Cover Page - USD ($) $ in Billions	12 Months Ended
Cover Page - USD ($) $ in Billions	Dec. 31, 2019	Jan. 31, 2020	Jun. 28, 2019
Document Information [Line Items]
Document Type	10-K
Document Fiscal Period Focus	FY
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Amendment Flag	false
Document Fiscal Year Focus	2019
Current Fiscal Year End Date	--12-31
Entity File Number	001-38872
Entity Registrant Name	Pinterest, Inc.
Entity Central Index Key	0001506293
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	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 14.8
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for the 2020 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, 2019.
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		363,567,902
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		209,050,139

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 649,666	$ 122,509
Marketable securities	1,063,679	505,304
Accounts receivable, net of allowances of $2,851 and $3,097 as of December 31, 2019 and 2018, respectively	316,367	221,932
Prepaid expenses and other current assets	37,522	39,607
Total current assets	2,067,234	889,352
Property and equipment, net	91,992	81,512
Operating lease right-of-use assets	188,251	145,203
Goodwill and intangible assets, net	14,576	14,071
Restricted cash	25,339	11,724
Other assets	5,925	10,869
Total assets	2,393,317	1,152,731
Current liabilities:
Accounts payable	34,334	22,169
Accrued expenses and other current liabilities	141,823	86,258
Total current liabilities	176,157	108,427
Operating lease liabilities	173,392	151,395
Other liabilities	20,063	22,073
Total liabilities	369,612	281,895
Commitments and contingencies
Redeemable convertible preferred stock, $0.00001 par value; no shares authorized, issued or outstanding as of December 31, 2019; 928,676 shares authorized, 308,373 shares issued and outstanding as of December 31, 2018; aggregate liquidation preference of $1,466,902 as of December 31, 2018	0	1,465,399
Stockholders’ equity (deficit):
Common stock		1
Additional paid-in capital	4,229,778	252,212
Accumulated other comprehensive income (loss)	647	(1,421)
Accumulated deficit	(2,206,726)	(845,355)
Total stockholders’ equity (deficit)	2,023,705	(594,563)
Total liabilities, redeemable convertible preferred stock, and stockholders’ equity (deficit)	2,393,317	$ 1,152,731
Class A and B common stock
Stockholders’ equity (deficit):
Common stock	$ 6

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Allowances	$ 2,851	$ 3,097
Redeemable convertible preferred stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Redeemable convertible preferred stock, shares authorized (in shares)	0	928,676,000
Redeemable convertible preferred stock, shares issued (in shares)	0	308,373,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	308,373,000
Redeemable convertible preferred stock, liquidation preference		$ 1,466,902
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	0	1,932,500,000
Common stock, shares issued (in shares)	0	127,298,000
Common stock, shares outstanding (in shares)	0	127,298,000
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	6,666,667,000	0
Common stock, shares issued (in shares)	360,850,000	0
Common stock, shares outstanding (in shares)	360,850,000	0
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	1,333,333,000	0
Common stock, shares issued (in shares)	209,054,000	0
Common stock, shares outstanding (in shares)	209,054,000	0

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 1,142,761	$ 755,932	$ 472,852
Costs and expenses:
Cost of revenue	358,903	241,584	178,664
Research and development	1,207,059	251,662	207,973
Sales and marketing	611,590	259,929	162,514
General and administrative	354,075	77,478	61,635
Total costs and expenses	2,531,627	830,653	610,786
Loss from operations	(1,388,866)	(74,721)	(137,934)
Interest income	30,164	13,152	8,313
Interest expense and other income (expense), net	(2,137)	(995)	(112)
Loss before provision for income taxes	(1,360,839)	(62,564)	(129,733)
Provision for income taxes	532	410	311
Net loss	$ (1,361,371)	$ (62,974)	$ (130,044)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (3.24)	$ (0.50)	$ (1.03)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	420,473	127,091	126,562

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1,361,371)	$ (62,974)	$ (130,044)
Other comprehensive income (loss), net of taxes:
Change in unrealized gain (loss) on available-for-sale marketable securities	2,057	(443)	(302)
Change in foreign currency translation adjustment	11	(212)	79
Comprehensive loss	$ (1,359,303)	$ (63,629)	$ (130,267)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance (in shares) at Dec. 31, 2016	301,408,000
Balance at Dec. 31, 2016	$ 1,315,615
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of redeemable convertible preferred stock for cash, net of issuance costs (in shares)	6,965,000
Issuance of redeemable convertible preferred stock for cash, net of issuance costs	$ 149,784
Balance (in shares) at Dec. 31, 2017	308,373,000
Balance at Dec. 31, 2017	$ 1,465,399
Beginning balance (in shares) at Dec. 31, 2016		126,433,000
Beginning balance at Dec. 31, 2016	(448,286)	$ 1	$ 204,530	$ (543)	$ (652,274)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock related to acquisitions, net (in shares)		30,000
Issuance of common stock related to acquisitions, net	1,239		1,239
Issuance of common stock related to purchase of intangible assets (in shares)		93,000
Issuance of common stock related to purchase of intangible assets	1,227		1,227
Issuance of common stock for cash upon exercise of stock options, net (in shares)		215,000
Issuance of common stock for cash upon exercise of stock options, net	551		551
Vesting of early exercised stock options	331		331
Share-based compensation	28,804		28,804
Other comprehensive income (loss)	(223)			(223)
Net loss	(130,044)				(130,044)
Ending balance (in shares) at Dec. 31, 2017		126,771,000
Ending balance at Dec. 31, 2017	$ (546,464)	$ 1	236,682	(766)	(782,381)
Balance (in shares) at Dec. 31, 2018	308,373,000
Balance at Dec. 31, 2018	$ 1,465,399
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash upon exercise of stock options, net (in shares)		527,000
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 loss	(62,974)				(62,974)
Ending balance (in shares) at Dec. 31, 2018		127,298,000
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)	(308,373,000)
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)		28,084,000
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)		308,622,000
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)		86,250,000
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)	19,650,000	19,650,000
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 loss	(1,361,371)				(1,361,371)
Ending balance (in shares) at Dec. 31, 2019		569,904,000
Ending balance at Dec. 31, 2019	$ 2,023,705	$ 6	$ 4,229,778	$ 647	$ (2,206,726)

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares
Proceeds from issuance of redeemable convertible preferred stock, gross	$ 150,000
Proceeds from issuance of redeemable convertible preferred stock (in dollars per share) \| $ / shares	$ 21.537276
Redeemable Convertible Preferred Stock
Issuance costs from issuance of redeemable convertible preferred stock	$ 216

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income (loss)	$ (1,361,371)	$ (62,974)	$ (130,044)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	27,791	20,859	16,135
Share-based compensation	1,377,781	14,859	28,804
Other	(3,990)	1,027	653
Changes in assets and liabilities:
Accounts receivable	(94,224)	(86,094)	(47,833)
Prepaid expenses and other assets	7,161	18,142	(1,345)
Operating lease right-of-use assets	32,378	18,492	8,611
Accounts payable	11,636	6,533	11,969
Accrued expenses and other liabilities	31,890	26,336	20,596
Operating lease liabilities	(28,395)	(17,549)	(10,459)
Net cash provided by (used in) operating activities	657	(60,369)	(102,913)
Investing activities
Purchases of property and equipment and intangible assets	(33,783)	(22,194)	(41,192)
Purchases of marketable securities	(1,075,875)	(518,711)	(515,165)
Sales of marketable securities	162,198	94,381	199,600
Maturities of marketable securities	360,959	561,087	298,512
Other investing activities	0	(500)	995
Net cash provided by (used in) investing activities	(586,501)	114,063	(57,250)
Financing activities
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	0	0	149,784
Proceeds from initial public offering, net of underwriters' discounts and commissions	1,573,200	0	0
Proceeds from exercise of stock options, net	41,344	671	480
Shares repurchased for tax withholdings on release of restricted stock units	(475,015)	0	0
Fees paid for revolving credit facility	0	(2,552)	0
Payment of deferred offering costs and other financing activities	(11,331)	(335)	0
Net cash provided by (used in) financing activities	1,128,198	(2,216)	150,264
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	99	(157)	145
Net increase in cash, cash equivalents, and restricted cash	542,453	51,321	(9,754)
Cash, cash equivalents, and restricted cash, beginning of period	135,290	83,969	93,723
Cash, cash equivalents, and restricted cash, end of period	677,743	135,290	83,969
Supplemental cash flow information
Accrued property and equipment	4,772	1,884	9,659
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$ 76,387	$ 11,416	$ 101,307

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of cash, cash equivalents and restricted cash to consolidated balance sheets
Cash and cash equivalents	$ 649,666	$ 122,509	$ 71,468
Restricted cash included in prepaid expenses and other current assets	2,738	1,057	851
Restricted cash	25,339	11,724	11,650
Total cash, cash equivalents, and restricted cash	$ 677,743	$ 135,290	$ 83,969

Description of Business and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

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, 2019, 2018 and 2017, we recorded total share-based compensation expense of $1,377.8 million, $14.9 million and $28.8 million, respectively.

Stock Split

On March 28, 2019, we effected a 1-for-3 reverse split of our capital stock. We have adjusted all share and per share amounts in the accompanying consolidated financial statements and notes to reflect the reverse stock split.

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.

Segments

We operate as a single operating segment. Our chief operating decision maker is our Chief Executive Officer, 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, 2019 and 2018.

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 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 on a straight-line basis over the requisite service period.

We measure RSUs based on the fair market value of our common stock on the grant date, and we account for forfeitures as they occur.

Valuation of Common Stock and Redeemable Convertible Preferred Stock Warrants

Until our IPO, we determined the fair value of our common stock and redeemable convertible preferred stock warrants using the most observable inputs available to us, including recent sales of our stock as well as income and market valuation approaches. The income approach estimates the value of our business based on the future cash flows we expect to generate discounted to their present value using an appropriate discount rate to reflect the risk of achieving

the expected cash flows. The market approach estimates the value of our business by applying valuation multiples derived from the observed valuation multiples of comparable public companies to our expected financial results.

We used the Probability Weighted Expected Return Method ("PWERM") to allocate the value of our business among our outstanding stock and share-based awards. We applied the PWERM by first defining the range of potential future liquidity outcomes for our business, such as an IPO, and then allocating its value to our outstanding stock and share-based awards based on the relative probability that each outcome will occur. We used the Option Pricing Method to allocate the value of our business to our outstanding stock and share-based awards under the non-IPO outcome we considered within the PWERM.

Applying these valuation and allocation approaches involved the use of estimates, judgments, and assumptions that are highly complex and subjective, such as those regarding our expected future revenue, expenses, and cash flows, discount rates, valuation multiples, the selection of comparable public companies, and the probability of future events. Changes in any or all of these estimates and assumptions, or the relationships between these assumptions, impacted our valuation as of each valuation date and may have a material impact on the valuation of our common stock and redeemable convertible preferred stock warrants.

Following our IPO, there is an active market for our Class A common stock and the warrants to purchase shares of our redeemable convertible preferred stock are no longer outstanding so we no longer apply these valuation and allocation approaches.

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 $55.0 million, $19.2 million and $13.7 million for the years ended December 31, 2019, 2018 and 2017, 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 other-than-temporary impairments 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 and Allowances for Doubtful Accounts and Sales Credits

We record accounts receivable at the original invoiced amount. We maintain an allowance for doubtful accounts 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 doubtful accounts 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 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 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.

One customer accounted for 10% of our revenue for the year ended December 31, 2019 and another accounted for 10% of our revenue for the year ended December 31, 2017. No customer accounted for more than 10% of our revenue for the year ended December 31, 2018.

Our accounts receivable are generally unsecured. We monitor our customers’ 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, 2019, 2018 and 2017.

Recent Accounting Pronouncements Not Yet Adopted

In June 2016, the 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 will adopt ASU 2016-13 effective January 1, 2020 and do not expect adoption to materially affect our consolidated financial statements.

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. ASU 2019-12 will be effective for us beginning January 1, 2021, and early adoption is permitted. We are currently evaluating the impact of adoption on our consolidated financial statements.

Cash, Cash Equivalents and Marketable Securities

12 Months Ended

Dec. 31, 2019

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, 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


	December 31, 2018
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Cash and cash equivalents:
Cash	$	48,238	$	—	$	—	$	48,238
Money market funds	785		—		—		785
Commercial paper	73,492		—		(6)		73,486

Total cash and cash equivalents	122,515		—		(6)		122,509
Marketable securities:
Corporate bonds	204,826		115		(771)		204,170
U.S. treasury securities	36,003		—		(82)		35,921
Commercial paper	90,207		4		(15)		90,196
Asset-backed securities	107,382		6		(730)		106,658
Certificates of deposit	68,343		26		(10)		68,359

Total marketable securities	506,761		151		(1,608)		505,304
Total	$	629,276	$	151	$	(1,614)	$	627,813

Gross unrealized losses for marketable securities that had been in an unrealized loss position for greater than 12 consecutive months were not material as of December 31, 2019 and 2018. We evaluated all available evidence and concluded that our marketable securities are not other than temporarily impaired as of December 31, 2019 and 2018.

The fair value of our marketable securities by contractual maturity is as follows (in thousands):


	December 31, 2019
Due in one year or less	$	768,347
Due after one to five years	295,332
Total	$	1,063,679

Net realized gains and losses from sales of available-for-sale securities were not material for any period presented.

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

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, 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


	December 31, 2018
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	785	$	—	$	—	$	785
Commercial paper	—		73,486		—		73,486

Marketable securities:
Corporate bonds	—		204,170		—		204,170
U.S. treasury securities	35,921		—		—		35,921
Commercial paper	—		90,196		—		90,196
Asset-backed securities	—		106,658		—		106,658
Certificates of deposit	—		68,359		—		68,359

Prepaid expenses and other current assets:
Certificates of deposit	—		1,057		—		1,057
Restricted cash:
Certificates of deposit	—		11,724		—		11,724
Other liabilities:
Redeemable convertible preferred stock warrants	$	—	$	—	$	4,934	$	4,934

We classify our marketable securities within Level 1 or Level 2 because we determine their fair values using quoted market prices or alternative pricing sources and models utilizing market observable inputs.

We classify our redeemable convertible preferred stock warrants within Level 3 because we determine their fair values using significant unobservable inputs, including the fair value of our redeemable convertible preferred stock, which we determine in the same manner as our common stock. Refer to our significant accounting policies in Note 1 for additional information.

We record changes in the fair value of our redeemable convertible preferred stock warrants in interest expense and other income (expense), net. These amounts were not material for the years ended December 31, 2019, 2018 and 2017.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Other Balance Sheet Components

12 Months Ended

Dec. 31, 2019

Other Balance Sheet Components [Abstract]

Other Balance Sheet Components

Property and Equipment, Net

Property and equipment, net consists of the following (in thousands):



	December 31,
			2019			2018
Leasehold improvements	$	109,807		$	93,843

Furniture and fixtures	22,353			18,529
Computer and network equipment	22,963			19,606
Total property and equipment	155,123			131,978
Less: accumulated depreciation	(73,270)			(51,249)
Construction in progress	10,139			783
Property and equipment, net	$	91,992		$	81,512

Depreciation expense was $26.3 million, $20.1 million and $14.6 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consists of the following (in thousands):



	December 31,
			2019			2018
Accrued hosting expenses	$	27,322		$	19,288
Accrued compensation	26,574			18,192

Operating lease liabilities	46,527			20,538
Other accrued expenses	41,400			28,240
Accrued expenses and other current liabilities	$	141,823		$	86,258

Goodwill and Intangible Assets, Net

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets, Net

Goodwill and Intangible Assets, NetGoodwill was unchanged during the years ended December 31, 2019 and 2018.

Intangible assets, net consists of the following (in thousands):


	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


	December 31, 2018
	Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount			Weighted-Average Useful Life ⁽¹⁾

Acquired patents		$	7,038		$	(465)		$	6,573		9.4 years
Acquired technology and other intangibles		4,385			(3,792)			593			1.5 years
Total intangible assets, net		$	11,423		$	(4,257)		$	7,166

(1)Based on the weighted-average useful life established as of acquisition date.

Amortization expense was $1.5 million, $0.7 million and $1.5 million for the years ended December 31, 2019, 2018 and 2017, respectively. Estimated future amortization expense as of December 31, 2019, is as follows (in thousands):


	Intangible Asset Amortization
2020	$	1,013
2021	1,009
2022	1,009
2023	1,009
2024	1,009
Thereafter	2,622
Total	$	7,671

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

As of December 31, 2019, our non-cancelable contractual commitments are as follows (in thousands):


	Purchase Commitments		Operating Leases		Total Commitments
2020	$	—	$	56,807	$	56,807
2021	—		47,623		47,623
2022	—		35,622		35,622
2023	171,316		14,953		186,269
2024	—		11,942		11,942
Thereafter	—		109,810		109,810
Total	$	171,316	$	276,757	$	448,073

Purchase Commitments

In May 2017, we amended the enterprise agreement governing our use of cloud computing infrastructure provided by AWS with an addendum. Under the agreement, as amended by the addendum, we are currently required to purchase at least $750.0 million (the contract commitment) of cloud services from AWS through July 2023 and were required to purchase at least $125.0 million (the initial commitment) of the contract commitment through June 2018. Except in limited circumstances, such as termination due to acquisition of us by another cloud services provider (which would result in an obligation to pay liquidated damages under the addendum, we are required to pay the difference if we fail to meet either commitment, but we are not otherwise subject to annual purchase commitments during the remainder of the six-year term of the addendum. As of December 31, 2019, we have fulfilled our initial commitment and our remaining contract commitment is $171.3 million. We expect to meet our remaining commitment.

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. The estimated commencement and expiration dates are in 2022 and 2033, respectively. We may terminate the lease prior to commencement if certain contingencies are not satisfied. We will be subject to total non-cancelable minimum lease payments of approximately $420.0 million, which is excluded from the table above, if these contingencies are met, and if the lease commences we will record a right-of-use asset and related lease liability of no more than that amount at lease commencement using our incremental borrowing rate at that date.

Legal Matters

We are involved in various lawsuits, claims and proceedings that arise in the ordinary course of business. While the results of legal matters are inherently uncertain, we do not believe 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.

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, 2019. 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, 2019.

Letters of Credit

We had $25.5 million and $10.6 million of secured letters of credit outstanding as of December 31, 2019 and 2018, 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.

Leases

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Leases

We have entered into various non-cancelable office space operating leases with original lease periods expiring between 2020 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, 2019, 2018 and 2017, are as follows (in thousands):


	Year Ended December 31,
	2019		2018		2017
Lease cost:
Operating lease cost	$	40,257	$	27,469	$	16,632
Short-term lease cost	3,456		2,765		2,739
Total	$	43,713	$	30,234	$	19,371

The weighted-average remaining term of our operating leases was 8.1 years and 10.7 years and the weighted-average discount rate used to measure the present value of our operating lease liabilities was 4.6% and 5.1% as of December 31, 2019 and 2018, respectively.

Maturities of our operating lease liabilities, which do not include short-term leases, as of December 31, 2019, are as follows (in thousands):


	Operating Leases
2020	$	55,700
2021	47,623
2022	35,622
2023	14,953
2024	11,942
Thereafter	109,810
Total lease payments	275,650
Less imputed interest	(55,730)
Total operating lease liabilities	$	219,920

Cash payments included in the measurement of our operating lease liabilities were $38.4 million, $26.2 million and $15.2 million for the years ended December 31, 2019, 2018 and 2017, respectively.

As of December 31, 2019, we have $420.0 million of undiscounted future payments under an operating lease that has not yet commenced, which are excluded from the table above. See Note 6 for additional information. As of December 31, 2019, we have not entered into any other material leases that have not yet commenced.

Share-Based Compensation

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

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, restricted stock 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, 2019.

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, restricted stock, 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. 89,911,091 shares of our Class A common stock were reserved for future issuance under our 2019 Plan as of December 31, 2019.

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 as of the closing of our IPO 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, commencing on January 1, 2020 and ending on (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, 2019, 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, 2018		76,635	$	2.22	4.5	$	1,285,338
Exercised		(19,650)	2.10
Forfeited		(19)	4.06
Outstanding as of December 31, 2019		56,966	$	2.25	3.5	$	933,299
Exercisable as of December 31, 2019		56,943	$	2.26	3.5	$	932,968

(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, 2019, 2018 and 2017, was $2.2 million, $18.6 million and $37.1 million, respectively. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2019, 2018 and 2017, was $425.1 million, $5.9 million and $3.7 million, respectively.

Restricted Stock Unit Activity

RSU activity during the year ended December 31, 2019, 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, 2018	77,882	$	17.79
Granted	36,526	20.91
Released	(50,161)	17.53
Forfeited	(7,456)	16.55
Outstanding as of December 31, 2019	56,791	$	20.19

Share-Based Compensation

Share-based compensation expense during the years ended December 31, 2019, 2018 and 2017, was as follows (in thousands):



	Year Ended December 31,
	2019		2018		2017
Cost of revenue	$	31,758	$	83	$	372
Research and development	867,191		13,155		19,811
Sales and marketing	239,315		784		6,267
General and administrative	239,517		837		2,354
Total share-based compensation	$	1,377,781	$	14,859	$	28,804

As of December 31, 2019, we had $635.1 million of unrecognized share-based compensation expense, which we expect to recognize over a weighted-average period of 3.2 years.

Redeemable Convertible Preferred Stock	12 Months Ended
Redeemable Convertible Preferred Stock	Dec. 31, 2019
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock Immediately prior to the completion of our IPO, all shares of our outstanding redeemable convertible preferred stock converted into 308,372,983 shares of Class B common stock on a one-for-one basis. There were no shares of redeemable convertible preferred stock issued and outstanding as of December 31, 2019. Prior to the completion of our IPO, the holders of our redeemable convertible preferred stock had the following preferences and privileges: Dividends The holders of Seed 1, Seed 2, Series A-1, Series A-2, Series B, Series C, Series D, Series E, Series F, Series G and Series H redeemable convertible preferred stock were entitled to receive non-cumulative dividends, out of any assets legally available therefore, prior and in preference to any declaration or payment of any dividend on the common stock at the rate of $0.00096, $0.00216, $0.00924, $0.01356, $0.057408, $0.373368, $0.518838, $0.6974736, $0.8152884, $1.7229822 and $1.7229822 per share (as adjusted for stock splits, stock dividends, combinations, subdivisions, recapitalizations, or the like) per annum on each outstanding share, when, as, and if declared by the board of directors. We have never declared or paid a dividend. Liquidation Preferences In the event of any deemed liquidation event or a voluntary or involuntary liquidation, dissolution, or winding up of Pinterest, the holders of each series of redeemable convertible preferred stock then outstanding would have been entitled to be paid out our assets available for distribution to stockholders, before any payment made to the holders of common stock, an amount per share equal to the greater of (a) the original issue price for such series of redeemable convertible preferred stock, plus any dividends declared but unpaid thereon, or (b) such amount per share as would have been payable had such shares of redeemable convertible preferred stock been converted into common stock immediately prior to such liquidation, dissolution, or winding up of Pinterest. The original purchase price of Seed 1, Seed 2, Series A-1, Series A-2, Series B, Series C, Series D, Series E, Series F, Series G and Series H redeemable convertible preferred stock was $0.012, $0.02724, $0.11568, $0.169968, $0.7175796, $4.667136, $6.48546, $8.71842, $10.191108, $21.537276 and $21.537276 per share (as adjusted for stock splits, stock dividends, combinations, subdivisions, recapitalizations, or the like). Unless the holders of our redeemable convertible preferred stock elected otherwise, a deemed liquidation would have occurred if Pinterest was merged or consolidated into another company in which the stockholders of Pinterest owned less than a majority of the voting stock of the surviving company, or if substantially all of our assets were sold, transferred, leased or exclusively licensed. If, upon any such liquidation, dissolution, or winding up of Pinterest, our assets available for distribution to stockholders had been insufficient to pay the holders of shares of redeemable convertible preferred stock the full amount to which they were entitled, the holders of shares of redeemable convertible preferred stock would have shared ratably in any distribution of the assets available for distribution in proportion to the respective amounts that would have otherwise been payable in respect of the shares held by them upon such distribution if all amounts payable on the shares were paid in full.

Net Loss Per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

We present net loss per share attributable to common stockholders in conformity with the two-class method required for participating securities, and we consider 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, 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,
	2019						2018		2017
	Class A		Class B		Common		Common
Numerator:
Net loss attributable to common stockholders	$	(459,412)	$	(901,959)	$	(62,974)	$	(130,044)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	141,894		278,579		127,091		126,562
Net loss per share attributable to common stockholders, basic and diluted	$	(3.24)	$	(3.24)	$	(0.50)	$	(1.03)

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,
	2019	2018	2017
Redeemable convertible preferred stock	95,469	308,373	305,409
Outstanding stock options	72,999	76,911	78,830
Unvested restricted stock units	69,800	68,795	48,238
Redeemable convertible preferred stock warrants	77	158	—
Common stock warrants	—	96	167
Shares subject to repurchase	—	—	40
Total	238,345	454,333	432,684

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Income Taxes

The components of loss before provision for income taxes are as follows (in thousands):


	Year Ended December 31,
	2019		2018		2017
United States	$	(1,266,677)	$	(31,641)	$	(90,906)
Foreign	(94,162)		(30,923)		(38,827)
Loss before provision for income taxes	$	(1,360,839)	$	(62,564)	$	(129,733)

Provision for income taxes consists of the following (in thousands):


	Year Ended December 31,
	2019		2018		2017
Current:
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	1,677		500		390
Total current tax expense	1,677		500		390
Deferred:
Federal	(555)		4		(23)
State	(76)		4		4
Foreign	(514)		(98)		(60)
Total deferred tax expense (benefit)	(1,145)		(90)		(79)
Provision for income taxes	$	532	$	410	$	311

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,
	2019		2018		2017
Tax at U.S. statutory rate	$	(285,776)	$	(13,138)	$	(44,109)
State income taxes, net of benefit	(77)		4		4
Foreign losses not benefited	20,932		6,891		13,518
Permanent book/tax differences	2,453		1,967		127
Share-based compensation	(84,366)		(864)		646
Change in valuation allowance	422,315		15,952		(50,017)
U.S corporate tax rate reduction	—		—		86,063
Tax credits	(74,399)		(10,460)		(5,923)
Other	(550)		58		2
Provision for income taxes	$	532	$	410	$	311

Due to our history of net operating losses and the full valuation allowance against our deferred tax assets, our provision for income taxes primarily relates to foreign taxes for the periods presented.

Significant components of our deferred tax assets and liabilities are as follows (in thousands):


	December 31,
	2019		2018
Deferred tax assets:
Net operating loss carryforwards	$	416,709	$	120,456
Research tax credits	167,489		53,459
Reserves, accruals, and other	15,960		5,379
Lease obligation	52,734		41,808
Share-based compensation	133,067		36,397
Total deferred tax assets	785,959		257,499
Less: valuation allowance	(737,003)		(216,866)
Deferred tax assets, net of valuation allowance	48,956		40,633
Deferred tax liabilities:
Depreciation and amortization	(46,398)		(38,417)
Prepaid expenses	(1,862)		(2,031)
Total deferred tax liabilities	(48,260)		(40,448)
Net deferred tax assets	$	696	$	185

On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (Tax Act). The Tax Act reduced the U.S. statutory corporate tax rate to 21%, effective January 1, 2018. Consequently, we recorded a decrease to our federal deferred tax assets of $86.1 million, which was fully offset by a reduction in our valuation allowance for the year ended December 31, 2017.

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, 2019, 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. deferred tax assets will not be realized as of December 31, 2019. Accordingly, we have established a full valuation allowance on our U.S. deferred tax assets. Our valuation allowance increased by $520.1 million and $25.3 million during the years ended December 31, 2019 and 2018, respectively, primarily due to U.S. federal and state tax losses and credits incurred during the period.

As of December 31, 2019, we had federal, California and other state net operating loss carryforwards of $1,880.8 million, $245.2 million and $599.7 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, 2019, we had federal and California research and development credit carryforwards of $151.4 million and $111.3 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, 2017	$	30,167

Increases for tax positions of current year	8,383
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

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, Altera filed a petition for a rehearing before the full Ninth Circuit. On November 12th, the Ninth Circuit Court denied Altera’s request for rehearing. Altera may subsequently appeal to the Supreme Court. We will continue to monitor future developments and their potential effects on our consolidated financial statements.

Recognizing the $129.2 million of gross unrecognized tax benefits we had as of December 31, 2019 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, 2019 and 2018.

We are subject to taxation in the U.S. and various other state and foreign jurisdictions. As we have net operating loss carry forwards 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 2014 and forward.

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

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Geographical Information

Revenue disaggregated by geography based on our customers’ billing addresses is as follows (in thousands):


	Year Ended December 31,
		2019		2018		2017
United States		$	1,010,186	$	697,170	$	443,842
International⁽¹⁾		132,575		58,762		29,010
Total revenue		$	1,142,761	$	755,932	$	472,852

(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,
		2019		2018
United States		$	266,763	$	222,188
International⁽¹⁾		13,480		4,527
Total property and equipment, net and operating lease right-of-use assets		$	280,243	$	226,715

(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 Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
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.
Segments	We operate as a single operating segment. Our chief operating decision maker is our Chief Executive Officer, 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. 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 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 on a straight-line basis over the requisite service period. We measure RSUs based on the fair market value of our common stock on the grant date, and we account for forfeitures as they occur.
Valuation of Common Stock and Redeemable Convertible Preferred Stock Warrants	Until our IPO, we determined the fair value of our common stock and redeemable convertible preferred stock warrants using the most observable inputs available to us, including recent sales of our stock as well as income and market valuation approaches. The income approach estimates the value of our business based on the future cash flows we expect to generate discounted to their present value using an appropriate discount rate to reflect the risk of achieving the expected cash flows. The market approach estimates the value of our business by applying valuation multiples derived from the observed valuation multiples of comparable public companies to our expected financial results. We used the Probability Weighted Expected Return Method ("PWERM") to allocate the value of our business among our outstanding stock and share-based awards. We applied the PWERM by first defining the range of potential future liquidity outcomes for our business, such as an IPO, and then allocating its value to our outstanding stock and share-based awards based on the relative probability that each outcome will occur. We used the Option Pricing Method to allocate the value of our business to our outstanding stock and share-based awards under the non-IPO outcome we considered within the PWERM. Applying these valuation and allocation approaches involved the use of estimates, judgments, and assumptions that are highly complex and subjective, such as those regarding our expected future revenue, expenses, and cash flows, discount rates, valuation multiples, the selection of comparable public companies, and the probability of future events. Changes in any or all of these estimates and assumptions, or the relationships between these assumptions, impacted our valuation as of each valuation date and may have a material impact on the valuation of our common stock and redeemable convertible preferred stock warrants. Following our IPO, there is an active market for our Class A common stock and the warrants to purchase shares of our redeemable convertible preferred stock are no longer outstanding so we no longer apply these valuation and allocation approaches.
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 other-than-temporary impairments 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 and Allowances for Doubtful Accounts and Sales Credits	We record accounts receivable at the original invoiced amount. We maintain an allowance for doubtful accounts 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 doubtful accounts and sales credits in accounts receivable, net in the consolidated balance sheets.
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 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 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.
Recent Accounting Pronouncement Not Yet Adopted	In June 2016, the 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 will adopt ASU 2016-13 effective January 1, 2020 and do not expect adoption to materially affect our consolidated financial statements. 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. ASU 2019-12 will be effective for us beginning January 1, 2021, and early adoption is permitted. We are currently evaluating the impact of adoption on our consolidated financial statements.

Description of Business and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

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,
			2019			2018
Leasehold improvements	$	109,807		$	93,843

Furniture and fixtures	22,353			18,529
Computer and network equipment	22,963			19,606
Total property and equipment	155,123			131,978
Less: accumulated depreciation	(73,270)			(51,249)
Construction in progress	10,139			783
Property and equipment, net	$	91,992		$	81,512

Cash, Cash Equivalents and Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2019

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, 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


	December 31, 2018
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Cash and cash equivalents:
Cash	$	48,238	$	—	$	—	$	48,238
Money market funds	785		—		—		785
Commercial paper	73,492		—		(6)		73,486

Total cash and cash equivalents	122,515		—		(6)		122,509
Marketable securities:
Corporate bonds	204,826		115		(771)		204,170
U.S. treasury securities	36,003		—		(82)		35,921
Commercial paper	90,207		4		(15)		90,196
Asset-backed securities	107,382		6		(730)		106,658
Certificates of deposit	68,343		26		(10)		68,359

Total marketable securities	506,761		151		(1,608)		505,304
Total	$	629,276	$	151	$	(1,614)	$	627,813

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, 2019
Due in one year or less	$	768,347
Due after one to five years	295,332
Total	$	1,063,679

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

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, 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


	December 31, 2018
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	785	$	—	$	—	$	785
Commercial paper	—		73,486		—		73,486

Marketable securities:
Corporate bonds	—		204,170		—		204,170
U.S. treasury securities	35,921		—		—		35,921
Commercial paper	—		90,196		—		90,196
Asset-backed securities	—		106,658		—		106,658
Certificates of deposit	—		68,359		—		68,359

Prepaid expenses and other current assets:
Certificates of deposit	—		1,057		—		1,057
Restricted cash:
Certificates of deposit	—		11,724		—		11,724
Other liabilities:
Redeemable convertible preferred stock warrants	$	—	$	—	$	4,934	$	4,934

Other Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2019

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,
			2019			2018
Leasehold improvements	$	109,807		$	93,843

Furniture and fixtures	22,353			18,529
Computer and network equipment	22,963			19,606
Total property and equipment	155,123			131,978
Less: accumulated depreciation	(73,270)			(51,249)
Construction in progress	10,139			783
Property and equipment, net	$	91,992		$	81,512

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consists of the following (in thousands):



	December 31,
			2019			2018
Accrued hosting expenses	$	27,322		$	19,288
Accrued compensation	26,574			18,192

Operating lease liabilities	46,527			20,538
Other accrued expenses	41,400			28,240
Accrued expenses and other current liabilities	$	141,823		$	86,258

Goodwill and Intangible Assets, Net (Tables)

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Composition of Intangible Assets, Net

Intangible assets, net consists of the following (in thousands):


	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


	December 31, 2018
	Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount			Weighted-Average Useful Life ⁽¹⁾

Acquired patents		$	7,038		$	(465)		$	6,573		9.4 years
Acquired technology and other intangibles		4,385			(3,792)			593			1.5 years
Total intangible assets, net		$	11,423		$	(4,257)		$	7,166

(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, 2019, is as follows (in thousands):


	Intangible Asset Amortization
2020	$	1,013
2021	1,009
2022	1,009
2023	1,009
2024	1,009
Thereafter	2,622
Total	$	7,671

Commitment and Contingencies (Tables)

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies Disclosure [Abstract]

Non-cancelable Contractual Commitments

As of December 31, 2019, our non-cancelable contractual commitments are as follows (in thousands):


	Purchase Commitments		Operating Leases		Total Commitments
2020	$	—	$	56,807	$	56,807
2021	—		47,623		47,623
2022	—		35,622		35,622
2023	171,316		14,953		186,269
2024	—		11,942		11,942
Thereafter	—		109,810		109,810
Total	$	171,316	$	276,757	$	448,073

Leases (Tables)

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Operating Lease Costs

Operating lease costs for the years ended December 31, 2019, 2018 and 2017, are as follows (in thousands):


	Year Ended December 31,
	2019		2018		2017
Lease cost:
Operating lease cost	$	40,257	$	27,469	$	16,632
Short-term lease cost	3,456		2,765		2,739
Total	$	43,713	$	30,234	$	19,371

Maturities of Operating Lease Liabilities

Maturities of our operating lease liabilities, which do not include short-term leases, as of December 31, 2019, are as follows (in thousands):


	Operating Leases
2020	$	55,700
2021	47,623
2022	35,622
2023	14,953
2024	11,942
Thereafter	109,810
Total lease payments	275,650
Less imputed interest	(55,730)
Total operating lease liabilities	$	219,920

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Stock Option Activity

Stock option activity during the year ended December 31, 2019, 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, 2018		76,635	$	2.22	4.5	$	1,285,338
Exercised		(19,650)	2.10
Forfeited		(19)	4.06
Outstanding as of December 31, 2019		56,966	$	2.25	3.5	$	933,299
Exercisable as of December 31, 2019		56,943	$	2.26	3.5	$	932,968

(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 activity during the year ended December 31, 2019, 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, 2018	77,882	$	17.79
Granted	36,526	20.91
Released	(50,161)	17.53
Forfeited	(7,456)	16.55
Outstanding as of December 31, 2019	56,791	$	20.19

Share-Based Compensation Expense

Share-based compensation expense during the years ended December 31, 2019, 2018 and 2017, was as follows (in thousands):



	Year Ended December 31,
	2019		2018		2017
Cost of revenue	$	31,758	$	83	$	372
Research and development	867,191		13,155		19,811
Sales and marketing	239,315		784		6,267
General and administrative	239,517		837		2,354
Total share-based compensation	$	1,377,781	$	14,859	$	28,804

Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2019

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,
	2019						2018		2017
	Class A		Class B		Common		Common
Numerator:
Net loss attributable to common stockholders	$	(459,412)	$	(901,959)	$	(62,974)	$	(130,044)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	141,894		278,579		127,091		126,562
Net loss per share attributable to common stockholders, basic and diluted	$	(3.24)	$	(3.24)	$	(0.50)	$	(1.03)

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,
	2019	2018	2017
Redeemable convertible preferred stock	95,469	308,373	305,409
Outstanding stock options	72,999	76,911	78,830
Unvested restricted stock units	69,800	68,795	48,238
Redeemable convertible preferred stock warrants	77	158	—
Common stock warrants	—	96	167
Shares subject to repurchase	—	—	40
Total	238,345	454,333	432,684

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

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,
	2019		2018		2017
United States	$	(1,266,677)	$	(31,641)	$	(90,906)
Foreign	(94,162)		(30,923)		(38,827)
Loss before provision for income taxes	$	(1,360,839)	$	(62,564)	$	(129,733)

Composition of the Provision for Income Taxes

Provision for income taxes consists of the following (in thousands):


	Year Ended December 31,
	2019		2018		2017
Current:
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	1,677		500		390
Total current tax expense	1,677		500		390
Deferred:
Federal	(555)		4		(23)
State	(76)		4		4
Foreign	(514)		(98)		(60)
Total deferred tax expense (benefit)	(1,145)		(90)		(79)
Provision for income taxes	$	532	$	410	$	311

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,
	2019		2018		2017
Tax at U.S. statutory rate	$	(285,776)	$	(13,138)	$	(44,109)
State income taxes, net of benefit	(77)		4		4
Foreign losses not benefited	20,932		6,891		13,518
Permanent book/tax differences	2,453		1,967		127
Share-based compensation	(84,366)		(864)		646
Change in valuation allowance	422,315		15,952		(50,017)
U.S corporate tax rate reduction	—		—		86,063
Tax credits	(74,399)		(10,460)		(5,923)
Other	(550)		58		2
Provision for income taxes	$	532	$	410	$	311

Significant Components of Deferred Tax Assets and Liabilities

Significant components of our deferred tax assets and liabilities are as follows (in thousands):


	December 31,
	2019		2018
Deferred tax assets:
Net operating loss carryforwards	$	416,709	$	120,456
Research tax credits	167,489		53,459
Reserves, accruals, and other	15,960		5,379
Lease obligation	52,734		41,808
Share-based compensation	133,067		36,397
Total deferred tax assets	785,959		257,499
Less: valuation allowance	(737,003)		(216,866)
Deferred tax assets, net of valuation allowance	48,956		40,633
Deferred tax liabilities:
Depreciation and amortization	(46,398)		(38,417)
Prepaid expenses	(1,862)		(2,031)
Total deferred tax liabilities	(48,260)		(40,448)
Net deferred tax assets	$	696	$	185

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, 2017	$	30,167

Increases for tax positions of current year	8,383
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

Geographical Information (Tables)

12 Months Ended

Dec. 31, 2019

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,
		2019		2018		2017
United States		$	1,010,186	$	697,170	$	443,842
International⁽¹⁾		132,575		58,762		29,010
Total revenue		$	1,142,761	$	755,932	$	472,852

(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,
		2019		2018
United States		$	266,763	$	222,188
International⁽¹⁾		13,480		4,527
Total property and equipment, net and operating lease right-of-use assets		$	280,243	$	226,715

(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 Summary of Significant Accounting Policies - Narrative (Details) $ / shares in Units, $ in Thousands					12 Months Ended
	Apr. 29, 2019 USD ($) $ / shares shares	Apr. 23, 2019 USD ($) $ / shares shares	Apr. 22, 2019 shares	Mar. 28, 2019	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Summary of Significant Accounting Policies [Line Items]
Share-based compensation \| $					$ 1,377,781	$ 14,859	$ 28,804
Reverse stock split ratio				0.33
Number of operating segments \| segment					1
Advertising expenses \| $					$ 55,000	19,200	$ 13,700
Estimated useful lives of intangible assets (up to)					10 years
Revenue \| Customer Concentration Risk \| One Customer
Summary of Significant Accounting Policies [Line Items]
Concentration percentage					10.00%		10.00%
RSUs
Summary of Significant Accounting Policies [Line Items]
Share-based compensation \| $					$ 1,377,800	$ 14,900	$ 28,800
RSUs \| 2009 Plan
Summary of Significant Accounting Policies [Line Items]
Service period					4 years
RSUs \| 2019 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) \| shares		75,000,000
Share price (in dollars per share) \| $ / shares		$ 19.00
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) \| shares	11,250,000
Share price (in dollars per share) \| $ / shares	$ 19.00
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) \| shares			308,621,636
Shares converted (in shares) \| 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) \| shares			456,213,756
Common stock reclassified (in shares) \| shares			1

Description of Business and Summary of Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
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 Marketable Securities - Composition of Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash and cash equivalents:
Amortized Cost	$ 649,672	$ 122,515
Unrealized Gains	1	0
Unrealized Losses	(7)	(6)
Fair Value	649,666	122,509
Marketable securities:
Amortized Cost	1,062,433	506,761
Unrealized Gains	1,326	151
Unrealized Losses	(80)	(1,608)
Fair Value	1,063,679	505,304
Cash, Cash Equivalents and Marketable Securities
Amortized Cost	1,712,105	629,276
Unrealized Gains	1,327	151
Unrealized Loss	(87)	(1,614)
Fair Value	1,713,345	627,813
Corporate bonds
Marketable securities:
Amortized Cost	449,496	204,826
Unrealized Gains	981	115
Unrealized Losses	(44)	(771)
Fair Value	450,433	204,170
U.S. treasury securities
Marketable securities:
Amortized Cost	201,561	36,003
Unrealized Gains	88	0
Unrealized Losses	(9)	(82)
Fair Value	201,640	35,921
Commercial paper
Marketable securities:
Amortized Cost	196,304	90,207
Unrealized Gains	31	4
Unrealized Losses	(7)	(15)
Fair Value	196,328	90,196
Asset-backed securities
Marketable securities:
Amortized Cost	114,425	107,382
Unrealized Gains	188	6
Unrealized Losses	(14)	(730)
Fair Value	114,599	106,658
Certificates of deposit
Marketable securities:
Amortized Cost	100,647	68,343
Unrealized Gains	38	26
Unrealized Losses	(6)	(10)
Fair Value	100,679	68,359
Cash
Cash and cash equivalents:
Amortized Cost	323,194	48,238
Fair Value	323,194	48,238
Money market funds
Cash and cash equivalents:
Amortized Cost	214,413	785
Fair Value	214,413	785
Commercial paper
Cash and cash equivalents:
Amortized Cost	105,359	73,492
Unrealized Gains	1
Unrealized Losses	(6)	(6)
Fair Value	105,354	$ 73,486
Corporate bonds
Cash and cash equivalents:
Amortized Cost	3,792
Unrealized Losses	(1)
Fair Value	3,791
Certificates of deposit
Cash and cash equivalents:
Amortized Cost	2,914
Fair Value	$ 2,914

Cash, Cash Equivalents and Marketable Securities - Fair Value of Marketable Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Due in one year or less	$ 768,347
Due after one to five years	295,332
Total	$ 1,063,679	$ 505,304

Fair Value of Financial Instruments - Fair Values of Financial Instruments Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 649,666	$ 122,509
Marketable securities	1,063,679	505,304
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	450,433	204,170
Corporate bonds \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	450,433	204,170
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	450,433	204,170
Corporate bonds \| 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	201,640	35,921
U.S. treasury securities \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	201,640	35,921
U.S. treasury securities \| Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	201,640	35,921
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
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	114,599	106,658
Asset-backed securities \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	114,599	106,658
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	114,599	106,658
Asset-backed 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	100,679	68,359
Certificates of deposit \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	100,679	68,359
Prepaid expenses and other current assets	2,738	1,057
Restricted cash	25,339	11,724
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	100,679	68,359
Prepaid expenses and other current assets	2,738	1,057
Restricted cash	25,339	11,724
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
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	196,328	90,196
Commercial paper \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	196,328	90,196
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	196,328	90,196
Commercial paper \| Recurring \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Redeemable convertible preferred stock warrants \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities		4,934
Redeemable convertible preferred stock warrants \| Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities		0
Redeemable convertible preferred stock warrants \| Recurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities		0
Redeemable convertible preferred stock warrants \| Recurring \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities		4,934
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	214,413	785
Money market funds \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	214,413	785
Money market funds \| Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	214,413	785
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	105,354	73,486
Commercial paper \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	105,354	73,486
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	105,354	73,486
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
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,914
Certificates of deposit \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,914
Certificates of deposit \| Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
Certificates of deposit \| Recurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,914
Certificates of deposit \| Recurring \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 0

Other Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation	$ (73,270)	$ (51,249)
Property and equipment, net	91,992	81,512
Depreciable Property and Equipment
Property, Plant and Equipment [Line Items]
Property and equipment	155,123	131,978
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	109,807	93,843
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	22,353	18,529
Computer and network equipment
Property, Plant and Equipment [Line Items]
Property and equipment	22,963	19,606
Construction in Progress
Property, Plant and Equipment [Line Items]
Property and equipment	$ 10,139	$ 783

Other Balance Sheet Components - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Balance Sheet Components [Abstract]
Depreciation expense	$ 26.3	$ 20.1	$ 14.6

Other Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other Balance Sheet Components [Abstract]
Accrued hosting expenses	$ 27,322	$ 19,288
Accrued compensation	26,574	18,192
Operating lease liabilities	46,527	20,538
Other accrued expenses	41,400	28,240
Accrued expenses and other current liabilities	$ 141,823	$ 86,258

Goodwill and Intangible Assets, Net - Composition of Intangible Assets, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 13,422	$ 11,423
Accumulated Amortization	(5,751)	(4,257)
Net Carrying Amount	$ 7,671	7,166
Weighted-Average Useful Life	10 years
Acquired patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 9,037	7,038
Accumulated Amortization	(1,370)	(465)
Net Carrying Amount	$ 7,667	$ 6,573
Weighted-Average Useful Life	9 years 1 month 6 days	9 years 4 months 24 days
Acquired technology and other intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4,385	$ 4,385
Accumulated Amortization	(4,381)	(3,792)
Net Carrying Amount	$ 4	$ 593
Weighted-Average Useful Life	1 year 6 months	1 year 6 months

Goodwill and Intangible Assets, Net - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 1.5	$ 0.7	$ 1.5

Goodwill and Intangible Assets, Net - Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 1,013
2021	1,009
2022	1,009
2023	1,009
2024	1,009
Thereafter	2,622
Net Carrying Amount	$ 7,671	$ 7,166

Commitments and Contingencies - Non-cancelable Contractual Commitments (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Purchase Commitments
2020	$ 0
2021	0
2022	0
2023	171,316
2024	0
Thereafter	0
Total	171,316
Operating Leases
2020	56,807
2021	47,623
2022	35,622
2023	14,953
2024	11,942
Thereafter	109,810
Total	276,757
Total Commitments
2020	56,807
2021	47,623
2022	35,622
2023	186,269
2024	11,942
Thereafter	109,810
Total	$ 448,073

Commitments and Contingencies - Narrative (Details) ft² in Thousands	1 Months Ended
	Nov. 30, 2018 USD ($)	May 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)
Commitments And Contingencies [Line Items]
Minimum required purchases		$ 750,000,000.0	$ 171,300,000
Required minimum purchases over the next twelve months		$ 125,000,000.0
Contract term		6 years
Area of office space (in sqft) \| ft²				490
Noncancelable minimum lease payments not yet commenced				$ 420,000,000.0
Secured letters of credit outstanding			25,500,000		$ 10,600,000
Revolving Credit Facility \| Line of Credit
Commitments And Contingencies [Line Items]
Term of borrowing agreement	5 years
Maximum borrowing capacity	$ 500,000,000.0
Increase in maximum borrowing capacity if the accordion option is exercised	$ 100,000,000.0
Maximum increase in maximum borrowing capacity as a percent of consolidated total assets	10.00%
Commitment fee rate	0.15%
Required minimum liquidity balance	$ 350,000,000.0
Remaining borrowing capacity			$ 500,000,000.0
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 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lease cost:
Operating lease cost	$ 40,257	$ 27,469	$ 16,632
Short-term lease cost	3,456	2,765	2,739
Total	$ 43,713	$ 30,234	$ 19,371

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Leases - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Weighted-average remaining term of operating leases	8 years 1 month 6 days	10 years 8 months 12 days
Weighted-average discount rate used to measure the present value of operating lease liabilities	4.60%	5.10%
Cash payments included in the measurement of operating lease liabilities	$ 38.4	$ 26.2	$ 15.2
Undiscounted future payments under operating leases that have not yet commenced	$ 420.0

Leases - Maturities of Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Leases [Abstract]
2020	$ 55,700
2021	47,623
2022	35,622
2023	14,953
2024	11,942
Thereafter	109,810
Total lease payments	275,650
Less imputed interest	(55,730)
Total operating lease liabilities	$ 219,920

Share-Based Compensation - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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	$ 2.2	$ 18.6	$ 37.1
Aggregate intrinsic value of stock options exercised	425.1	$ 5.9	$ 3.7
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 635.1
Weighted-average recognition period for unrecognized share-based compensation expense	3 years 2 months 12 days
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)	89,911,091
2019 Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years

Share-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Shares
Beginning balance (in shares)	76,635
Exercised (in shares)	(19,650)
Forfeited (in shares)	(19)
Ending balance (in shares)	56,966	76,635
Exercisable (in shares)	56,943
Weighted-Average Exercise Price
Beginning balance (in dollars per share)	$ 2.22
Exercised (in dollars per share)	2.10
Forfeited (in dollars per share)	4.06
Ending balance (in dollars per share)	2.25	$ 2.22
Exercisable (in dollars per share)	$ 2.26
Weighted-Average Remaining Contractual Term, Outstanding	3 years 6 months	4 years 6 months
Weighted-Average Remaining Contractual Term, Exercisable	3 years 6 months
Aggregate Intrinsic Value, Outstanding	$ 933,299	$ 1,285,338
Aggregate Intrinsic Value, Exercisable	$ 932,968

Share-Based Compensation - Restricted Stock Unit Activity (Details) - RSUs shares in Thousands	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Shares
Beginning balance (in shares) \| shares	77,882
Granted (in shares) \| shares	36,526
Released (in shares) \| shares	(50,161)
Forfeited (in shares) \| shares	(7,456)
Ending balance (in shares) \| shares	56,791
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share) \| $ / shares	$ 17.79
Granted (in dollars per share) \| $ / shares	20.91
Released (in dollars per share) \| $ / shares	17.53
Forfeited (in dollars per share) \| $ / shares	16.55
Ending balance (in dollars per share) \| $ / shares	$ 20.19

Share-Based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation	$ 1,377,781	$ 14,859	$ 28,804
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation	31,758	83	372
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation	867,191	13,155	19,811
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation	239,315	784	6,267
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation	$ 239,517	$ 837	$ 2,354

Redeemable Convertible Preferred Stock (Details) - $ / shares	Apr. 22, 2019	Dec. 31, 2019	Dec. 31, 2018
Temporary Equity [Line Items]
Shares of redeemable convertible preferred stock issued (in shares)		0	308,373,000
Class B Common Stock \| Redeemable Convertible Preferred Stock Converted
Temporary Equity [Line Items]
Shares issued in conversion (in shares)	308,372,983
Share conversion ratio (in shares)	1
Seed 1 Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	$ 0.00096
Liquidation preference (in dollars per share)	0.012
Seed 2 Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.00216
Liquidation preference (in dollars per share)	0.02724
Series A-1 Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.00924
Liquidation preference (in dollars per share)	0.11568
Series A-2 Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.01356
Liquidation preference (in dollars per share)	0.169968
Series B Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.057408
Liquidation preference (in dollars per share)	0.7175796
Series C Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.373368
Liquidation preference (in dollars per share)	4.667136
Series D Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.518838
Liquidation preference (in dollars per share)	6.48546
Series E Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.6974736
Liquidation preference (in dollars per share)	8.71842
Series F Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	0.8152884
Liquidation preference (in dollars per share)	10.191108
Series G Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	1.7229822
Liquidation preference (in dollars per share)	21.537276
Series H Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Non-cumulative dividend preference rate per annum (in dollars per share)	1.7229822
Liquidation preference (in dollars per share)	$ 21.537276

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net loss attributable to common stockholders	$ (1,361,371)	$ (62,974)	$ (130,044)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	420,473	127,091	126,562
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (3.24)	$ (0.50)	$ (1.03)
Class A
Numerator:
Net loss attributable to common stockholders	$ (459,412)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	141,894
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (3.24)
Class B
Numerator:
Net loss attributable to common stockholders	$ (901,959)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	278,579
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (3.24)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	238,345	454,333	432,684
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)	95,469	308,373	305,409
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	72,999	76,911	78,830
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	69,800	68,795	48,238
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)	77	158	0
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	96	167
Shares subject to repurchase
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average anti-dilutive shares of common stock (in shares)	0	0	40

Income Taxes - Components of Loss Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ (1,266,677)	$ (31,641)	$ (90,906)
Foreign	(94,162)	(30,923)	(38,827)
Loss before provision for income taxes	$ (1,360,839)	$ (62,564)	$ (129,733)

Income Taxes - Composition of the Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 0	$ 0	$ 0
State	0	0	0
Foreign	1,677	500	390
Total current tax expense	1,677	500	390
Deferred:
Federal	(555)	4	(23)
State	(76)	4	4
Foreign	(514)	(98)	(60)
Total deferred tax expense (benefit)	(1,145)	(90)	(79)
Provision for income taxes	$ 532	$ 410	$ 311

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax at U.S. statutory rate	$ (285,776)	$ (13,138)	$ (44,109)
State income taxes, net of benefit	(77)	4	4
Foreign losses not benefited	20,932	6,891	13,518
Permanent book/tax differences	2,453	1,967	127
Share-based compensation	(84,366)	(864)	646
Change in valuation allowance	422,315	15,952	(50,017)
U.S corporate tax rate reduction	0	0	86,063
Tax credits	(74,399)	(10,460)	(5,923)
Other	(550)	58	2
Provision for income taxes	$ 532	$ 410	$ 311

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 416,709	$ 120,456
Research tax credits	167,489	53,459
Reserves, accruals, and other	15,960	5,379
Lease obligation	52,734	41,808
Share-based compensation	133,067	36,397
Total deferred tax assets	785,959	257,499
Less: valuation allowance	(737,003)	(216,866)
Deferred tax assets, net of valuation allowance	48,956	40,633
Deferred tax liabilities:
Depreciation and amortization	(46,398)	(38,417)
Prepaid expenses	(1,862)	(2,031)
Total deferred tax liabilities	(48,260)	(40,448)
Net deferred tax assets	$ 696	$ 185

Income Taxes - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 22, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Decrease to federal deferred tax assets upon enactment of the Tax Cuts and Jobs Act	$ 86,100
Increase (decrease) in deferred tax asset valuation allowance		$ 520,100	$ 25,300
Gross unrecognized tax benefits		129,185	$ 38,550	$ 30,167
Federal
Income Taxes [Line Items]
Net operating loss carryforwards		1,880,800
Federal \| Research Tax Credits
Income Taxes [Line Items]
Tax credit carryforwards		151,400
State \| California
Income Taxes [Line Items]
Net operating loss carryforwards		245,200
State \| California \| Research Tax Credits
Income Taxes [Line Items]
Tax credit carryforwards		111,300
State \| Other States
Income Taxes [Line Items]
Net operating loss carryforwards		$ 599,700

Income Taxes - Changes in Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance	$ 38,550	$ 30,167
Decreases for tax positions of prior years	(50)
Increases for tax positions of current year	90,685	8,383
Balance	$ 129,185	$ 38,550

Geographical Information (Details) - USD ($) $ in Thousands	12 Months Ended
Geographical Information (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,142,761	$ 755,932	$ 472,852
Total property and equipment, net and operating lease right-of-use assets	280,243	226,715
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	1,010,186	697,170	443,842
Total property and equipment, net and operating lease right-of-use assets	266,763	222,188
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	132,575	58,762	$ 29,010
Total property and equipment, net and operating lease right-of-use assets	$ 13,480	$ 4,527

Label	Element	Value
Accounting Standards Update 2014-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (63,000)
Accounting Standards Update 2014-09 [Member] \| Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (63,000)