Revenue by Services a

Revenue - Revenue by Services and Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue:
Revenue	$ 1,283,817	$ 936,233	$ 3,510,262	$ 2,427,308
United States
Revenue:
Revenue	741,879	512,637	1,951,174	1,345,948
Japan
Revenue:
Revenue	159,151	132,392	480,558	371,763
Rest of World
Revenue:
Revenue	382,787	291,204	1,078,530	709,597
Advertising services
Revenue:
Revenue	1,140,504	808,449	3,092,755	2,052,635
Data licensing and other
Revenue:
Revenue	$ 143,313	$ 127,784	$ 417,507	$ 374,673

Revenue - Summary of Contract B

Revenue - Summary of Contract Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Unbilled revenue	$ 41,089	$ 44,063
Deferred revenue	$ 92,871	$ 62,191

Revenue - Additional Informatio

Revenue - Additional Information (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Deferred revenue, revenue recognized	$ 51,300	$ 61,800
Aggregate amount of transaction price allocated to remaining performance obligations	$ 578,182	$ 578,182

Revenue - Summary of Revenue Ex

Revenue - Summary of Revenue Expected to Recognize on Remaining Performance Obligations Over the Time Periods (Details) $ in Thousands	Sep. 30, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized on remaining performance obligations	$ 578,182
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized on remaining performance obligations	$ 75,661
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized on remaining performance obligations	$ 211,907
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized on remaining performance obligations	$ 290,614
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period

Cash, Cash Equivalents and Sh_3

Cash, Cash Equivalents and Short-term Investments - Schedule of Components (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Cash and cash equivalents:
Cash	$ 271,236	$ 285,002
Total cash and cash equivalents	3,473,865	1,988,429	$ 2,201,073
Short-term investments:
Debt securities, available-for-sale	3,916,287	5,482,653
Marketable equity securities	21,160	1,220
Total short-term investments	3,937,447	5,483,873
Money market funds
Cash and cash equivalents:
Total cash and cash equivalents	3,038,524	1,158,927
U.S. government and agency securities
Short-term investments:
Debt securities, available-for-sale	450,275	910,259
Corporate notes, commercial paper and certificates of deposit
Cash and cash equivalents:
Total cash and cash equivalents	164,105	544,500
Short-term investments:
Debt securities, available-for-sale	$ 3,466,012	$ 4,572,394

Cash, Cash Equivalents and Sh_4

Cash, Cash Equivalents and Short-term Investments - Contractual Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash And Cash Equivalents And Marketable Securities [Abstract]
Due within one year	$ 1,798,169
Due after one year through five years	2,118,118
Total	$ 3,916,287	$ 5,482,653

Cash, Cash Equivalents and Sh_5

Cash, Cash Equivalents and Short-term Investments - Summary of Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Gross Amortized Cost	$ 3,906,511	$ 5,454,779
Gross Unrealized Gains	11,216	28,116
Gross Unrealized Losses	(1,440)	(242)
Debt securities, available-for-sale	3,916,287	5,482,653
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Gross Amortized Cost	450,361	909,092
Gross Unrealized Gains	138	1,177
Gross Unrealized Losses	(224)	(10)
Debt securities, available-for-sale	450,275	910,259
Corporate notes, commercial paper and certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Gross Amortized Cost	3,456,150	4,545,687
Gross Unrealized Gains	11,078	26,939
Gross Unrealized Losses	(1,216)	(232)
Debt securities, available-for-sale	$ 3,466,012	$ 4,572,394

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Instruments on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Net Asset (Liability) [Abstract]
Debt securities, available-for-sale	$ 3,916,287	$ 5,482,653
Marketable equity securities	21,160	1,220
Other current assets	1,025	5,529
Other current liabilities	3,015	1,028
Fair Value, Measurements, Recurring
Fair Value, Net Asset (Liability) [Abstract]
Marketable equity securities	21,160	1,220
Assets	7,141,101	7,192,829
Liabilities	3,015	1,028
Fair Value, Measurements, Recurring | Foreign currency contracts
Fair Value, Net Asset (Liability) [Abstract]
Other current assets	1,025	5,529
Other current liabilities	3,015	1,028
Fair Value, Measurements, Recurring | Money market funds
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents	3,038,524	1,158,927
Fair Value, Measurements, Recurring | Corporate notes
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents		1,347
Debt securities, available-for-sale	2,586,251	2,829,521
Fair Value, Measurements, Recurring | Commercial paper
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents	164,105	543,153
Debt securities, available-for-sale	593,297	1,240,670
Fair Value, Measurements, Recurring | U.S. government and agency securities
Fair Value, Net Asset (Liability) [Abstract]
Debt securities, available-for-sale	450,275	910,259
Fair Value, Measurements, Recurring | Certificates of deposit
Fair Value, Net Asset (Liability) [Abstract]
Debt securities, available-for-sale	286,464	502,203
Fair Value, Measurements, Recurring | Level 1
Fair Value, Net Asset (Liability) [Abstract]
Marketable equity securities	21,160	1,220
Assets	3,059,684	1,160,147
Liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign currency contracts
Fair Value, Net Asset (Liability) [Abstract]
Other current assets	0	0
Other current liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 | Money market funds
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents	3,038,524	1,158,927
Fair Value, Measurements, Recurring | Level 1 | Corporate notes
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents		0
Debt securities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial paper
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents	0	0
Debt securities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. government and agency securities
Fair Value, Net Asset (Liability) [Abstract]
Debt securities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Certificates of deposit
Fair Value, Net Asset (Liability) [Abstract]
Debt securities, available-for-sale	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Net Asset (Liability) [Abstract]
Marketable equity securities	0	0
Assets	4,081,417	6,032,682
Liabilities	3,015	1,028
Fair Value, Measurements, Recurring | Level 2 | Foreign currency contracts
Fair Value, Net Asset (Liability) [Abstract]
Other current assets	1,025	5,529
Other current liabilities	3,015	1,028
Fair Value, Measurements, Recurring | Level 2 | Money market funds
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 | Corporate notes
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents		1,347
Debt securities, available-for-sale	2,586,251	2,829,521
Fair Value, Measurements, Recurring | Level 2 | Commercial paper
Fair Value, Net Asset (Liability) [Abstract]
Cash equivalents	164,105	543,153
Debt securities, available-for-sale	593,297	1,240,670
Fair Value, Measurements, Recurring | Level 2 | U.S. government and agency securities
Fair Value, Net Asset (Liability) [Abstract]
Debt securities, available-for-sale	450,275	910,259
Fair Value, Measurements, Recurring | Level 2 | Certificates of deposit
Fair Value, Net Asset (Liability) [Abstract]
Debt securities, available-for-sale	$ 286,464	$ 502,203

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Fair Values of Convertible and Senior Notes Outstanding (Details) - USD ($)	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 5,039,418,000
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	3,529,798,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	1,509,620,000
Convertible Notes Due 2024 | Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	1,444,285,000
Debt instrument, principal amount	$ 1,150,000,000		$ 1,150,000,000		$ 1,150,000,000
Debt Instrument, percentage	0.25%				0.25%
Convertible Notes Due 2024 | Convertible Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 1,444,285,000
Convertible Notes Due 2024 | Convertible Notes | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	0
Convertible Notes Due 2025 | Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	1,509,620,000
Debt instrument, principal amount	$ 1,000,000,000		$ 1,000,000,000
Debt Instrument, percentage	0.375%		0.375%
Convertible Notes Due 2025 | Convertible Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 0
Convertible Notes Due 2025 | Convertible Notes | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	1,509,620,000
Convertible Notes Due 2026 | Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	1,341,763,000
Debt instrument, principal amount	$ 1,437,500,000	$ 1,440,000,000
Debt Instrument, percentage	0.00%	0.00%
Convertible Notes Due 2026 | Convertible Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 1,341,763,000
Convertible Notes Due 2026 | Convertible Notes | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	0
Senior Notes Due 2027 | Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	743,750,000
Debt instrument, principal amount	$ 700,000,000		$ 700,000,000	$ 700,000,000
Debt Instrument, percentage	3.875%			3.875%
Senior Notes Due 2027 | Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 743,750,000
Senior Notes Due 2027 | Senior Notes | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Notional principal of foreign currency contracts outstanding	$ 524.4		$ 524.4		$ 729.8
Net gain (losses) on foreign currency contracts	$ (3.7)	$ (7.1)	$ (0.5)	$ (18.3)

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Fair Values of Outstanding Derivative Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Foreign currency contracts not designated as hedging instruments	$ 1,025	$ 5,529
Liabilities
Foreign currency contracts not designated as hedging instruments	$ 3,015	$ 1,028

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property and equipment, net
Property and equipment, net	$ 4,165,311	$ 3,354,531
Less: Accumulated depreciation and amortization	(2,111,831)	(1,860,737)
Property and equipment, net	2,053,480	1,493,794
Equipment
Property and equipment, net
Property and equipment, net	2,171,491	1,830,459
Furniture and leasehold improvements
Property and equipment, net
Property and equipment, net	393,950	362,766
Capitalized software
Property and equipment, net
Property and equipment, net	892,829	811,371
Construction in progress
Property and equipment, net
Property and equipment, net	$ 707,041	$ 349,935

Property and Equipment, Net - B

Property and Equipment, Net - By Geographic (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property and equipment, net:
Property and equipment, net	$ 2,053,480	$ 1,493,794
United States
Property and equipment, net:
Property and equipment, net	2,018,861	1,460,163
International
Property and equipment, net:
Property and equipment, net	$ 34,619	$ 33,631

Operating Leases - Additional I

Operating Leases - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease right-of-use assets obtained in exchange for operating lease obligations	$ 352.5	$ 253.9

Operating Leases - Summary of F

Operating Leases - Summary of Future Lease Payments under Leases and Sublease Income (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Operating Leases
Remainder of 2021	$ 54,407
2022	279,750
2023	236,335
2024	235,587
2025	230,852
Thereafter	895,980
Total future lease payments (receipts)	1,932,911
Less: leases not yet commenced	(576,997)
Less: imputed interest	(156,849)
Total operating lease liabilities	1,199,065
Sublease Income
Remainder of 2021	(2,833)
2022	(3,888)
2023	(2,616)
2024	(1,629)
2025	(120)
Thereafter	0
Total future lease payments (receipts)	(11,086)
Reconciliation of operating lease liabilities as shown in the consolidated balance sheets
Operating lease liabilities, short-term	218,301	$ 177,147
Operating lease liabilities, long-term	980,764	$ 819,748
Total operating lease liabilities	$ 1,199,065

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Goodwill Activities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Goodwill
Beginning balance	$ 1,312,346
Acquisitions	13,893
Reclassified to assets held for sale	(28,800)
Other	(3,613)
Ending balance	$ 1,293,826

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment charges on goodwill			$ 0	$ 0
Amortization of intangible assets	$ 10,800,000	$ 5,400,000	$ 30,600,000	$ 18,000,000

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 130,631	$ 111,953
Accumulated Amortization	(83,929)	(53,615)
Net Carrying Value	46,702	58,338
Patents and developed technologies
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	119,862	110,153
Accumulated Amortization	(74,209)	(53,265)
Net Carrying Value	45,653	56,888
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	10,769	1,800
Accumulated Amortization	(9,720)	(350)
Net Carrying Value	$ 1,049	$ 1,450

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Schedule of Estimated Future Amortization Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2021	$ 7,105
2022	17,369
2023	7,843
2024	6,026
2025	1,863
Thereafter	6,496
Net Carrying Value	$ 46,702	$ 58,338

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
Accrued compensation	$ 290,088	$ 171,681
Deferred revenue	92,826	58,976
Accrued professional services	55,116	27,404
Accrued publisher, content and ad network costs	43,379	42,541
Accrued tax liabilities	41,875	40,384
Accrued other	205,984	172,546
Total	1,688,768	663,532
Litigation settlement accrual
Loss Contingencies [Line Items]
Legal settlement accrual	809,500	0
Federal Trade Commissions | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Legal settlement accrual	$ 150,000	$ 150,000

Acquisitions and Other Invest_2

Acquisitions and Other Investments - 2021 Acquisition (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 1,293,826	$ 1,312,346
Goodwill, expected tax deductible amount	2,100
Other acquisitions
Business Acquisition [Line Items]
Purchase price of acquisition	24,100
Acquisition purchase price allocated to net assets	500
Goodwill	13,900
Other acquisitions | Developed Technology Rights
Business Acquisition [Line Items]
Acquisition purchase price allocated to finite lived intangible assets	$ 9,700
Intangible assets, estimated useful life	1 year

Acquisitions and Other Invest_3

Acquisitions and Other Investments - Investments in Privately-Held Companies (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Apr. 01, 2021	Mar. 31, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Non-marketable equity securities, combines carrying value		$ 179,500,000		$ 179,500,000				$ 85,800,000
Financing receivable, converted to preferred shares						$ 30,000,000
Sale of convertible loans	$ 30,000,000
Upward price adjustment, annual amount		24,900,000		60,900,000
Other Assets
Schedule of Investments [Line Items]
Non-marketable equity securities, combines carrying value		30,000,000		30,000,000
Investments in Privately-Held Companies
Schedule of Investments [Line Items]
Financing receivable, after allowance for credit loss							$ 60,000,000
Other Expense
Schedule of Investments [Line Items]
Equity securities without readily determinable FV, impairment loss		$ 0	$ 300,000	$ 0	$ 8,800,000

Assets Held for Sale (Details)

Assets Held for Sale (Details) - Held-for-sale, not discontinued operations - MoPub - Subsequent Event - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Oct. 06, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration		$ 1,050
Gain (loss) on disposal, pre-tax	$ 1,000

Convertible Notes and Senior _3

Convertible Notes and Senior Notes - Additional Information (Details) $ / shares in Units, shares in Millions	Sep. 15, 2021USD ($)	Mar. 31, 2021USD ($)dD$ / sharesshares	Sep. 30, 2021USD ($)$ / shares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)Dd$ / shares	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Repayments of convertible notes					$ 954,000,000	$ 0
Exercise price of the warrants (USD per share) | $ / shares			$ 80.20		$ 80.20
Convertible notes, long-term			$ 3,556,934,000		$ 3,556,934,000		$ 1,875,878,000
Proceeds from issuance of warrants concurrent with note hedges					161,144,000	0
Amortization of debt discount, prior to capitalization of interest			2,700,000	$ 29,600,000	7,800,000	82,400,000
Coupon interest expense			$ 10,500,000	$ 10,900,000	$ 32,100,000	$ 31,700,000
Convertible Notes Due 2021
Debt Instrument [Line Items]
Exercise price of the warrants (USD per share) | $ / shares			$ 105.28		$ 105.28
Convertible Notes Due 2021 | Convertible Notes
Debt Instrument [Line Items]
Principal										$ 954,000,000
Debt instrument, interest rate percentage										1.00%
Proceeds from offerings, net of transaction costs										$ 939,500,000
Repayments of convertible notes	$ 954,000,000
Debt discount										14,300,000
Debt issuance costs										$ 200,000
Convertible Notes Due 2021 | Common stock | Convertible Notes
Debt Instrument [Line Items]
Debt Instrument, conversion ratio					0.0128793
Convertible Notes Due 2024
Debt Instrument [Line Items]
Exercise price of the warrants (USD per share) | $ / shares			80.20		$ 80.20
Convertible Notes Due 2026
Debt Instrument [Line Items]
Conversion price (USD per share) | $ / shares		$ 130.03
Exercise price of the warrants (USD per share) | $ / shares		163.02	$ 163.02		$ 163.02
Convertible Notes Due At 2021 and 2024 | Convertible Notes | Scenario One
Debt Instrument [Line Items]
Convertible debt instrument, consecutive trading days threshold | d					30
Convertible debt instrument, percentage of conversion price to trigger conversion to common stock					130.00%
Convertible Notes Due At 2021 and 2024 | Convertible Notes | Scenario Two
Debt Instrument [Line Items]
Convertible debt instrument, trading days threshold | D					5
Convertible debt instrument, consecutive trading days threshold | D					5
Convertible debt instrument, percentage of conversion price to trigger conversion to common stock					98.00%
Convertible Notes Due At 2021 and 2024 | Minimum | Convertible Notes | Scenario One
Debt Instrument [Line Items]
Convertible debt instrument, trading days threshold | d					20
Senior Notes | Senior Notes Due 2027
Debt Instrument [Line Items]
Principal			$ 700,000,000		$ 700,000,000		700,000,000	$ 700,000,000
Debt instrument, interest rate percentage			3.875%		3.875%			3.875%
Proceeds from offerings, net of transaction costs								$ 691,900,000
Debt issuance costs								$ 8,100,000
Interest rate during period			3.875%	3.875%	3.875%	3.875%
Remaining period for convertible debt					74 months
Convertible Notes
Debt Instrument [Line Items]
Exercise price of the warrants (USD per share) | $ / shares		$ 163.02
Convertible Notes | Convertible Notes Due 2025
Debt Instrument [Line Items]
Principal			$ 1,000,000,000		$ 1,000,000,000		$ 1,000,000,000
Debt instrument, interest rate percentage			0.375%		0.375%		0.375%
Proceeds from offerings, net of transaction costs							$ 985,300,000
Convertible debt instrument, trading days threshold | d					20
Convertible debt instrument, consecutive trading days threshold | d					30
Convertible debt instrument, percentage of conversion price to trigger conversion to common stock					130.00%
Debt issuance costs							14,700,000
Carrying amount of the equity component							121,413,000
Convertible notes, long-term			$ 989,866,000		$ 989,866,000		886,175,000
Redemption price percentage					100.00%
Interest rate during period			0.375%	2.99%	0.375%	2.99%
Remaining period for convertible debt					41 months
Convertible Notes | Convertible Notes Due 2025 | Common stock
Debt Instrument [Line Items]
Conversion price (USD per share) | $ / shares			$ 41.50		$ 41.50
Debt Instrument, conversion ratio					0.0240964
Convertible Notes | Convertible Notes Due 2021
Debt Instrument [Line Items]
Principal							954,000,000
Shares covered by convertible note hedge | shares									12.3
Number of securities called by warrants or rights (in shares) | shares									12.3
Exercise price of the warrants (USD per share) | $ / shares									$ 105.28
Carrying amount of the equity component							283,283,000
Convertible notes, long-term							917,866,000
Proceeds from issuance of warrants concurrent with note hedges									$ 172,900,000
Convertible Notes | Convertible Notes Due 2021 | Common stock
Debt Instrument [Line Items]
Conversion price (USD per share) | $ / shares									$ 77.64
Convertible Notes | Convertible Notes Due 2024
Debt Instrument [Line Items]
Principal			$ 1,150,000,000		$ 1,150,000,000		1,150,000,000		$ 1,150,000,000
Debt instrument, interest rate percentage			0.25%		0.25%				0.25%
Proceeds from offerings, net of transaction costs									$ 1,140,000,000
Conversion price (USD per share) | $ / shares									$ 57.14
Shares covered by convertible note hedge | shares									20.1
Payments for derivative instrument									$ 268,000,000
Number of securities called by warrants or rights (in shares) | shares									20.1
Exercise price of the warrants (USD per share) | $ / shares									$ 80.20
Debt issuance costs									$ 12,300,000
Carrying amount of the equity component							254,981,000
Convertible notes, long-term			$ 1,144,431,000		$ 1,144,431,000		$ 989,703,000
Proceeds from issuance of warrants concurrent with note hedges									$ 186,800,000
Interest rate during period			0.25%	4.46%	0.25%	4.46%
Remaining period for convertible debt					32 months
Convertible Notes | Convertible Notes Due 2024 | Common stock
Debt Instrument [Line Items]
Conversion price (USD per share) | $ / shares			$ 57.14		$ 57.14				$ 57.14
Debt Instrument, conversion ratio					0.0175001
Convertible Notes | Convertible Notes Due 2026
Debt Instrument [Line Items]
Principal		$ 1,440,000,000	$ 1,437,500,000		$ 1,437,500,000
Debt instrument, interest rate percentage		0.00%	0.00%		0.00%
Proceeds from offerings, net of transaction costs		$ 1,420,000,000
Convertible debt instrument, consecutive trading days threshold | d		30
Shares covered by convertible note hedge | shares		11.1
Payments for derivative instrument		$ 213,500,000
Number of securities called by warrants or rights (in shares) | shares		11.1
Convertible notes, long-term			$ 1,422,637,000		$ 1,422,637,000
Redemption price percentage		100.00%
Proceeds from issuance of warrants concurrent with note hedges		$ 161,100,000
Remaining period for convertible debt					53 months
Convertible Notes | Convertible Notes Due 2026 | Scenario One
Debt Instrument [Line Items]
Convertible debt instrument, consecutive trading days threshold | d		30
Convertible debt instrument, percentage of conversion price to trigger conversion to common stock		130.00%
Convertible Notes | Convertible Notes Due 2026 | Scenario Two
Debt Instrument [Line Items]
Convertible debt instrument, trading days threshold | D		5
Convertible debt instrument, consecutive trading days threshold | D		5
Convertible debt instrument, percentage of conversion price to trigger conversion to common stock		98.00%
Convertible Notes | Convertible Notes Due 2026 | Minimum | Scenario One
Debt Instrument [Line Items]
Convertible debt instrument, trading days threshold | d		20
Convertible Notes | Convertible Notes Due 2026 | Common stock
Debt Instrument [Line Items]
Conversion price (USD per share) | $ / shares		$ 130.03
Debt Instrument, conversion ratio		0.076905

Convertible Notes and Senior _4

Convertible Notes and Senior Notes - Components of Notes (Details) - USD ($)	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2014
Principal amounts:
Net carrying amount	$ 0		$ 917,866,000
Net carrying amount	3,556,934,000		1,875,878,000
Net carrying amount	693,744,000		692,994,000
Convertible Notes Due 2021 | Convertible Notes
Principal amounts:
Principal						$ 954,000,000
Convertible Notes | Convertible Notes Due 2021
Principal amounts:
Principal			954,000,000
Unamortized debt discount and issuance costs			(36,134,000)
Net carrying amount			917,866,000
Carrying amount of the equity component			283,283,000
Convertible Notes | Convertible Notes Due 2024
Principal amounts:
Principal	1,150,000,000		1,150,000,000		$ 1,150,000,000
Unamortized debt discount and issuance costs	(5,569,000)		(160,297,000)
Net carrying amount	1,144,431,000		989,703,000
Carrying amount of the equity component			254,981,000
Convertible Notes | Convertible Notes Due 2025
Principal amounts:
Principal	1,000,000,000		1,000,000,000
Unamortized debt discount and issuance costs	(10,134,000)		(113,825,000)
Net carrying amount	989,866,000		886,175,000
Carrying amount of the equity component			121,413,000
Convertible Notes | Convertible Notes Due 2026
Principal amounts:
Principal	1,437,500,000	$ 1,440,000,000
Unamortized debt discount and issuance costs	(14,863,000)
Net carrying amount	1,422,637,000
Senior Notes | Senior Notes Due 2027
Principal amounts:
Principal	700,000,000		700,000,000	$ 700,000,000
Unamortized debt discount and issuance costs	(6,256,000)		(7,006,000)
Net carrying amount	$ 693,744,000		692,994,000
Carrying amount of the equity component			$ 0

Net Income (Loss) per Share - C

Net Income (Loss) per Share - Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator
Net income (loss)	$ (536,757)	$ 28,659	$ (403,103)	$ (1,357,742)
Denominator
Weighted-average common shares outstanding (shares)	799,537	793,065	798,559	787,831
Weighted-average restricted stock subject to repurchase (shares)	(1,552)	(2,238)	(1,784)	(2,043)
Weighted-average shares used to compute basic net income per share (shares)	797,985	790,827	796,775	785,788
Basic net income per share attributable to common stockholders (USD per share)	$ (0.67)	$ 0.04	$ (0.51)	$ (1.73)
Numerator
Net income (loss)	$ (536,757)	$ 28,659	$ (403,103)	$ (1,357,742)
Denominator
Number of shares used in basic computation (shares)	797,985	790,827	796,775	785,788
Weighted-average effect of dilutive securities:
Convertible notes (shares)	0	0	0	0
RSUs (shares)	0	12,194	0	0
Stock options (shares)	0	2,221	0	0
Other (shares)	0	1,141	0	0
Weighted-average shares used to compute diluted net income (loss) per share	797,985	806,383	796,775	785,788
Diluted net income per share attributable to common stockholders (USD per share)	$ (0.67)	$ 0.04	$ (0.51)	$ (1.73)

Net Income (Loss) per Share - A

Net Income (Loss) per Share - Antidilutive Securities (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Warrants
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive securities excluded from the computation of diluted net income per share	43,467	32,412	43,467	32,412
Convertible notes
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive securities excluded from the computation of diluted net income per share	55,277	0	55,277	0
RSUs
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive securities excluded from the computation of diluted net income per share	39,192	2,549	39,192	38,932
Shares subject to repurchase and others
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive securities excluded from the computation of diluted net income per share	8,348	3,317	8,348	7,930
Stock options
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive securities excluded from the computation of diluted net income per share	907	26	907	2,917

Net Income (Loss) per Share -_2

Net Income (Loss) per Share - Additional Information (Details) - $ / shares	Sep. 30, 2021	Mar. 31, 2021
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Exercise price of the warrants (USD per share)	$ 80.20
Convertible Notes Due 2021
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Exercise price of the warrants (USD per share)	105.28
Convertible Notes Due 2024
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Exercise price of the warrants (USD per share)	80.20
Convertible Notes Due 2026
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Exercise price of the warrants (USD per share)	$ 163.02	$ 163.02

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2019	Jan. 15, 2021	Dec. 31, 2020	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, authorized amount							$ 2,000,000		$ 2,000,000
Stock repurchased during period (in shares)	2,600,000		11,200,000
Repurchases of common stock	$ 169,400		$ 664,800
Treasury stock (shares)	87,000		87,000					98,000
Treasury stock, value	$ 5,291		$ 5,291					$ 5,297
Issuance of common stock upon purchases under employee stock purchase plan (shares)			1,500,000	1,400,000
Employee stock purchase plan (ESOP), weighted average purchase price of shares purchased			$ 25.69	$ 24.65
Stock options outstanding (shares)	900,000		900,000					1,400,000
Gross unamortized stock-based compensation expense related to unvested awards	$ 1,880,000		$ 1,880,000
Unrecognized share-based compensation expense, weighted average recognition period			3 years
Internal Use Software and Website Development Costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, capitalized amount	$ 22,300	$ 10,200	$ 63,800	$ 29,100
Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of unvested restricted common shares (shares)	1,400,000		1,400,000					2,000,000
Restricted Common Stock | All Acquisitions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity compensation service period			4 years
PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of unvested restricted common shares (shares)	534,000		534,000					729,000
Share-based compensation arrangement by share-based payment award, award vesting period						1 year
Fair value of stock units vested			$ 9,400	22,700
PRSUs | Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period					3 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of unvested restricted common shares (shares)	39,192,000		39,192,000					36,611,000
Fair value of stock units vested	$ 301,800	$ 147,700	$ 764,400	363,600
Market-based RSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of unvested restricted common shares (shares)	3,304,000		3,304,000					917,000
Fair value of stock units vested			$ 17,200	$ 13,400
Market-based RSU | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period						2 years
Market-based RSU | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period			5 years			6 years
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (shares)	60,000,000		60,000,000
Outstanding shares of common stock percentage			5.00%
2013 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (shares)	11,300,000		11,300,000
Outstanding shares of common stock percentage			1.00%

Stockholders' Equity - Summary

Stockholders' Equity - Summary of PRSUs Activity (Details) - PRSUs	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Shares
Unvested and outstanding, beginning of period (shares) | shares	729,000
Number of shares granted (shares) | shares	348,000
Unearned performance shares cancelled (shares) | shares	(365,000)
Vested (shares) | shares	(121,000)
Forfeited or canceled (shares) | shares	(57,000)
Unvested and outstanding, end of period (shares) | shares	534,000
Shares granted, percentage of target level	100.00%
Weighted- Average Grant- Date Fair Value Per Share
Unvested and outstanding, beginning of period (USD per share) | $ / shares	$ 27.77
Granted (USD per share) | $ / shares	71.22
Unearned performance shares cancelled (USD per share) | $ / shares	27.77
Vested (USD per share) | $ / shares	27.77
Forfeited or canceled (USD per share) | $ / shares	52.76
Unvested and outstanding, end of period (USD per share) | $ / shares	$ 53.40
Shares vested, percentage of target level	50.00%

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of TSR RSUs Activity (Details)	9 Months Ended
	Sep. 30, 2021$ / sharesshares
TSR RSUs
Shares
Shares granted, percentage of target level	100.00%
Weighted- Average Grant- Date Fair Value Per Share
Shares vested, percentage of target level	52.00%
PRSUs
Shares
Unvested and outstanding, beginning of period (shares) | shares	729,000
Granted (shares) | shares	348,000
Unearned performance shares cancelled (shares) | shares	(365,000)
Vested (shares) | shares	(121,000)
Forfeited or canceled (shares) | shares	(57,000)
Unvested and outstanding, end of period (shares) | shares	534,000
Shares granted, percentage of target level	100.00%
Weighted- Average Grant- Date Fair Value Per Share
Unvested and outstanding, beginning of period (USD per share) | $ / shares	$ 27.77
Granted (USD per share) | $ / shares	71.22
Unearned performance shares cancelled (USD per share) | $ / shares	27.77
Vested (USD per share) | $ / shares	27.77
Forfeited or canceled (USD per share) | $ / shares	52.76
Unvested and outstanding, end of period (USD per share) | $ / shares	$ 53.40
Shares vested, percentage of target level	50.00%
Market-based RSU
Shares
Unvested and outstanding, beginning of period (shares) | shares	917,000
Granted (shares) | shares	2,888,000
Unearned performance shares cancelled (shares) | shares	(207,000)
Vested (shares) | shares	(224,000)
Forfeited or canceled (shares) | shares	(70,000)
Unvested and outstanding, end of period (shares) | shares	3,304,000
Weighted- Average Grant- Date Fair Value Per Share
Unvested and outstanding, beginning of period (USD per share) | $ / shares	$ 30.90
Granted (USD per share) | $ / shares	36.32
Unearned performance shares cancelled (USD per share) | $ / shares	30.60
Vested (USD per share) | $ / shares	30.60
Forfeited or canceled (USD per share) | $ / shares	52.03
Unvested and outstanding, end of period (USD per share) | $ / shares	$ 35.23

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of RSU Activity Excluding PRSUs and TSR RSUs (Details) - RSUs	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Shares
Unvested and outstanding, beginning of period (shares) | shares	36,611,000
Granted (shares) | shares	19,790,000
Vested (shares) | shares	(12,685,000)
Canceled (shares) | shares	(4,524,000)
Unvested and outstanding, end of period (shares) | shares	39,192,000
Weighted- Average Grant- Date Fair Value Per Share
Unvested and outstanding, beginning of period (USD per share) | $ / shares	$ 32.28
Granted (USD per share) | $ / shares	64.54
Vested (USD per share) | $ / shares	35.16
Canceled (USD per share) | $ / shares	38.35
Unvested and outstanding, end of period (USD per share) | $ / shares	$ 46.94

Stockholders' Equity - Compensa

Stockholders' Equity - Compensation Expense Allocated (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 164,295	$ 115,969	$ 453,370	$ 346,748
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	11,627	8,581	33,479	23,333
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	101,515	66,111	269,983	204,686
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	27,105	25,550	84,647	73,572
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 24,048	$ 15,727	$ 65,261	$ 45,157

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020
Income Tax Contingency [Line Items]
Provision (benefit) for income taxes	$ (190,325)	$ 1,024	$ (192,675)	$ 1,082,784
Deferred tax assets, net of valuation allowance	1,130,000		1,130,000
Unrecognized tax benefits	383,300		383,300
Unrecognized tax benefits, if recognized, would affect the effective tax rate	$ 295,900		$ 295,900
Foreign Tax Authority
Income Tax Contingency [Line Items]
Income taxes related to establishment of deferred tax asset valuation allowance				1,100,000
Income taxes excluding provision for income tax related to establishment of deferred tax asset valuation allowance				$ 18,600
Deferred tax assets, valuation allowance					$ 1,100,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	Sep. 15, 2021	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2021	Jan. 31, 2021	Jan. 15, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2014
Other Commitments [Line Items]
Amount of indebtedness to be incurred before increase through amendment		$ 4,500,000
Increased amount of indebtedness to be incurred after amendment		6,000,000
Repayments of convertible notes		954,000	$ 0
Insurance settlements receivable					$ 38,000
Stock repurchase program, authorized amount						$ 2,000,000			$ 2,000,000
Litigation settlement accrual
Other Commitments [Line Items]
Legal settlement accrual, current		809,500					$ 0
Litigation Settlement, Amount Awarded to Other Party		809,500
Unfavorable Regulatory Action | Federal Trade Commissions
Other Commitments [Line Items]
Legal settlement accrual, current		150,000					150,000
Loss contingency accrual								$ 150,000
Minimum | Unfavorable Regulatory Action | Federal Trade Commissions
Other Commitments [Line Items]
Loss contingency, estimate of possible loss								150,000
Maximum | Unfavorable Regulatory Action | Federal Trade Commissions
Other Commitments [Line Items]
Loss contingency, estimate of possible loss								$ 250,000
Convertible Notes Due 2026 | Convertible Notes
Other Commitments [Line Items]
Debt instrument, principal amount		1,437,500		$ 1,440,000
Contractual obligation to settle commitments		1,440,000
Convertible Notes Due 2021 | Convertible Notes
Other Commitments [Line Items]
Debt instrument, principal amount										$ 954,000
Repayments of convertible notes	$ 954,000
Convertible Notes Due 2021 | Convertible Notes
Other Commitments [Line Items]
Debt instrument, principal amount							$ 954,000
Revolving Credit Facility
Other Commitments [Line Items]
Unsecured revolving credit facility		$ 500,000