Cloudflare (NET) 10-Q5 Nov 212021 Q3 Quarterly reportFinancial data

Company Profile

Cover

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2021	Oct. 22, 2021
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-39039
Entity Registrant Name	Cloudflare, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-0805829
Entity Address, Address Line One	101 Townsend Street
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94107
City Area Code	888
Local Phone Number	993-5273
Title of 12(b) Security	Class A Common Stock, $0.001 par value
Trading Symbol	NET
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
Amendment Flag	false
Entity Central Index Key	0001477333
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2021
Current Fiscal Year End Date	--12-31
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		273,882,797
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		47,862,782

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 618,231	$ 108,895
Available-for-sale securities	1,195,646	923,201
Accounts receivable, net	84,705	63,499
Contract assets	5,049	3,538
Restricted cash short-term	471	2,591
Prepaid expenses and other current assets	26,475	28,230
Total current assets	1,930,577	1,129,954
Property and equipment, net	176,556	123,688
Goodwill	17,167	17,167
Acquired intangible assets, net	700	2,800
Operating lease right-of-use assets	101,260	43,148
Deferred contract acquisition costs, noncurrent	61,607	44,176
Restricted cash	6,660	6,660
Other noncurrent assets	20,987	13,058
Total assets	2,315,514	1,380,651
Current liabilities:
Accounts payable	34,561	14,485
Accrued expenses and other current liabilities	33,841	20,217
Accrued compensation	37,185	25,410
Operating lease liabilities	23,450	17,717
Liability for early exercise of unvested stock options	5,505	8,603
Deferred revenue	92,415	54,945
Total current liabilities	226,957	141,377
Convertible senior notes, net	1,143,308	383,275
Operating lease liabilities, noncurrent	81,113	27,309
Deferred revenue, noncurrent	4,561	1,891
Other noncurrent liabilities	6,425	9,859
Total liabilities	1,462,364	563,711
Commitments and contingencies (Note 8)
Stockholders’ Equity:
Additional paid-in capital	1,456,371	1,236,993
Accumulated deficit	(603,328)	(420,520)
Accumulated other comprehensive income (loss)	(211)	163
Total stockholders’ equity	853,150	816,940
Total liabilities and stockholders’ equity	2,315,514	1,380,651
Class A common stock
Stockholders’ Equity:
Common stock, value, issued	273	249
Class B common stock
Stockholders’ Equity:
Common stock, value, issued	$ 45	$ 55

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Class A common stock
Stockholders’ Equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	2,250,000,000	2,250,000,000
Common stock, shares issued (in shares)	273,574,792	249,401,232
Common stock, shares outstanding (in shares)	273,574,792	249,401,232
Class B common stock
Stockholders’ Equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	315,000,000	315,000,000
Common stock, shares issued (in shares)	48,038,501	59,238,742
Common stock, shares outstanding (in shares)	48,038,501	59,238,742

CONDENSED CONSOLIDATED STATEMEN

CONDENSED 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	$ 172,347	$ 114,162	$ 462,830	$ 305,133
Cost of revenue	37,525	27,005	104,638	71,990
Gross profit	134,822	87,157	358,192	233,143
Operating expenses:
Sales and marketing	85,877	55,982	231,846	154,323
Research and development	46,770	30,902	127,646	92,387
General and administrative	28,669	21,525	85,320	68,460
Total operating expenses	161,316	108,409	444,812	315,170
Loss from operations	(26,494)	(21,252)	(86,620)	(82,027)
Non-operating income (expense):
Interest income	385	1,316	1,302	5,742
Interest expense	(12,448)	(9,828)	(33,126)	(14,902)
Loss on extinguishment of debt	(72,234)	0	(72,234)	0
Other income (expense), net	361	(208)	(368)	58
Total non-operating income (expense), net	(83,936)	(8,720)	(104,426)	(9,102)
Loss before income taxes	(110,430)	(29,972)	(191,046)	(91,129)
Benefit from income taxes	(3,095)	(3,504)	(8,238)	(5,780)
Net loss	$ (107,335)	$ (26,468)	$ (182,808)	$ (85,349)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	314,543	301,689	309,618	298,628
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	314,543	301,689	309,618	298,628

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE 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 loss	$ (107,335)	$ (26,468)	$ (182,808)	$ (85,349)
Other comprehensive income (loss):
Change in unrealized gain (loss) on investments, net of tax	(167)	(654)	(374)	509
Other comprehensive income (loss)	(167)	(654)	(374)	509
Comprehensive loss	$ (107,502)	$ (27,122)	$ (183,182)	$ (84,840)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Restricted Stock Units (RSUs)	Restricted Stock	Share-based Payment Arrangement	Cumulative Effect, Period of Adoption, Adjustment	Conversion of Class B to Class A common stock	Additional paid-in capital	Additional paid-in capitalRestricted Stock Units (RSUs)	Additional paid-in capitalShare-based Payment Arrangement	Additional paid-in capitalConversion of Class B to Class A common stock	Accumulated deficit	Accumulated deficitCumulative Effect, Period of Adoption, Adjustment	Accumulated other comprehensive loss	Class A common stock	Class A common stockCommon stock	Class A common stockCommon stockRestricted Stock Units (RSUs)	Class A common stockCommon stockRestricted Stock	Class A common stockCommon stockShare-based Payment Arrangement	Class A common stockCommon stockConversion of Class B to Class A common stock	Class B common stock	Class B common stockCommon stock	Class B common stockCommon stockRestricted Stock Units (RSUs)	Class B common stockCommon stockConversion of Class B to Class A common stock
Beginning balance (in shares) at Dec. 31, 2019															87,072,000						213,101,000
Beginning balance at Dec. 31, 2019	$ 725,828				$ 556		$ 1,027,179				$ (301,706)	$ 556	$ 61		$ 87						$ 207
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with acquisition (in shares)															107,000
Issuance of common stock in connection with acquisition	1,821						1,821
Issuance of restricted stock in connection with acquisition (in shares)																	841,000
Issuance of common stock upon exercise of stock options (in shares)																					3,509,000
Issuance of common stock upon exercise of stock options	5,725						5,721														$ 4
Repurchases of unvested common stock (in shares)															(39,000)
Issuance of common stock related to early exercised stock options (in shares)																					78,000
Vesting of shares issued upon early exercise of stock options	3,651						3,649														$ 2
Issuance of common stock related to settlement of RSUs (in shares)															279,000						2,094,000
Issuance of common stock related to settlement of RSUs	0						(2)														$ 2
Tax withholding (in shares)																(11,000)		(13,000)				(410,000)
Tax withholding		$ (7,606)		$ (376)				$ (7,606)	$ (376)
Conversion of Class B to Class A common stock (in shares)																			144,852,000				(144,852,000)
Conversion of Class B to Class A common stock						$ 0				$ 0									$ 146				$ (146)
Equity component of convertible senior notes, net of issuance costs	200,812						200,812				0
Purchases of capped calls related to convertible senior notes	(67,333)						(67,333)
Issuance of common stock in connection with partial repurchase of convertible senior notes	0
Common stock issued under employee stock purchase plan (in shares)															421,000
Common stock issued under employee stock purchase plan	5,447						5,447
Stock-based compensation	42,762						42,762
Net loss	(85,349)										(85,349)				$ (45,059)						$ (40,290)
Other comprehensive loss	509												509
Ending balance (in shares) at Sep. 30, 2020															233,509,000						73,520,000
Ending balance at Sep. 30, 2020	826,447						1,212,074				(386,499)		570		$ 233						$ 69
Beginning balance (in shares) at Jun. 30, 2020															184,900,000						120,524,000
Beginning balance at Jun. 30, 2020	835,618						1,194,125				(360,031)		1,224		$ 184						$ 116
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)																					927,000
Issuance of common stock upon exercise of stock options	1,390						1,388														$ 2
Repurchases of unvested common stock (in shares)															(2,000)
Issuance of common stock related to early exercised stock options (in shares)																					42,000
Vesting of shares issued upon early exercise of stock options	1,140						1,140
Issuance of common stock related to settlement of RSUs (in shares)															197,000						449,000
Issuance of common stock related to settlement of RSUs	(1)						(1)
Tax withholding (in shares)																						(8,000)
Tax withholding		(299)						(299)
Conversion of Class B to Class A common stock (in shares)																			48,414,000				(48,414,000)
Conversion of Class B to Class A common stock	0																		$ 49				$ (49)
Stock-based compensation	15,721						15,721
Net loss	(26,468)										(26,468)				$ (18,119)						$ (8,349)
Other comprehensive loss	(654)												(654)
Ending balance (in shares) at Sep. 30, 2020															233,509,000						73,520,000
Ending balance at Sep. 30, 2020	826,447						1,212,074				(386,499)		570		$ 233						$ 69
Beginning balance (in shares) at Dec. 31, 2020														249,401,232	249,401,000					59,238,742	59,239,000
Beginning balance at Dec. 31, 2020	$ 816,940						1,236,993				(420,520)		163		$ 249						$ 55
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with acquisition (in shares)	948,000
Issuance of restricted stock in connection with acquisition (in shares)			841,000
Issuance of common stock upon exercise of stock options (in shares)	3,307,000														567,000						2,705,000
Issuance of common stock upon exercise of stock options	$ 16,802						16,799														$ 3
Repurchases of unvested common stock (in shares)															(74,000)
Issuance of common stock related to early exercised stock options (in shares)																					35,000
Vesting of shares issued upon early exercise of stock options	3,004						3,003														$ 1
Issuance of common stock related to settlement of RSUs (in shares)															1,083,000						990,000
Issuance of common stock related to settlement of RSUs	0						(2)								$ 1						$ 1
Tax withholding (in shares)																					(22,000)
Tax withholding	(2,033)						(2,033)
Conversion of Class B to Class A common stock (in shares)															14,908,000						(14,908,000)
Conversion of Class B to Class A common stock	0														$ 15						$ (15)
Equity component of convertible senior notes, net of issuance costs	262,077						262,077
Purchases of capped calls related to convertible senior notes	(86,293)						(86,293)
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)															7,559,000
Issuance of common stock in connection with partial repurchase of convertible senior notes	920,249						920,241								$ 8
Equity component of extinguishment of convertible senior notes	(965,684)						(965,684)
Common stock issued under employee stock purchase plan (in shares)															131,000
Common stock issued under employee stock purchase plan	7,174						7,174
Stock-based compensation	64,096						64,096
Net loss	(182,808)										(182,808)				$ (153,359)						$ (29,449)
Other comprehensive loss	(374)												(374)
Ending balance (in shares) at Sep. 30, 2021														273,574,792	273,575,000					48,038,501	48,039,000
Ending balance at Sep. 30, 2021	853,150						1,456,371				(603,328)		(211)		$ 273						$ 45
Beginning balance (in shares) at Jun. 30, 2021															263,096,000						49,269,000
Beginning balance at Jun. 30, 2021	801,096						1,296,824				(495,993)		(44)		$ 263						$ 46
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)															156,000						894,000
Issuance of common stock upon exercise of stock options	5,283						5,282								$ 0						$ 1
Repurchases of unvested common stock (in shares)															(7,000)
Issuance of common stock related to early exercised stock options (in shares)																					1,000
Vesting of shares issued upon early exercise of stock options	952						952
Issuance of common stock related to settlement of RSUs (in shares)															333,000						321,000
Issuance of common stock related to settlement of RSUs	(1)						(1)
Tax withholding (in shares)																						(8,000)
Tax withholding		$ (943)						$ (943)
Conversion of Class B to Class A common stock (in shares)															2,438,000						(2,438,000)
Conversion of Class B to Class A common stock	0														$ 2						$ (2)
Equity component of convertible senior notes, net of issuance costs	262,077						262,077
Purchases of capped calls related to convertible senior notes	(86,293)						(86,293)
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)															7,559,000
Issuance of common stock in connection with partial repurchase of convertible senior notes	920,249						920,241								$ 8
Equity component of extinguishment of convertible senior notes	(965,684)						(965,684)
Stock-based compensation	23,916						23,916
Net loss	(107,335)										(107,335)				$ (91,665)						$ (15,670)
Other comprehensive loss	(167)												(167)
Ending balance (in shares) at Sep. 30, 2021														273,574,792	273,575,000					48,038,501	48,039,000
Ending balance at Sep. 30, 2021	$ 853,150						$ 1,456,371				$ (603,328)		$ (211)		$ 273						$ 45

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ 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, 2020
Cash Flows From Operating Activities
Net loss	$ (107,335)	$ (26,468)	$ (182,808)	$ (85,349)
Adjustments to reconcile net loss to cash provided by (used in) operating activities:
Depreciation and amortization expense			48,275	35,029
Non-cash operating lease costs			17,740	14,134
Amortization of deferred contract acquisition costs	7,773	4,623	20,688	12,085
Stock-based compensation expense			61,638	40,091
Amortization of debt discount and issuance costs			30,488	12,865
Net accretion of discounts and amortization of premiums on available-for-sale securities			6,004	248
Deferred income taxes			(10,678)	(6,808)
Provision for bad debt	900	300	2,911	2,794
Loss on extinguishment of debt	72,234	0	72,234	0
Exchange of convertible senior notes attributable to the accreted interest related to debt discount			(29,353)	0
Other			111	(73)
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable, net			(24,117)	(17,710)
Contract assets			(1,511)	(23)
Deferred contract acquisition costs			(38,119)	(24,615)
Prepaid expenses and other current assets			723	(6,131)
Other noncurrent assets			1,462	(930)
Accounts payable			5,820	4,648
Accrued expenses and other current liabilities			22,147	8,545
Operating lease liabilities			(16,315)	(15,131)
Deferred revenue			40,140	18,425
Other noncurrent liabilities			(3,449)	(410)
Net cash provided by (used in) operating activities			24,031	(8,316)
Cash Flows From Investing Activities
Purchases of property and equipment			(64,652)	(45,962)
Capitalized internal-use software			(11,105)	(14,333)
Cash paid for acquisitions, net of cash acquired			0	(13,691)
Purchases of available-for-sale securities			(1,060,883)	(956,147)
Sales of available-for-sale securities			15,756	0
Maturities of available-for-sale securities			766,304	515,044
Other investing activities			53	395
Net cash used in investing activities			(354,527)	(514,694)
Cash Flows From Financing Activities
Gross proceeds from issuance of convertible senior notes			1,293,750	575,000
Purchases of capped calls related to convertible senior notes			(86,293)	(67,333)
Cash consideration paid in exchange of convertible senior debt			(370,647)	0
Cash paid for issuance costs on convertible senior notes			(18,760)	(12,542)
Proceeds from the exercise of stock options			16,802	5,724
Proceeds from the early exercise of stock options			95	180
Repurchases of unvested common stock			(188)	(113)
Payments on note payable			0	(200)
Proceeds from the issuance of common stock for employee stock purchase plan			7,174	5,447
Payment of indemnity holdback			(2,188)	0
Net cash provided by financing activities			837,712	498,180
Net increase (decrease) in cash, cash equivalents, and restricted cash			507,216	(24,830)
Cash, cash equivalents, and restricted cash, beginning of period			118,146	145,636	$ 145,636
Cash, cash equivalents, and restricted cash, end of period	625,362	$ 120,806	625,362	120,806	$ 118,146
Supplemental Disclosure of Cash Flow Information:
Cash paid for interest			2,957	34
Cash paid for income taxes, net of refunds			1,265	623
Cash paid for operating lease liabilities			15,919	15,256
Supplemental Disclosure of Non-cash Investing and Financing Activities:
Stock-based compensation capitalized for software development			2,398	2,560
Accounts payable and accrued expenses related to property and equipment additions			21,677	4,076
Vesting of early exercised stock options			3,004	3,651
Indemnity holdback consideration associated with business combinations			0	2,187
Issuance of common stock related to an acquisition			0	1,821
Operating lease right-of-use assets obtained in exchange for operating lease liabilities			74,406	7,975
Derecognition of build-to-suit lease			0	9,886
Debt issuance costs, accrued but not paid			1,037	0
Issuance of common stock in connection with partial repurchase of convertible senior notes	$ 920,249		920,249	0
Restricted Stock
Cash Flows From Financing Activities
Payment of tax withholding obligation			(2,033)	(7,607)
Common stock
Cash Flows From Financing Activities
Payment of tax withholding obligation			$ 0	$ (376)

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
Organization and Basis of Presentation	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Organization and Description of Business Cloudflare, Inc. (the Company, Cloudflare, we, us, or our) is a global cloud services provider that delivers a broad range of services to businesses of all sizes and in all geographies, making them more secure, enhancing the performance of their business-critical applications, and eliminating the cost and complexity of managing individual network hardware. Cloudflare’s network serves as a scalable, easy-to-use, unified control plane to deliver security, performance, and reliability across on-premise, hybrid, cloud, and software-as-a-service (SaaS) applications. The Company was incorporated in Delaware in July 2009. The Company is headquartered in San Francisco, California. Basis of Presentation and Principles of Consolidation The accompanying interim condensed consolidated financial statements and accompanying notes have been prepared in conformity with generally accepted accounting principles in the United States (U.S. GAAP) and applicable regulations of the Securities and Exchange Commission (the SEC) regarding interim financial reporting, and include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company’s fiscal year ends on December 31. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the applicable required disclosures and regulations of the SEC. Therefore, these unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020 . Initial Public Offering In September 2019, the Company completed an initial public offering (IPO) in which it issued and sold Class A common stock for net proceeds of $565.0 million, after deducting underwriting discounts and commissions and offering costs. Upon completion of the IPO, all of the Company's outstanding redeemable convertible preferred stock was automatically converted into Class A common stock and Class B common stock. In addition, all of the outstanding warrants to purchase shares of the Company's redeemable convertible preferred stock were automatically converted into outstanding warrants to purchase shares of Class B common stock, and all of the shares of Class B common stock held by former employees were automatically converted into Class A common stock. Unaudited Interim Condensed Consolidated Financial Information The accompanying interim condensed consolidated balance sheet as of September 30, 2021, the condensed consolidated statements of operations and of comprehensive loss for the three and nine months ended September 30, 2021 and 2020, the condensed consolidated statements of cash flows for the nine months ended September 30, 2021 and 2020, the condensed consolidated statements of stockholders’ equity for the three and nine months ended September 30, 2021 and 2020, and the related footnote disclosures are unaudited. These unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. GAAP. In management’s opinion, the unaudited interim condensed consolidated financial statements include all adjustments necessary to state fairly the Company’s financial position as of September 30, 2021, its results of operations for the three and nine months ended September 30, 2021 and 2020, and its cash flows for the nine months ended September 30, 2021 and 2020. The results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results expected for the full year ending December 31, 2021 or any future period. The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020 . Use of Estimates

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Significant Accounting Policies The Company's significant accounting policies are discussed in the "Notes to Consolidated Financial Statements, Note 2. Summary of Significant Accounting Policies" in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020. There have been no significant changes to these policies that have had a material impact on the Company's condensed consolidated financial statements and related notes, except as noted below. Convertible Senior Notes The Company accounts for its 0.75% Convertible Senior Notes due 2025 (the 2025 Notes) and its 0.00% Convertible Senior Notes due 2026 (the 2026 Notes and together with the 2025 Notes, the Notes) as separate liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component, representing the conversion option, was calculated by deducting the fair value of the liability component from the total principal of the Notes. The excess of the principal amount of the liability component over its book value (debt discount) is amortized to interest expense over the term of the Notes. In accounting for the issuance costs related to the Notes, the allocation of issuance costs incurred between the liability and equity components was based on their relative values. Issuance costs attributable to the liability component are being amortized over the contractual term of the Notes. Transactions involving contemporaneous exchanges of cash between the same debtor and creditor in connection with the issuance of a new debt obligation and satisfaction of an existing debt obligation by the debtor should be evaluated for an exchange transaction if the exchange is determined to have substantially different terms. For exchange transactions that are considered an extinguishment of debt, the total consideration for such an exchange is separated into liability and equity components by estimating the fair value of a similar liability without a conversion option and assigning the residual value to the equity component. The gain or loss on extinguishment of the debt is subsequently determined by comparing repurchase consideration allocated to the liability component to the sum of the carrying value of the liability component, net of the proportionate amounts of unamortized debt discount and remaining unamortized debt issuance costs. Recent Accounting Pronouncements Recently Issued Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (ASC 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (ASC 815-40). The FASB issued this ASU to simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity's own equity. The Company does not have any contracts on its own equity; however, the Company does have convertible debt. This ASU removes the separation models for 1) convertible debt with a cash conversion feature and 2) convertible instruments with a beneficial conversion feature, as well as enhances the related disclosure and earnings per share guidance. Additionally, this update requires that convertible debt be recognized as a single liability measured at its amortized cost, if no bifurcation is required, and as a result, interest expense will be closer to the coupon interest rate. For public business entities, these amendments are effective for fiscal years beginning after December 15, 2021, with early adoption permitted for fiscal years beginning after December 15, 2020. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Reclassification of prior year presentation Certain prior year amounts have been reclassified for consistency with the current year presentation. Specifically, Accrued compensation is now presented as a separate line item on the condensed consolidated balance sheets and was previously included within Accrued expense and other current liabilities.

Revenue

Revenue	9 Months Ended
Revenue	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Disaggregation of Revenue Subscription and support revenue is recognized over time and accounted for substantially all of the Company’s revenue for the three and nine months ended September 30, 2021 and 2020. The following table summarizes the revenue by region based on the billing address of customers who use the Company’s products: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Amount Percentage Amount Percentage Amount Percentage Amount Percentage United States $ 90,734 53 % $ 59,277 52 % $ 241,900 52 % $ 151,970 50 % Europe, Middle East, and Africa 45,264 26 % 27,943 25 % 120,492 26 % 76,961 25 % Asia Pacific 24,519 14 % 19,634 17 % 70,239 15 % 55,827 18 % Other 11,830 7 % 7,308 6 % 30,199 7 % 20,375 7 % Total $ 172,347 100 % $ 114,162 100 % $ 462,830 100 % $ 305,133 100 % The following table summarizes the revenue from contracts by type of customer: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Amount Percentage Amount Percentage Amount Percentage Amount Percentage Channel partners $ 19,527 11 % $ 12,159 11 % $ 51,761 11 % $ 31,471 10 % Direct customers 152,820 89 % 102,003 89 % 411,069 89 % 273,662 90 % Total $ 172,347 100 % $ 114,162 100 % $ 462,830 100 % $ 305,133 100 % Contract Balances Contract liabilities consist of deferred revenue and include payments received in advance of performance under the contract. Such amounts are recognized as revenue over the contractual period. For the nine months ended September 30, 2021 and 2020, the Company recognized revenue of $52.7 million and $30.1 million, respectively, that was included in the corresponding contract liability balance at the beginning of the periods presented. The Company receives payments from customers based upon contractual billing schedules; accounts receivable are recorded when the right to consideration becomes unconditional. Standard payment terms are due upon receipt. Contract assets include amounts related to the Company’s contractual right to consideration for both completed and partially completed performance obligations that have not been invoiced. The following table summarizes the activity of the deferred contract acquisition costs: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Beginning balance $ 56,587 $ 33,880 $ 44,176 $ 25,184 Capitalization of contract acquisition costs 12,793 8,457 38,119 24,615 Amortization of deferred contract acquisition costs (7,773) (4,623) (20,688) (12,085) Ending balance $ 61,607 $ 37,714 $ 61,607 $ 37,714 The Company did not recognize any impairment losses of deferred contract acquisition costs during the periods presented. Remaining Performance Obligations As of September 30, 2021, the aggregate amount of the transaction price allocated to remaining performance obligations was $545.4 million. As of September 30, 2021, the Company expected to recognize 75% of its remaining performance obligations as revenue over the next 12 months with the remainder recognized thereafter.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is defined as the exchange price that would be received from sale of an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Assets and liabilities measured at fair value are classified into the following categories: • Level I: Observable inputs are unadjusted quoted prices in active markets for identical assets or liabilities; • Level II: Observable inputs are quoted prices for similar assets and liabilities in active markets or inputs other than quoted prices that are observable for the assets or liabilities, either directly or indirectly through market corroboration, for substantially the full term of the financial instruments; and • Level III: Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. These inputs are based on the Company’s own assumptions used to measure assets and liabilities at fair value and require significant management judgment or estimation. The Company's cash equivalents are comprised of highly liquid money market funds and commercial paper. The Company classifies money market funds within Level I of the fair value hierarchy because they are valued based on quoted market prices in active markets. The Company classifies its investments, which are comprised of U.S. treasury securities, U.S. government agency securities, commercial paper, and corporate bonds, within Level II of the fair value hierarchy because the fair value of these securities is priced by using inputs based on non-binding market consensus prices that are primarily corroborated by observable market data or quoted market prices for similar instruments. The Company recognizes transfers between levels within the fair value hierarchy, if any, at the end of each period. There were no transfers between levels during the periods presented. The following table summarizes the Company’s cash and available-for-sale securities’ amortized cost, unrealized gains (losses), and fair value by significant investment category reported as cash and cash equivalents, restricted cash, or available-for-sale securities as of September 30, 2021 and December 31, 2020. (in thousands) Reported as: September 30, 2021 Amortized Unrealized Unrealized Fair Value Cash & Available-for-sale securities Restricted Cash $ 74,429 $ — $ — $ 74,429 $ 73,958 $ — $ 471 Level I: Money market funds 550,933 — — 550,933 544,273 — 6,660 Level II: Corporate bonds 171,027 8 (36) 170,999 — 170,998 — U.S. treasury securities 746,873 45 (151) 746,767 — 746,767 — U.S. government agency securities 3,001 — — 3,001 — 3,001 — Commercial paper 274,880 — — 274,880 — 274,880 — Subtotal 1,195,781 53 (187) 1,195,647 — 1,195,646 — Total assets measured at fair value on a recurring basis $ 1,821,143 $ 53 $ (187) $ 1,821,009 $ 618,231 $ 1,195,646 $ 7,131 (in thousands) Reported as: December 31, 2020 Amortized Unrealized Unrealized Fair Cash & Available-for-sale securities Restricted Cash $ 22,114 $ — $ — $ 22,114 $ 19,523 $ — $ 2,591 Level I: Money market funds 71,038 — — 71,038 64,378 — 6,660 Level II: Corporate bonds 169,324 43 (26) 169,341 — 169,341 — U.S. treasury securities 576,652 223 (4) 576,871 — 576,871 — U.S. government agency securities 15,617 4 (1) 15,620 — 15,620 — Commercial paper 186,363 — — 186,363 24,994 161,369 — Subtotal 947,956 270 (31) 948,195 24,994 923,201 — Total assets measured at fair value on a recurring basis $ 1,041,108 $ 270 $ (31) $ 1,041,347 $ 108,895 $ 923,201 $ 9,251 As of September 30, 2021 and December 31, 2020, the Company had $6.7 million in the long-term restricted cash related to irrevocable standby letters of credit established according to the requirements under lease agreements. The aggregate fair value of the Company’s money market funds approximated amortized cost and, as such, there were no unrealized gains or losses on money market funds as of September 30, 2021 and December 31, 2020. Realized gains and losses, net of tax, were not material for any of the periods presented. The amortized cost of available-for-sale investments with maturities less than one year was $723.8 million and $866.5 million as of September 30, 2021 and December 31, 2020, respectively. The amortized cost of available-for-sale investments with maturities greater than one year was $472.0 million and $56.5 million as of September 30, 2021 and December 31, 2020, respectively. As of September 30, 2021, net unrealized loss on investments were $0.2 million and were included in accumulated other comprehensive income on the condensed consolidated balance sheets. As of December 31, 2020, net unrealized gains on investments were $0.2 million net of tax and were included in accumulated other comprehensive income on the condensed consolidated balance sheets. The unrealized gains and losses on available-for-sale investments are related to U.S. treasury securities, U.S. government agency securities, commercial paper, and corporate bonds. The Company determined any unrealized losses to be temporary. Factors considered in determining whether a loss is temporary include the financial condition and near-term prospects of the investee, the extent of the loss related to the credit of the issuer, the expected cash flows from the security, the Company’s intent to sell the security, and whether or not the Company will be required to sell the security before the recovery of its amortized cost. As of September 30, 2021, the Company's investment portfolio consisted of investment grade securities with an average credit rating of AA. The Company carries the 2026 Notes issued in August 2021 at face value less the unamortized discount and issuance costs on its condensed consolidated balance sheets and presents that fair value for disclosure purposes only. As of September 30, 2021 , the fair value of the 2026 Notes was $1,243.6 million. The fair value of the 2026 Notes, which are classified as Level II financial instruments, was determined based on the quoted bid prices of the 2026 Notes in an over-the-counter market on the last trading day of the reporting period. The Company carries the 2025 Notes issued in May 2020 at face value less the unamortized discount and issuance costs on its condensed consolidated balance sheets and presents that fair value for disclosure purposes only. As of September 30, 2021 , the fair value of the 2025 Notes was $529.8 million. The fair value of the 2025 Notes, which are classified as Level II financial instruments, was determined based on the quoted bid prices of the 2025 Notes in an over-the-counter market on the last trading day of the reporting period. For further details on the Notes, refer to Note 7 to these condensed consolidated financial statements. The Company classifies financial instruments in Level III of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level III financial instruments typically also rely on a number of inputs that are readily observable, either directly or indirectly. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. There were no financial instruments classified as Level III of the fair value hierarchy as of September 30, 2021 and December 31, 2020.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
Balance Sheet Components	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Accounts Receivable, Net As of September 30, 2021 and December 31, 2020, the Company’s allowance for doubtful accounts was $2.4 million and $1.7 million, respectively. Bad debt expense for the three months ended September 30, 2021 and 2020 was $0.9 million and $0.3 million, respectively, and $2.9 million and $2.8 million for the nine months ended September 30, 2021 and 2020, respectively. For the three months ended September 30, 2021 and 2020, write-off of uncollectible accounts receivable was $0.9 million and $0.4 million, respectively, and $2.2 million and $1.9 million for the nine months ended September 30, 2021 and 2020, respectively. Property and Equipment, Net Property and equipment, net consisted of the following: September 30, 2021 December 31, 2020 (in thousands) Property and equipment: Servers—network infrastructure $ 144,253 $ 108,988 Construction in progress 43,662 11,242 Capitalized internal-use software 64,559 49,618 Office and computer equipment 23,803 17,867 Office furniture 6,503 5,657 Software 4,253 1,808 Leasehold improvements 12,148 10,686 Asset retirement obligation 430 430 Gross property and equipment 299,611 206,296 Less accumulated depreciation and amortization (123,055) (82,608) Total property and equipment, net $ 176,556 $ 123,688 Depreciation and amortization expense on property and equipment for the three months ended September 30, 2021 and 2020 was $16.1 million and $12.1 million, respectively, and $45.2 million and $32.8 million for the nine months ended September 30, 2021 and 2020, respectively. This includes amortization expense for capitalized internal-use software which totaled $4.5 million and $3.4 million for the three months ended September 30, 2021 and 2020, respectively, and $13.3 million and $8.7 million for the nine months ended September 30, 2021 and 2020, respectively. Goodwill As of September 30, 2021 and December 31, 2020, the Company's goodwill was $17.2 million . No goodwill impairments were recorded during the nine months ended September 30, 2021 and 2020. Acquired Intangible Assets, Net Acquired intangible assets, net consisted of the following: September 30, 2021 Gross Carrying Accumulated Net Book (in thousands) Developed technology $ 5,600 $ 4,900 $ 700 Total acquired intangible assets, net $ 5,600 $ 4,900 $ 700 December 31, 2020 Gross Carrying Accumulated Net Book (in thousands) Developed technology $ 5,600 $ 2,800 $ 2,800 Total acquired intangible assets, net $ 5,600 $ 2,800 $ 2,800 Amortization of acquired intangible assets was $0.7 million for the three months ended September 30, 2021 and 2020 and $2.1 million for the nine months ended September 30, 2021 and 2020. As of September 30, 2021, the estimated future amortization expense of acquired intangible assets was as follows: Estimated (in thousands) Year ending December 31, 2021 (remaining three months) $ 700 Total $ 700

Leases

Leases	9 Months Ended
Leases	Sep. 30, 2021
Leases [Abstract]
Leases	Leases The Company's lease portfolio consists of real estate and co-location agreements in the U.S. and internationally. The real estate leases include leases for office space and have remaining lease terms of up to 9.8 years. Certain of these leases contain options that allow the Company to extend or terminate the lease agreement. The Company's co-location leases have remaining lease terms of up to 6.6 years. All of the Company's leases are classified as operating leases. On July 6, 2021, the Company entered a triple net lease (the "Austin Lease") for 128,195 square feet of office space in Austin, Texas. The Lease has an accounting lease term of 121 months plus two options to renew for five years each at 100% market rate. At lease commencement, it was not reasonably certain that these renewal options will be exercised. The total fixed payments per the terms of the Austin Lease are approximately $$46.2 million plus the Company's share of operating costs for the maturity of the lease. During the three months ended September 30, 2021, the reasonably certain holding period for two foreign real estate leases was modified as the Company became reasonably certain that the renewal options for these agreements would be exercised. The reasonably certain holding period for both leases increased by their respective renewal term lengths, which amounted to an additional undiscounted cash payment of $26.8 million based on the terms of their existing agreements. The Company also subleased one of its leased office spaces. The lease term of the sublease ended during the three months ended June 30, 2021. Sublease income, which is recorded as a reduction of rent expense was zero and $1.1 million for the three and nine months ended September 30, 2021, respectively, and $0.7 million and $2.1 million f or the three months and nine months ended September 30, 2020, respectively. The components of lease cost related to the Company's operating leases included in the condensed consolidated statements of operations were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Operating lease cost $ 6,736 $ 4,802 $ 17,740 $ 14,134 Sublease income — (694) (1,096) (2,111) Total lease cost $ 6,736 $ 4,108 $ 16,644 $ 12,023 Variable lease cost and short-term lease cost for the three and nine months ended September 30, 2021 were not material. As of September 30, 2021, the Company had $28.8 million of total undiscounted future payments under operating leases that have not yet commenced, which were not included on the condensed consolidated balance sheets. These operating leases will commence between October 2021 and October 2024 and have an average lease term of 4.1 years. As of September 30, 2021, the weighted-average remaining term of the Company’s operating leases was 6.2 years and the weighted-average discount rate used to measure the present value of the operating lease liabilities was 3.5%. Maturities of the operating lease liabilities as of September 30, 2021 are as follows: September 30, 2021 (in thousands) 2021 (remaining three months) $ 7,024 2022 23,435 2023 19,003 2024 17,275 2025 10,972 Thereafter 41,190 Total lease payments $ 118,899 Less: Imputed interest $ (14,336) Total operating lease liabilities $ 104,563
Leases	Leases The Company's lease portfolio consists of real estate and co-location agreements in the U.S. and internationally. The real estate leases include leases for office space and have remaining lease terms of up to 9.8 years. Certain of these leases contain options that allow the Company to extend or terminate the lease agreement. The Company's co-location leases have remaining lease terms of up to 6.6 years. All of the Company's leases are classified as operating leases. On July 6, 2021, the Company entered a triple net lease (the "Austin Lease") for 128,195 square feet of office space in Austin, Texas. The Lease has an accounting lease term of 121 months plus two options to renew for five years each at 100% market rate. At lease commencement, it was not reasonably certain that these renewal options will be exercised. The total fixed payments per the terms of the Austin Lease are approximately $$46.2 million plus the Company's share of operating costs for the maturity of the lease. During the three months ended September 30, 2021, the reasonably certain holding period for two foreign real estate leases was modified as the Company became reasonably certain that the renewal options for these agreements would be exercised. The reasonably certain holding period for both leases increased by their respective renewal term lengths, which amounted to an additional undiscounted cash payment of $26.8 million based on the terms of their existing agreements. The Company also subleased one of its leased office spaces. The lease term of the sublease ended during the three months ended June 30, 2021. Sublease income, which is recorded as a reduction of rent expense was zero and $1.1 million for the three and nine months ended September 30, 2021, respectively, and $0.7 million and $2.1 million f or the three months and nine months ended September 30, 2020, respectively. The components of lease cost related to the Company's operating leases included in the condensed consolidated statements of operations were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Operating lease cost $ 6,736 $ 4,802 $ 17,740 $ 14,134 Sublease income — (694) (1,096) (2,111) Total lease cost $ 6,736 $ 4,108 $ 16,644 $ 12,023 Variable lease cost and short-term lease cost for the three and nine months ended September 30, 2021 were not material. As of September 30, 2021, the Company had $28.8 million of total undiscounted future payments under operating leases that have not yet commenced, which were not included on the condensed consolidated balance sheets. These operating leases will commence between October 2021 and October 2024 and have an average lease term of 4.1 years. As of September 30, 2021, the weighted-average remaining term of the Company’s operating leases was 6.2 years and the weighted-average discount rate used to measure the present value of the operating lease liabilities was 3.5%. Maturities of the operating lease liabilities as of September 30, 2021 are as follows: September 30, 2021 (in thousands) 2021 (remaining three months) $ 7,024 2022 23,435 2023 19,003 2024 17,275 2025 10,972 Thereafter 41,190 Total lease payments $ 118,899 Less: Imputed interest $ (14,336) Total operating lease liabilities $ 104,563

Convertible Senior Notes

Convertible Senior Notes	9 Months Ended
Convertible Senior Notes	Sep. 30, 2021
Debt Disclosure [Abstract]
Convertible Senior Notes	Convertible Senior Notes 2026 Convertible Senior Notes In August 2021, the Company issued $1,293.8 million aggregate principal amount of the 2026 Notes in a private offering to qualified institutional buyers pursuant to Rule 144A promulgated under the Securities Act, including the initial purchasers’ exercise in full of their option to purchase an additional $168.8 million aggregate principal amounts of the 2026 Notes. The total net proceeds from the issuance of the 2026 Notes, after deducting initial purchaser discounts and debt issuance costs, were $1,274.0 million. The 2026 Notes are senior unsecured obligations of the Company and will mature on August 15, 2026, unless earlier redeemed, repurchased, or converted, and are governed by the terms of the indenture dated August 13, 2021 (the 2026 Indenture). The 2026 Notes are 0% convertible senior notes and therefore do not bear regular cash interest. The 2026 Notes are convertible at an initial conversion rate of 5.2263 shares of the Company's Class A common stock per $1,000 principal amount of the 2026 Notes, which is equivalent to an initial conversion price of approximately $191.34 per share, subject to adjustment upon the occurrence of specified events in accordance with the terms of the 2026 Indenture. The 2026 Notes may be converted at any time on or after May 15, 2026 until the close of business on the second scheduled trading day immediately preceding the maturity date. Holders of the 2026 Notes may convert all or any portion of their 2026 Notes at their option at any time prior to the close of business on the business day immediately preceding May 15, 2026 only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2021 (and only during such calendar quarter), if the last reported sale price of the Company's Class A common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, 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 in which the trading price 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 Class A common stock and the conversion rate on each such trading day; (3) if the Company calls such 2026 Notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events. In addition, if the 2026 Notes are converted prior to the maturity date following certain specified corporate events or because the Company issues a notice of redemption, the Company will increase the conversion rate for such 2026 Notes converted in connection with such a corporate event or during the related redemption period, as the case may be, in certain circumstances set forth in the 2026 Indenture. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company's Class A common stock, or a combination of cash and shares of the Company's Class A common stock, at the Company's election. It is the Company’s current intent to settle the principal amount of 2026 Notes in cash. The Company may not redeem the 2026 Notes prior to August 20, 2024. The Company may redeem for cash all or any portion of the 2026 Notes (subject to the partial redemption limitation (as defined below)), at its option, on or after August 20, 2024, if the last reported sale price of the Company’s Class A 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 preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the 2026 Notes to be redeemed, plus any accrued and unpaid special interest to, but excluding, the redemption date. If the Company elects to redeem fewer than all of the outstanding 2026 Notes, at least $100.0 million aggregate principal amount of 2026 Notes must be outstanding and not subject to redemption as of the relevant redemption date. No sinking fund is provided for the 2026 Notes. If the Company undergoes a fundamental change (as defined in the 2026 Indenture), holders of the 2026 Notes may require the Company to repurchase for cash all or any portion of their notes at a repurchase price equal to 100% of the principal amount of the 2026 Notes to be repurchased, plus accrued and unpaid special interest to, but excluding, the fundamental change repurchase date. In accounting for the issuance of the 2026 Notes, the Company separated the 2026 Notes into liability and equity components. The initial carrying amount of the liability component of approximately $1,027.6 million, net of costs incurred, was calculated by using an effective interest rate of 4.65%, which was determined by measuring the fair value of similar debt instruments that did not have an associated convertible feature. The carrying amount of the equity component representing the conversion option and recorded in additional paid-in capital was $266.2 million and was determined by deducting the fair value of the liability component from the par value of the 2026 Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount represents a debt discount that is amortized to interest expense over the contractual term of the 2026 Notes. In accounting for the issuance costs related to the 2026 Notes, the Company allocated the total amount incurred to the liability and equity components based on the proportion of the proceeds allocated to the debt and equity components. Issuance costs attributable to the liability component were $15.7 million (presented as a reduction to the carrying amount of debt) and are being amortized to interest expense over the contractual term of the 2026 Notes. The issuance costs attributable to the equity component were $4.1 million and are netted against the equity component in additional paid-in capital. The net carrying amount of the liability component of the 2026 Notes was as follows: September 30, 2021 (in thousands) Principal $ 1,293,750 Unamortized debt discount (260,150) Unamortized debt issuance costs (15,327) Carrying amount of the liability component, net $ 1,018,273 The net carrying amount of the equity component of the 2026 Notes was as follows: September 30, 2021 (in thousands) Proceeds allocated to the conversion option (debt discount) $ 266,150 Less: allocated issuance costs (4,073) Carrying amount of the equity component, net $ 262,077 Based on the closing price of the Company's Class A common stock of $112.65 on September 30, 2021 , the if-converted value of the 2026 Notes does not exceed its principal amount. The remaining life of the 2026 Notes was approximately 59 months as of September 30, 2021 . The following table sets forth total interest expense recognized related to the 2026 Notes: Three Months Ended September 30, Nine Months Ended September 30, 2021 2021 (in thousands) Coupon interest expense $ — $ — Amortization of debt discount 6,000 6,000 Amortization of debt issuance costs 397 397 Total $ 6,397 $ 6,397 2026 Capped Call Transactions In connection with the offering of the 2026 Notes, the Company entered into privately-negotiated capped call transactions (the 2026 Capped Calls) with certain financial institution counterparties. The 2026 Capped Calls each have an initial strike price of approximately $191.34 per share of the Company's Class A common stock, subject to certain adjustments, which corresponds to the initial conversion price of the 2026 Notes. The 2026 Capped Calls each have an initial cap price of approximately $250.94 per share, subject to certain adjustments. The 2026 Capped Calls initially cover, subject to anti-dilution adjustments, approximately 6.8 million shares of the Company's Class A common stock. The 2026 Capped Calls are intended to generally offset potential dilution to the Company's Class A common stock upon conversion of the 2026 Notes and/or offset the potential cash payments that the Company could be required to make in excess of the principal amount upon any conversion, subject to the cap price. The 2026 Capped Calls are subject to either adjustment or termination upon the occurrence of certain specified events affecting the Company, including a merger event, a tender offer, and a nationalization, insolvency, or delisting involving the Company. The 2026 Capped Calls expire in incremental components on each trading date between July 17, 2026 and August 13, 2026. The 2026 Capped Calls are recorded in stockholders' equity and are not accounted for as derivatives. The premium paid for the purchase of the 2026 Capped Calls of $86.3 million was recorded as a reduction to additional paid-in capital on the condensed consolidated balance sheets. 2025 Convertible Senior Notes In May 2020, the Company issued $575.0 million aggregate principal amount of the 2025 Notes in a private offering to qualified institutional buyers pursuant to Rule 144A promulgated under the Securities Act, including t he initial purchasers' exercise in full of their option to purchase an additional $75.0 million aggregate principal amount of the 2025 Notes. The total net proceeds from the issuance of the 2025 Notes, after deducting initial purchaser discounts and debt issuance costs, were $562.5 million . Immediately following the closings of the 2025 Notes Exchange (defined below), $175.0 million in aggregate principal amount of the 2025 Notes remained outstanding as of September 30, 2021. The 2025 Notes are senior unsecured obligations of the Company and will mature on May 15, 2025, unless earlier redeemed, repurchased, or converted, and are governed by the terms of the Indenture dated May 15, 2020 (the 2025 Indenture and, together with the 2026 Indenture, the Indentures). Interest on the 2025 Notes is payable semi-annually in arrears on May 15 and November 15 of each year, beginning on November 15, 2020, at a rate of 0.75% per year. The 2025 Notes are convertible at an initial conversion rate of 26.7187 shares of the Company's Class A common stock per $1,000 principal amount of the 2025 Notes, which is equivalent to an initial conversion price of approximately $37.43 per share, subject to adjustment upon the occurrence of specified events in accordance with the terms of the 2025 Indenture. The 2025 Notes may be converted at any time on or after February 15, 2025 until the close of business on the second scheduled trading day immediately preceding the maturity date. Holders of the 2025 Notes may convert all or any portion of their 2025 Notes at their option at any time prior to the close of business on the business day immediately preceding February 15, 2025 only under the following circumstances: (1) during any calendar quarter (and only during such calendar quarter), if the last reported sale price of the Company's Class A common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, 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 in which the trading price per $1,000 principal amount of the 2025 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 Class A common stock and the conversion rate on each such trading day; (3) if the Company calls such 2025 Notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events. The circumstances described in paragraph (1) above were met during the third quarter of 2021 and as a result, the 2025 Notes are convertible at the option of the holder from October 1, 2021 until December 31, 2021. As of September 30, 2021, no holders had converted the 2025 Notes. In addition, if the 2025 Notes are converted prior to the maturity date following certain specified corporate events or because the Company issues a notice of redemption, the Company will increase the conversion rate for such 2025 Notes converted in connection with such a corporate event or during the related redemption period, as the case may be, in certain circumstances set forth in the 2025 Indenture. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company's Class A common stock, or a combination of cash and shares of the Company's Class A common stock, at the Company's election. It is the Company’s current intent to settle the principal amount of 2025 Notes in cash. The Company may not redeem the 2025 Notes prior to May 20, 2023. The Company may redeem for cash all or any portion of the 2025 Notes, at its option, on or after May 20, 2023, if the last reported sale price of the Company’s Class A 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 preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the 2025 Notes to be redeemed, plus any accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the 2025 Notes. If the Company undergoes a fundamental change (as defined in the 2025 Indenture), holders of the 2025 Notes may require the Company to repurchase for cash all or any portion of their notes at a repurchase price equal to 100% of the principal amount of the 2025 Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In accounting for the issuance of the 2025 Notes, the Company separated the 2025 Notes into liability and equity components . The carrying amount of the liability component was calculated by using an effective interest rate of 10.0%, which was determined by measuring the fair value of similar debt instruments that did not have an associated convertible feature. The carrying amount of the equity component representing the conversion option and recorded in additional paid-in capital was $205.3 million and was determined by deducting the fair value of the liability component from the par value of the 2025 Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount represents a debt discount that is amortized to interest expense over the contractual term of the 2025 Notes. In accounting for the issuance costs related to the 2025 Notes, the Company allocated the total amount incurred to the liability and equity components based on the proportion of the proceeds allocated to the debt and equity components. Issuance costs attributable to the liability component were $8.0 million (presented as a reduction to the carrying amount of debt) and are being amortized to interest expense over the contractual term of the 2025 Notes. The issuance costs attributable to the equity component were $4.5 million and are netted against the equity component in additional paid-in capital. 2025 Notes Exchange On August 13, 2021, the Company closed privately-negotiated exchange agreements with certain holders of the 2025 Notes to exchange approximately $400.0 million in aggregate principal amount of the 2025 Notes (the 2025 Notes Exchange) for an aggregate of $400.7 million in cash (including accrued interest) and approximately 7.6 million shares of the Company’s Class A common stock (the Exchange Shares) for aggregate consideration of $1,321.0 million. The Company used a portion of the net proceeds from the offering of the 2026 Notes to fund the 2025 Notes Exchange. As a result, the Company recorded a debt extinguishment loss of $72.2 million, representing the difference between the fair value of the liability component of $355.3 million and the carrying value of the 2025 Notes Exchange of $283.1 million at the closing date. The fair value of the liability component was calculated by using an effective interest rate of 4.08%, which was determined by measuring the fair value of similar debt instruments that did not have an associated convertible feature and adjusted to reflect the term of the remaining 2025 Notes. The aggregate consideration of $1,321.0 million was allocated between the fair value of the liability component of $355.3 million and the reacquisition of the equity component of $965.7 million, which was recorded as a reduction to additional paid-in capital and offset by the additional paid-in capital for the Exchange Shares issued. The net carrying amount of the liability component of the 2025 Notes was as follows: September 30, 2021 December 31, 2020 (in thousands) Principal $ 175,000 $ 575,000 Unamortized debt discount (48,187) (184,674) Unamortized debt issuance costs (1,778) (7,051) Carrying amount of the liability component, net $ 125,035 $ 383,275 The net carrying amount of the equity component of the 2025 Notes was as follows: September 30, 2021 December 31, 2020 (in thousands) Proceeds allocated to the conversion option (debt discount) $ 62,480 $ 205,290 Less: allocated issuance costs (1,363) (4,478) Carrying amount of the equity component, net $ 61,117 $ 200,812 Based on the closing price of the Company's Class A common stock o f $112.65 on September 30, 2021, the if-converted value of the 2025 Notes exceeded its principal amount by approximately $351.7 million. The remaining life of the 2025 Notes was approximately 44 months as of September 30, 2021. The following table sets forth total interest expense recognized related to the 2025 Notes: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Coupon interest expense $ 678 $ 1,078 $ 2,834 $ 1,629 Amortization of debt discount 5,682 8,159 23,029 12,256 Amortization of debt issuance costs 255 403 1,062 609 Total $ 6,615 $ 9,640 $ 26,925 $ 14,494 2025 Capped Call Transactions In connection with the offering of the 2025 Notes, the Company entered into privately-negotiated capped call transactions (the 2025 Capped C alls and, together with the 2026 Capped Calls, the capped call transactions) with certain financial institution counterparties . The 2025 Capped Calls each have an initial strike price of approximately $37.43 per share of the Company's Class A common stock, subject to certain adjustments, which corresponds to the initial conversion price of the 2025 Notes. The 2025 Capped Calls each have an initial cap price of $57.58 per share, subject to certain adjustments. The 2025 Capped Calls initially cover, subject to anti-dilution adjustments, approximately 15.4 million shares of the Company's Class A common stock. The 2025 Capped Calls are intended to generally offset potential dilution to the Company's Class A common stock upon conversion of the 2025 Notes and/or offset the potential cash payments that the Company could be required to make in excess of the principal amount upon any conversion, subject to the cap price. The 2025 Capped Calls are subject to either adjustment or termination upon the occurrence of certain specified events affecting the Company, including a merger event, a tender offer, and a nationalization, insolvency, or delisting involving the Company. The 2025 Capped Calls expire in incremental components on each trading date between March 18, 2025 and May 13, 2025. As of September 30, 2021, the terms of the 2025 Capped Calls have not been adjusted and no 2025 Capped Calls were exercised in connection with the 2025 Notes Exchange. The 2025 Capped Calls are recorded in stockholders' equity and are not accounted for as derivatives. The premium paid for the purchase of the 2025 Capped Calls of $67.3 million was recorded as a reduction to additional paid-in capital on the condensed consolidated balance sheets.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Purchase Commitments Open purchase commitments are for the purchase of services under non-cancelable contracts. They are not recorded as liabilities on the condensed consolidated balance sheet as of September 30, 2021 as the Company has not yet received the related services. Refer to the table below for purchase commitments under non-cancelable contracts with various vendors as of September 30, 2021. Bandwidth & Co-location Commitments The Company enters into long-term non-cancelable agreements with providers in various countries to purchase capacity, such as bandwidth and co-location space, for the Company’s global network. Bandwidth and co-location costs for paying customers are recorded as cost of revenue in the condensed consolidated statements of operations and as sales and marketing expense in the condensed consolidated statements of operations for free customers. Such costs totaled $19.6 million and $13.5 million for the three months ended September 30, 2021 and 2020, respectively, and $54.6 million and $36.6 million for the nine months ended September 30, 2021 and 2020, respectively. Refer to the table below for long-term bandwidth and co-location commitments under non-cancelable contracts with various networks and Internet service providers as of September 30, 2021. For the lease components of co-location agreements, refer to Note 6 to these condensed consolidated financial statements. Payments Due by Period as of September 30, 2021 Total 2021 (remaining three months) 2022 2023 2024 2025 Thereafter (in thousands) Non-cancelable: Open purchase agreements (1) $ 25,394 $ 5,219 $ 8,019 $ 5,754 $ 1,374 $ 752 $ 4,276 Bandwidth and other co-location related commitments (2) 52,677 6,738 21,741 9,377 5,614 4,395 4,812 Total $ 78,071 $ 11,957 $ 29,760 $ 15,131 $ 6,988 $ 5,147 $ 9,088 (1) Open purchase commitments are for the purchase of services under non-cancelable contracts. They were not recorded as liabilities on the condensed consolidated balance sheet as of September 30, 2021 as the Company had not yet received the related services. (2) Long-term commitments for bandwidth usage and other co-location related commitments with various networks and Internet service providers. The costs for services not yet received were not recorded as liabilities on the condensed consolidated balance sheet as of September 30, 2021. Legal Matters From time to time the Company is a party to various legal proceedings that arise in the ordinary course of business. In addition, third parties may from time to time assert claims against the Company in the form of letters and other communications. Management currently believes that there is no pending or threatened legal proceeding to which the Company is a party that is likely to have a material adverse effect on the Company’s condensed consolidated financial statements. However, the results of legal proceedings are inherently unpredictable and if an unfavorable ruling were to occur in any of the legal proceedings there exists the possibility of a material adverse effect on the Company’s financial position, results of operations, and cash flows. The Company accrues for legal proceedings that it considers probable and for which the loss can be reasonably estimated. The Company also discloses material contingencies when it believes a loss is not probable but reasonably possible. Legal costs incurred and expected to be incurred related to litigation matters are expensed as incurred. The Company’s network and associated products are subject to various restrictions under U.S. export control and sanctions laws and regulations, including the U.S. Department of Commerce’s Export Administration Regulations (EAR) and various economic and trade sanctions regulations administered by the U.S. Department of the Treasury’s Office of Foreign Assets Controls (OFAC). The U.S. export control laws and U.S. economic sanctions laws include restrictions or prohibitions on the sale or supply of certain products and services to U.S. embargoed or sanctioned countries, governments, persons and entities and also require authorization for the export of certain encryption items. In addition, various countries regulate the import of certain encryption technology, including through import permitting and licensing requirements and have enacted or could enact laws that could limit the Company’s ability to distribute its network. Although the Company takes precautions to prevent its network and associated products from being accessed or used in violation of such laws, the Company may have inadvertently allowed its network and associated products to be accessed or used by some customers in apparent violation of U.S. economic sanctions laws, including by users in embargoed or sanctioned countries, and the Company may have exported or allowed the download of certain software prior to making required filings with the U.S. Department of Commerce’s Bureau of Industry and Security. As a result, the Company has submitted to OFAC and to the Bureau of Industry and Security a voluntary self-disclosure concerning potential violations, and the Company has submitted a voluntary self-disclosure to the Census Bureau regarding potential violations of the Foreign Trade Regulations related to some incorrect electronic export information statements to the U.S. government for certain hardware exports, which were authorized. The voluntary self-disclosure to the Census Bureau was completed with no penalties in November 2019, and the voluntary self-disclosure to the Bureau of Industry and Security was completed with no penalties in June 2020. The voluntary self-disclosure to OFAC remains under review. If the Company is found to be in violation of U.S. economic sanctions or export control laws, it could result in substantial fines and penalties for the Company and for the individuals working for the Company. The Company may also be adversely affected through other penalties, reputational harm, loss of access to certain markets or otherwise. No loss has been recognized in the condensed consolidated financial statements for this loss contingency as it is not probable a loss has been incurred and the range of a possible loss is not yet estimable. Guarantees and Indemnifications If the Company's services do not meet certain service level commitments, its contracted customers and certain of its pay-as-you-go customers are entitled to receive service credits, and in certain cases, refunds, each representing a form of variable consideration. To date, the Company has not incurred any material costs as a result of such commitments. The Company’s arrangements generally include certain provisions for indemnifying customers against liabilities if its products or services infringe a third-party’s intellectual property rights. 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. To date, the Company has not incurred any material costs as a result of such obligations and has not accrued any liabilities related to such obligations in the condensed consolidated financial statements. The Company has also agreed to indemnify its directors, executive officers, and certain other employees for costs associated with any fees, expenses, judgments, fines, and settlement amounts incurred by them in any action or proceeding to which any of them are, or are threatened to be, made a party by reason of their service as a director or officer. The Company maintains director and officer insurance coverage that would generally enable it to recover

Common Stock

Common Stock	9 Months Ended
Common Stock	Sep. 30, 2021
Equity [Abstract]
Common Stock	Common Stock The Company’s amended and restated certificate of incorporation authorizes the issuance of Class A common stock and Class B common stock. The holder of each share of Class A common stock is entitled to one vote per share, while the holder of each share of Class B common stock is entitled to 10 votes per share. As of September 30, 2021 and December 31, 2020, the Company was authorized to issue 2,250,000,000 shares of Class A common stock and 315,000,000 shares of Class B common stock, each with a par value of $0.001 per share. There were 273,574,792 and 249,401,232 shares of Class A common stock issued and outstanding as of September 30, 2021 and December 31, 2020, respectively. The number of shares of Class B common stock issued and outstanding was 48,038,501 and 59,238,742, as of September 30, 2021 and December 31, 2020, respectively. Holders of the Company’s Class A common stock and Class B common stock are entitled to dividends when, as and if, declared by the Company’s Board of Directors, subject to the rights of the holders of all classes of stock outstanding having priority rights to dividends. Any dividends paid to the holders of the Class A common stock and Class B common stock will be paid on a pro rata basis. As of September 30, 2021 and December 31, 2020, the Company had not declared any dividends. The rights of the holders of Class A and Class B common stock are identical, except with respect to voting and conversion. Shares of the Company's Class B common stock are convertible into an equivalent number of shares of the Company's Class A common stock and generally convert into shares of the Company's Class A common stock upon cessation of employment or transfer, except for certain transfers described in the Company's amended and restated certificate of incorporation. Class A common stock and Class B common stock are referred to, collectively, as common stock throughout the notes to these condensed consolidated financial statements, unless otherwise indicated. Common Stock Reserved for Future Issuance Shares of common stock reserved for future issuance, on an as-if converted basis, are as follows: September 30, 2021 December 31, 2020 (in thousands) 2025 Notes 6,078 19,972 2026 Notes 10,311 — Stock options issued and outstanding 14,722 18,186 Remaining shares available for issuance under the 2019 Plan 39,085 24,539 Outstanding and unsettled restricted stock units (RSUs) 7,715 7,808 Shares available for issuance under the ESPP 8,186 5,230 Total shares of common stock reserved 86,097 75,735

Stock-based Compensation

Stock-based Compensation	9 Months Ended
Stock-based Compensation	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-based Compensation	Stock-based Compensation Equity Incentive Plans In 2010, the Company's Board of Directors adopted and stockholders approved the 2010 Equity Incentive Plan (2010 Plan). The 2010 Plan is a broad-based retention program and is intended to attract and retain talented employees, directors, and non-employee consultants. The 2010 Plan provides for the granting of stock options, restricted stock, RSUs, and stock appreciation rights to employees, directors, and consultants. Incentive stock options may be granted only to employees. All other awards under the 2010 Plan, including non-qualified stock options, may be granted to employees, directors, and consultants. Except for qualifying assumptions and substitutions of options, the exercise price of an incentive stock option and non-qualified stock option shall not be less than 100% of the fair market value of such shares on the date of grant. Prior to the Company's IPO, stock-based awards forfeited, canceled, or repurchased generally were returned to the pool of shares of common stock available for issuance under the 2010 Plan. In connection with the IPO, the 2010 Plan was terminated effective immediately prior to the effectiveness of the 2019 Equity Incentive Plan (2019 Plan) and the Company ceased granting any additional awards under the 2010 Plan. All outstanding awards under the 2010 Plan at the time of the termination of the 2010 Plan remain subject to the terms of the 2010 Plan, and any shares underlying stock options that expire or terminate or are forfeited or repurchased by the Company under the 2010 Plan will be automatically transferred to the 2019 Plan. In 2019, the Company's Board of Directors adopted and stockholders approved the 2019 Plan, which became effective one business day prior to the effective date of the Company's registration statement on Form S-1 for the IPO. The 2019 Plan provides for the granting of stock options, restricted stock, RSUs, stock appreciation rights, performance shares, performance stock units, and performance awards for the Company's Class A common stock to the Company's employees, directors, and consultants. Except as otherwise indicated below, the maximum number of shares of Class A common stock that may be issued under the 2019 Plan will not exceed 66,661,953 shares of the Company's Class A common stock, which is the sum of (1) 29,335,000 new shares, plus (2) an additional number of shares of Class A common stock not to exceed 37,326,953, consisting of the total number of shares of Class A or Class B common stock subject to outstanding awards granted under the 2010 Plan that, on or after the 2019 Plan became effective, are canceled, expire, or otherwise terminate prior to exercise or settlement; are repurchased by the Company because of the failure to vest; or are forfeited, tendered to, or withheld by the Company (or not issued) to satisfy a tax withholding obligation or the payment of an exercise price, if any, as such shares become available from time to time. Stock-based awards under the 2019 Plan that expire or are forfeited, canceled, or repurchased generally are returned to the pool of shares of Class A common stock available for issuance under the 2019 Plan. In addition, the number of shares of the Company's Class A common stock reserved for issuance under the 2019 Plan will automatically increase on January 1 of each calendar year, starting on January 1, 2021 through January 1, 2029, in an amount equal to the least of (i) 29,335,000 shares, (ii) 5% of the total number of shares of Class A and Class B common stock outstanding on December 31 of the fiscal year before the date of each automatic increase, or (iii) a lesser number of shares determined by the compensation committee of the Company's Board of Directors prior to the applicable January 1. Stock Options Under the 2010 Plan and 2019 Plan, at exercise, stock option awards entitle the holder to receive one share of Class B or Class A common stock, in the case of the 2010 Plan, or one share of Class A common stock, in the case of the 2019 Plan. Stock options granted under the 2010 Plan and the 2019 Plan generally vest over a four-year period subject to remaining continuously employed and expire no more than 10 years from the date of grant. The following table summarizes the stock options activity under the 2010 Plan and 2019 Plan for the nine months ended September 30, 2021: Stock Options Outstanding (in thousands, except year and per share data) Shares Subject to Options Outstanding Weighted- Average Exercise Price per Option Weighted- Average Remaining Contractual Terms (in years) Aggregate Intrinsic Value Balances as of December 31, 2020 18,186 $ 3.92 7.0 $ 1,310,650 Options granted — $ — Options exercised (3,307) $ 5.11 $ 288,298 Options canceled/forfeited/expired (157) $ 2.71 Balances as of September 30, 2021 14,722 $ 3.66 6.2 $ 1,604,528 Vested and expected to vest as of September 30, 2021 14,722 $ 3.66 6.2 $ 1,604,516 Exercisable as of September 30, 2021 13,658 $ 2.55 6.0 $ 1,503,760 The Company did not grant any stock options during the three and nine months ended September 30, 2021. The weighted-average assumptions used to determine the fair value of stock options granted during the nine months ended September 30, 2020 were as follows: Nine months ended September 30, 2020 Expected term (in years) 6.0 Expected volatility 40.3 % Risk-free interest rate 0.7 % Dividend yield — The weighted-average grant date fair value of options granted during the nine months ended September 30, 2020 was $9.74 per share. The aggregate intrinsic value is the difference between the exercise price of the option and the estimated fair value of the underlying common stock. Options exercisable include 7,259,920 and 10,765,894 options that were unvested as of September 30, 2021 and December 31, 2020, respectively. The total grant date fair value for vested options in the nine months ended September 30, 2021 and 2020 was $11.4 million and $5.5 million, respectively. As of September 30, 2021 and December 31, 2020, there was $13.7 million and $20.6 million, respectively, of unrecognized stock-based compensation expense related to unvested stock options that is expected to be recognized over a weighted-average period of 2.1 years and 2.6 years, respectively. Early Exercises of Stock Options The 2010 Plan allows for the early exercise of stock options for certain individuals as determined by the Company’s Board of Directors. Shares of common stock issued upon early exercises of unvested options are not deemed, for accounting purposes, to be issued until those shares vest according to their respective vesting schedules and accordingly, the consideration received for early exercises is initially recorded as a liability and reclassified to common stock and additional paid-in capital as the underlying awards vest. Stock options that are early exercised are subject to a repurchase option that allows the Company to repurchase within six months of an individual’s termination for any reason, including death and disability (or in the case of shares issued upon exercise of an option after termination, within six months of the date of exercise), any unvested shares of such individual for a repurchase price equal to the amount previously paid by the individual for such unvested shares. As of September 30, 2021 and December 31, 2020, the Company had $5.5 million and $8.6 million, respectively, recorded in liability for early exercise of unvested stock options, and the related number of unvested shares subject to repurchase was 2,505,209 and 3,871,772, respectively. Restricted Stock and Restricted Stock Units RSUs granted under the 2010 Plan generally vest upon the satisfaction of both a service-based vesting condition and a performance vesting condition, as defined below, occurring before these RSUs expire. RSUs granted under the 2019 Plan generally vest upon the satisfaction of a service-based vesting condition. The service-based vesting condition for employees under both the 2010 Plan and the 2019 Plan is typically satisfied over a four-year period, subject to remaining continuously employed. The performance vesting condition under the 2010 Plan was deemed satisfied upon the effective date of the Company's registration statement on Form S-1 filed with the SEC in connection with the IPO. In connection with the acquisition of S2 Systems Corporation (S2), the Company issued 948,000 shares of Class A common stock to former S2 shareholders, some of which have joined the Company as employees. Of these issued shares, 841,000 shares are restricted stock that is subject to vesting, with 77.8% of this restricted stock vesting in two years from the acquisition date and the remainder of this restricted stock vesting in three years from the acquisition date, in each case subject to remaining continuously employed. None of these restricted shares vested during the three and nine months ended September 30, 2021. The total grant date fair value for vested shares in the nine months ended September 30, 2020 was $1.8 million. The total stock-based compensation expense for shares of unvested restricted stock for the nine months ended September 30, 2021 and 2020 was $4.2 million and $4.2 million, respectively. As of September 30, 2021 and 2020, the total unrecognized stock-based compensation expense related to unvested restricted stock was $4.6 million and $10.2 million, respectively. For further details on the S2 acquisition, refer to Note 13 to these condensed consolidated financial statements. RSU and restricted stock activity for the nine months ended September 30, 2021 was as follows: Restricted Stock and RSUs Weighted-Average (in thousands, except per share data) Unvested and outstanding as of December 31, 2020 8,629 $ 21.38 Granted - RSUs 1,683 $ 91.54 Granted - Restricted stock — $ — Vested - RSUs (2,052) $ 19.26 Vested - Restricted stock — $ — Forfeited (545) $ 28.80 Unvested as of September 30, 2021 7,715 $ 37.14 Vested and not yet released — $ — Outstanding as of September 30, 2021 7,715 $ 37.14 The total grant date fair value for vested RSUs for the nine months ended September 30, 2021 and 2020 was $39.5 million and $19.6 million, respectively. The total stock-based compensation expense for RSUs for the three months ended September 30, 2021 and 2020 was $18.8 million and $10.3 million, respectively, and for the nine months ended September 30, 2021 and 2020 was $48.5 million and $27.8 million, respectively. As of September 30, 2021 and December 31, 2020, the total unrecognized stock-based compensation expense related to unvested RSUs was $231.7 million and $141.8 million, respectively, that is expected to be recognized over a weighted-average period of 3.3 years and 3.5 years, respectively 2019 Employee Stock Purchase Plan In September 2019, the Company's Board of Directors adopted and stockholders approved the 2019 Employee Stock Purchase Plan (ESPP), which became effective one business day prior to the effective date of the Company's registration statement on Form S-1 filed with the SEC in connection with the IPO. A total of 5,870,000 shares of Class A common stock were initially reserved for sale under the ESPP. The number of shares of Class A common stock reserved for issuance includes an annual increase on the first day of each fiscal year, beginning on January 1, 2021, by the least of (1) 5,870,000 shares of Class A common stock, (2) 1% of the total number of shares of Class A and Class B common stock outstanding on December 31 of the fiscal year before the date of each automatic increase; or (3) such lesser amount as the compensation committee of the Company's Board of Directors may determine prior to the applicable January 1. Generally, all regular employees, including executive officers, employed by the Company or by any of its designated subsidiaries, except for those holding 5% or more of the total combined voting power or value of all classes of common stock, may participate in the ESPP and may contribute, normally through payroll deductions, up to 10% of their eligible compensation for the purchase of Class A common stock under the ESPP. Unless otherwise determined by the compensation committee of the Board of Directors, Class A common stock will be purchased for the accounts of employees participating in the ESPP at a price per share that is the lesser of (1) 85% of the fair market value of a share of the Company's Class A common stock on the first date of an offering period, or (2) 85% of the fair market value of a share of the Company's Class A common stock on the date of purchase. The ESPP generally provides for six-month offering periods beginning on the first day of trading on or after November 15 and May 15 of each year and terminating on the last trading day on or before May 15 and November 15, approximately six months later, with identical purchase periods. Current employees cannot sell the shares of Class A common stock purchased under the ESPP until the day after the one-year anniversary of the purchase date of such shares, except for the withholding or sale of shares by the Company to meet any applicable tax withholding obligations. No employee may purchase (i) during each purchase period more than 1,500 shares of Class A common stock and (ii) shares under the ESPP at a rate in excess of $25,000 worth of the Company's Class A common stock based on the fair market value per share of the Company's Class A common stock at the beginning of an offering for each calendar year such purchase right is outstanding. During the three and nine months ended September 30, 2021, respectively, zero and 130,870 shares of Class A common stock were purchased under the ESPP. During the three and nine months ended September 30, 2020, respectively, zero and 421,300 shares of Class A common stock were purchased under the ESPP. As of September 30, 2021 and December 31, 2020, the total unrecognized stock-based compensation expense related to the ESPP was $0.9 million and $2.0 million, respectively, that is expected to be recognized over a weighted average period of 0.1 years. The weighted-average assumptions used to determine the fair value of the ESPP during the periods presented were as follows: Nine months ended September 30, 2021 2020 Expected term (in years) 0.5 0.5 Risk-free interest rate 0.04 % 0.15 % Expected volatility 65.6 % 65.20 % Dividend yield — % — % Stock-based Compensation Expense The following table sets forth the total stock-based compensation expense included in the Company’s condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Cost of revenue $ 672 $ 311 $ 1,665 $ 858 Sales and marketing 6,983 4,406 19,236 11,177 Research and development 11,389 6,749 29,262 18,213 General and administrative 4,005 3,279 11,475 9,843 Total stock-based compensation expense $ 23,049 $ 14,745 $ 61,638 $ 40,091

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	9 Months Ended
Net Loss per Share Attributable to Common Stockholders	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Class A Class B Class A Class B Class A Class B Class A Class B (in thousands, except per share data) Net loss attributable to common stockholders $ (91,665) $ (15,670) $ (18,119) $ (8,349) $ (153,359) $ (29,449) $ (45,059) $ (40,290) Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 268,621 45,922 206,528 95,161 259,741 49,877 157,656 140,972 Net loss per share attributable to common stockholders, basic and diluted $ (0.34) $ (0.34) $ (0.09) $ (0.09) $ (0.59) $ (0.59) $ (0.29) $ (0.29) Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share as the inclusion of all potential common shares outstanding would have been antidilutive. The potential shares of common stock that were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive are as follows: September 30, 2021 2020 (in thousands) 2025 Notes 4,676 15,363 2026 Notes 6,761 — Shares subject to repurchase 2,505 4,354 Unexercised stock options 14,722 19,065 Unvested restricted stock and RSUs 7,715 8,524 Shares issuable pursuant to the ESPP 141 228 Total 36,520 47,534

Income Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The computation of the provision for (benefit from) income taxes for interim periods is determined by applying the estimated annual effective tax rate to year-to-date earnings from recurring operations and adjusting for discrete tax items recorded in the period. The Company's ability to estimate the geographic mix of earnings is impacted by the relatively high-growth nature of the business, fluctuations of business operations by country, and implementation of tax planning strategies. The Company recorded an income tax benefit of $3.1 million and $3.5 million f or the three months ended September 30, 2021 and 2020, respectively, and an income tax benefit $8.2 million and $5.8 million for the nine months ended September 30, 2021 and 2020, respectively. The benefit from income taxes of $3.1 million for the three months ended September 30, 2021 was primarily related to the excess tax benefits from stock-based compensation deductions in the United Kingdom, offset by withholding taxes in the U.S. and income tax expense from profitable foreign jurisdictions. The benefit from income taxes of $3.5 million for the three months ended September 30, 2020 was primarily related to excess tax benefits from stock-based compensation deductions in the United Kingdom, offset by withholding taxes in the U.S. and income tax expense from profitable foreign jurisdictions. The benefit from income taxes of $8.2 million for the nine months ended September 30, 2021 was primarily related to the excess tax benefits from stock-based compensation deductions and the remeasurement of deferred tax assets from an enacted tax rate change in the United Kingdom, offset by withholding taxes in the U.S. and income tax expense from profitable foreign jurisdictions. The benefit from income taxes of $5.8 million for the nine months ended September 30, 2020 was primarily related to the partial release of the U.S. valuation allowance in connection with the acquisition of S2 and excess tax benefit from stock-based compensation deductions in the United Kingdom, offset by withholding taxes in the U.S. and income tax expense from profitable foreign jurisdictions.

Business Combinations

Business Combinations	9 Months Ended
Business Combinations	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Business Combinations	Business Combinations In January 2020, the Company acquired all of the outstanding shares of S2, a company based in Kirkland, Washington that has developed browser isolation technology, for a total purchase consideration of $17.7 million. The Company is incorporating S2's technology into the Company's Cloudflare Gateway product. The total purchase consideration included (i) acquisition-date cash payments of $13.7 million, net of $0.1 million of cash acquired, (ii) $1.8 million in shares of the Company’s Class A common stock, and (iii) a cash holdback of $2.2 million, which the Company is retaining for up to 18 months and will be payable to the previous owners of S2, subject to offset by the Company for any of the previous owners’ indemnification obligations in connection with the acquisition. Such cash holdback was paid in full during the three months ended September 30, 2021. Concurrent with the closing of the acquisition, the Company made a cash payment of $6.9 million to repay S2’s debt, which was part of the acquisition-date cash payments included in the purchase consideration. In connection with the acquisition, the Company entered into compensation arrangements for stock-based and cash awards with a value totaling $20.3 million, of which $1.4 million and $10.0 million were recognized as total compensation expense during the three and nine months ended September 30, 2020, respectively. The Company recorded an additional $1.4 million and $4.2 million of compensation expense during the three and nine months ended September 30, 2021, respectively. The remaining compensation amount of $4.7 million is being recognized over a future weighted-average period of 1.5 years subject to the recipients’ continued service with the Company. The fair values of assets acquired and liabilities assumed on the acquisition date are summarized as follows (in thousands): Prepaid expenses and other current assets $ 6 Developed technology 5,600 Goodwill 13,084 Total assets acquired 18,690 Accrued expenses and other current liabilities (208) Other noncurrent liabilities (782) Total purchase price $ 17,700 A note payable of $0.2 million, included in accrued expenses and other current liabilities in the table above, assumed on the acquisition date, was paid off during the fiscal year ended December 31, 2020. The acquired assets and assumed liabilities were recorded at their estimated fair values. The estimated useful life for the acquired developed technology is two years. The excess of the purchase price over the fair value of the net assets acquired was allocated to goodwill, none of which is expected to be deductible for tax purposes. Goodwill is primarily attributable to the assembled workforce as well as the anticipated synergies from the integration of S2's technology with the Company's technology. A purchase accounting adjustment of $0.8 million to revise purchase consideration and goodwill was made during the fiscal year ended December 31, 2020. This acquisition did not have a material impact on the Company’s condensed consolidated financial statements; therefore, historical and pro forma disclosures have not been presented.

Segment and Geographic Informat

Segment and Geographic Information	9 Months Ended
Segment and Geographic Information	Sep. 30, 2021
Segment Reporting [Abstract]
Segment and Geographic Information	Segment and Geographic Information The Company’s chief operating decision maker (CODM) is its CEO, President and COO, and CFO. Collectively, the CODM reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. The Company has no segment managers who are held accountable by the CODM for operations, operating results, and planning for levels or components below the consolidated unit level. Accordingly, the Company has determined it has a single operating segment. Refer to Note 3 to these condensed consolidated financial statements for revenue by geography. The Company’s property and equipment, net, by geographic area were as follows: September 30, 2021 December 31, 2020 (in thousands) United States $ 118,750 $ 79,078 Rest of the world 57,806 44,610 Total property and equipment, net $ 176,556 $ 123,688 No single country other than the United States accounted for more than 10% of total property and equipment, net as of September 30, 2021 and December 31, 2020.

Subsequent Events

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn October 15, 2021, the Company acquired a company that has developed a server-side rendering technology for approximately $12.8 million. The purchase accounting for this acquisition is in progress.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation and Principles of ConsolidationThe accompanying interim condensed consolidated financial statements and accompanying notes have been prepared in conformity with generally accepted accounting principles in the United States (U.S. GAAP) and applicable regulations of the Securities and Exchange Commission (the SEC) regarding interim financial reporting, and include the accounts of the Company and its wholly-owned subsidiaries. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the applicable required disclosures and regulations of the SEC. Therefore, these unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020 .
Principles of Consolidation	All intercompany balances and transactions have been eliminated in consolidation.
Fiscal Period	The Company’s fiscal year ends on December 31.
Use of Estimates	Use of EstimatesThe preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed in the condensed consolidated financial statements and accompanying notes to the condensed consolidated financial statements. Such estimates include, but are not limited to, allowance for doubtful accounts, deferred contract acquisitions costs, the period of benefit generated from the Company’s deferred contract acquisition costs, the capitalization and estimated useful life of internal-use software, the assessment of recoverability of intangible assets and their estimated useful lives, useful lives of property and equipment, liability and equity allocation of convertible senior notes, the determination of the incremental borrowing rate used for operating lease liabilities, the valuation and recognition of stock-based compensation expense, uncertain tax positions, and the recognition and measurement of current and deferred income tax assets and liabilities. Management bases these estimates and assumptions on historical experience and on various other assumptions that are believed to be reasonable. Due to the COVID-19 pandemic, there is ongoing uncertainty and significant disruption in the global economy and financial markets. The Company is not aware of any specific event or circumstance that would require an update to its estimates or assumptions or a revision of the carrying value of its assets or liabilities as of November 5, 2021, the date of issuance of this Quarterly Report on Form 10-Q. These estimates and assumptions may change in the future, however, as new events occur and additional information is obtained. Actual results could differ materially from these estimates.
Convertible Senior Notes	Convertible Senior Notes The Company accounts for its 0.75% Convertible Senior Notes due 2025 (the 2025 Notes) and its 0.00% Convertible Senior Notes due 2026 (the 2026 Notes and together with the 2025 Notes, the Notes) as separate liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component, representing the conversion option, was calculated by deducting the fair value of the liability component from the total principal of the Notes. The excess of the principal amount of the liability component over its book value (debt discount) is amortized to interest expense over the term of the Notes. In accounting for the issuance costs related to the Notes, the allocation of issuance costs incurred between the liability and equity components was based on their relative values. Issuance costs attributable to the liability component are being amortized over the contractual term of the Notes. Transactions involving contemporaneous exchanges of cash between the same debtor and creditor in connection with the issuance of a new debt obligation and satisfaction of an existing debt obligation by the debtor should be evaluated for an exchange transaction if the exchange is determined to have substantially different terms. For exchange transactions that are considered an extinguishment of debt, the total consideration for such an exchange is separated into liability and equity components by estimating the fair value of a similar liability without a conversion option and assigning the residual value to the equity component. The gain or loss on extinguishment of the debt is subsequently determined by comparing repurchase consideration allocated to the liability component to the sum of the carrying value of the liability component, net of the proportionate amounts of unamortized debt discount and remaining unamortized debt issuance costs.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Issued Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (ASC 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (ASC 815-40). The FASB issued this ASU to simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity's own equity. The Company does not have any contracts on its own equity; however, the Company does have convertible debt. This ASU removes the separation models for 1) convertible debt with a cash conversion feature and 2) convertible instruments with a beneficial conversion feature, as well as enhances the related disclosure and earnings per share guidance. Additionally, this update requires that convertible
Reclassification of prior year presentation	Reclassification of prior year presentation Certain prior year amounts have been reclassified for consistency with the current year presentation. Specifically, Accrued compensation is now presented as a separate line item on the condensed consolidated balance sheets and was previously included within Accrued expense and other current liabilities.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
Revenue (Tables)	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table summarizes the revenue by region based on the billing address of customers who use the Company’s products: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Amount Percentage Amount Percentage Amount Percentage Amount Percentage United States $ 90,734 53 % $ 59,277 52 % $ 241,900 52 % $ 151,970 50 % Europe, Middle East, and Africa 45,264 26 % 27,943 25 % 120,492 26 % 76,961 25 % Asia Pacific 24,519 14 % 19,634 17 % 70,239 15 % 55,827 18 % Other 11,830 7 % 7,308 6 % 30,199 7 % 20,375 7 % Total $ 172,347 100 % $ 114,162 100 % $ 462,830 100 % $ 305,133 100 % The following table summarizes the revenue from contracts by type of customer: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Amount Percentage Amount Percentage Amount Percentage Amount Percentage Channel partners $ 19,527 11 % $ 12,159 11 % $ 51,761 11 % $ 31,471 10 % Direct customers 152,820 89 % 102,003 89 % 411,069 89 % 273,662 90 % Total $ 172,347 100 % $ 114,162 100 % $ 462,830 100 % $ 305,133 100 %
Schedule of Deferred Contract Acquisition Costs	The following table summarizes the activity of the deferred contract acquisition costs: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Beginning balance $ 56,587 $ 33,880 $ 44,176 $ 25,184 Capitalization of contract acquisition costs 12,793 8,457 38,119 24,615 Amortization of deferred contract acquisition costs (7,773) (4,623) (20,688) (12,085) Ending balance $ 61,607 $ 37,714 $ 61,607 $ 37,714

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Fair Value by Significant Investment Category	The following table summarizes the Company’s cash and available-for-sale securities’ amortized cost, unrealized gains (losses), and fair value by significant investment category reported as cash and cash equivalents, restricted cash, or available-for-sale securities as of September 30, 2021 and December 31, 2020. (in thousands) Reported as: September 30, 2021 Amortized Unrealized Unrealized Fair Value Cash & Available-for-sale securities Restricted Cash $ 74,429 $ — $ — $ 74,429 $ 73,958 $ — $ 471 Level I: Money market funds 550,933 — — 550,933 544,273 — 6,660 Level II: Corporate bonds 171,027 8 (36) 170,999 — 170,998 — U.S. treasury securities 746,873 45 (151) 746,767 — 746,767 — U.S. government agency securities 3,001 — — 3,001 — 3,001 — Commercial paper 274,880 — — 274,880 — 274,880 — Subtotal 1,195,781 53 (187) 1,195,647 — 1,195,646 — Total assets measured at fair value on a recurring basis $ 1,821,143 $ 53 $ (187) $ 1,821,009 $ 618,231 $ 1,195,646 $ 7,131 (in thousands) Reported as: December 31, 2020 Amortized Unrealized Unrealized Fair Cash & Available-for-sale securities Restricted Cash $ 22,114 $ — $ — $ 22,114 $ 19,523 $ — $ 2,591 Level I: Money market funds 71,038 — — 71,038 64,378 — 6,660 Level II: Corporate bonds 169,324 43 (26) 169,341 — 169,341 — U.S. treasury securities 576,652 223 (4) 576,871 — 576,871 — U.S. government agency securities 15,617 4 (1) 15,620 — 15,620 — Commercial paper 186,363 — — 186,363 24,994 161,369 — Subtotal 947,956 270 (31) 948,195 24,994 923,201 — Total assets measured at fair value on a recurring basis $ 1,041,108 $ 270 $ (31) $ 1,041,347 $ 108,895 $ 923,201 $ 9,251

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
Balance Sheet Components (Tables)	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following: September 30, 2021 December 31, 2020 (in thousands) Property and equipment: Servers—network infrastructure $ 144,253 $ 108,988 Construction in progress 43,662 11,242 Capitalized internal-use software 64,559 49,618 Office and computer equipment 23,803 17,867 Office furniture 6,503 5,657 Software 4,253 1,808 Leasehold improvements 12,148 10,686 Asset retirement obligation 430 430 Gross property and equipment 299,611 206,296 Less accumulated depreciation and amortization (123,055) (82,608) Total property and equipment, net $ 176,556 $ 123,688
Schedule of Acquired Intangible Assets, Net	Acquired intangible assets, net consisted of the following: September 30, 2021 Gross Carrying Accumulated Net Book (in thousands) Developed technology $ 5,600 $ 4,900 $ 700 Total acquired intangible assets, net $ 5,600 $ 4,900 $ 700 December 31, 2020 Gross Carrying Accumulated Net Book (in thousands) Developed technology $ 5,600 $ 2,800 $ 2,800 Total acquired intangible assets, net $ 5,600 $ 2,800 $ 2,800
Schedule of Estimated Future Amortization Expense of Acquired Intangible Assets	As of September 30, 2021, the estimated future amortization expense of acquired intangible assets was as follows: Estimated (in thousands) Year ending December 31, 2021 (remaining three months) $ 700 Total $ 700

Leases (Tables)

Leases (Tables)	9 Months Ended
Leases (Tables)	Sep. 30, 2021
Leases [Abstract]
Schedule of Lease Costs	The components of lease cost related to the Company's operating leases included in the condensed consolidated statements of operations were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Operating lease cost $ 6,736 $ 4,802 $ 17,740 $ 14,134 Sublease income — (694) (1,096) (2,111) Total lease cost $ 6,736 $ 4,108 $ 16,644 $ 12,023
Schedule of Lease Liability Maturities	Maturities of the operating lease liabilities as of September 30, 2021 are as follows: September 30, 2021 (in thousands) 2021 (remaining three months) $ 7,024 2022 23,435 2023 19,003 2024 17,275 2025 10,972 Thereafter 41,190 Total lease payments $ 118,899 Less: Imputed interest $ (14,336) Total operating lease liabilities $ 104,563

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	9 Months Ended
Convertible Senior Notes (Tables)	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Convertible Debt	The net carrying amount of the liability component of the 2026 Notes was as follows: September 30, 2021 (in thousands) Principal $ 1,293,750 Unamortized debt discount (260,150) Unamortized debt issuance costs (15,327) Carrying amount of the liability component, net $ 1,018,273 The net carrying amount of the equity component of the 2026 Notes was as follows: September 30, 2021 (in thousands) Proceeds allocated to the conversion option (debt discount) $ 266,150 Less: allocated issuance costs (4,073) Carrying amount of the equity component, net $ 262,077 The net carrying amount of the liability component of the 2025 Notes was as follows: September 30, 2021 December 31, 2020 (in thousands) Principal $ 175,000 $ 575,000 Unamortized debt discount (48,187) (184,674) Unamortized debt issuance costs (1,778) (7,051) Carrying amount of the liability component, net $ 125,035 $ 383,275 The net carrying amount of the equity component of the 2025 Notes was as follows: September 30, 2021 December 31, 2020 (in thousands) Proceeds allocated to the conversion option (debt discount) $ 62,480 $ 205,290 Less: allocated issuance costs (1,363) (4,478) Carrying amount of the equity component, net $ 61,117 $ 200,812
Schedule of Interest Expense	The following table sets forth total interest expense recognized related to the 2026 Notes: Three Months Ended September 30, Nine Months Ended September 30, 2021 2021 (in thousands) Coupon interest expense $ — $ — Amortization of debt discount 6,000 6,000 Amortization of debt issuance costs 397 397 Total $ 6,397 $ 6,397 The following table sets forth total interest expense recognized related to the 2025 Notes: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Coupon interest expense $ 678 $ 1,078 $ 2,834 $ 1,629 Amortization of debt discount 5,682 8,159 23,029 12,256 Amortization of debt issuance costs 255 403 1,062 609 Total $ 6,615 $ 9,640 $ 26,925 $ 14,494

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
Commitments and Contingencies (Tables)	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Purchase Commitments	Refer to the table below for long-term bandwidth and co-location commitments under non-cancelable contracts with various networks and Internet service providers as of September 30, 2021. For the lease components of co-location agreements, refer to Note 6 to these condensed consolidated financial statements. Payments Due by Period as of September 30, 2021 Total 2021 (remaining three months) 2022 2023 2024 2025 Thereafter (in thousands) Non-cancelable: Open purchase agreements (1) $ 25,394 $ 5,219 $ 8,019 $ 5,754 $ 1,374 $ 752 $ 4,276 Bandwidth and other co-location related commitments (2) 52,677 6,738 21,741 9,377 5,614 4,395 4,812 Total $ 78,071 $ 11,957 $ 29,760 $ 15,131 $ 6,988 $ 5,147 $ 9,088 (1) Open purchase commitments are for the purchase of services under non-cancelable contracts. They were not recorded as liabilities on the condensed consolidated balance sheet as of September 30, 2021 as the Company had not yet received the related services. (2) Long-term commitments for bandwidth usage and other co-location related commitments with various networks and Internet service providers. The costs for services not yet received were not recorded as liabilities on the condensed consolidated balance sheet as of September 30, 2021.

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended
Common Stock (Tables)	Sep. 30, 2021
Equity [Abstract]
Schedule of Common Stock Reserved for Future Issuance	Shares of common stock reserved for future issuance, on an as-if converted basis, are as follows: September 30, 2021 December 31, 2020 (in thousands) 2025 Notes 6,078 19,972 2026 Notes 10,311 — Stock options issued and outstanding 14,722 18,186 Remaining shares available for issuance under the 2019 Plan 39,085 24,539 Outstanding and unsettled restricted stock units (RSUs) 7,715 7,808 Shares available for issuance under the ESPP 8,186 5,230 Total shares of common stock reserved 86,097 75,735

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
Stock-based Compensation (Tables)	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Stock-based Awards	The following table summarizes the stock options activity under the 2010 Plan and 2019 Plan for the nine months ended September 30, 2021: Stock Options Outstanding (in thousands, except year and per share data) Shares Subject to Options Outstanding Weighted- Average Exercise Price per Option Weighted- Average Remaining Contractual Terms (in years) Aggregate Intrinsic Value Balances as of December 31, 2020 18,186 $ 3.92 7.0 $ 1,310,650 Options granted — $ — Options exercised (3,307) $ 5.11 $ 288,298 Options canceled/forfeited/expired (157) $ 2.71 Balances as of September 30, 2021 14,722 $ 3.66 6.2 $ 1,604,528 Vested and expected to vest as of September 30, 2021 14,722 $ 3.66 6.2 $ 1,604,516 Exercisable as of September 30, 2021 13,658 $ 2.55 6.0 $ 1,503,760
Schedule of Assumptions Used to Determine the Fair Value of Stock Options Granted	The weighted-average assumptions used to determine the fair value of stock options granted during the nine months ended September 30, 2020 were as follows: Nine months ended September 30, 2020 Expected term (in years) 6.0 Expected volatility 40.3 % Risk-free interest rate 0.7 % Dividend yield —
Schedule of Restricted Stock Units Activity	RSU and restricted stock activity for the nine months ended September 30, 2021 was as follows: Restricted Stock and RSUs Weighted-Average (in thousands, except per share data) Unvested and outstanding as of December 31, 2020 8,629 $ 21.38 Granted - RSUs 1,683 $ 91.54 Granted - Restricted stock — $ — Vested - RSUs (2,052) $ 19.26 Vested - Restricted stock — $ — Forfeited (545) $ 28.80 Unvested as of September 30, 2021 7,715 $ 37.14 Vested and not yet released — $ — Outstanding as of September 30, 2021 7,715 $ 37.14
Schedule of Fair Value Assumptions for Employee Stock Purchase Plan	The weighted-average assumptions used to determine the fair value of the ESPP during the periods presented were as follows: Nine months ended September 30, 2021 2020 Expected term (in years) 0.5 0.5 Risk-free interest rate 0.04 % 0.15 % Expected volatility 65.6 % 65.20 % Dividend yield — % — %
Schedule of Stock-based Compensation Expense	The following table sets forth the total stock-based compensation expense included in the Company’s condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Cost of revenue $ 672 $ 311 $ 1,665 $ 858 Sales and marketing 6,983 4,406 19,236 11,177 Research and development 11,389 6,749 29,262 18,213 General and administrative 4,005 3,279 11,475 9,843 Total stock-based compensation expense $ 23,049 $ 14,745 $ 61,638 $ 40,091

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Class A Class B Class A Class B Class A Class B Class A Class B (in thousands, except per share data) Net loss attributable to common stockholders $ (91,665) $ (15,670) $ (18,119) $ (8,349) $ (153,359) $ (29,449) $ (45,059) $ (40,290) Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 268,621 45,922 206,528 95,161 259,741 49,877 157,656 140,972 Net loss per share attributable to common stockholders, basic and diluted $ (0.34) $ (0.34) $ (0.09) $ (0.09) $ (0.59) $ (0.59) $ (0.29) $ (0.29)
Schedule of Potential Shares of Common Stock Excluded from Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders	The potential shares of common stock that were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive are as follows: September 30, 2021 2020 (in thousands) 2025 Notes 4,676 15,363 2026 Notes 6,761 — Shares subject to repurchase 2,505 4,354 Unexercised stock options 14,722 19,065 Unvested restricted stock and RSUs 7,715 8,524 Shares issuable pursuant to the ESPP 141 228 Total 36,520 47,534

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
Business Combinations (Tables)	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Schedule of Assets Acquired and Liabilities Assumed	The fair values of assets acquired and liabilities assumed on the acquisition date are summarized as follows (in thousands): Prepaid expenses and other current assets $ 6 Developed technology 5,600 Goodwill 13,084 Total assets acquired 18,690 Accrued expenses and other current liabilities (208) Other noncurrent liabilities (782) Total purchase price $ 17,700

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	9 Months Ended
Segment and Geographic Information (Tables)	Sep. 30, 2021
Segment Reporting [Abstract]
Schedule of Property and Equipment, Net by Geographic Area	The Company’s property and equipment, net, by geographic area were as follows: September 30, 2021 December 31, 2020 (in thousands) United States $ 118,750 $ 79,078 Rest of the world 57,806 44,610 Total property and equipment, net $ 176,556 $ 123,688

Organization and Basis of Pre_2

Organization and Basis of Presentation (Details) $ in Millions	1 Months Ended
	Sep. 30, 2019USD ($)
Class A common stock \| Initial Public Offering
Class of Stock [Line Items]
Aggregate proceeds received from initial public offering, net of underwriters' discounts and commissions	$ 565

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - Convertible Debt	Sep. 30, 2021	Aug. 31, 2021	May 31, 2020
2026 Notes
Debt Instrument [Line Items]
Interest rate	0.00%	0.00%
2025 Notes
Debt Instrument [Line Items]
Interest rate	0.75%		0.75%

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 172,347	$ 114,162	$ 462,830	$ 305,133
Geographic Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	100.00%	100.00%	100.00%	100.00%
Sales Channel Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	100.00%	100.00%	100.00%	100.00%
Channel partners
Disaggregation of Revenue [Line Items]
Revenue	$ 19,527	$ 12,159	$ 51,761	$ 31,471
Channel partners \| Sales Channel Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	11.00%	11.00%	11.00%	10.00%
Direct customers
Disaggregation of Revenue [Line Items]
Revenue	$ 152,820	$ 102,003	$ 411,069	$ 273,662
Direct customers \| Sales Channel Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	89.00%	89.00%	89.00%	90.00%
United States
Disaggregation of Revenue [Line Items]
Revenue	$ 90,734	$ 59,277	$ 241,900	$ 151,970
United States \| Geographic Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	53.00%	52.00%	52.00%	50.00%
Europe, Middle East, and Africa
Disaggregation of Revenue [Line Items]
Revenue	$ 45,264	$ 27,943	$ 120,492	$ 76,961
Europe, Middle East, and Africa \| Geographic Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	26.00%	25.00%	26.00%	25.00%
Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue	$ 24,519	$ 19,634	$ 70,239	$ 55,827
Asia Pacific \| Geographic Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	14.00%	17.00%	15.00%	18.00%
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 11,830	$ 7,308	$ 30,199	$ 20,375
Other \| Geographic Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
Percentage of Revenue	7.00%	6.00%	7.00%	7.00%

Revenue - Narratives (Details)

Revenue - Narratives (Details) - USD ($) $ in Millions	9 Months Ended
Revenue - Narratives (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue recognized	$ 52.7	$ 30.1

Revenue - Deferred Contract Acq

Revenue - Deferred Contract Acquisition Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Capitalized Contract Cost [Roll Forward]
Beginning balance	$ 56,587	$ 33,880	$ 44,176	$ 25,184
Capitalization of contract acquisition costs	12,793	8,457	38,119	24,615
Amortization of deferred contract acquisition costs	(7,773)	(4,623)	(20,688)	(12,085)
Ending balance	$ 61,607	$ 37,714	$ 61,607	$ 37,714

Revenue - Remaining Performance

Revenue - Remaining Performance Obligations (Details) $ in Millions	Sep. 30, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligation, amount	$ 545.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, percent	75.00%
Remaining performance obligation, expected timing of satisfaction	12 months

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Cash and Available-for-sale Debt Securities' Amortized Cost, Unrealized Gains (Losses) and Fair Value by Significant Investment Category (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 618,231,000	$ 108,895,000
Amortized Cost	1,821,143,000	1,041,108,000
Unrealized Gain	53,000	270,000
Unrealized (Loss)	(187,000)	(31,000)
Fair Value	1,821,009,000	1,041,347,000
Cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	74,429,000	22,114,000
Unrealized Gain	0	0
Unrealized (Loss)	0	0
Fair Value	74,429,000	22,114,000
Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrealized Gain	0	0
Unrealized (Loss)	0	0
Level I \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	550,933,000	71,038,000
Unrealized Gain	0	0
Unrealized (Loss)	0	0
Fair Value	550,933,000	71,038,000
Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	1,195,781,000	947,956,000
Unrealized Gain	53,000	270,000
Unrealized (Loss)	(187,000)	(31,000)
Fair Value	1,195,647,000	948,195,000
Level II \| Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	171,027,000	169,324,000
Unrealized Gain	8,000	43,000
Unrealized (Loss)	(36,000)	(26,000)
Fair Value	170,999,000	169,341,000
Level II \| U.S. treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	746,873,000	576,652,000
Unrealized Gain	45,000	223,000
Unrealized (Loss)	(151,000)	(4,000)
Fair Value	746,767,000	576,871,000
Level II \| U.S. government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	3,001,000	15,617,000
Unrealized Gain	0	4,000
Unrealized (Loss)	0	(1,000)
Fair Value	3,001,000	15,620,000
Level II \| Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	274,880,000	186,363,000
Unrealized Gain	0	0
Unrealized (Loss)	0	0
Fair Value	274,880,000	186,363,000
Cash & Cash Equivalents \| Fair Value, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets measured at fair value on a recurring basis	618,231,000	108,895,000
Cash & Cash Equivalents \| Fair Value, Recurring \| Cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	73,958,000	19,523,000
Cash & Cash Equivalents \| Fair Value, Recurring \| Level I \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	544,273,000	64,378,000
Cash & Cash Equivalents \| Fair Value, Recurring \| Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	24,994,000
Cash & Cash Equivalents \| Fair Value, Recurring \| Level II \| Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Cash & Cash Equivalents \| Fair Value, Recurring \| Level II \| U.S. treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Cash & Cash Equivalents \| Fair Value, Recurring \| Level II \| U.S. government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Cash & Cash Equivalents \| Fair Value, Recurring \| Level II \| Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	24,994,000
Available-for-sale securities \| Fair Value, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	1,195,646,000	923,201,000
Available-for-sale securities \| Fair Value, Recurring \| Cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Available-for-sale securities \| Fair Value, Recurring \| Level I \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Available-for-sale securities \| Fair Value, Recurring \| Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	1,195,646,000	923,201,000
Available-for-sale securities \| Fair Value, Recurring \| Level II \| Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	170,998,000	169,341,000
Available-for-sale securities \| Fair Value, Recurring \| Level II \| U.S. treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	746,767,000	576,871,000
Available-for-sale securities \| Fair Value, Recurring \| Level II \| U.S. government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	3,001,000	15,620,000
Available-for-sale securities \| Fair Value, Recurring \| Level II \| Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	274,880,000	161,369,000
Restricted Cash \| Fair Value, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets measured at fair value on a recurring basis	7,131,000	9,251,000
Restricted Cash \| Fair Value, Recurring \| Cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	471,000	2,591,000
Restricted Cash \| Fair Value, Recurring \| Level I \| Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	6,660,000	6,660,000
Restricted Cash \| Fair Value, Recurring \| Level II
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Restricted Cash \| Fair Value, Recurring \| Level II \| Corporate bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Restricted Cash \| Fair Value, Recurring \| Level II \| U.S. treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Restricted Cash \| Fair Value, Recurring \| Level II \| U.S. government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Restricted Cash \| Fair Value, Recurring \| Level II \| Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narratives (Details) - USD ($)	Sep. 30, 2021	Aug. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted cash	$ 6,660,000		$ 6,660,000
Amortized cost of available-for-sale investments with maturities less than one year	723,800,000		866,500,000
Amortized cost of available-for-sale investments with maturities greater than one year	472,000,000		56,500,000
Net unrealized gains (loss) on investments, net of tax	(200,000)		200,000
Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 529,800,000
Convertible Debt \| 2026 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate	0.00%	0.00%
Debt instrument, fair value	$ 1,243,600,000
Money market funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrealized gain	0		0
Unrealized (loss)	$ 0		$ 0

Balance Sheet Components - Acco

Balance Sheet Components - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Allowance for doubtful accounts	$ 2,400		$ 2,400		$ 1,700
Bad debt expense	900	$ 300	2,911	$ 2,794
Write-off of uncollectible accounts receivable	$ 900	$ 400	$ 2,200	$ 1,900

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 299,611		$ 299,611		$ 206,296
Less accumulated depreciation and amortization	(123,055)		(123,055)		(82,608)
Total property and equipment, net	176,556		176,556		123,688
Depreciation and amortization expense	16,100	$ 12,100	45,200	$ 32,800
Servers—network infrastructure
Property, Plant and Equipment [Line Items]
Gross property and equipment	144,253		144,253		108,988
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property and equipment	43,662		43,662		11,242
Capitalized internal-use software
Property, Plant and Equipment [Line Items]
Gross property and equipment	64,559		64,559		49,618
Depreciation and amortization expense			13,300	$ 8,700
Office and computer equipment
Property, Plant and Equipment [Line Items]
Gross property and equipment	23,803		23,803		17,867
Office furniture
Property, Plant and Equipment [Line Items]
Gross property and equipment	6,503		6,503		5,657
Software
Property, Plant and Equipment [Line Items]
Gross property and equipment	4,253		4,253		1,808
Depreciation and amortization expense	4,500	$ 3,400
Leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property and equipment	12,148		12,148		10,686
Asset retirement obligation
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 430		$ 430		$ 430

Balance Sheet Components - Good

Balance Sheet Components - Goodwill (Details) - USD ($)	9 Months Ended
Balance Sheet Components - Goodwill (Details) - USD ($)	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Goodwill	$ 17,167,000		$ 17,167,000
Goodwill, impairment loss	$ 0	$ 0

Balance Sheet Components - Acqu

Balance Sheet Components - Acquired Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 5,600		$ 5,600		$ 5,600
Accumulated Amortization	4,900		4,900		2,800
Net Book Value	700		700		2,800
Amortization of acquired intangible assets	700	$ 700	2,100	$ 2,100
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,600		5,600		5,600
Accumulated Amortization	4,900		4,900		2,800
Net Book Value	$ 700		$ 700		$ 2,800

Balance Sheet Components - Esti

Balance Sheet Components - Estimated Future Amortization Expense of Acquired Intangible Assets, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
2021 (remaining three months)	$ 700
Net Book Value	$ 700	$ 2,800

Leases - Narratives (Details)

Leases - Narratives (Details) $ in Thousands	Jul. 06, 2021USD ($)ft²option	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)
Lessee, Lease, Description [Line Items]
Remaining lease term (up to)		9 years 9 months 18 days		9 years 9 months 18 days
Operating lease liability		$ 104,563		$ 104,563
Additional undiscounted cash payment		26,800		26,800
Sublease income		0	$ 694	1,096	$ 2,111
Lease not yet commenced, undiscounted amount		$ 28,800		$ 28,800
Lease not yet commenced, term of contract		4 years 1 month 6 days		4 years 1 month 6 days
Weighted average remaining lease term		6 years 2 months 12 days		6 years 2 months 12 days
Operating lease, weighted average discount rate, percent		3.50%		3.50%
Austin Lease
Lessee, Lease, Description [Line Items]
Operating lease liability	$ 46,200
Building
Lessee, Lease, Description [Line Items]
Area of office space \| ft²	128,195
Lease term	121 months
Number of renewal options \| option	2
Renewal term	5 years
Market rate (in percent)	100.00%
Co-location Asset Lease
Lessee, Lease, Description [Line Items]
Remaining lease term (up to)		6 years 7 months 6 days		6 years 7 months 6 days

Leases - Schedule of Lease Cost

Leases - Schedule of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 6,736	$ 4,802	$ 17,740	$ 14,134
Sublease income	0	(694)	(1,096)	(2,111)
Total lease cost	$ 6,736	$ 4,108	$ 16,644	$ 12,023

Leases - Lease Liability Maturi

Leases - Lease Liability Maturities (Details) $ in Thousands	Sep. 30, 2021USD ($)
Leases [Abstract]
2021 (remaining three months)	$ 7,024
2022	23,435
2023	19,003
2024	17,275
2025	10,972
Thereafter	41,190
Total lease payments	118,899
Less: Imputed interest	(14,336)
Total operating lease liabilities	$ 104,563

Convertible Senior Notes - Narr

Convertible Senior Notes - Narratives (Details)	Aug. 30, 2021$ / sharesshares	Aug. 13, 2021USD ($)shares	May 31, 2020USD ($)$ / sharesshares	Aug. 31, 2021USD ($)day$ / shares	May 31, 2020USD ($)day$ / sharesshares	Sep. 30, 2021USD ($)$ / shares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)$ / shares	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Gross proceeds from issuance of convertible senior notes								$ 1,293,750,000	$ 575,000,000
Closing share price (in dollars per share) \| $ / shares						$ 112.65		$ 112.65
Purchases of capped calls related to convertible senior notes						$ 86,293,000		$ 86,293,000	67,333,000
Repayments of convertible debt								370,647,000	0
Loss on extinguishment of debt						72,234,000	$ 0	$ 72,234,000	$ 0
2026 Notes
Debt Instrument [Line Items]
Convertible debt, equity component				$ 266,200,000
2025 Notes
Debt Instrument [Line Items]
Gross proceeds from issuance of convertible senior notes					$ 562,500,000
Conversion price (in dollars per share) \| $ / shares			$ 37.43		$ 37.43
Convertible debt, equity component			$ 205,300,000		$ 205,300,000
Remaining life, convertible debt								44 months
Convertible Debt
Debt Instrument [Line Items]
Debt instrument, fair value						$ 529,800,000		$ 529,800,000
Convertible Debt \| 2026 Notes
Debt Instrument [Line Items]
Debt principal amount				1,293,800,000
Face amount, additional principal issuable				168,800,000
Gross proceeds from issuance of convertible senior notes				$ 1,274,000,000
Interest rate				0.00%		0.00%		0.00%
Convertible debt, conversion ratio								0.0052263
Conversion price (in dollars per share) \| $ / shares				$ 191.34
Redemption price, percentage				100.00%
Minimum redeemable face amount				$ 100,000,000
Principal				1,027,600,000		$ 1,293,750,000		$ 1,293,750,000
Convertible debt, equity component						262,077,000		$ 262,077,000
Issuance cost, liability component				15,700,000
Issuance cost, equity component				$ 4,100,000
Remaining life, convertible debt								59 months
Purchases of capped calls related to convertible senior notes		$ 86,300,000
Debt instrument, fair value						1,243,600,000		$ 1,243,600,000
Amount outstanding						1,018,273,000		1,018,273,000
Proceeds allocated to the conversion option (debt discount)						$ 266,150,000		$ 266,150,000
Convertible Debt \| 2025 Notes
Debt Instrument [Line Items]
Debt principal amount			575,000,000		575,000,000
Face amount, additional principal issuable			$ 75,000,000		$ 75,000,000
Interest rate			0.75%		0.75%	0.75%		0.75%
Convertible debt, conversion ratio								0.0267187
Redemption price, percentage					100.00%
Principal			$ 175,000,000		$ 175,000,000	$ 175,000,000		$ 175,000,000		$ 575,000,000
Convertible debt, equity component						61,117,000		61,117,000		200,812,000
Issuance cost, liability component			$ 8,000,000		8,000,000
Issuance cost, equity component					$ 4,500,000
Purchases of capped calls related to convertible senior notes		67,300,000
Repurchased face amount		400,000,000
Repayments of convertible debt		400,700,000
Issuance of common stock for exchange of convertible senior notes		1,321,000,000
Loss on extinguishment of debt		72,200,000
Debt instrument, fair value		355,300,000
Amount outstanding		$ 283,100,000				125,035,000		125,035,000		383,275,000
Effective interest rate		4.08%
Proceeds allocated to the conversion option (debt discount)		$ 965,700,000				$ 62,480,000		62,480,000		$ 205,290,000
Converted value in excess of principal								$ 351,700,000
Convertible Debt \| Class A common stock \| 2026 Notes
Debt Instrument [Line Items]
Shares covered by capped calls (in shares) \| shares	6,800,000
Convertible Debt \| Class A common stock \| 2026 Notes \| Long \| Capped Calls
Debt Instrument [Line Items]
Strike price (in dollars per share) \| $ / shares	$ 191.34
Capped call, initial cap price (in dollars per share) \| $ / shares	$ 250.94
Convertible Debt \| Class A common stock \| 2025 Notes
Debt Instrument [Line Items]
Number of shares issued upon debt conversion \| shares		7,600,000
Convertible Debt \| Class A common stock \| 2025 Notes \| Long \| Capped Calls
Debt Instrument [Line Items]
Strike price (in dollars per share) \| $ / shares			$ 37.43
Shares covered by capped calls (in shares) \| shares			15,400,000		15,400,000
Capped call, initial cap price (in dollars per share) \| $ / shares			$ 57.58		$ 57.58
Measurement Input, Effective Interest Rate \| Convertible Debt \| 2026 Notes
Debt Instrument [Line Items]
Measurement input				0.0465
Measurement Input, Effective Interest Rate \| Convertible Debt \| 2025 Notes
Debt Instrument [Line Items]
Measurement input			0.100		0.100
Last Reported Stock Price At Lease 130% Of The Debt Conversion Price \| 2025 Notes
Debt Instrument [Line Items]
Conversion requirement, threshold trading days (at least) \| day					20
Conversion requirement, threshold consecutive trading days \| day					30
Conversion requirement, threshold percentage of stock price trigger (at least)					130.00%
Last Reported Stock Price At Lease 130% Of The Debt Conversion Price \| Convertible Debt \| 2026 Notes
Debt Instrument [Line Items]
Conversion requirement, threshold trading days (at least) \| day				20
Conversion requirement, threshold consecutive trading days \| day				30
Conversion requirement, threshold percentage of stock price trigger (at least)				130.00%
Principal Amount Less Than 98% of the Product \| 2025 Notes
Debt Instrument [Line Items]
Conversion requirement, threshold trading days (at least) \| day					5
Conversion requirement, threshold consecutive trading days \| day					5
Conversion requirement, threshold percentage of stock price trigger (at least)					98.00%
Principal Amount Less Than 98% of the Product \| Convertible Debt \| 2026 Notes
Debt Instrument [Line Items]
Conversion requirement, threshold trading days (at least) \| day				5
Conversion requirement, threshold consecutive trading days \| day				5
Conversion requirement, threshold percentage of stock price trigger (at least)				98.00%

Convertible Senior Notes - Liab

Convertible Senior Notes - Liability Component (Details) - Convertible Debt - USD ($) $ in Thousands	Sep. 30, 2021	Aug. 31, 2021	Aug. 13, 2021	Dec. 31, 2020	May 31, 2020
2026 Notes
Debt Instrument [Line Items]
Principal	$ 1,293,750	$ 1,027,600
Unamortized debt discount	(260,150)
Unamortized debt issuance costs	(15,327)
Carrying amount of the liability component, net	1,018,273
2025 Notes
Debt Instrument [Line Items]
Principal	175,000			$ 575,000	$ 175,000
Unamortized debt discount	(48,187)			(184,674)
Unamortized debt issuance costs	(1,778)			(7,051)
Carrying amount of the liability component, net	$ 125,035		$ 283,100	$ 383,275

Convertible Senior Notes - Equi

Convertible Senior Notes - Equity Component (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Aug. 31, 2021	Aug. 13, 2021	Dec. 31, 2020	May 31, 2020
2026 Notes
Debt Instrument [Line Items]
Carrying amount of the equity component, net		$ 266,200
2025 Notes
Debt Instrument [Line Items]
Carrying amount of the equity component, net					$ 205,300
Convertible Debt \| 2026 Notes
Debt Instrument [Line Items]
Proceeds allocated to the conversion option (debt discount)	$ 266,150
Less: allocated issuance costs	(4,073)
Carrying amount of the equity component, net	262,077
Convertible Debt \| 2025 Notes
Debt Instrument [Line Items]
Proceeds allocated to the conversion option (debt discount)	62,480		$ 965,700	$ 205,290
Less: allocated issuance costs	(1,363)			(4,478)
Carrying amount of the equity component, net	$ 61,117			$ 200,812

Convertible Senior Notes - Sche

Convertible Senior Notes - Schedule of Interest Components (Details) - Convertible Debt - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
2026 Notes
Debt Instrument [Line Items]
Coupon interest expense	$ 0		$ 0
Amortization of debt discount	6,000		6,000
Amortization of debt issuance costs	397		397
Total	6,397		6,397
2025 Notes
Debt Instrument [Line Items]
Coupon interest expense	678	$ 1,078	2,834	$ 1,629
Amortization of debt discount	5,682	8,159	23,029	12,256
Amortization of debt issuance costs	255	403	1,062	609
Total	$ 6,615	$ 9,640	$ 26,925	$ 14,494

Commitments and Contingencies -

Commitments and Contingencies - Narratives (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Cost and expenses related to bandwidth and other co-location commitments	$ 19.6	$ 13.5	$ 54.6	$ 36.6

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Purchase Commitments (Details) $ in Thousands	Sep. 30, 2021USD ($)
Open purchase agreements
Total payments due, open purchase agreements	$ 25,394
2021 (remaining three months)	5,219
2022	8,019
2023	5,754
2024	1,374
2025	752
Thereafter	4,276
Bandwidth and other co-location related commitments
Total payments due, bandwidth and co-location commitments	52,677
2021 (remaining six months)	6,738
2022	21,741
2023	9,377
2024	5,614
2025	4,395
Thereafter	4,812
Total
Total	78,071
2021 (remaining six months)	11,957
2022	29,760
2023	15,131
2024	6,988
2025	5,147
Thereafter	$ 9,088

Common Stock - Narratives (Deta

Common Stock - Narratives (Details)	Sep. 30, 2021vote$ / sharesshares	Dec. 31, 2020$ / sharesshares
Class A common stock
Class of Stock [Line Items]
Common stock, number of votes per share \| vote	1
Common stock, shares authorized (in shares)	2,250,000,000	2,250,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	273,574,792	249,401,232
Common stock, shares outstanding (in shares)	273,574,792	249,401,232
Class B common stock
Class of Stock [Line Items]
Common stock, number of votes per share \| vote	10
Common stock, shares authorized (in shares)	315,000,000	315,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	48,038,501	59,238,742
Common stock, shares outstanding (in shares)	48,038,501	59,238,742

Common Stock - Schedule of Comm

Common Stock - Schedule of Common Stock Reserved for Future Issuance (Details) - shares shares in Thousands	Sep. 30, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Shares of common stock reserved (in shares)	86,097	75,735
2019 Plan
Class of Stock [Line Items]
Shares of common stock reserved (in shares)	39,085	24,539
Stock options issued and outstanding
Class of Stock [Line Items]
Shares of common stock reserved (in shares)	14,722	18,186
Outstanding and unsettled restricted stock units (RSUs)
Class of Stock [Line Items]
Shares of common stock reserved (in shares)	7,715	7,808
Shares available for issuance under the ESPP
Class of Stock [Line Items]
Shares of common stock reserved (in shares)	8,186	5,230
Convertible Debt \| 2025 Notes
Class of Stock [Line Items]
Shares of common stock reserved (in shares)	6,078	19,972
Convertible Debt \| 2026 Notes
Class of Stock [Line Items]
Shares of common stock reserved (in shares)	10,311	0

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
Stock-based Compensation - Narrative (Details) - USD ($)	Sep. 30, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)		0		0
Total grant date fair value for vested options				$ 11,400,000	$ 5,500,000
Issuance of common stock in connection with acquisition (in shares)				948,000
Stock-based compensation expense		$ 23,049,000	$ 14,745,000	$ 61,638,000	$ 40,091,000
Class A common stock \| 2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance (in shares)		66,661,953		66,661,953
Number of new shares authorized for issuance (in shares)		29,335,000		29,335,000
Number of additional shares authorized for issuance (in shares)		37,326,953		37,326,953
Class A and Class B Common Stock \| 2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential increase in number of shares authorized, as a percentage of total common stock outstanding				5.00%
Stock options issued and outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value for options granted (in dollars per share)					$ 9.74
Unvested options exercisable (in shares)		7,259,920		7,259,920		10,765,894
Options unrecognized stock-based compensation expense		$ 13,700,000		$ 13,700,000		$ 20,600,000
Weighted-average remaining vesting period				2 years 1 month 6 days		2 years 7 months 6 days
Liability for early exercise of stock options		$ 5,500,000		$ 5,500,000		$ 8,600,000
Number of unvested shares expected to be repurchased (in shares)				2,505,209		3,871,772
Stock options issued and outstanding \| 2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Expiration period				10 years
Stock options issued and outstanding \| Common stock \| 2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of common stock, percentage of fair market value				100.00%
Stock options issued and outstanding \| Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise stock option awards (in shares)		1		1
Stock options issued and outstanding \| Class A common stock \| 2019 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise stock option awards (in shares)		1		1
Stock options issued and outstanding \| Class B common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise stock option awards (in shares)		1		1
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Weighted-average remaining vesting period				3 years 3 months 18 days		3 years 6 months
Number of shares vested during the period (in shares)				2,052,000
Stock-based compensation expense		$ 18,800,000	10,300,000	$ 48,500,000	$ 27,800,000
Unrecognized stock-based compensation expense		$ 231,700,000		231,700,000		$ 141,800,000
Total grant date fair value for vested shares				$ 39,500,000	19,600,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of restricted stock in connection with acquisition (in shares)				841,000
Number of shares vested during the period (in shares)		0		0
Restricted stock issued in connection with acquisition, aggregate grant date fair value					1,800,000
Stock-based compensation expense				$ 4,200,000	4,200,000
Unrecognized stock-based compensation expense		$ 4,600,000	$ 10,200,000	$ 4,600,000	$ 10,200,000
Restricted Stock \| Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				2 years
Vesting percentage				77.80%
Restricted Stock \| Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Shares available for issuance under the ESPP \| 2019 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average remaining vesting period				1 month 6 days
Unrecognized stock-based compensation expense		$ 900,000		$ 900,000		$ 2,000,000
Maximum ownership percentage threshold for participation	5.00%
Maximum contribution percentage per employee	10.00%
Shares available for issuance under the ESPP \| Class A common stock \| 2019 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares allowable under the plan (in shares)	5,870,000
Purchase price of common stock, percentage of fair value	85.00%
Offering period	6 months
Purchase period	6 months
Maximum number of shares available for repurchase for each employee (more than, in shares)	1,500
Maximum value of shares available for repurchase for each employee	$ 25,000
Number of shares repurchased (in shares)		0	0	130,870	421,300
Shares available for issuance under the ESPP \| Class A and Class B Common Stock \| 2019 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential increase in number of share authorized, as a percentage of total common stock outstanding	1.00%

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Stock-based Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Shares Subject to Options Outstanding
Stock options outstanding, beginning balance (in shares)		18,186,000
Stock options granted (in shares)	0	0
Stock options exercised (in shares)		(3,307,000)
Stock options canceled, forfeited, expired (in shares)		(157,000)
Stock options outstanding, ending balance (in shares)	14,722,000	14,722,000	18,186,000
Stock options vested and expected to vest (in shares)	14,722,000	14,722,000
Stock options exercisable (in shares)	13,658,000	13,658,000
Weighted- Average Exercise Price per Option
Stock options outstanding, weighted-average exercise price, beginning balance (in dollars per share)		$ 3.92
Stock options granted, weighted-average exercise price (in dollars per share)		0
Stock options exercised, weighted-average exercise price (in dollars per share)		5.11
Stock options canceled, forfeited, expired, weighted-averaged exercise price (in dollars per share)		2.71
Stock options outstanding, weighted-average exercise price, ending balance (in dollars per share)	$ 3.66	3.66	$ 3.92
Stock options vested and expected to vest, weighted-average exercise price (in dollars per share)	3.66	3.66
Stock options exercisable, weighted-average exercise price (in dollars per share)	$ 2.55	$ 2.55
Weighted- Average Remaining Contractual Terms (in years)
Stock options outstanding, weighted-average remaining contractual term		6 years 2 months 12 days	7 years
Stock options vested and expected to vest, weighted-average remaining contractual term		6 years 2 months 12 days
Stock options exercisable, weighted-average remaining contractual term		6 years
Aggregate Intrinsic Value
Stock options outstanding, aggregate intrinsic value	$ 1,604,528	$ 1,604,528	$ 1,310,650
Stock options exercised, aggregate intrinsic value		288,298
Stock options vested and expected to vest, aggregate intrinsic value	1,604,516	1,604,516
Stock options exercisable, aggregate intrinsic value	$ 1,503,760	$ 1,503,760

Stock-based Compensation - Sc_2

Stock-based Compensation - Schedule of Assumptions Used to Determine the Fair Value of Stock Options Granted (Details) - Stock options issued and outstanding	9 Months Ended
	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years
Expected volatility	40.30%
Risk-free interest rate	0.70%
Dividend yield	0.00%

Stock-based Compensation - Sc_3

Stock-based Compensation - Schedule of Restricted Stock Units Activity (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2021$ / sharesshares	Sep. 30, 2021$ / sharesshares
Restricted Stock and Restricted Stock Units
Restricted Stock and RSUs
Unvested and outstanding, beginning balance (in shares) \| shares		8,629,000
Forfeited (in shares) \| shares		(545,000)
Unvested, ending balance (in shares) \| shares	7,715,000	7,715,000
Vested and not yet released (in shares) \| shares	0	0
Outstanding at end of period (in shares) \| shares	7,715,000	7,715,000
Weighted-Average Grant Date Fair Value
Unvested, weighted average grant date fair value, beginning balance (in dollars per share) \| $ / shares		$ 21.38
Forfeited (in dollars per share) \| $ / shares		28.80
Unvested, weighted average grant date fair value, ending balance (in dollars per share) \| $ / shares	$ 37.14	37.14
Vested and not yet released, weighted-average grant date fair value (in dollars per share) \| $ / shares	0	0
Outstanding at end of period, weighted-average grant date fair value (in dollars per share) \| $ / shares	$ 37.14	$ 37.14
Restricted Stock Units (RSUs)
Restricted Stock and RSUs
Granted (in shares) \| shares		1,683,000
Vested (in shares) \| shares		(2,052,000)
Weighted-Average Grant Date Fair Value
Granted (in dollars per share) \| $ / shares		$ 91.54
Vested (in dollars per share) \| $ / shares		$ 19.26
Restricted Stock
Restricted Stock and RSUs
Granted (in shares) \| shares		0
Vested (in shares) \| shares	0	0
Weighted-Average Grant Date Fair Value
Granted (in dollars per share) \| $ / shares		$ 0
Vested (in dollars per share) \| $ / shares		$ 0

Stock-based Compensation - Sc_4

Stock-based Compensation - Schedule of Fair Value Assumptions for Employee Stock Purchase Plan (Details) - Shares available for issuance under the ESPP	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months
Risk-free interest rate	0.04%	0.15%
Expected volatility	65.60%	65.20%
Dividend yield	0.00%	0.00%

Stock-based Compensation - Sc_5

Stock-based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 23,049	$ 14,745	$ 61,638	$ 40,091
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	672	311	1,665	858
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	6,983	4,406	19,236	11,177
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	11,389	6,749	29,262	18,213
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 4,005	$ 3,279	$ 11,475	$ 9,843

Net Loss per Share Attributab_3

Net Loss per Share Attributable to Common Stockholders - Schedule of Computation of Basic and Diluted Earnings per Share Attributable to Common Stockholders (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
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to common stockholders	$ (107,335)	$ (26,468)	$ (182,808)	$ (85,349)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	314,543	301,689	309,618	298,628
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	314,543	301,689	309,618	298,628
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)
Class A common stock \| Common stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to common stockholders	$ (91,665)	$ (18,119)	$ (153,359)	$ (45,059)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	268,621	206,528	259,741	157,656
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	268,621	206,528	259,741	157,656
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)
Class B common stock \| Common stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to common stockholders	$ (15,670)	$ (8,349)	$ (29,449)	$ (40,290)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	45,922	95,161	49,877	140,972
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	45,922	95,161	49,877	140,972
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.34)	$ (0.09)	$ (0.59)	$ (0.29)

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Schedule of Potential Shares of Common Stock Excluded from Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of diluted net loss per share attributable to common stockholders (in shares)	36,520	47,534
2025 Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of diluted net loss per share attributable to common stockholders (in shares)	4,676	15,363
2026 Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of diluted net loss per share attributable to common stockholders (in shares)	6,761	0
Shares subject to repurchase
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of diluted net loss per share attributable to common stockholders (in shares)	2,505	4,354
Unexercised stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of diluted net loss per share attributable to common stockholders (in shares)	14,722	19,065
Unvested restricted stock and RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of diluted net loss per share attributable to common stockholders (in shares)	7,715	8,524
Shares issuable pursuant to the ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of diluted net loss per share attributable to common stockholders (in shares)	141	228

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Benefit from income taxes	$ 3,095	$ 3,504	$ 8,238	$ 5,780

Business Combinations - Narrati

Business Combinations - Narratives (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Business Acquisition [Line Items]
Repayments of notes payable				$ 0	$ 200
S2 Systems Corporation
Business Acquisition [Line Items]
Consideration transferred	$ 17,700
Cash payments to acquire businesses	13,700
Cash acquired	100
Value of shares issued	1,800
Consideration held back	$ 2,200
Consideration holdback period (up to)	18 months
Payments to settle acquiree's outstanding debt	$ 6,900
Compensation arrangements value	$ 20,300
Compensation arrangement with individual, compensation expense		$ 1,400	$ 1,400	4,200	$ 10,000
Compensation arrangement with individual, recorded liability		$ 4,700		$ 4,700
Compensation arrangement, weighted-average remaining recognition period				1 year 6 months
Repayments of notes payable						$ 200
Estimated useful life of acquired developed technology	2 years
Purchase accounting adjustment						$ 800

Business Combinations - Schedul

Business Combinations - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Jan. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 17,167	$ 17,167
S2 Systems Corporation
Business Acquisition [Line Items]
Prepaid expenses and other current assets			$ 6
Developed technology			5,600
Goodwill			13,084
Total assets acquired			18,690
Accrued expenses and other current liabilities			(208)
Other noncurrent liabilities			(782)
Total purchase price			$ 17,700

Segment and Geographic Inform_3

Segment and Geographic Information - Narratives (Details)	9 Months Ended
Segment and Geographic Information - Narratives (Details)	Sep. 30, 2021segment
Segment Reporting [Abstract]
Number of operating segments	1

Segment and Geographic Inform_4

Segment and Geographic Information - Schedule of Property and Equipment, Net by Geographic Area (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Property and equipment, net	$ 176,556	$ 123,688
United States
Segment Reporting Information [Line Items]
Property and equipment, net	118,750	79,078
Rest of the world
Segment Reporting Information [Line Items]
Property and equipment, net	$ 57,806	$ 44,610

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions	Oct. 15, 2021USD ($)
Subsequent Event
Subsequent Event [Line Items]
Consideration transferred or transferrable	$ 12.8

Uncategorized Items - cloud-202

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2016-02 [Member]