Pinterest (PINS) 10-K 5 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2020	Jan. 29, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38872
Entity Registrant Name	Pinterest, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-3607129
Entity Address, Address Line One	505 Brannan Street
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94107
City Area Code	415
Local Phone Number	762-7100
Title of 12(b) Security	Class A Common Stock, $0.00001 par value
Trading Symbol	PINS
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 9.4
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for the 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. Such Definitive Proxy Statement will be filed with the Securities and Exchange Commission within 120 days after the end of the registrant’s fiscal year ended December 31, 2020.
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Fiscal Year Focus	2020
Entity Central Index Key	0001506293
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		532,423,430
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		96,091,207

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 669,230	$ 649,666
Marketable securities	1,091,076	1,063,679
Accounts receivable, net of allowances of $8,811 and $2,851 as of December 31, 2020 and 2019, respectively	563,733	316,367
Prepaid expenses and other current assets	33,502	37,522
Total current assets	2,357,541	2,067,234
Property and equipment, net	69,375	91,992
Operating lease right-of-use assets	155,916	188,251
Goodwill and intangible assets, net	13,562	14,576
Restricted cash	9,110	25,339
Other assets	3,955	5,925
Total assets	2,609,459	2,393,317
Current liabilities:
Accounts payable	49,491	34,334
Accrued expenses and other current liabilities	155,340	141,823
Total current liabilities	204,831	176,157
Operating lease liabilities	139,321	173,392
Other liabilities	22,936	20,063
Total liabilities	367,088	369,612
Commitments and contingencies
Stockholders’ equity:
Common stock	6	6
Additional paid-in capital	4,574,934	4,229,778
Accumulated other comprehensive income	2,480	647
Accumulated deficit	(2,335,049)	(2,206,726)
Total stockholders’ equity	2,242,371	2,023,705
Total liabilities and stockholders’ equity	$ 2,609,459	$ 2,393,317

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Allowances	$ 8,811	$ 2,851
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	6,666,667	6,666,667
Common stock, shares issued (in shares)	530,140	360,850
Common stock, shares outstanding (in shares)	530,140	360,850
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	1,333,333	1,333,333
Common stock, shares issued (in shares)	96,232	209,054
Common stock, shares outstanding (in shares)	96,232	209,054

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 1,692,658	$ 1,142,761	$ 755,932
Costs and expenses:
Cost of revenue	449,358	358,903	241,584
Research and development	606,194	1,207,059	251,662
Sales and marketing	442,807	611,590	259,929
General and administrative	336,803	354,075	77,478
Total costs and expenses	1,835,162	2,531,627	830,653
Loss from operations	(142,504)	(1,388,866)	(74,721)
Interest income	16,119	30,164	13,152
Interest expense and other income (expense), net	(635)	(2,137)	(995)
Loss before provision for income taxes	(127,020)	(1,360,839)	(62,564)
Provision for income taxes	1,303	532	410
Net loss	$ (128,323)	$ (1,361,371)	$ (62,974)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.22)	$ (3.24)	$ (0.50)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	596,264	420,473	127,091

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (128,323)	$ (1,361,371)	$ (62,974)
Other comprehensive income (loss), net of taxes:
Change in unrealized gain (loss) on available-for-sale marketable securities	1,670	2,057	(443)
Change in foreign currency translation adjustment	163	11	(212)
Comprehensive loss	$ (126,490)	$ (1,359,303)	$ (63,629)

CONSOLIDATED STATEMENTS OF REDE

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance (in shares) at Dec. 31, 2017	308,373
Balance at Dec. 31, 2017	$ 1,465,399
Balance (in shares) at Dec. 31, 2018	308,373
Balance at Dec. 31, 2018	$ 1,465,399
Beginning balance (in shares) at Dec. 31, 2017		126,771
Beginning balance at Dec. 31, 2017	(546,464)	$ 1	$ 236,682	$ (766)	$ (782,381)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash upon exercise of stock options, net (in shares)		527
Issuance of common stock for cash upon exercise of stock options, net	671		671
Share-based compensation	14,859		14,859
Other comprehensive income (loss)	(655)			(655)
Net income (loss)	(62,974)				(62,974)
Ending balance (in shares) at Dec. 31, 2018		127,298
Ending balance at Dec. 31, 2018	$ (594,563)	$ 1	252,212	(1,421)	(845,355)
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock and redeemable convertible preferred stock warrants to common stock in connection with initial public offering (in shares)	(308,373)
Conversion of redeemable convertible preferred stock and redeemable convertible preferred stock warrants to common stock in connection with initial public offering	$ (1,465,399)
Balance (in shares) at Dec. 31, 2019	0
Balance at Dec. 31, 2019	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Release of restricted stock units (in shares)		28,084
Release of restricted stock units	1	$ 1
Shares repurchased for tax withholdings on release of restricted stock units	(475,015)		(475,015)
Conversion of redeemable convertible preferred stock and redeemable convertible preferred stock warrants to common stock in connection with initial public offering (in shares)		308,622
Conversion of redeemable convertible preferred stock and redeemable convertible preferred stock warrants to common stock in connection with initial public offering	1,470,077	$ 3	1,470,074
Issuance of common stock in connection with initial public offering net of underwriters' discounts and commissions and offering costs (in shares)		86,250
Issuance of common stock in connection with initial public offering net of underwriters' discounts and commissions and offering costs	1,563,383	$ 1	1,563,382
Issuance of common stock for cash upon exercise of stock options, net (in shares)		19,650
Issuance of common stock for cash upon exercise of stock options, net	41,344		41,344
Share-based compensation	1,377,781		1,377,781
Other comprehensive income (loss)	2,068			2,068
Net income (loss)	(1,361,371)				(1,361,371)
Ending balance (in shares) at Dec. 31, 2019		569,904
Ending balance at Dec. 31, 2019	$ 2,023,705	$ 6	4,229,778	647	(2,206,726)
Balance (in shares) at Dec. 31, 2020	0
Balance at Dec. 31, 2020	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Release of restricted stock units (in shares)		19,890
Release of restricted stock units	0	$ 0
Shares repurchased for tax withholdings on release of restricted stock units	$ (56,894)		(56,894)
Issuance of common stock for cash upon exercise of stock options, net (in shares)	34,149	34,149
Issuance of common stock for cash upon exercise of stock options, net	$ 78,282		78,282
Issuance of common stock related to charitable contributions (in shares)		150
Issuance of common stock related to charitable contributions	2,748		2,748
Issuance of restricted stock awards, net (in shares)		2,279
Share-based compensation	321,020		321,020
Other comprehensive income (loss)	1,833			1,833
Net income (loss)	(128,323)				(128,323)
Ending balance (in shares) at Dec. 31, 2020		626,372
Ending balance at Dec. 31, 2020	$ 2,242,371	$ 6	$ 4,574,934	$ 2,480	$ (2,335,049)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss attributable to common stockholders	$ (128,323)	$ (1,361,371)	$ (62,974)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	36,988	27,791	20,859
Share-based compensation	321,020	1,377,781	14,859
Other	11,080	(3,990)	1,027
Changes in assets and liabilities:
Accounts receivable	(253,173)	(94,224)	(86,094)
Prepaid expenses and other assets	4,128	7,161	18,142
Operating lease right-of-use assets	41,898	32,378	18,492
Accounts payable	15,721	11,636	6,533
Accrued expenses and other liabilities	23,647	31,890	26,336
Operating lease liabilities	(44,160)	(28,395)	(17,549)
Net cash provided by (used in) operating activities	28,826	657	(60,369)
Investing activities
Purchases of property and equipment and intangible assets	(17,401)	(33,783)	(22,194)
Purchases of marketable securities	(1,216,260)	(1,075,875)	(518,711)
Sales of marketable securities	265,422	162,198	94,381
Maturities of marketable securities	920,300	360,959	561,087
Other investing activities	316	0	(500)
Net cash provided by (used in) investing activities	(47,623)	(586,501)	114,063
Financing activities
Proceeds from initial public offering, net of underwriters' discounts and commissions	0	1,573,200	0
Proceeds from exercise of stock options, net	78,282	41,344	671
Shares repurchased for tax withholdings on release of restricted stock units	(56,894)	(475,015)	0
Fees paid for revolving credit facility	0	0	(2,552)
Payment of deferred offering costs and other financing activities	(1,750)	(11,331)	(335)
Net cash provided by (used in) financing activities	19,638	1,128,198	(2,216)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	327	99	(157)
Net increase in cash, cash equivalents, and restricted cash	1,168	542,453	51,321
Cash, cash equivalents, and restricted cash, beginning of period	677,743	135,290	83,969
Cash, cash equivalents, and restricted cash, end of period	678,911	677,743	135,290
Supplemental cash flow information
Accrued property and equipment	820	4,772	1,884
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$ 15,089	$ 76,387	$ 11,416

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of cash, cash equivalents and restricted cash to consolidated balance sheets
Cash and cash equivalents	$ 669,230	$ 649,666	$ 122,509
Restricted cash included in prepaid expenses and other current assets	571	2,738	1,057
Restricted cash	9,110	25,339	11,724
Total cash, cash equivalents, and restricted cash	$ 678,911	$ 677,743	$ 135,290

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Description of Business and Summary of Significant Accounting Policies	Description of Business and Summary of Significant Accounting Policies Description of Business Pinterest was incorporated in Delaware in 2008 and is headquartered in San Francisco, California. Pinterest is a visual discovery engine that people around the globe use to find the inspiration to create a life they love. We generate revenue by delivering ads on our website and mobile application. Basis of Presentation and Consolidation We prepared the accompanying consolidated financial statements in accordance with generally accepted accounting principles in the United States ("GAAP"). The consolidated financial statements include the accounts of Pinterest, Inc. and its wholly owned subsidiaries. We have eliminated all intercompany balances and transactions. Reclassifications We have reclassified certain amounts in prior periods to conform with current presentation. Initial Public Offering On April 23, 2019, we closed our initial public offering ("IPO") in which we issued and sold 75,000,000 shares of Class A common stock at $19.00 per share. We received net proceeds of $1,368.0 million after deducting underwriting discounts and commissions and before deducting offering costs of $9.8 million. Immediately prior to the completion of our IPO, all shares of our outstanding redeemable convertible preferred stock and redeemable convertible preferred stock warrants converted into 308,621,636 shares of Class B common stock on a one-for-one basis, and immediately thereafter but still prior to the completion of our IPO, all of our outstanding common stock were reclassified into 456,213,756 shares of Class B common stock on a one-for-one basis. On April 29, 2019, we issued and sold an additional 11,250,000 shares of Class A common stock at $19.00 per share pursuant to the underwriters’ option to purchase additional shares. We received additional net proceeds of $205.2 million after deducting underwriting discounts and commissions. Upon pricing our IPO, the performance condition for restricted stock units ("RSUs") granted under our 2009 Stock Plan (the "2009 Plan") was deemed satisfied, and we recorded cumulative share-based compensation expense for those RSUs for which the service condition had been satisfied at that date. For the years ended December 31, 2020, 2019 and 2018, we recorded total share-based compensation expense of $321.0 million, $1,377.8 million and $14.9 million, respectively. Use of Estimates Preparing our consolidated financial statements in conformity with GAAP requires us to make estimates and judgments that affect amounts reported in the consolidated financial statements and accompanying notes. We base these estimates and judgments on historical experience and various other assumptions that we consider reasonable. GAAP requires us to make estimates and assumptions in several areas, including the fair values of financial instruments, assets acquired and liabilities assumed through business combinations, common stock prior to our IPO, share-based awards, and contingencies as well as the collectability of our accounts receivable, the useful lives of our intangible assets and property and equipment, the incremental borrowing rate we use to determine our operating lease liabilities, and revenue recognition, among others. Actual results could differ materially from these estimates and judgments. Some of our estimates may require increased judgment due to the significant volatility, uncertainty and economic disruption of the COVID-19 pandemic. We continue to monitor the effects of the COVID-19 pandemic, and our estimates and judgments may change materially as new events occur or additional information becomes available to us. Segments We operate as a single operating segment. Our chief operating decision maker is our Chief Executive Officer ("CEO"), who reviews financial information presented on a consolidated basis, accompanied by disaggregated information about our revenue, for purposes of making operating decisions, assessing financial performance and allocating resources. Revenue Recognition We generate revenue by delivering ads on our website and mobile application. We recognize revenue only after transferring control of promised goods or services to customers, which occurs when a user clicks on an ad contracted on a cost per click (“CPC”) basis, views an ad contracted on a cost per thousand impressions (“CPM”) basis or views a video ad contracted on a cost per view ("CPV") basis. We typically bill customers on a CPC, CPM or CPV basis, and our payment terms vary by customer type and location. The term between billing and payment due dates is not significant. We occasionally offer customers free ad inventory, and revenue is recognized only after satisfying our contractual performance obligations. When contracts with our customers contain multiple performance obligations, we allocate the overall transaction price, which is the amount of consideration to which we expect to be entitled in exchange for promised goods or services, to each of the distinct performance obligations based on their relative standalone selling prices. We generally determine standalone selling prices based on the effective price charged per contracted click, impression or view, and we do not disclose the value of unsatisfied performance obligations because the original expected duration of our contracts is generally less than one year. We record sales commissions in sales and marketing expense as incurred because we would amortize these over a period of less than one year. Deferred revenue was not material as of December 31, 2020 and 2019. Cost of Revenue Cost of revenue consists primarily of expenses associated with the delivery of our service, including the cost of hosting our website and mobile application. Cost of revenue also includes personnel-related expense, including salaries, benefits and share-based compensation, for employees on our operations teams, payments associated with partner arrangements, credit card and other transaction processing fees, and allocated facilities and other supporting overhead costs. Share-Based Compensation RSUs granted under our 2009 Plan are subject to both a service condition, which is typically satisfied over four years, and a performance condition, which was deemed satisfied upon the pricing of our IPO. We did not record any share-based compensation expense for our RSUs prior to our IPO because the performance condition had not yet been satisfied. Upon pricing our IPO, we recorded cumulative share-based compensation expense using the accelerated attribution method for those RSUs granted under our 2009 Plan for which the service condition had been satisfied at that date. We will record the remaining unrecognized share-based compensation expense over the remainder of the requisite service period. RSUs and restricted stock awards ("RSAs") granted under our 2019 Omnibus Incentive Plan (the "2019 Plan") are subject only to a service condition, which is typically satisfied over four years. We record share-based compensation expense for these RSUs and RSAs on a straight-line basis over the requisite service period. We measure RSUs and RSAs based on the fair market value of our common stock on the grant date, and we account for forfeitures as they occur. Income Taxes We account for income taxes using the asset and liability method. We recognize deferred tax assets and liabilities for temporary differences between the financial reporting and tax bases of assets and liabilities using the enacted statutory tax rates in effect for the years in which we expect the differences to reverse. We establish valuation allowances to reduce deferred tax assets to the amounts we believe it is more likely than not we will be able to realize. We recognize tax benefits from uncertain tax positions when we believe it is more likely than not that the tax position is sustainable on examination by tax authorities based on its technical merits. We recognize taxes on Global Intangible Low-Taxed Income ("GILTI") as a current period expense when incurred. Advertising Expenses We record advertising expenses as incurred and include these in sales and marketing in the consolidated statements of operations. Advertising expenses were $30.3 million, $55.0 million and $19.2 million for the years ended December 31, 2020, 2019 and 2018, respectively. Marketable Securities We invest in highly liquid corporate debt securities, U.S. treasury securities, asset-backed securities, U.S. government agency securities, money market funds and certificates of deposit. We classify marketable investments with stated maturities of ninety days or less from the date of purchase as cash equivalents and those with stated maturities greater than ninety days from the date of purchase as marketable securities. We classify our marketable securities as available-for-sale investments in our current assets because they are available for use to support current operations. We carry our marketable investments at fair value and record unrealized gains or losses, net of taxes, in accumulated other comprehensive income (loss) in stockholders’ equity (deficit). We determine realized gains and losses on the sale of marketable investments using a specific identification method and record these and any expected credit losses in interest expense and other income (expense), net. Restricted Cash Our restricted cash primarily consists of certificates of deposit underlying secured letters of credit issued in connection with our operating leases. Restrictions typically lapse at the end of the lease term, and we classify restricted cash as current or non-current based on the remaining term of the restriction. Fair Value Measurements We account for certain assets and liabilities at fair value, which is the amount we believe market participants would receive to sell an asset or pay to transfer a liability in an orderly transaction. We categorize these assets and liabilities into the three levels below based on the degree to which the inputs we use to measure their fair values are observable in active markets. We use the most observable inputs available to us when measuring fair value. • Level 1: Observable inputs such as quoted prices for identical assets or liabilities in active markets • Level 2: Observable inputs such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in inactive markets, or inputs that are derived principally from or corroborated by observable market data or other means • Level 3: Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities Accounts Receivable, Net of Allowances We record accounts receivable at the original invoiced amount. We maintain an allowance for credit losses for any receivables we may be unable to collect. We estimate uncollectible receivables based on our receivables’ age, our customers’ credit quality and current economic conditions, among other factors that may affect our customers’ ability to pay. We also maintain an allowance for sales credits, which we determine based on historical credits issued to customers. We include the allowances for credit losses and sales credits in accounts receivable, net in the consolidated balance sheets. Property and Equipment We carry property and equipment at cost less accumulated depreciation and calculate depreciation using the straight-line method over our assets’ estimated useful lives, which are generally: Property and Equipment Useful Life Computer and network equipment 3 years Furniture and fixtures 4 years Leasehold improvements Lesser of estimated useful life or remaining lease term Leases and Operating Lease Incremental Borrowing Rate We lease office space under operating leases with expiration dates through 2033. We determine whether an arrangement constitutes a lease at inception and record lease liabilities and right-of-use assets on our consolidated balance sheets at lease commencement. We measure lease liabilities based on the present value of the total lease payments not yet paid discounted based on the more readily determinable of the rate implicit in the lease or our incremental borrowing rate, which is the estimated rate we would be required to pay for a collateralized borrowing equal to the total lease payments over the term of the lease. We estimate our incremental borrowing rate based on an analysis of publicly traded debt securities of companies with credit and financial profiles similar to our own. We measure right-of-use assets based on the corresponding lease liability adjusted for (i) payments made to the lessor at or before the commencement date, (ii) initial direct costs we incur and (iii) tenant incentives under the lease. We begin recognizing rent expense when the lessor makes the underlying asset available to us, we do not assume renewals or early terminations unless we are reasonably certain to exercise these options at commencement, and we do not allocate consideration between lease and non-lease components. For short-term leases, we record rent expense in our consolidated statements of operations on a straight-line basis over the lease term and record variable lease payments as incurred. Business Combinations We include the results of operations of businesses that we acquire in our consolidated financial statements beginning on their respective acquisition dates. We allocate the fair value of the purchase consideration to the assets acquired and liabilities assumed based on their estimated fair values. When the fair value of the purchase consideration exceeds the fair values of the identifiable assets and liabilities acquired, we record the excess as goodwill. Long-Lived Assets, Including Goodwill and Intangible Assets We record definite-lived intangible assets at fair value less accumulated amortization. We calculate amortization using the straight-line method over the assets’ estimated useful lives of up to ten years. We review our property and equipment and intangible assets for impairment whenever events or circumstances indicate that an asset’s carrying value may not be recoverable. We measure recoverability by comparing an asset’s carrying value to the future undiscounted cash flows that we expect it to generate. If this test indicates that the asset’s carrying value is not recoverable, we record an impairment charge to reduce the asset’s carrying value to its fair value. We did not record material property and equipment or intangible asset impairments during the periods presented. We review goodwill for impairment at least annually or more frequently if current circumstances or events indicate that the fair value of our single reporting unit may be less than its carrying value. We did not record any goodwill impairment during the periods presented. Website Development Costs We capitalize costs to develop our website and mobile application when preliminary development efforts are successfully completed, management has authorized and committed project funding, and it is probable that the project will be completed and the software will be used as intended. Due to the iterative process by which we perform upgrades and the relatively short duration of our development projects, development costs meeting our capitalization criteria were not material during the periods presented. Loss Contingencies We are involved in various lawsuits, claims and proceedings that arise in the ordinary course of business. We record a liability for these when we believe it is probable that we have incurred a loss and can reasonably estimate the loss. We regularly evaluate current information to determine whether we should adjust a recorded liability or record a new one. Foreign Currency The functional currency of our international subsidiaries is generally their local currency. We translate these subsidiaries’ financial statements into U.S. dollars using month-end exchange rates for assets and liabilities and average exchange rates for revenue and costs and expenses. We record translation gains and losses in accumulated other comprehensive income (loss) in stockholders’ equity (deficit). We record foreign exchange gains and losses in interest expense and other income (expense), net. Our net foreign exchange gains and losses were not material for the periods presented. Concentration of Business Risk We have an agreement with Amazon Web Services (“AWS”) to provide the cloud computing infrastructure we use to host our website, mobile application and many of the internal tools we use to operate our business. We are currently required to maintain a substantial majority of our monthly usage of certain compute, storage, data transfer and other services on AWS. Any transition of the cloud services currently provided by AWS to another cloud services provider would be difficult to implement and would cause us to incur significant time and expense. Concentration of Credit Risk Financial instruments that may potentially expose us to concentrations of credit risk primarily consist of cash, cash equivalents, marketable securities and restricted cash. Our investment policy is meant to preserve capital and maintain liquidity. The policy limits our marketable investments to investment-grade securities and limits our credit exposure by limiting our concentration in any one corporate issuer or sector and by establishing a minimum credit rating for marketable investments we purchase. Although we deposit cash and marketable investments with multiple financial institutions, our deposits may exceed insurable limits. No customer accounted for more than 10% of our revenue for the years ended December 31, 2020 and December 31, 2018. One customer accounted for 10% of our revenue for the year ended December 31, 2019. Our accounts receivable are generally unsecured. We monitor our custo mers’ credit quality on an ongoing basis and maintain reserves for estimated credit losses. Bad debt expense was not material for the years ended December 31, 2020, 2019 and 2018. Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which requires the measurement and recognition of expected credit losses for financial assets not held at fair value. ASU 2016-13 replaces the existing incurred loss impairment model with a forward-looking expected credit loss model which will result in earlier recognition of credit losses. We adopted ASU 2016-13 as of January 1, 2020, using the modified retrospective method, and while the effects of adoption on our consolidated financial statements were not material, we continue to monitor the effects of the COVID-19 pandemic on expected credit losses. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which simplifies the accounting for income taxes by removing certain exceptions to the general principles for income taxes. We elected to early adopt ASU 2019-12 effective as of January 1, 2020, and the effects of adoption on our consolidated financial statements were not material.

Cash, Cash Equivalents and Mark

Cash, Cash Equivalents and Marketable Securities	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Marketable Securities	Cash, Cash Equivalents and Marketable Securities Cash, cash equivalents and marketable securities consist of the following (in thousands): December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 352,061 $ — $ — $ 352,061 Money market funds 225,643 — — 225,643 Commercial paper 48,530 2 — 48,532 U.S. treasury securities 39,997 1 — 39,998 Certificates of deposit 2,996 — — 2,996 Total cash and cash equivalents 669,227 3 — 669,230 Marketable securities: Corporate bonds 452,723 1,782 (18) 454,487 U.S. treasury securities 202,795 260 (1) 203,054 Commercial paper 234,170 86 (3) 234,253 Certificates of deposit 134,828 57 (3) 134,882 Municipal securities 17,604 22 (7) 17,619 U.S. agency bonds 16,012 6 — 16,018 Non-U.S. government and supranational bonds 15,938 13 (1) 15,950 Asset-backed securities 14,752 61 — 14,813 Total marketable securities 1,088,822 2,287 (33) 1,091,076 Total $ 1,758,049 $ 2,290 $ (33) $ 1,760,306 December 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 323,194 $ — $ — $ 323,194 Money market funds 214,413 — — 214,413 Commercial paper 105,359 1 (6) 105,354 Corporate bonds 3,792 — (1) 3,791 Certificates of deposit 2,914 — — 2,914 Total cash and cash equivalents 649,672 1 (7) 649,666 Marketable securities: Corporate bonds 449,496 981 (44) 450,433 U.S. treasury securities 201,561 88 (9) 201,640 Commercial paper 196,304 31 (7) 196,328 Asset-backed securities 114,425 188 (14) 114,599 Certificates of deposit 100,647 38 (6) 100,679 Total marketable securities 1,062,433 1,326 (80) 1,063,679 Total $ 1,712,105 $ 1,327 $ (87) $ 1,713,345 Our allowance for credit losses for our marketable securities was not material as of December 31, 2020 and 2019. We continue to monitor the effects of the COVID-19 pandemic on expected credit losses. The fair value of our marketable securities by contractual maturity is as follows (in thousands): December 31, 2020 Due in one year or less $ 787,395 Due after one to five years 303,681 Total $ 1,091,076 Net realized gains and losses from sales of available-for-sale securities were not material for any period presented.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The fair values of the financial instruments we measure at fair value on a recurring basis are as follows (in thousands): December 31, 2020 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 225,643 $ — $ — $ 225,643 Commercial paper — 48,532 — 48,532 U.S. treasury securities 39,998 — — 39,998 Certificates of deposit — 2,996 — 2,996 Marketable securities: Corporate bonds — 454,487 — 454,487 Commercial paper — 234,253 — 234,253 U.S. treasury securities 203,054 — — 203,054 Certificates of deposit — 134,882 — 134,882 Municipal securities — 17,619 — 17,619 U.S. agency bonds — 16,018 — 16,018 Non-U.S. government and supranational bonds — 15,950 — 15,950 Asset-backed securities — 14,813 — 14,813 Prepaid expenses and other current assets: Certificates of deposit — 571 — 571 Restricted cash: Certificates of deposit $ — $ 9,110 $ — $ 9,110 December 31, 2019 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 214,413 $ — $ — $ 214,413 Commercial paper — 105,354 — 105,354 Corporate bonds — 3,791 — 3,791 Certificates of deposit — 2,914 — 2,914 Marketable securities: Corporate bonds — 450,433 — 450,433 U.S. treasury securities 201,640 — — 201,640 Commercial paper — 196,328 — 196,328 Asset-backed securities — 114,599 — 114,599 Certificates of deposit — 100,679 — 100,679 Prepaid expenses and other current assets: Certificates of deposit — 2,738 — 2,738 Restricted cash: Certificates of deposit $ — $ 25,339 $ — $ 25,339

Other Balance Sheet Components

Other Balance Sheet Components	12 Months Ended
	Dec. 31, 2020
Other Balance Sheet Components [Abstract]
Other Balance Sheet Components	Other Balance Sheet Components Property and Equipment, Net Property and equipment, net consists of the following (in thousands): December 31, 2020 2019 Leasehold improvements $ 101,242 $ 109,807 Furniture and fixtures 24,516 22,353 Computer and network equipment 27,230 22,963 Total property and equipment 152,988 155,123 Less: accumulated depreciation (83,770) (73,270) Construction in progress 157 10,139 Property and equipment, net $ 69,375 $ 91,992 Depreciation expense was $36.0 million, $26.3 million and $20.1 million for the years ended December 31, 2020, 2019 and 2018, respectively. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consists of the following (in thousands): December 31, 2020 2019 Accrued hosting expenses $ 39,233 $ 27,322 Accrued compensation 33,215 26,574 Operating lease liabilities 43,633 46,527 Other accrued expenses 39,259 41,400 Accrued expenses and other current liabilities $ 155,340 $ 141,823

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Net	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, Net	Goodwill and Intangible Assets, Net Goodwill was unchanged during the years ended December 31, 2020 and 2019. Intangible assets, net consists of the following (in thousands): December 31, 2020 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted-Average Useful Life (1) Acquired patents $ 9,037 $ (2,380) $ 6,657 9.1 years Acquired technology and other intangibles 4,385 (4,385) — 1.5 years Total intangible assets, net $ 13,422 $ (6,765) $ 6,657 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted-Average Useful Life (1) Acquired patents $ 9,037 $ (1,370) $ 7,667 9.1 years Acquired technology and other intangibles 4,385 (4,381) 4 1.5 years Total intangible assets, net $ 13,422 $ (5,751) $ 7,671 (1) Based on the weighted-average useful life established as of acquisition date. Amortization expense was $1.0 million, $1.5 million and $0.7 million for the years ended December 31, 2020, 2019 and 2018, respectively. Estimated future amortization expense as of December 31, 2020, is as follows (in thousands): Intangible Asset Amortization 2021 $ 1,009 2022 1,009 2023 1,009 2024 1,009 2025 999 Thereafter 1,622 Total $ 6,657

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies As of December 31, 2020, our non-cancelable contractual commitments, consisting of operating leases, are as follows (in thousands): Total Commitments 2021 $ 52,472 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total $ 231,006 Operating Leases In March 2019, we entered into a lease for approximately 490,000 square feet of office space to be constructed near our current headquarters campus in San Francisco, California. In August 2020, we entered into an agreement to terminate the lease which involved a one-time payment of $89.5 million. As a result of the termination, we eliminated potential future total minimum lease payments of approximately $440.0 million. Legal Matters We are involved in various lawsuits, claims and proceedings that arise in the ordinary course of business, including those described below. While the results of legal matters are inherently uncertain, we do not believe there is a reasonable possibility that the ultimate resolution of these matters, either individually or in aggregate, will have a material adverse effect on our business, financial position, results of operations, or cash flows. On November 23, 2020, Pinterest and our CEO and Chief Financial Officer were named as defendants in a putative securities class action filed in the U.S. District Court for the Northern District of California. The lawsuit alleges claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 (the “Exchange Act”) and alleges that defendants made material false and misleading public statements about our revenue and user growth in 2019. The complaint seeks damages, litigation costs, and interest. We continue to evaluate these claims but do not believe this litigation will have a material impact on our financial position or results of operations. In November and December 2020, certain or our executives and members of our board of directors were named as defendants in derivative lawsuits filed in the U.S. District Court for the Northern District of California. Pinterest was also named as a nominal defendant. The lawsuits purport to assert claims for breach of fiduciary duty in connection with allegations of gender and racial discrimination at Pinterest. In addition, the lawsuits purport to assert claims for waste, abuse of control, aiding and abetting breaches of fiduciary duties, unjust enrichment, and violations of Section 14(a) of the Exchange Act. The complaints seek declaratory and injunctive relief, corporate governance changes, monetary damages, interest, disgorgement, and fees and costs. We continue to evaluate these claims but do not believe this litigation will have a material impact on our financial position or results of operations. Revolving Credit Facility In November 2018, we entered into a five-year $500.0 million revolving credit facility with an accordion option which, if exercised, would allow us to increase the aggregate commitments by the greater of $100.0 million and 10% of our consolidated total assets, provided we are able to secure additional lender commitments and satisfy certain other conditions. Interest on any borrowings under the revolving credit facility accrues at either LIBOR plus 1.50% or at an alternative base rate plus 0.50%, at our election, and we are required to pay an annual commitment fee that accrues at 0.15% per annum on the unused portion of the aggregate commitments under the revolving credit facility. The revolving credit facility also allows us to issue letters of credit, which reduce the amount we can borrow. We are required to pay a fee that accrues at 1.50% per annum on the average aggregate daily maximum amount available to be drawn under any outstanding letters of credit. The revolving credit facility contains customary conditions to borrowing, events of default and covenants, including covenants that restrict our ability to incur indebtedness, grant liens, make distributions to holders of our stock or the stock of our subsidiaries, make investments or engage in transactions with our affiliates. The revolving credit facility also contains two financial maintenance covenants: a consolidated total assets covenant and a minimum liquidity balance of $350.0 million, which includes any available borrowing capacity. The obligations under the revolving credit facility are secured by liens on substantially all of our domestic assets, including certain domestic intellectual property assets. Our total borrowing capacity under the revolving credit facility is $500.0 million as of December 31, 2020. We have not issued any letters of credit against the revolving credit facility and are in compliance with all covenants under the revolving credit facility as of December 31, 2020. Letters of Credit We had $7.5 million and $25.5 million of secured letters of credit outstanding as of December 31, 2020 and 2019, respectively. These primarily relate to our office space leases and are fully collateralized by certificates of deposit which we record in prepaid expenses and other current assets or restricted cash in our consolidated balance sheets based on the term of the remaining restriction.
Commitments and Contingencies	Commitments and Contingencies As of December 31, 2020, our non-cancelable contractual commitments, consisting of operating leases, are as follows (in thousands): Total Commitments 2021 $ 52,472 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total $ 231,006 Operating Leases In March 2019, we entered into a lease for approximately 490,000 square feet of office space to be constructed near our current headquarters campus in San Francisco, California. In August 2020, we entered into an agreement to terminate the lease which involved a one-time payment of $89.5 million. As a result of the termination, we eliminated potential future total minimum lease payments of approximately $440.0 million. Legal Matters We are involved in various lawsuits, claims and proceedings that arise in the ordinary course of business, including those described below. While the results of legal matters are inherently uncertain, we do not believe there is a reasonable possibility that the ultimate resolution of these matters, either individually or in aggregate, will have a material adverse effect on our business, financial position, results of operations, or cash flows. On November 23, 2020, Pinterest and our CEO and Chief Financial Officer were named as defendants in a putative securities class action filed in the U.S. District Court for the Northern District of California. The lawsuit alleges claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 (the “Exchange Act”) and alleges that defendants made material false and misleading public statements about our revenue and user growth in 2019. The complaint seeks damages, litigation costs, and interest. We continue to evaluate these claims but do not believe this litigation will have a material impact on our financial position or results of operations. In November and December 2020, certain or our executives and members of our board of directors were named as defendants in derivative lawsuits filed in the U.S. District Court for the Northern District of California. Pinterest was also named as a nominal defendant. The lawsuits purport to assert claims for breach of fiduciary duty in connection with allegations of gender and racial discrimination at Pinterest. In addition, the lawsuits purport to assert claims for waste, abuse of control, aiding and abetting breaches of fiduciary duties, unjust enrichment, and violations of Section 14(a) of the Exchange Act. The complaints seek declaratory and injunctive relief, corporate governance changes, monetary damages, interest, disgorgement, and fees and costs. We continue to evaluate these claims but do not believe this litigation will have a material impact on our financial position or results of operations. Revolving Credit Facility In November 2018, we entered into a five-year $500.0 million revolving credit facility with an accordion option which, if exercised, would allow us to increase the aggregate commitments by the greater of $100.0 million and 10% of our consolidated total assets, provided we are able to secure additional lender commitments and satisfy certain other conditions. Interest on any borrowings under the revolving credit facility accrues at either LIBOR plus 1.50% or at an alternative base rate plus 0.50%, at our election, and we are required to pay an annual commitment fee that accrues at 0.15% per annum on the unused portion of the aggregate commitments under the revolving credit facility. The revolving credit facility also allows us to issue letters of credit, which reduce the amount we can borrow. We are required to pay a fee that accrues at 1.50% per annum on the average aggregate daily maximum amount available to be drawn under any outstanding letters of credit. The revolving credit facility contains customary conditions to borrowing, events of default and covenants, including covenants that restrict our ability to incur indebtedness, grant liens, make distributions to holders of our stock or the stock of our subsidiaries, make investments or engage in transactions with our affiliates. The revolving credit facility also contains two financial maintenance covenants: a consolidated total assets covenant and a minimum liquidity balance of $350.0 million, which includes any available borrowing capacity. The obligations under the revolving credit facility are secured by liens on substantially all of our domestic assets, including certain domestic intellectual property assets. Our total borrowing capacity under the revolving credit facility is $500.0 million as of December 31, 2020. We have not issued any letters of credit against the revolving credit facility and are in compliance with all covenants under the revolving credit facility as of December 31, 2020. Letters of Credit We had $7.5 million and $25.5 million of secured letters of credit outstanding as of December 31, 2020 and 2019, respectively. These primarily relate to our office space leases and are fully collateralized by certificates of deposit which we record in prepaid expenses and other current assets or restricted cash in our consolidated balance sheets based on the term of the remaining restriction. We have entered into various non-cancelable office space operating leases with original lease periods expiring between 2021 and 2033. These do not contain material variable rent payments, residual value guarantees, covenants or other restrictions. Operating lease costs for the years ended December 31, 2020, 2019 and 2018, are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Lease cost: Operating lease cost $ 51,285 $ 40,257 $ 27,469 Short-term lease cost 3,933 3,456 2,765 Total $ 55,218 $ 43,713 $ 30,234 The weighted-average remaining term of our operating leases was 8.1 years and 8.1 years, and the weighted-average discount rate used to measure the present value of our operating lease liabilities was 4.8% and 4.6% as of December 31, 2020 and 2019, respectively. Maturities of our operating lease liabilities, which do not include short-term leases, as of December 31, 2020, are as follows (in thousands): Operating Leases 2021 $ 51,396 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total lease payments 229,930 Less imputed interest (46,976) Total operating lease liabilities $ 182,954

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Commitments and Contingencies As of December 31, 2020, our non-cancelable contractual commitments, consisting of operating leases, are as follows (in thousands): Total Commitments 2021 $ 52,472 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total $ 231,006 Operating Leases In March 2019, we entered into a lease for approximately 490,000 square feet of office space to be constructed near our current headquarters campus in San Francisco, California. In August 2020, we entered into an agreement to terminate the lease which involved a one-time payment of $89.5 million. As a result of the termination, we eliminated potential future total minimum lease payments of approximately $440.0 million. Legal Matters We are involved in various lawsuits, claims and proceedings that arise in the ordinary course of business, including those described below. While the results of legal matters are inherently uncertain, we do not believe there is a reasonable possibility that the ultimate resolution of these matters, either individually or in aggregate, will have a material adverse effect on our business, financial position, results of operations, or cash flows. On November 23, 2020, Pinterest and our CEO and Chief Financial Officer were named as defendants in a putative securities class action filed in the U.S. District Court for the Northern District of California. The lawsuit alleges claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 (the “Exchange Act”) and alleges that defendants made material false and misleading public statements about our revenue and user growth in 2019. The complaint seeks damages, litigation costs, and interest. We continue to evaluate these claims but do not believe this litigation will have a material impact on our financial position or results of operations. In November and December 2020, certain or our executives and members of our board of directors were named as defendants in derivative lawsuits filed in the U.S. District Court for the Northern District of California. Pinterest was also named as a nominal defendant. The lawsuits purport to assert claims for breach of fiduciary duty in connection with allegations of gender and racial discrimination at Pinterest. In addition, the lawsuits purport to assert claims for waste, abuse of control, aiding and abetting breaches of fiduciary duties, unjust enrichment, and violations of Section 14(a) of the Exchange Act. The complaints seek declaratory and injunctive relief, corporate governance changes, monetary damages, interest, disgorgement, and fees and costs. We continue to evaluate these claims but do not believe this litigation will have a material impact on our financial position or results of operations. Revolving Credit Facility In November 2018, we entered into a five-year $500.0 million revolving credit facility with an accordion option which, if exercised, would allow us to increase the aggregate commitments by the greater of $100.0 million and 10% of our consolidated total assets, provided we are able to secure additional lender commitments and satisfy certain other conditions. Interest on any borrowings under the revolving credit facility accrues at either LIBOR plus 1.50% or at an alternative base rate plus 0.50%, at our election, and we are required to pay an annual commitment fee that accrues at 0.15% per annum on the unused portion of the aggregate commitments under the revolving credit facility. The revolving credit facility also allows us to issue letters of credit, which reduce the amount we can borrow. We are required to pay a fee that accrues at 1.50% per annum on the average aggregate daily maximum amount available to be drawn under any outstanding letters of credit. The revolving credit facility contains customary conditions to borrowing, events of default and covenants, including covenants that restrict our ability to incur indebtedness, grant liens, make distributions to holders of our stock or the stock of our subsidiaries, make investments or engage in transactions with our affiliates. The revolving credit facility also contains two financial maintenance covenants: a consolidated total assets covenant and a minimum liquidity balance of $350.0 million, which includes any available borrowing capacity. The obligations under the revolving credit facility are secured by liens on substantially all of our domestic assets, including certain domestic intellectual property assets. Our total borrowing capacity under the revolving credit facility is $500.0 million as of December 31, 2020. We have not issued any letters of credit against the revolving credit facility and are in compliance with all covenants under the revolving credit facility as of December 31, 2020. Letters of Credit We had $7.5 million and $25.5 million of secured letters of credit outstanding as of December 31, 2020 and 2019, respectively. These primarily relate to our office space leases and are fully collateralized by certificates of deposit which we record in prepaid expenses and other current assets or restricted cash in our consolidated balance sheets based on the term of the remaining restriction. We have entered into various non-cancelable office space operating leases with original lease periods expiring between 2021 and 2033. These do not contain material variable rent payments, residual value guarantees, covenants or other restrictions. Operating lease costs for the years ended December 31, 2020, 2019 and 2018, are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Lease cost: Operating lease cost $ 51,285 $ 40,257 $ 27,469 Short-term lease cost 3,933 3,456 2,765 Total $ 55,218 $ 43,713 $ 30,234 The weighted-average remaining term of our operating leases was 8.1 years and 8.1 years, and the weighted-average discount rate used to measure the present value of our operating lease liabilities was 4.8% and 4.6% as of December 31, 2020 and 2019, respectively. Maturities of our operating lease liabilities, which do not include short-term leases, as of December 31, 2020, are as follows (in thousands): Operating Leases 2021 $ 51,396 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total lease payments 229,930 Less imputed interest (46,976) Total operating lease liabilities $ 182,954

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation Equity Incentive Plan In June 2009, our board of directors adopted and approved our 2009 Plan, which provides for the issuance of stock options, RSAs and RSUs to qualified employees, directors and consultants. Stock options granted under our 2009 Stock Plan have a maximum life of 10 years and an exercise price not less than 100% of the fair market value of our common stock on the date of grant. RSUs granted under our 2009 Plan have a maximum life of seven years. No shares of our common stock were reserved for future issuance under our 2009 Plan as of December 31, 2020. Our 2019 Plan became effective upon closing of our IPO and succeeds our 2009 Plan. Our 2019 Plan provides for the issuance of stock options, RSAs, RSUs and other equity- or cash-based awards to qualified employees, directors and consultants. Stock options granted under our 2019 Plan have a maximum life of 10 years and an exercise price not less than 100% of the fair market value of our common stock on the date of grant. 99,801,162 shares of our Class A common stock were reserved for future issuance under our 2019 Plan as of December 31, 2020. The number of shares of our Class A common stock available for issuance under the 2019 Plan will be increased by the number of shares of our Class B common stock subject to awards outstanding under our 2009 Plan that would, but for the terms of the 2019 Plan, have returned to the share reserves of the 2009 Plan pursuant to the terms of such awards, including as the result of forfeiture, repurchase, expiration or retention by us in order to satisfy an award’s exercise price or tax withholding obligations. In addition, the number of shares of our Class A common stock reserved for issuance under our 2019 Plan will automatically increase on the first day of each fiscal year through and including January 1, 2029, in an amount equal to 5% of the total number of shares of our Class A common stock and our Class B common stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by our board of directors. Stock Option Activity Stock option activity during the year ended December 31, 2020, was as follows (in thousands, except per share amounts): Stock Options Outstanding Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value (1) (in years) Outstanding as of December 31, 2019 56,966 $ 2.25 3.5 $ 933,299 Granted 1,130 22.35 Exercised (34,149) 2.29 Outstanding as of December 31, 2020 23,947 $ 3.15 2.9 $ 1,502,604 Exercisable as of December 31, 2020 23,099 $ 2.45 2.7 $ 1,465,680 (1) We calculate intrinsic value based on the difference between the exercise price of in-the-money-stock options and the fair value of our common stock as of the respective balance sheet date. The total grant-date fair value of stock options vested during the years ended December 31, 2020, 2019 and 2018, was $3.3 million, $2.2 million and $18.6 million, respectively. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2020, 2019 and 2018, was $1,023.9 million, $425.1 million and $5.9 million, respectively. Restricted Stock Unit and Restricted Stock Award Activity RSU and RSA activity during the year ended December 31, 2020, was as follows (in thousands, except per share amounts): Restricted Stock Units Outstanding Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2019 56,791 $ 20.19 Granted 31,224 19.75 Released (23,304) 19.57 Forfeited (10,632) 18.89 Outstanding as of December 31, 2020 54,079 $ 20.45 Share-Based Compensation Share-based compensation expense during the years ended December 31, 2020, 2019 and 2018, was as follows (in thousands): Year Ended December 31, 2020 2019 2018 Cost of revenue $ 7,865 $ 31,758 $ 83 Research and development 218,718 867,191 13,155 Sales and marketing 35,645 239,315 784 General and administrative 58,792 239,517 837 Total share-based compensation $ 321,020 $ 1,377,781 $ 14,859 As of December 31, 2020, we had $742.7 million of unrecognized share-based compensation expense, which we expect to recognize over a weighted-average period of 3.0 years.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders We present net loss per share attributable to common stockholders using the two-class method required for multiple classes of common stock and participating securities. Holders of our Class A and Class B common stock have identical rights except with respect to voting, conversion and transfer rights and therefore share equally in our net losses. Prior to our IPO, we considered all series of our redeemable convertible preferred stock participating securities. We have not allocated net loss attributable to common stockholders to our redeemable convertible preferred stock because the holders of our redeemable convertible preferred stock are not contractually obligated to share in our losses. We calculate basic net loss per share attributable to common stockholders by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share attributable to common stockholders gives effect to all potential shares of common stock, including common stock issuable upon conversion of our redeemable convertible preferred stock and redeemable convertible preferred stock warrants, stock options, RSAs, RSUs and common stock warrants to the extent these are dilutive. We calculated basic and diluted net loss per share attributable to common stockholders as follows (in thousands, except per share amounts): Year Ended December 31, 2020 2019 2018 Class A Class B Class A Class B Common Numerator: Net loss attributable to common stockholders $ (96,499) $ (31,824) $ (459,412) $ (901,959) $ (62,974) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 448,392 147,872 141,894 278,579 127,091 Net loss per share attributable to common stockholders, basic and diluted $ (0.22) $ (0.22) $ (3.24) $ (3.24) $ (0.50) Basic net loss per share is the same as diluted net loss per share because we reported net losses for all periods presented. We excluded the following weighted-average potential shares of common stock from our calculation of diluted net loss per share attributable to common stockholders because these would be anti-dilutive (in thousands): Year Ended December 31, 2020 2019 2018 Redeemable convertible preferred stock — 95,469 308,373 Outstanding stock options 40,067 72,999 76,911 Unvested restricted stock units and restricted stock awards 63,603 69,800 68,795 Redeemable convertible preferred stock warrants — 77 158 Common stock warrants — — 96 Total 103,670 238,345 454,333

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of loss before provision for income taxes are as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 49,973 $ (1,266,677) $ (31,641) Foreign (176,993) (94,162) (30,923) Loss before provision for income taxes $ (127,020) $ (1,360,839) $ (62,564) Provision for income taxes consists of the following (in thousands): Year Ended December 31, 2020 2019 2018 Current: Federal $ — $ — $ — State 79 — — Foreign 691 1,677 500 Total current tax expense 770 1,677 500 Deferred: Federal 654 (555) 4 State 5 (76) 4 Foreign (126) (514) (98) Total deferred tax expense (benefit) 533 (1,145) (90) Provision for income taxes $ 1,303 $ 532 $ 410 The difference between income taxes computed at the statutory federal income tax rate and the provision for income taxes is attributable to the following (in thousands): Year Ended December 31, 2020 2019 2018 Tax at U.S. statutory rate $ (26,674) $ (285,776) $ (13,138) State income taxes, net of benefit 84 (77) 4 Foreign losses not benefited 37,716 20,932 6,891 Permanent book/tax differences 1,051 2,453 1,967 Legal settlement 2,290 — — Share-based compensation (303,245) (84,366) (864) Change in valuation allowance 352,410 422,315 15,952 Tax credits (63,205) (74,399) (10,460) Other 876 (550) 58 Provision for income taxes $ 1,303 $ 532 $ 410 The primary difference between our effective tax rate and the federal statutory rate is the full valuation allowance we have established on our federal, state and foreign net operating losses and credits. Significant components of our deferred tax assets and liabilities are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Net operating loss carryforwards $ 784,721 $ 416,709 Research tax credits 269,658 167,489 Reserves, accruals, and other 18,106 15,960 Lease obligation 44,446 52,734 Share-based compensation 96,932 133,067 Total deferred tax assets 1,213,863 785,959 Less: valuation allowance (1,176,910) (737,003) Deferred tax assets, net of valuation allowance 36,953 48,956 Deferred tax liabilities: Depreciation and amortization (34,576) (46,398) Prepaid expenses (1,523) (1,862) Total deferred tax liabilities (36,099) (48,260) Net deferred tax assets $ 854 $ 696 In December 2019, we completed an intra-entity asset transfer of certain of our intellectual property rights to an Irish subsidiary where our international business is headquartered. The transfer resulted in a step-up in the tax basis of the transferred intellectual property rights and a correlated increase in foreign deferred tax assets. As of December 31, 2020, we believe it is more likely than not that these additional foreign deferred tax assets will not be realized and, therefore, are offset by a full valuation allowance. Due to our history of losses we believe it is more likely than not that our U.S. and Irish deferred tax assets will not be realized as of December 31, 2020. Accordingly, we have established a full valuation allowance on our U.S. and Irish deferred tax assets. Our valuation allowance increased by $439.9 and $520.1 million during the years ended December 31, 2020 and 2019, respectively, primarily due to U.S. federal and state tax losses and credits incurred during the period. As of December 31, 2020, we had federal, California and other state net operating loss carryforwards of $3,282.2 million, $405.6 million and $1214.9 million, respectively. If not utilized, these will begin to expire in 2028, 2028 and 2026, respectively. Utilization of our net operating loss carryforwards may be subject to annual limitations due to the ownership change limitations provided by Section 382 of the Internal Revenue Code and similar state provisions. Our net operating loss carryforwards could expire before utilization if subject to annual limitations. As of December 31, 2020, we had $37.9 million of Irish net operating loss carryforwards that can be carried forward indefinitely. As of December 31, 2020, we had federal and California research and development credit carryforwards of $241.6 million and $181.7 million, respectively. If not utilized, our federal carryforwards will begin to expire in 2030. Our California carryforwards do not expire. Changes in gross unrecognized tax benefits were as follows (in thousands): Gross Unrecognized Tax Benefits Balance as of December 31, 2018 $ 38,550 Decreases for tax positions of prior years (50) Increases for tax positions of current year 90,685 Balance as of December 31, 2019 $ 129,185 Increases for tax positions of prior years 886 Decreases for tax positions of prior years (37,250) Increases for tax positions of current year 47,339 Balance as of December 31, 2020 $ 140,160 On June 7, 2019, a three-judge panel from the U.S. Court of Appeals for the Ninth Circuit overturned the U.S. Tax Court's decision in Altera Corp. v. Commissioner and upheld the portion of the Treasury regulations under Section 482 of the Internal Revenue Code that requires related parties in a cost-sharing arrangement to share expenses related to share-based compensation. As a result of this decision, our gross unrecognized tax benefits increased to reflect the impact of including share-based compensation in cost-sharing arrangements. On July 22, 2019, the taxpayer filed a petition for a rehearing before the full Ninth Circuit. and the request was denied on November 12, 2019. On February 10, 2020, the taxpayer filed a petition to appeal the decision to the Supreme Court and on June 22, 2020, the Supreme Court denied the petition. As a result of the Supreme Court’s action, our U.S. deferred tax asset related to net operating losses was reduced by $24.4 million and we no longer consider this to be an uncertain tax position. There is no impact on our effective tax rate for the year ended December 31, 2020, due to our full valuation allowance against our deferred tax assets. Recognizing the $140.2 million of gross unrecognized tax benefits we had as of December 31, 2020 would not affect our effective tax rate as their recognition would be offset by the reversal of related deferred tax assets, which are subject to a full valuation allowance. We do not expect our gross unrecognized tax benefits to change significantly within the next 12 months. We recognize interest and penalties related to uncertain tax positions in provision for income taxes. Accrued interest and penalties are not material as of December 31, 2020 and 2019. We are subject to taxation in the U.S. and various other state and foreign jurisdictions. As we have net operating loss carryforwards for U.S. federal and state jurisdictions, the statute of limitations is open for all tax years. For material foreign jurisdictions, the tax years open to examination include the years 2015 and forward. The Internal Revenue Service has started an examination of our U.S. consolidated federal income tax return for calendar year 2018. We believe that we have adequately reserved for any adjustments to the provision for income taxes or other tax items that may ultimately result from these examinations. We have not recognized deferred taxes for the difference between the financial reporting basis and the tax basis of our investment in our foreign subsidiaries because we have the ability and intent to maintain our investments for the foreseeable future.

Geographical Information

Geographical Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Geographical Information	Geographical Information Revenue disaggregated by geography based on our customers’ billing addresses is as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 1,404,282 $ 1,010,186 $ 697,170 International (1) 288,376 132,575 58,762 Total revenue $ 1,692,658 $ 1,142,761 $ 755,932 (1) No individual country other than the United States exceeded 10% of our total revenue for any period presented. Property and equipment, net and operating lease right-of-use assets by geography is as follows (in thousands): December 31, 2020 2019 United States $ 213,831 $ 266,763 International (1) 11,460 13,480 Total property and equipment, net and operating lease right-of-use assets $ 225,291 $ 280,243 (1) No individual country other than the United States exceeded 10% of our total property and equipment, net and operating lease right-of-use assets for any period presented.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	We prepared the accompanying consolidated financial statements in accordance with generally accepted accounting principles in the United States ("GAAP"). The consolidated financial statements include the accounts of Pinterest, Inc. and its wholly owned subsidiaries. We have eliminated all intercompany balances and transactions.
Consolidation	We prepared the accompanying consolidated financial statements in accordance with generally accepted accounting principles in the United States ("GAAP"). The consolidated financial statements include the accounts of Pinterest, Inc. and its wholly owned subsidiaries. We have eliminated all intercompany balances and transactions.
Reclassifications	We have reclassified certain amounts in prior periods to conform with current presentation.
Use of Estimates	Preparing our consolidated financial statements in conformity with GAAP requires us to make estimates and judgments that affect amounts reported in the consolidated financial statements and accompanying notes. We base these estimates and judgments on historical experience and various other assumptions that we consider reasonable. GAAP requires us to make estimates and assumptions in several areas, including the fair values of financial instruments, assets acquired and liabilities assumed through business combinations, common stock prior to our IPO, share-based awards, and contingencies as well as the collectability of our accounts receivable, the useful lives of our intangible assets and property and equipment, the incremental borrowing rate we use to determine our operating lease liabilities, and revenue recognition, among others. Actual results could differ materially from these estimates and judgments. Some of our estimates may require increased judgment due to the significant volatility, uncertainty and economic disruption of the COVID-19 pandemic. We continue to monitor the effects of the COVID-19 pandemic, and our estimates and judgments may change materially as new events occur or additional information becomes available to us.
Segments	We operate as a single operating segment. Our chief operating decision maker is our Chief Executive Officer ("CEO"), who reviews financial information presented on a consolidated basis, accompanied by disaggregated information about our revenue, for purposes of making operating decisions, assessing financial performance and allocating resources.
Revenue Recognition and Cost of Revenue	We generate revenue by delivering ads on our website and mobile application. We recognize revenue only after transferring control of promised goods or services to customers, which occurs when a user clicks on an ad contracted on a cost per click (“CPC”) basis, views an ad contracted on a cost per thousand impressions (“CPM”) basis or views a video ad contracted on a cost per view ("CPV") basis. We typically bill customers on a CPC, CPM or CPV basis, and our payment terms vary by customer type and location. The term between billing and payment due dates is not significant. We occasionally offer customers free ad inventory, and revenue is recognized only after satisfying our contractual performance obligations. When contracts with our customers contain multiple performance obligations, we allocate the overall transaction price, which is the amount of consideration to which we expect to be entitled in exchange for promised goods or services, to each of the distinct performance obligations based on their relative standalone selling prices. We generally determine standalone selling prices based on the effective price charged per contracted click, impression or view, and we do not disclose the value of unsatisfied performance obligations because the original expected duration of our contracts is generally less than one year. We record sales commissions in sales and marketing expense as incurred because we would amortize these over a period of less than one year.
Share-Based Compensation	RSUs granted under our 2009 Plan are subject to both a service condition, which is typically satisfied over four years, and a performance condition, which was deemed satisfied upon the pricing of our IPO. We did not record any share-based compensation expense for our RSUs prior to our IPO because the performance condition had not yet been satisfied. Upon pricing our IPO, we recorded cumulative share-based compensation expense using the accelerated attribution method for those RSUs granted under our 2009 Plan for which the service condition had been satisfied at that date. We will record the remaining unrecognized share-based compensation expense over the remainder of the requisite service period. RSUs and restricted stock awards ("RSAs") granted under our 2019 Omnibus Incentive Plan (the "2019 Plan") are subject only to a service condition, which is typically satisfied over four years. We record share-based compensation expense for these RSUs and RSAs on a straight-line basis over the requisite service period.
Income Taxes	We account for income taxes using the asset and liability method. We recognize deferred tax assets and liabilities for temporary differences between the financial reporting and tax bases of assets and liabilities using the enacted statutory tax rates in effect for the years in which we expect the differences to reverse. We establish valuation allowances to reduce deferred tax assets to the amounts we believe it is more likely than not we will be able to realize. We recognize tax benefits from uncertain tax positions when we believe it is more likely than not that the tax position is sustainable on examination by tax authorities based on its technical merits. We recognize taxes on Global Intangible Low-Taxed Income ("GILTI") as a current period expense when incurred.
Advertising Expenses	We record advertising expenses as incurred and include these in sales and marketing in the consolidated statements of operations.
Marketable Securities	We invest in highly liquid corporate debt securities, U.S. treasury securities, asset-backed securities, U.S. government agency securities, money market funds and certificates of deposit. We classify marketable investments with stated maturities of ninety days or less from the date of purchase as cash equivalents and those with stated maturities greater than ninety days from the date of purchase as marketable securities. We classify our marketable securities as available-for-sale investments in our current assets because they are available for use to support current operations. We carry our marketable investments at fair value and record unrealized gains or losses, net of taxes, in accumulated other comprehensive income (loss) in stockholders’ equity (deficit). We determine realized gains and losses on the sale of marketable investments using a specific identification method and record these and any expected credit losses in interest expense and other income (expense), net.
Restricted Cash	Our restricted cash primarily consists of certificates of deposit underlying secured letters of credit issued in connection with our operating leases. Restrictions typically lapse at the end of the lease term, and we classify restricted cash as current or non-current based on the remaining term of the restriction.
Fair Value Measurements	We account for certain assets and liabilities at fair value, which is the amount we believe market participants would receive to sell an asset or pay to transfer a liability in an orderly transaction. We categorize these assets and liabilities into the three levels below based on the degree to which the inputs we use to measure their fair values are observable in active markets. We use the most observable inputs available to us when measuring fair value. • Level 1: Observable inputs such as quoted prices for identical assets or liabilities in active markets • Level 2: Observable inputs such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in inactive markets, or inputs that are derived principally from or corroborated by observable market data or other means • Level 3: Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities
Accounts Receivable, Net of Allowances	We record accounts receivable at the original invoiced amount. We maintain an allowance for credit losses for any receivables we may be unable to collect. We estimate uncollectible receivables based on our receivables’ age, our customers’ credit quality and current economic conditions, among other factors that may affect our customers’ ability to pay. We also maintain an allowance for sales credits, which we determine based on historical credits issued to customers. We include the allowances for credit losses and sales credits in accounts receivable, net in the consolidated balance sheets.
Property and Equipment	We carry property and equipment at cost less accumulated depreciation and calculate depreciation using the straight-line method over our assets’ estimated useful lives, which are generally: Property and Equipment Useful Life Computer and network equipment 3 years Furniture and fixtures 4 years Leasehold improvements Lesser of estimated useful life or remaining lease term
Leases and Operating Lease Incremental Borrowing Rate	We lease office space under operating leases with expiration dates through 2033. We determine whether an arrangement constitutes a lease at inception and record lease liabilities and right-of-use assets on our consolidated balance sheets at lease commencement. We measure lease liabilities based on the present value of the total lease payments not yet paid discounted based on the more readily determinable of the rate implicit in the lease or our incremental borrowing rate, which is the estimated rate we would be required to pay for a collateralized borrowing equal to the total lease payments over the term of the lease. We estimate our incremental borrowing rate based on an analysis of publicly traded debt securities of companies with credit and financial profiles similar to our own. We measure right-of-use assets based on the corresponding lease liability adjusted for (i) payments made to the lessor at or before the commencement date, (ii) initial direct costs we incur and (iii) tenant incentives under the lease. We begin recognizing rent expense when the lessor makes the underlying asset available to us, we do not assume renewals or early terminations unless we are reasonably certain to exercise these options at commencement, and we do not allocate consideration between lease and non-lease components. For short-term leases, we record rent expense in our consolidated statements of operations on a straight-line basis over the lease term and record variable lease payments as incurred.
Business Combinations	We include the results of operations of businesses that we acquire in our consolidated financial statements beginning on their respective acquisition dates. We allocate the fair value of the purchase consideration to the assets acquired and liabilities assumed based on their estimated fair values. When the fair value of the purchase consideration exceeds the fair values of the identifiable assets and liabilities acquired, we record the excess as goodwill.
Long-Lived Assets, Including Goodwill and Intangible Assets	We record definite-lived intangible assets at fair value less accumulated amortization. We calculate amortization using the straight-line method over the assets’ estimated useful lives of up to ten years. We review our property and equipment and intangible assets for impairment whenever events or circumstances indicate that an asset’s carrying value may not be recoverable. We measure recoverability by comparing an asset’s carrying value to the future undiscounted cash flows that we expect it to generate. If this test indicates that the asset’s carrying value is not recoverable, we record an impairment charge to reduce the asset’s carrying value to its fair value. We did not record material property and equipment or intangible asset impairments during the periods presented. We review goodwill for impairment at least annually or more frequently if current circumstances or events indicate that the fair value of our single reporting unit may be less than its carrying value. We did not record any goodwill impairment during the periods presented.
Website Development Costs	We capitalize costs to develop our website and mobile application when preliminary development efforts are successfully completed, management has authorized and committed project funding, and it is probable that the project will be completed and the software will be used as intended. Due to the iterative process by which we perform upgrades and the relatively short duration of our development projects, development costs meeting our capitalization criteria were not material during the periods presented.
Loss Contingencies	We are involved in various lawsuits, claims and proceedings that arise in the ordinary course of business. We record a liability for these when we believe it is probable that we have incurred a loss and can reasonably estimate the loss. We regularly evaluate current information to determine whether we should adjust a recorded liability or record a new one.
Foreign Currency	The functional currency of our international subsidiaries is generally their local currency. We translate these subsidiaries’ financial statements into U.S. dollars using month-end exchange rates for assets and liabilities and average exchange rates for revenue and costs and expenses. We record translation gains and losses in accumulated other comprehensive income (loss) in stockholders’ equity (deficit). We record foreign exchange gains and losses in interest expense and other income (expense), net. Our net foreign exchange gains and losses were not material for the periods presented.
Concentration of Business Risk	We have an agreement with Amazon Web Services (“AWS”) to provide the cloud computing infrastructure we use to host our website, mobile application and many of the internal tools we use to operate our business. We are currently required to maintain a substantial majority of our monthly usage of certain compute, storage, data transfer and other services on AWS. Any transition of the cloud services currently provided by AWS to another cloud services provider would be difficult to implement and would cause us to incur significant time and expense.
Concentration of Credit Risk	Financial instruments that may potentially expose us to concentrations of credit risk primarily consist of cash, cash equivalents, marketable securities and restricted cash. Our investment policy is meant to preserve capital and maintain liquidity. The policy limits our marketable investments to investment-grade securities and limits our credit exposure by limiting our concentration in any one corporate issuer or sector and by establishing a minimum credit rating for marketable investments we purchase. Although we deposit cash and marketable investments with multiple financial institutions, our deposits may exceed insurable limits.
Credit Losses on Accounts Receivable	Our accounts receivable are generally unsecured. We monitor our customers’ credit quality on an ongoing basis and maintain reserves for estimated credit losses.
Recently Adopted Accounting Pronouncements	In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which requires the measurement and recognition of expected credit losses for financial assets not held at fair value. ASU 2016-13 replaces the existing incurred loss impairment model with a forward-looking expected credit loss model which will result in earlier recognition of credit losses. We adopted ASU 2016-13 as of January 1, 2020, using the modified retrospective method, and while the effects of adoption on our consolidated financial statements were not material, we continue to monitor the effects of the COVID-19 pandemic on expected credit losses. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which simplifies the accounting for income taxes by removing certain exceptions to the general principles for income taxes. We elected to early adopt ASU 2019-12 effective as of January 1, 2020, and the effects of adoption on our consolidated financial statements were not material.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Estimated Useful Lives of Property and Equipment	We carry property and equipment at cost less accumulated depreciation and calculate depreciation using the straight-line method over our assets’ estimated useful lives, which are generally: Property and Equipment Useful Life Computer and network equipment 3 years Furniture and fixtures 4 years Leasehold improvements Lesser of estimated useful life or remaining lease term Property and equipment, net consists of the following (in thousands): December 31, 2020 2019 Leasehold improvements $ 101,242 $ 109,807 Furniture and fixtures 24,516 22,353 Computer and network equipment 27,230 22,963 Total property and equipment 152,988 155,123 Less: accumulated depreciation (83,770) (73,270) Construction in progress 157 10,139 Property and equipment, net $ 69,375 $ 91,992

Cash, Cash Equivalents and Ma_2

Cash, Cash Equivalents and Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Composition of Cash, Cash Equivalents and Marketable Securities	Cash, cash equivalents and marketable securities consist of the following (in thousands): December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 352,061 $ — $ — $ 352,061 Money market funds 225,643 — — 225,643 Commercial paper 48,530 2 — 48,532 U.S. treasury securities 39,997 1 — 39,998 Certificates of deposit 2,996 — — 2,996 Total cash and cash equivalents 669,227 3 — 669,230 Marketable securities: Corporate bonds 452,723 1,782 (18) 454,487 U.S. treasury securities 202,795 260 (1) 203,054 Commercial paper 234,170 86 (3) 234,253 Certificates of deposit 134,828 57 (3) 134,882 Municipal securities 17,604 22 (7) 17,619 U.S. agency bonds 16,012 6 — 16,018 Non-U.S. government and supranational bonds 15,938 13 (1) 15,950 Asset-backed securities 14,752 61 — 14,813 Total marketable securities 1,088,822 2,287 (33) 1,091,076 Total $ 1,758,049 $ 2,290 $ (33) $ 1,760,306 December 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash and cash equivalents: Cash $ 323,194 $ — $ — $ 323,194 Money market funds 214,413 — — 214,413 Commercial paper 105,359 1 (6) 105,354 Corporate bonds 3,792 — (1) 3,791 Certificates of deposit 2,914 — — 2,914 Total cash and cash equivalents 649,672 1 (7) 649,666 Marketable securities: Corporate bonds 449,496 981 (44) 450,433 U.S. treasury securities 201,561 88 (9) 201,640 Commercial paper 196,304 31 (7) 196,328 Asset-backed securities 114,425 188 (14) 114,599 Certificates of deposit 100,647 38 (6) 100,679 Total marketable securities 1,062,433 1,326 (80) 1,063,679 Total $ 1,712,105 $ 1,327 $ (87) $ 1,713,345
Fair Value of Marketable Securities by Contractual Maturity	The fair value of our marketable securities by contractual maturity is as follows (in thousands): December 31, 2020 Due in one year or less $ 787,395 Due after one to five years 303,681 Total $ 1,091,076

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Values of Financial Instruments Measured on a Recurring Basis	The fair values of the financial instruments we measure at fair value on a recurring basis are as follows (in thousands): December 31, 2020 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 225,643 $ — $ — $ 225,643 Commercial paper — 48,532 — 48,532 U.S. treasury securities 39,998 — — 39,998 Certificates of deposit — 2,996 — 2,996 Marketable securities: Corporate bonds — 454,487 — 454,487 Commercial paper — 234,253 — 234,253 U.S. treasury securities 203,054 — — 203,054 Certificates of deposit — 134,882 — 134,882 Municipal securities — 17,619 — 17,619 U.S. agency bonds — 16,018 — 16,018 Non-U.S. government and supranational bonds — 15,950 — 15,950 Asset-backed securities — 14,813 — 14,813 Prepaid expenses and other current assets: Certificates of deposit — 571 — 571 Restricted cash: Certificates of deposit $ — $ 9,110 $ — $ 9,110 December 31, 2019 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 214,413 $ — $ — $ 214,413 Commercial paper — 105,354 — 105,354 Corporate bonds — 3,791 — 3,791 Certificates of deposit — 2,914 — 2,914 Marketable securities: Corporate bonds — 450,433 — 450,433 U.S. treasury securities 201,640 — — 201,640 Commercial paper — 196,328 — 196,328 Asset-backed securities — 114,599 — 114,599 Certificates of deposit — 100,679 — 100,679 Prepaid expenses and other current assets: Certificates of deposit — 2,738 — 2,738 Restricted cash: Certificates of deposit $ — $ 25,339 $ — $ 25,339

Other Balance Sheet Components

Other Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2020
Other Balance Sheet Components [Abstract]
Property and Equipment, Net	We carry property and equipment at cost less accumulated depreciation and calculate depreciation using the straight-line method over our assets’ estimated useful lives, which are generally: Property and Equipment Useful Life Computer and network equipment 3 years Furniture and fixtures 4 years Leasehold improvements Lesser of estimated useful life or remaining lease term Property and equipment, net consists of the following (in thousands): December 31, 2020 2019 Leasehold improvements $ 101,242 $ 109,807 Furniture and fixtures 24,516 22,353 Computer and network equipment 27,230 22,963 Total property and equipment 152,988 155,123 Less: accumulated depreciation (83,770) (73,270) Construction in progress 157 10,139 Property and equipment, net $ 69,375 $ 91,992
Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consists of the following (in thousands): December 31, 2020 2019 Accrued hosting expenses $ 39,233 $ 27,322 Accrued compensation 33,215 26,574 Operating lease liabilities 43,633 46,527 Other accrued expenses 39,259 41,400 Accrued expenses and other current liabilities $ 155,340 $ 141,823

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Composition of Intangible Assets, Net	Intangible assets, net consists of the following (in thousands): December 31, 2020 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted-Average Useful Life (1) Acquired patents $ 9,037 $ (2,380) $ 6,657 9.1 years Acquired technology and other intangibles 4,385 (4,385) — 1.5 years Total intangible assets, net $ 13,422 $ (6,765) $ 6,657 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted-Average Useful Life (1) Acquired patents $ 9,037 $ (1,370) $ 7,667 9.1 years Acquired technology and other intangibles 4,385 (4,381) 4 1.5 years Total intangible assets, net $ 13,422 $ (5,751) $ 7,671 (1) Based on the weighted-average useful life established as of acquisition date.
Estimated Future Amortization Expense	Estimated future amortization expense as of December 31, 2020, is as follows (in thousands): Intangible Asset Amortization 2021 $ 1,009 2022 1,009 2023 1,009 2024 1,009 2025 999 Thereafter 1,622 Total $ 6,657

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Maturities of Operating Lease Liabilities	As of December 31, 2020, our non-cancelable contractual commitments, consisting of operating leases, are as follows (in thousands): Total Commitments 2021 $ 52,472 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total $ 231,006 Maturities of our operating lease liabilities, which do not include short-term leases, as of December 31, 2020, are as follows (in thousands): Operating Leases 2021 $ 51,396 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total lease payments 229,930 Less imputed interest (46,976) Total operating lease liabilities $ 182,954
Non-cancelable Contractual Commitments	As of December 31, 2020, our non-cancelable contractual commitments, consisting of operating leases, are as follows (in thousands): Total Commitments 2021 $ 52,472 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total $ 231,006

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Operating Lease Costs	Operating lease costs for the years ended December 31, 2020, 2019 and 2018, are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Lease cost: Operating lease cost $ 51,285 $ 40,257 $ 27,469 Short-term lease cost 3,933 3,456 2,765 Total $ 55,218 $ 43,713 $ 30,234
Maturities of Operating Lease Liabilities	As of December 31, 2020, our non-cancelable contractual commitments, consisting of operating leases, are as follows (in thousands): Total Commitments 2021 $ 52,472 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total $ 231,006 Maturities of our operating lease liabilities, which do not include short-term leases, as of December 31, 2020, are as follows (in thousands): Operating Leases 2021 $ 51,396 2022 35,224 2023 21,559 2024 11,942 2025 12,300 Thereafter 97,509 Total lease payments 229,930 Less imputed interest (46,976) Total operating lease liabilities $ 182,954

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock Option Activity	Stock option activity during the year ended December 31, 2020, was as follows (in thousands, except per share amounts): Stock Options Outstanding Shares Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value (1) (in years) Outstanding as of December 31, 2019 56,966 $ 2.25 3.5 $ 933,299 Granted 1,130 22.35 Exercised (34,149) 2.29 Outstanding as of December 31, 2020 23,947 $ 3.15 2.9 $ 1,502,604 Exercisable as of December 31, 2020 23,099 $ 2.45 2.7 $ 1,465,680 (1) We calculate intrinsic value based on the difference between the exercise price of in-the-money-stock options and the fair value of our common stock as of the respective balance sheet date.
Restricted Stock Unit Activity	RSU and RSA activity during the year ended December 31, 2020, was as follows (in thousands, except per share amounts): Restricted Stock Units Outstanding Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2019 56,791 $ 20.19 Granted 31,224 19.75 Released (23,304) 19.57 Forfeited (10,632) 18.89 Outstanding as of December 31, 2020 54,079 $ 20.45
Share-Based Compensation Expense	Share-based compensation expense during the years ended December 31, 2020, 2019 and 2018, was as follows (in thousands): Year Ended December 31, 2020 2019 2018 Cost of revenue $ 7,865 $ 31,758 $ 83 Research and development 218,718 867,191 13,155 Sales and marketing 35,645 239,315 784 General and administrative 58,792 239,517 837 Total share-based compensation $ 321,020 $ 1,377,781 $ 14,859

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Calculation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	We calculated basic and diluted net loss per share attributable to common stockholders as follows (in thousands, except per share amounts): Year Ended December 31, 2020 2019 2018 Class A Class B Class A Class B Common Numerator: Net loss attributable to common stockholders $ (96,499) $ (31,824) $ (459,412) $ (901,959) $ (62,974) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 448,392 147,872 141,894 278,579 127,091 Net loss per share attributable to common stockholders, basic and diluted $ (0.22) $ (0.22) $ (3.24) $ (3.24) $ (0.50)
Weighted-Average Anti-Dilutive Shares of Common Stock Excluded from the Calculation of Diluted Net Loss Per Share	Basic net loss per share is the same as diluted net loss per share because we reported net losses for all periods presented. We excluded the following weighted-average potential shares of common stock from our calculation of diluted net loss per share attributable to common stockholders because these would be anti-dilutive (in thousands): Year Ended December 31, 2020 2019 2018 Redeemable convertible preferred stock — 95,469 308,373 Outstanding stock options 40,067 72,999 76,911 Unvested restricted stock units and restricted stock awards 63,603 69,800 68,795 Redeemable convertible preferred stock warrants — 77 158 Common stock warrants — — 96 Total 103,670 238,345 454,333

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Components of Loss Before Provision for Income Taxes	The components of loss before provision for income taxes are as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 49,973 $ (1,266,677) $ (31,641) Foreign (176,993) (94,162) (30,923) Loss before provision for income taxes $ (127,020) $ (1,360,839) $ (62,564)
Composition of the Provision for Income Taxes	Provision for income taxes consists of the following (in thousands): Year Ended December 31, 2020 2019 2018 Current: Federal $ — $ — $ — State 79 — — Foreign 691 1,677 500 Total current tax expense 770 1,677 500 Deferred: Federal 654 (555) 4 State 5 (76) 4 Foreign (126) (514) (98) Total deferred tax expense (benefit) 533 (1,145) (90) Provision for income taxes $ 1,303 $ 532 $ 410
Reconciliation of the Difference Between Income Taxes Computed at the Statutory Federal Income Tax Rate and the Provision for Income Taxes	The difference between income taxes computed at the statutory federal income tax rate and the provision for income taxes is attributable to the following (in thousands): Year Ended December 31, 2020 2019 2018 Tax at U.S. statutory rate $ (26,674) $ (285,776) $ (13,138) State income taxes, net of benefit 84 (77) 4 Foreign losses not benefited 37,716 20,932 6,891 Permanent book/tax differences 1,051 2,453 1,967 Legal settlement 2,290 — — Share-based compensation (303,245) (84,366) (864) Change in valuation allowance 352,410 422,315 15,952 Tax credits (63,205) (74,399) (10,460) Other 876 (550) 58 Provision for income taxes $ 1,303 $ 532 $ 410
Significant Components of Deferred Tax Assets and Liabilities	Significant components of our deferred tax assets and liabilities are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Net operating loss carryforwards $ 784,721 $ 416,709 Research tax credits 269,658 167,489 Reserves, accruals, and other 18,106 15,960 Lease obligation 44,446 52,734 Share-based compensation 96,932 133,067 Total deferred tax assets 1,213,863 785,959 Less: valuation allowance (1,176,910) (737,003) Deferred tax assets, net of valuation allowance 36,953 48,956 Deferred tax liabilities: Depreciation and amortization (34,576) (46,398) Prepaid expenses (1,523) (1,862) Total deferred tax liabilities (36,099) (48,260) Net deferred tax assets $ 854 $ 696
Changes in Gross Unrecognized Tax Benefits	Changes in gross unrecognized tax benefits were as follows (in thousands): Gross Unrecognized Tax Benefits Balance as of December 31, 2018 $ 38,550 Decreases for tax positions of prior years (50) Increases for tax positions of current year 90,685 Balance as of December 31, 2019 $ 129,185 Increases for tax positions of prior years 886 Decreases for tax positions of prior years (37,250) Increases for tax positions of current year 47,339 Balance as of December 31, 2020 $ 140,160

Geographical Information (Table

Geographical Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Revenue Disaggregated by Geography	Revenue disaggregated by geography based on our customers’ billing addresses is as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 1,404,282 $ 1,010,186 $ 697,170 International (1) 288,376 132,575 58,762 Total revenue $ 1,692,658 $ 1,142,761 $ 755,932 (1) No individual country other than the United States exceeded 10% of our total revenue for any period presented.
Property and Equipment, Net and Operating Lease Right-of-Use Assets by Geography	Property and equipment, net and operating lease right-of-use assets by geography is as follows (in thousands): December 31, 2020 2019 United States $ 213,831 $ 266,763 International (1) 11,460 13,480 Total property and equipment, net and operating lease right-of-use assets $ 225,291 $ 280,243 (1) No individual country other than the United States exceeded 10% of our total property and equipment, net and operating lease right-of-use assets for any period presented.

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies - Narrative (Details) $ / shares in Units, $ in Thousands	Apr. 29, 2019USD ($)$ / sharesshares	Apr. 23, 2019USD ($)$ / sharesshares	Apr. 22, 2019shares	Mar. 28, 2019	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary of Significant Accounting Policies [Line Items]
Share-based compensation | $					$ 321,020	$ 1,377,781	$ 14,859
Reverse stock split ratio				0.33
Number of operating segments | segment					1
Advertising expenses | $					$ 30,300	$ 55,000	$ 19,200
Estimated useful lives of intangible assets (up to)					10 years
Unvested restricted stock units and restricted stock awards | 2019 Plan
Summary of Significant Accounting Policies [Line Items]
Service period					4 years
RSUs | 2009 Plan
Summary of Significant Accounting Policies [Line Items]
Service period					4 years
Class A Common Stock | IPO
Summary of Significant Accounting Policies [Line Items]
Shares sold (in shares)		75,000,000
Share price (in dollars per share) | $ / shares		$ 19
Net proceeds | $		$ 1,368,000
Estimated offering costs | $		$ 9,800
Class A Common Stock | Over-Allotment Option
Summary of Significant Accounting Policies [Line Items]
Shares sold (in shares)	11,250,000
Share price (in dollars per share) | $ / shares	$ 19
Net proceeds | $	$ 205,200
Redeemable Convertible Preferred Stock and Redeemable Convertible Preferred Stock Warrants Converted | Class B Common Stock
Summary of Significant Accounting Policies [Line Items]
Shares issued in conversion (in shares)			308,621,636
Shares converted (in shares)			1
Common Stock Reclassified Into Class B Common Stock | Class B Common Stock
Summary of Significant Accounting Policies [Line Items]
Shares issued in conversion (in shares)			456,213,756
Common stock reclassified (in shares)			1

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2020
Computer and network equipment
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful Life	4 years

Cash, Cash Equivalents and Ma_3

Cash, Cash Equivalents and Marketable Securities - Composition of Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Cash and cash equivalents:
Amortized Cost	$ 669,227	$ 649,672
Unrealized Gains	3	1
Unrealized Losses	0	(7)
Fair Value	669,230	649,666
Marketable securities:
Amortized Cost	1,088,822	1,062,433
Unrealized Gains	2,287	1,326
Unrealized Losses	(33)	(80)
Fair Value	1,091,076	1,063,679
Total
Amortized Cost	1,758,049	1,712,105
Unrealized Gains	2,290	1,327
Unrealized Losses	(33)	(87)
Fair Value	1,760,306	1,713,345
Corporate bonds
Marketable securities:
Amortized Cost	452,723	449,496
Unrealized Gains	1,782	981
Unrealized Losses	(18)	(44)
Fair Value	454,487	450,433
U.S. treasury securities
Marketable securities:
Amortized Cost	202,795	201,561
Unrealized Gains	260	88
Unrealized Losses	(1)	(9)
Fair Value	203,054	201,640
Commercial paper
Marketable securities:
Amortized Cost	234,170	196,304
Unrealized Gains	86	31
Unrealized Losses	(3)	(7)
Fair Value	234,253	196,328
Asset-backed securities
Marketable securities:
Amortized Cost	14,752	114,425
Unrealized Gains	61	188
Unrealized Losses	0	(14)
Fair Value	14,813	114,599
U.S. agency bonds
Marketable securities:
Amortized Cost	16,012
Unrealized Gains	6
Unrealized Losses	0
Fair Value	16,018
Certificates of deposit
Marketable securities:
Amortized Cost	134,828	100,647
Unrealized Gains	57	38
Unrealized Losses	(3)	(6)
Fair Value	134,882	100,679
Municipal securities
Marketable securities:
Amortized Cost	17,604
Unrealized Gains	22
Unrealized Losses	(7)
Fair Value	17,619
Non-U.S. government and supranational bonds
Marketable securities:
Amortized Cost	15,938
Unrealized Gains	13
Unrealized Losses	(1)
Fair Value	15,950
Cash
Cash and cash equivalents:
Amortized Cost	352,061	323,194
Fair Value	352,061	323,194
Money market funds
Cash and cash equivalents:
Amortized Cost	225,643	214,413
Fair Value	225,643	214,413
Commercial paper
Cash and cash equivalents:
Amortized Cost	48,530	105,359
Unrealized Gains	2	1
Unrealized Losses	0	(6)
Fair Value	48,532	105,354
Corporate bonds
Cash and cash equivalents:
Amortized Cost		3,792
Unrealized Losses		(1)
Fair Value		3,791
U.S. treasury securities
Cash and cash equivalents:
Amortized Cost	39,997
Unrealized Gains	1
Fair Value	39,998
Certificates of deposit
Cash and cash equivalents:
Amortized Cost	2,996	2,914
Fair Value	$ 2,996	$ 2,914

Cash, Cash Equivalents and Ma_4

Cash, Cash Equivalents and Marketable Securities - Fair Value of Marketable Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Due in one year or less	$ 787,395
Due after one to five years	303,681
Total	$ 1,091,076	$ 1,063,679

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Fair Values of Financial Instruments Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 669,230	$ 649,666
Marketable securities	1,091,076	1,063,679
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	454,487	450,433
Corporate bonds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	454,487	450,433
Corporate bonds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Corporate bonds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	454,487	450,433
Corporate bonds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	234,253	196,328
Commercial paper | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	234,253	196,328
Commercial paper | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Commercial paper | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	234,253	196,328
Commercial paper | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	203,054	201,640
U.S. treasury securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	203,054	201,640
U.S. treasury securities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	203,054	201,640
U.S. treasury securities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
U.S. treasury securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	134,882	100,679
Certificates of deposit | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	134,882	100,679
Prepaid expenses and other current assets	571	2,738
Restricted cash	9,110	25,339
Certificates of deposit | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Prepaid expenses and other current assets	0	0
Restricted cash	0	0
Certificates of deposit | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	134,882	100,679
Prepaid expenses and other current assets	571	2,738
Restricted cash	9,110	25,339
Certificates of deposit | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Prepaid expenses and other current assets	0	0
Restricted cash	0	0
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	17,619
Municipal securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	17,619
Municipal securities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
Municipal securities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	17,619
Municipal securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
U.S. agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,018
U.S. agency bonds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,018
U.S. agency bonds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
U.S. agency bonds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,018
U.S. agency bonds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
Non-U.S. government and supranational bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	15,950
Non-U.S. government and supranational bonds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	15,950
Non-U.S. government and supranational bonds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
Non-U.S. government and supranational bonds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	15,950
Non-U.S. government and supranational bonds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	14,813	114,599
Asset-backed securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	14,813	114,599
Asset-backed securities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Asset-backed securities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	14,813	114,599
Asset-backed securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	225,643	214,413
Money market funds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	225,643	214,413
Money market funds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	225,643	214,413
Money market funds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Money market funds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	48,532	105,354
Commercial paper | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	48,532	105,354
Commercial paper | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Commercial paper | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	48,532	105,354
Commercial paper | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		3,791
Corporate bonds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		3,791
Corporate bonds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		0
Corporate bonds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		3,791
Corporate bonds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		0
U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	39,998
U.S. treasury securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	39,998
U.S. treasury securities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	39,998
U.S. treasury securities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
U.S. treasury securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,996	2,914
Certificates of deposit | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,996	2,914
Certificates of deposit | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Certificates of deposit | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,996	2,914
Certificates of deposit | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

Other Balance Sheet Component_2

Other Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation	$ (83,770)	$ (73,270)
Property and equipment, net	69,375	91,992
Depreciable Property and Equipment
Property, Plant and Equipment [Line Items]
Property and equipment	152,988	155,123
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	101,242	109,807
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	24,516	22,353
Computer and network equipment
Property, Plant and Equipment [Line Items]
Property and equipment	27,230	22,963
Construction in Progress
Property, Plant and Equipment [Line Items]
Property and equipment	$ 157	$ 10,139

Other Balance Sheet Component_3

Other Balance Sheet Components - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Balance Sheet Components [Abstract]
Depreciation expense	$ 36	$ 26.3	$ 20.1

Other Balance Sheet Component_4

Other Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other Balance Sheet Components [Abstract]
Accrued hosting expenses	$ 39,233	$ 27,322
Accrued compensation	33,215	26,574
Operating lease liabilities	43,633	46,527
Other accrued expenses	39,259	41,400
Accrued expenses and other current liabilities	$ 155,340	$ 141,823
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets, Net - Composition of Intangible Assets, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 13,422	$ 13,422
Accumulated Amortization	(6,765)	(5,751)
Net Carrying Amount	$ 6,657	7,671
Weighted-Average Useful Life	10 years
Acquired patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 9,037	9,037
Accumulated Amortization	(2,380)	(1,370)
Net Carrying Amount	$ 6,657	$ 7,667
Weighted-Average Useful Life	9 years 1 month 6 days	9 years 1 month 6 days
Acquired technology and other intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4,385	$ 4,385
Accumulated Amortization	(4,385)	(4,381)
Net Carrying Amount	$ 0	$ 4
Weighted-Average Useful Life	1 year 6 months	1 year 6 months

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets, Net - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 1	$ 1.5	$ 0.7

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets, Net - Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 1,009
2021	1,009
2022	1,009
2023	1,009
2024	999
Thereafter	1,622
Net Carrying Amount	$ 6,657	$ 7,671

Commitments and Contingencies -

Commitments and Contingencies - Non-cancelable Contractual Commitments (Details) $ in Thousands	Dec. 31, 2020USD ($)
Total Commitments
2021	$ 52,472
2022	35,224
2023	21,559
2024	11,942
2025	12,300
Thereafter	97,509
Total	$ 231,006

Commitments and Contingencies_2

Commitments and Contingencies - Narrative (Details) ft² in Thousands	1 Months Ended
	Aug. 31, 2020USD ($)	Nov. 30, 2018USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Mar. 31, 2019USD ($)ft²
Commitments And Contingencies [Line Items]
Area of office space (in sqft) | ft²					490
One-time payment for lease termination	$ 89,500,000
Noncancelable minimum lease payments not yet commenced					$ 440,000,000
Secured letters of credit outstanding			$ 7,500,000	$ 25,500,000
Revolving Credit Facility | Line of Credit
Commitments And Contingencies [Line Items]
Term of borrowing agreement		5 years
Maximum borrowing capacity		$ 500,000,000
Increase in maximum borrowing capacity if the accordion option is exercised		$ 100,000,000
Maximum increase in maximum borrowing capacity as a percent of consolidated total assets		10.00%
Commitment fee rate		0.15%
Required minimum liquidity balance		$ 350,000,000
Remaining borrowing capacity			$ 500,000,000
Revolving Credit Facility | Line of Credit | LIBOR
Commitments And Contingencies [Line Items]
Basis spread on variable rate		1.50%
Revolving Credit Facility | Line of Credit | Alternative Base Rate
Commitments And Contingencies [Line Items]
Basis spread on variable rate		0.50%
Revolving Credit Facility | Letter of Credit
Commitments And Contingencies [Line Items]
Commitment fee rate		1.50%

Leases - Operating Lease Costs

Leases - Operating Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lease cost:
Operating lease cost	$ 51,285	$ 40,257	$ 27,469
Short-term lease cost	3,933	3,456	2,765
Total	$ 55,218	$ 43,713	$ 30,234

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Weighted-average remaining term of operating leases	8 years 1 month 6 days	8 years 1 month 6 days
Weighted-average discount rate used to measure the present value of operating lease liabilities	4.80%	4.60%
Cash payments included in the measurement of operating lease liabilities	$ 54.3	$ 38.4	$ 26.2

Leases - Maturities of Operatin

Leases - Maturities of Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 51,396
2022	35,224
2023	21,559
2024	11,942
2025	12,300
Thereafter	97,509
Total lease payments	229,930
Less imputed interest	(46,976)
Total operating lease liabilities	$ 182,954

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of outstanding shares, additional reserve	5.00%
Grant-date fair value of stock options vested	$ 3.3	$ 2.2	$ 18.6
Aggregate intrinsic value of stock options exercised	1,023.9	$ 425.1	$ 5.9
Unrecognized share-based compensation expense	$ 742.7
Weighted-average recognition period for unrecognized share-based compensation expense	3 years
2009 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance (in shares)	0
2009 Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
2009 Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	7 years
2019 Plan | Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance (in shares)	99,801,162
2019 Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Shares
Beginning balance (in shares)	56,966
Granted (in shares)	1,130
Exercised (in shares)	(34,149)
Ending balance (in shares)	23,947	56,966
Exercisable (in shares)	23,099
Weighted-Average Exercise Price
Beginning balance (in dollars per share)	$ 2.25
Granted (in dollars per share)	22.35
Exercised (in dollars per share)	2.29
Ending balance (in dollars per share)	3.15	$ 2.25
Exercisable (in dollars per share)	$ 2.45
Weighted-Average Remaining Contractual Term, Outstanding	2 years 10 months 24 days	3 years 6 months
Weighted-Average Remaining Contractual Term, Exercisable	2 years 8 months 12 days
Aggregate Intrinsic Value, Outstanding	$ 1,502,604	$ 933,299
Aggregate Intrinsic Value, Exercisable	$ 1,465,680

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Stock Unit Activity (Details) - Unvested restricted stock units and restricted stock awards shares in Thousands	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Shares
Beginning balance (in shares) | shares	56,791
Granted (in shares) | shares	31,224
Released (in shares) | shares	(23,304)
Forfeited (in shares) | shares	(10,632)
Ending balance (in shares) | shares	54,079
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 20.19
Granted (in dollars per share) | $ / shares	19.75
Released (in dollars per share) | $ / shares	19.57
Forfeited (in dollars per share) | $ / shares	18.89
Ending balance (in dollars per share) | $ / shares	$ 20.45

Share-Based Compensation - Shar

Share-Based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 321,020	$ 1,377,781	$ 14,859
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	7,865	31,758	83
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	218,718	867,191	13,155
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	35,645	239,315	784
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 58,792	$ 239,517	$ 837

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Calculation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss attributable to common stockholders	$ (128,323)	$ (1,361,371)	$ (62,974)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	596,264	420,473	127,091
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.22)	$ (3.24)	$ (0.50)
Class A
Numerator:
Net loss attributable to common stockholders	$ (96,499)	$ (459,412)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	448,392	141,894
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.22)	$ (3.24)
Class B
Numerator:
Net loss attributable to common stockholders	$ (31,824)	$ (901,959)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	147,872	278,579
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.22)	$ (3.24)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Weighted-Average Anti-Dilutive Shares of Common Stock Excluded from the Calculation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	103,670	238,345	454,333
Redeemable convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	0	95,469	308,373
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	40,067	72,999	76,911
Redeemable convertible preferred stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	0	77	158
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	0	0	96
Restricted Stock Units (RSUs) And Restricted Stock Awards (RSAs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	63,603	69,800	68,795

Income Taxes - Components of Lo

Income Taxes - Components of Loss Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States	$ 49,973	$ (1,266,677)	$ (31,641)
Foreign	(176,993)	(94,162)	(30,923)
Loss before provision for income taxes	$ (127,020)	$ (1,360,839)	$ (62,564)

Income Taxes - Composition of t

Income Taxes - Composition of the Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 0	$ 0	$ 0
State	79	0	0
Foreign	691	1,677	500
Total current tax expense	770	1,677	500
Deferred:
Federal	654	(555)	4
State	5	(76)	4
Foreign	(126)	(514)	(98)
Total deferred tax expense (benefit)	533	(1,145)	(90)
Provision for income taxes	$ 1,303	$ 532	$ 410

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of the Difference Between Income Taxes Computed at the Statutory Federal Income Tax Rate and the Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax at U.S. statutory rate	$ (26,674)	$ (285,776)	$ (13,138)
State income taxes, net of benefit	84	(77)	4
Foreign losses not benefited	37,716	20,932	6,891
Permanent book/tax differences	1,051	2,453	1,967
Legal settlement	2,290	0	0
Share-based compensation	(303,245)	(84,366)	(864)
Change in valuation allowance	352,410	422,315	15,952
Tax credits	(63,205)	(74,399)	(10,460)
Other	876	(550)	58
Provision for income taxes	$ 1,303	$ 532	$ 410

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 784,721	$ 416,709
Research tax credits	269,658	167,489
Reserves, accruals, and other	18,106	15,960
Lease obligation	44,446	52,734
Share-based compensation	96,932	133,067
Total deferred tax assets	1,213,863	785,959
Less: valuation allowance	(1,176,910)	(737,003)
Deferred tax assets, net of valuation allowance	36,953	48,956
Deferred tax liabilities:
Depreciation and amortization	(34,576)	(46,398)
Prepaid expenses	(1,523)	(1,862)
Total deferred tax liabilities	(36,099)	(48,260)
Net deferred tax assets	$ 854	$ 696

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Jun. 22, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Increase (decrease) in deferred tax asset valuation allowance		$ 439,900	$ 520,100
Reduction in deferred tax assets related to net operating losses	$ 24,400
Gross unrecognized tax benefits		140,160	$ 129,185	$ 38,550
Federal
Income Taxes [Line Items]
Net operating loss carryforwards		3,282,200
Federal | Research Tax Credits
Income Taxes [Line Items]
Tax credit carryforwards		241,600
State | California
Income Taxes [Line Items]
Net operating loss carryforwards		405,600
State | California | Research Tax Credits
Income Taxes [Line Items]
Tax credit carryforwards		181,700
State | Other States
Income Taxes [Line Items]
Net operating loss carryforwards		1,214,900
Foreign | Ireland
Income Taxes [Line Items]
Net operating loss carryforwards		$ 37,900

Income Taxes - Changes in Gross

Income Taxes - Changes in Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance	$ 129,185	$ 38,550
Increases for tax positions of prior years	886
Increases for tax positions of prior years	(37,250)	(50)
Increases for tax positions of current year	47,339	90,685
Balance	$ 140,160	$ 129,185

Geographical Information (Detai

Geographical Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,692,658	$ 1,142,761	$ 755,932
Total property and equipment, net and operating lease right-of-use assets	225,291	280,243
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	1,404,282	1,010,186	697,170
Total property and equipment, net and operating lease right-of-use assets	213,831	266,763
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	288,376	132,575	$ 58,762
Total property and equipment, net and operating lease right-of-use assets	$ 11,460	$ 13,480