Etsy (ETSY) 10-K 26 Feb 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	001-36911
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-4898921
Entity Address, Address Line One	117 Adams Street
Entity Address, City or Town	Brooklyn
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	11201
City Area Code	718
Local Phone Number	880-3660
Title of 12(b) Security	Common Stock
Trading Symbol	ETSY
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 7,314,888,157
Entity Common Stock, Shares Outstanding (in shares)		117,949,068
Documents Incorporated by Reference	Portions of the registrant’s Proxy Statement for its 2020 Annual Meeting of Stockholders, to be filed with the Securities and Exchange Commission no later than 120 days after December 31, 2019 , are incorporated by reference in Part III of this Annual Report on Form 10-K.
Entity Registrant Name	ETSY INC
Entity Central Index Key	0001370637
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 443,293	$ 366,985
Short-term investments	373,959	257,302
Accounts receivable, net	15,386	12,244
Prepaid and other current assets	38,614	22,686
Funds receivable and seller accounts	49,786	21,072
Total current assets	921,038	680,289
Restricted cash	5,341	5,341
Property and equipment, net	144,864
Property and equipment, net		120,179
Goodwill	138,731	37,482
Intangible assets, net	199,236	34,589
Deferred tax assets	14,257	23,464
Long-term investments	89,343	0
Other assets	29,542	507
Total assets	1,542,352	901,851
Current liabilities:
Accounts payable	26,324	26,545
Accrued expenses	88,345	49,158
Finance lease obligations—current	8,275
Finance lease obligations—current		3,884
Funds payable and amounts due to sellers	49,786	21,072
Deferred revenue	7,617	7,478
Other current liabilities	8,181	3,925
Total current liabilities	188,528	112,062
Finance lease obligations—net of current portion	53,611
Finance lease obligations—net of current portion		2,095
Deferred tax liabilities	64,497	30,455
Facility financing obligation	0	59,991
Long-term debt, net	785,126	276,486
Other liabilities	43,956	19,864
Total liabilities	1,135,718	500,953
Commitments and contingencies (Note 14)
Stockholders’ equity:
Common stock ($0.001 par value, 120,000,000 and 1,400,000,000 shares authorized as of December 31, 2014 and December 31, 2015; 44,180,939 and 112,563,354 shares issued and outstanding as of December 31, 2014, and December 31, 2015, respectively)	119	120
Preferred stock ($0.001 par value, 25,000,000 shares authorized as of December 31, 2019 and 2018)	0	0
Additional paid-in capital	642,628	562,033
Accumulated deficit	(227,414)	(153,442)
Accumulated other comprehensive (loss) income	(8,699)	(7,813)
Total stockholders’ equity	406,634	400,898
Total liabilities and stockholders’ equity	$ 1,542,352	$ 901,851

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	1,400,000,000	1,400,000,000
Common stock, shares issued (in shares)	118,342,772	119,771,702
Common stock, shares outstanding (in shares)	118,342,772	119,771,702
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 818,379	$ 603,693	$ 441,231
Cost of revenue	271,036	190,762	150,986
Gross profit	547,343	412,931	290,245
Operating expenses:
Marketing	215,570	158,013	109,085
Product development	121,878	97,249	74,616
General and administrative	121,134	82,883	91,486
Asset impairment charges	0	0	3,162
Total operating expenses	458,582	338,145	278,349
Income from operations	88,761	74,786	11,896
Other (expense) income:
Interest expense	(24,320)	(22,178)	(11,130)
Interest and other income	13,199	8,957	2,394
Foreign exchange gain (loss)	3,006	(6,487)	29,105
Total other (expense) income	(8,115)	(19,708)	20,369
Income before income taxes	80,646	55,078	32,265
Benefit for income taxes	15,248	22,413	49,535
Net income	$ 95,894	$ 77,491	$ 81,800
Net income per share attributable to common stockholders:
Basic (in dollars per share)	$ 0.80	$ 0.64	$ 0.69
Diluted (in dollars per share)	$ 0.76	$ 0.61	$ 0.68
Weighted average common shares outstanding:
Basic (in shares)	119,665,248	120,146,076	118,538,687
Diluted (in shares)	125,720,073	127,084,785	122,267,673

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 95,894	$ 77,491	$ 81,800
Other comprehensive (loss) income:
Cumulative translation adjustment	(1,078)	(1,399)	(24,898)
Unrealized gains (losses) on marketable securities, net of tax expense (benefit) of $65, $0, and ($15), respectively	192	(35)	47
Total other comprehensive loss	(886)	(1,434)	(24,851)
Comprehensive income	$ 95,008	$ 76,057	$ 56,949

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Unrealized holding gain (loss) arising during period, tax	$ 65	$ 0	$ (15)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income
Beginning balance (in shares) at Dec. 31, 2016		115,973,039
Beginning balance at Dec. 31, 2016	$ 344,757	$ 116	$ 442,510	$ (116,341)	$ 18,472
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 26,594		26,594
Exercise of vested options (in shares)	5,760,263	5,760,263
Exercise of vested options	$ 33,838	$ 6	33,832
Vesting of restricted stock units, net of shares withheld (in shares)		622,167
Vesting of restricted stock units, net of shares withheld	$ (6,417)	$ 1	(6,418)
Stock repurchase (in shares)	(586,231)	(586,231)
Stock repurchase	$ (10,301)	$ (1)		(10,300)
Conversion of liability-classified restricted shares upon vesting	2,838		2,838
Other comprehensive loss	(24,851)				(24,851)
Net income	81,800			81,800
Ending balance (in shares) at Dec. 31, 2017		121,769,238
Ending balance at Dec. 31, 2017	396,894	$ 122	499,441	(96,290)	(6,379)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 40,483		40,483
Exercise of vested options (in shares)	1,588,779	1,588,779
Exercise of vested options	$ 18,253	$ 1	18,252
Issuance of convertible senior notes, net of issuance costs and taxes	53,323		53,323
Purchase of capped call, net of taxes	(25,400)		(25,400)
Vesting of restricted stock units, net of shares withheld (in shares)		860,102
Vesting of restricted stock units, net of shares withheld	$ (24,065)	$ 1	(24,066)
Stock repurchase (in shares)	(5,032,648)	(4,446,417)
Stock repurchase	$ (134,647)	$ (4)		(134,643)
Other comprehensive loss	(1,434)				(1,434)
Net income	$ 77,491			77,491
Ending balance (in shares) at Dec. 31, 2018	119,771,702	119,771,702
Ending balance at Dec. 31, 2018	$ 400,898	$ 120	562,033	(153,442)	(7,813)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 45,697		45,697
Exercise of vested options (in shares)	840,835	840,835
Exercise of vested options	$ 9,791	$ 1	9,790
Issuance of convertible senior notes, net of issuance costs and taxes	115,980		115,980
Purchase of capped call, net of taxes	(58,324)		(58,324)
Vesting of restricted stock units, net of shares withheld (in shares)		832,642
Vesting of restricted stock units, net of shares withheld	$ (32,547)	$ 1	(32,548)
Stock repurchase (in shares)	(6,040,859)	(3,102,407)
Stock repurchase	$ (176,985)	$ (3)		(176,982)
Other comprehensive loss	(886)				(886)
Net income	$ 95,894			95,894
Ending balance (in shares) at Dec. 31, 2019	118,342,772	118,342,772
Ending balance at Dec. 31, 2019	$ 406,634	$ 119	$ 642,628	$ (227,414)	$ (8,699)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 95,894	$ 77,491	$ 81,800
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	44,395	38,231	26,559
Depreciation and amortization expense	48,031	26,742	27,197
Bad debt expense	10,963	4,124	2,497
Foreign exchange (gain) loss	(5,708)	5,997	(27,424)
Amortization of debt issuance costs	2,006	1,191	463
Non-cash interest expense	19,108	10,968	3,117
Interest (income) expense on marketable securities	(4,182)	(2,887)	426
Loss on disposal of assets	1,667	136	520
Asset impairment charges	0	0	3,162
Deferred income taxes	(15,248)	(22,414)	(49,535)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(12,656)	17,215	(8,826)
Funds receivable and seller accounts	(23,177)	23,436	(13,477)
Prepaid expenses and other current assets	(14,156)	(4,785)	3,024
Other assets	4,045	43	(28)
Accounts payable	(953)	13,364	2,837
Accrued and other current liabilities	37,410	23,079	(2,659)
Funds payable and amounts due to sellers	23,177	(23,436)	13,477
Deferred revenue	191	1,331	434
Other liabilities	(3,887)	9,099	5,537
Net cash provided by operating activities	206,920	198,925	69,101
Cash flows from investing activities
Cash paid for asset acquisition and intangible assets	(1,963)	(35,494)	0
Acquisition of businesses, net of cash acquired	(270,409)	0	0
Purchases of property and equipment	(7,528)	(1,019)	(3,948)
Development of internal-use software	(7,750)	(19,537)	(9,208)
Purchases of marketable securities	(661,821)	(514,286)	(62,348)
Sales of marketable securities	461,098	284,943	137,340
Net cash (used in) provided by investing activities	(488,373)	(285,393)	61,836
Cash flows from financing activities
Payment of tax obligations on vested equity awards	(32,547)	(24,065)	(6,417)
Repurchase of stock	(176,985)	(134,647)	(10,301)
Proceeds from exercise of stock options	9,791	18,253	33,838
Proceeds from issuance of convertible senior notes	650,000	345,000	0
Payment of debt issuance costs	(11,904)	(9,962)	0
Purchase of capped call	(76,180)	(34,224)	0
Payments on finance lease obligations	(10,833)
Payments on finance lease obligations		(6,057)	(7,798)
Payments on facility financing obligation	0	(10,164)	(5,883)
Other financing, net	8,265	(128)	3,116
Net cash provided by financing activities	359,607	144,006	6,555
Effect of exchange rate changes on cash	(1,846)	(5,995)	(3,642)
Net increase in cash, cash equivalents, and restricted cash	76,308	51,543	133,850
Cash, cash equivalents, and restricted cash at beginning of period	372,326	320,783	186,933
Cash, cash equivalents, and restricted cash at end of period	448,634	372,326	320,783
Supplemental cash flow disclosures:
Cash paid for interest	3,206	10,002	7,555
Cash paid for income taxes	2,084	966	1,003
Supplemental non-cash disclosures:
Stock-based compensation capitalized in development of capitalized software	1,302	2,252	807
Additions to development of internal-use software and property and equipment included in accounts payable and accrued expenses	1,148	1,211	956
Right-of-assets obtained in exchange for new lease liabilities:
Finance Leases	849
Finance Leases		2,122	5,586
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Total cash, cash equivalents, and restricted cash	$ 372,326	$ 372,326	$ 186,933

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Note 1—Basis of Presentation and Summary of Significant Accounting Policies Description of Business Etsy, Inc. (the “Company” or “Etsy”) was incorporated in Delaware in February 2006. Etsy is the global marketplace for unique and creative goods. The Company generates revenue primarily from transaction and listing fees, payments processing fees, advertising services, and shipping label sales. Basis of Consolidation The Consolidated Financial Statements include the accounts of Etsy and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. On August 15, 2019, Etsy acquired all of the issued and outstanding capital stock of Reverb Holdings, Inc. (“Reverb”). The financial results of Reverb have been included in Etsy’s Consolidated Financial Statements from the date of acquisition. See “ Note 5—Business Combinations .” Reclassifications Certain items in the prior years’ Consolidated Financial Statements have been reclassified to conform to the current year presentation reflected in the Consolidated Financial Statements. Specifically, the Company reclassified $4.0 million and $3.3 million previously included in Other revenue to Marketplace revenue (see “ Note 2—Revenue ”) for the years ended December 31, 2018 and 2017 , respectively, to conform to the current year presentation. Use of Estimates The preparation of the Company’s Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets, liabilities, and equity at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. The accounting estimates that require management’s most difficult and subjective judgments include: leases, including determining the incremental borrowing rate; income taxes, including the accounting for uncertain tax positions; purchase price allocations for business combinations, valuation of the acquired intangibles purchased in a business combination; valuation of goodwill and intangible assets; stock-based compensation; and fair value of financial instruments. The Company evaluates its estimates and judgments on an ongoing basis and revises them when necessary. Actual results may differ from the original or revised estimates. Revenue Recognition The Company’s revenue is diversified; generated from a mix of marketplace activities and other optional services to help sellers to generate more sales and scale their businesses. Revenues are recognized as the Company transfers control of promised goods or services to sellers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company evaluates whether it is appropriate to recognize revenue on a gross or net basis based upon its evaluation of whether the Company obtains control of the specified goods or services by considering if it is primarily responsible for fulfillment of the promise, has inventory risk, and has the latitude in establishing pricing and selecting suppliers, among other factors. Based on its evaluation of these factors, revenue is recorded either gross or net of costs associated with the transaction. With the exception of shipping labels, the Company’s revenues are recognized on a gross basis. Sales and usage-based taxes are excluded from revenues. Etsy Marketplace revenue: As members of the Etsy marketplace, Etsy sellers receive the benefit of marketplace activities, including listing items for sale, completing sales transactions, and payments processing, which represents a single stand-ready performance obligation. Etsy sellers pay a fixed listing fee of $0.20 for each item listed on Etsy.com for a period of four months or, if earlier, until a sale occurs. Variable fees include the 5% transaction fee that an Etsy seller pays for each completed transaction, inclusive of shipping fees charged, and Etsy Payments fees for processing payments, including foreign currency payments. On July 16, 2018 , the Company increased the seller transaction fee from 3.5% to 5% of each completed transaction, and now applies it to the cost of shipping in addition to the cost of the item. Etsy Payments processing fees vary between 3.0% to 4.5% of an item’s total sale price, including shipping, plus a flat fee per order, depending on the country in which a seller’s bank account is located. The Company earns additional fees on transactions in which currency conversions are performed. The listing fee is recognized ratably over a four -month listing period, unless the item is sold or the seller re-lists it, at which time any remaining listing fee is recognized. The transaction fee and Etsy Payments fees are recognized when the corresponding transaction is consummated. Listing fees are nonrefundable while transaction fees and Etsy Payments fees are recorded net of refunds. Marketplace revenue also includes revenue generated through our commercial partnerships, which was recorded in its own Other revenue line prior to the fourth quarter of 2019. Reverb Marketplace revenue: The Reverb seller transaction fee is a variable fee, which is 3.5% of each completed transaction, including both the cost of the item and the shipping. There are no Reverb listing fees. Variable fees also include payments fees for processing payments, including foreign currency payments. Payments processing fees vary between 2.5% - 2.7% of an item’s total sale price, including shipping, plus a flat fee per order, depending on the currency in which a listing is denominated. Etsy Services revenue: Services revenue is derived from optional services offered to Etsy sellers, which primarily include advertising services and Etsy Shipping Labels. Each service below represents an individual obligation that the Company must perform when an Etsy seller chooses to use the service. • Revenue from Promoted Listings, Etsy.com’s on-site advertising service, consists of cost-per-click fees an Etsy seller pays for prominent placement of the seller’s listings in search results in the Etsy.com marketplace. Promoted Listings fees are based on an auction system, which utilizes the budget that each Etsy seller sets when using Promoted Listings to determine the cost-per-click fee. Promoted Listing fees are nonrefundable and are charged to a seller’s Etsy bill when the Promoted Listing is clicked, at which time revenue is recognized. In the third quarter of 2019, Etsy streamlined Promoted Listings and Google Shopping, an off-site marketing tool for Etsy sellers, into one unified ad platform called Etsy Ads, where Etsy sellers can set a budget, which allows Etsy to allocate that budget between channels, targeting optimal return on seller spend. Due to this new offering, Etsy no longer offered its Promoted Listings service as a standalone advertising service after September 30, 2019. Revenue from Etsy Ads consists of cost-per-click fees, which are nonrefundable and are charged to a seller’s Etsy bill when the ad is clicked, at which time revenue is recognized. The revenue the Company recognizes related to Etsy Ads is recorded on a gross basis in Services revenue with an offsetting expense recorded in cost of revenue. • Revenue from Etsy Shipping Labels consists of fees an Etsy seller pays the Company when she purchases shipping labels through its platform, net of the cost the Company incurs in purchasing those shipping labels. The Company provides its sellers access to purchase shipping labels from the United States Postal Service, FedEx, Canada Post, Royal Mail, and DAI Post at discounted pricing due to the volume of purchases through its platform. The Company recognizes Etsy Shipping Label revenue when an Etsy seller purchases a shipping label. The Company recognizes Etsy Shipping Label revenue on a net basis as it is an agent in this arrangement and does not take control of shipping labels prior to transferring the labels to the Etsy Seller. Etsy Shipping Label revenue is recorded net of refunds. Reverb Services revenue : Reverb has its own on-site advertising service called Bump advertising. Reverb sellers have the ability to determine their own ad rate as a percentage of their item’s final sale price. Revenue from Bump advertising is recognized at the time the item is sold. Reverb also provides its sellers access to purchase shipping labels at discounted pricing due to the volume of purchases through its platform. Revenue from shipping labels consists of fees a Reverb seller pays when they purchase shipping labels directly through the Reverb platform, net of the cost we incur in purchasing those shipping labels. Reverb recognizes shipping label revenue when a Reverb seller purchases a shipping label. Reverb recognizes shipping label revenue on a net basis as it is an agent in this arrangement and does not take control of shipping labels prior to transferring the labels to the Reverb seller. Shipping label revenue is recorded net of refunds. Cost of Revenue Cost of revenue primarily consists of the cost of interchange and other fees for credit card processing services, credit card verification service fees, and credit card chargebacks to support payments revenue, and costs of refunds made to buyers that the Company is not able to collect from sellers. Cost of revenue also includes expenses associated with the operation and maintenance of the Company’s platform and its data centers, including employee-related costs, hosting and bandwidth costs, and depreciation and amortization. With the shift to Etsy Ads in the third quarter of 2019, amounts spent on Google Shopping, which were previously recorded on a net basis in Other revenue, are recorded on a gross basis in Services revenue with an offsetting expense recorded in cost of revenue. Marketing Marketing expenses largely consist of direct marketing and indirect employee-related expenses to support our marketing initiatives. Direct marketing includes digital marketing, brand marketing, television and video, public relations and communications, market research, marketing partnerships, and customer relationship management. Digital marketing, also referred to as performance marketing, primarily consists of targeted promotional campaigns through electronic channels, such as product listing ads, search engine marketing, affiliate programs, display advertising, and social channels, which are focused on buyer acquisition and retargeting. Advertising expenses are recognized as incurred, with the exception of certain production expenses related to television and display advertising which are deferred until the first time an advertisement airs or is published. If such advertising is not expected to occur, costs are expensed immediately. Advertising expenses related to direct marketing, included in marketing expenses on the Consolidated Statements of Operations, were $175.2 million , $129.1 million , and $78.4 million in the years ended December 31, 2019 , 2018 , and 2017 , respectively. Product Development Product development expenses consist primarily of employee-related expenses for engineering, product management, product design, and product research activities. Additional expenses include consulting costs related to the development, quality assurance, and testing of new technology and enhancement of our existing technology. Stock-Based Compensation The Company accounts for its stock-based compensation awards in accordance with ASC Topic 718 —Compensation—Stock Compensation (“ASC 718”). Stock options and restricted stock units (“RSUs”) are awarded to employees and members of the Company’s Board of Directors and are measured at fair value at each grant date. The Company calculates the fair value of stock options on the date of grant using the Black-Scholes option-pricing model and the expense is recognized over the requisite service period. Prior to the IPO, the Company utilized equity valuations based on comparable publicly-traded companies, discounted free cash flows, an analysis of the Company’s enterprise value, and other factors deemed relevant in estimating the fair value of its common stock. Subsequent to the IPO, the Company has used the closing price of its common stock on Nasdaq as the fair value of its common stock. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. Expected volatilities are based on implied volatilities from market comparisons of Etsy and certain publicly traded companies, and other factors. The expected term of stock options granted has been determined using the simplified method, which uses the midpoint between the vesting date and the contractual term. The fair value of RSUs is determined based on the closing price of the Company’s common stock on Nasdaq on the grant date. The requisite service period for stock options and RSUs is generally four years from the date of grant. The Company recognizes forfeitures as they occur. The Company accounted for stock-based compensation arrangements related to the A Little Market (“ALM”) acquisition in restricted shares, subject to a put option that allows the holder of the shares to put the shares back to the Company for cash, as liability-classified stock awards. These awards were re-measured at fair value each reporting period, with changes in fair value being charged to the Consolidated Statement of Operations. Compensation expense was recognized using a graded vesting methodology for each separately vesting tranche as though the award were, in substance, multiple awards. Unless the put option was exercised, the restricted shares were to be reclassified from a liability to an equity classified award upon the termination of the put option at the vesting of each separate tranche. In 2017, all outstanding restricted shares subject to a put option became fully vested and the Company is no longer required to remeasure these awards at fair value going forward. Foreign Currency The Company has determined that the functional currency for each of its foreign operations is the currency of the primary cash flow of the operations, which is generally the local currency in which the operation is located. All assets and liabilities are translated into U.S. dollars using exchange rates in effect at the balance sheet date. Revenue and expenses are translated using average exchange rates during the period. Foreign currency translation adjustments are reflected in stockholders’ equity as a component of other comprehensive income (loss). Transaction gains and losses including intercompany balances denominated in a currency other than the functional currency of the entity involved are included in foreign exchange gain (loss) within other income (expense) in the Consolidated Statement of Operations. Income Taxes The income tax benefit is based on income before income taxes and is accounted for under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to settle. The Company recognizes future tax benefits, such as net operating losses and tax credits, to the extent that realizing these benefits is considered in its judgment to be more likely than not. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income or expense in the period that includes the enactment date. The Company regularly reviews the recoverability of its deferred tax assets by considering its historic profitability, projected future taxable income, timing of the reversals of existing temporary differences and the feasibility of its tax planning strategies. Where appropriate the Company records a valuation allowance against deferred tax assets that are deemed more likely than not to be realizable. On December 22, 2017 the Tax Cuts and Jobs Act of 2017 (the “TCJA”) was signed into law. The TCJA requires the Company to make an accounting policy election of either (1) treating taxes due on future U.S. inclusions in taxable income related to Global Intangible Low Taxed Income ("GILTI") as a current period expense when incurred (the “period cost method”) or (2) factoring such amounts into the Company’s measurement of its deferred taxes (the “deferred method”). The Company has recorded tax expense related to GILTI in its effective tax rate beginning in 2018, and has elected to treat taxes due on future U.S. inclusions in taxable income related to GILTI as a current period expense when incurred using the period cost method. The Company accounts for uncertainty in income taxes using a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by the taxing authorities. The amount recognized is measured as the largest amount of benefit that has a greater than 50% likelihood of being realized upon ultimate audit settlement. The Company recognizes interest and penalties, if any, associated with income tax matters as part of the income tax provision and includes accrued interest and penalties with the related income tax liability in the Consolidated Balance Sheets. Net Income (Loss) Per Share Basic net income per share attributable to common stockholders is computed by dividing the net income attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted net income per share is computed by dividing net income for the period by the weighted-average number of shares of common stock and potentially dilutive common stock outstanding during the period. Net income in the diluted net income per share calculation is adjusted for income or loss from fair value adjustments on instruments accounted for as liabilities, but which may be settled in shares. The dilutive effect of outstanding options and stock-based compensation awards is reflected in diluted net income per share by application of the treasury stock and if-converted methods. Since the Company expects to settle in cash the principal outstanding under the 0.125% Convertible Senior Notes due 2026 (the “ 2019 Notes ”) (see “ Note 13—Debt ”), it uses the treasury stock method when calculating the potential dilutive effect of the conversion spread on diluted net income per share, if applicable. The Company uses the if-converted method when calculating the dilutive effect of the 0% Convertible Senior Notes due 2023 (the “ 2018 Notes ”) for the reporting periods starting in the third quarter of 2019, and used the treasury stock method for previous reporting periods. The calculation of diluted net income (loss) per share excludes all anti-dilutive common shares. For periods in which the Company has reported net losses, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, because dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Segment Data The Company identifies operating segments as components of an entity for which discrete financial information is available and is regularly reviewed by the chief operating decision maker in making decisions regarding resource allocation and performance assessment. The Company defines the term “chief operating decision maker” to be its chief executive officer. The Company has determined it has two operating segments, Etsy and Reverb, which qualify for aggregation as one reportable segment, for purposes of allocating resources and evaluating financial performance. Cash and Cash Equivalents, and Short- and Long-term Investments The Company considers all investments with an original maturity of three months or less at time of purchase to be cash equivalents. Cash restricted by third parties is not considered cash and cash equivalents. Short-term investments, consisting of U.S. Government and agency securities, corporate bonds, commercial paper, and certificates of deposit with original maturities of greater than three months but less than one year when purchased, are classified as available-for-sale and are reported at fair value using the specific identification method. Long-term investments, consisting of U.S. Government and agency securities, corporate bonds, and certificates of deposit with original maturities of greater than twelve months but less than 37 months when purchased, are classified as available-for-sale and are reported at fair value using the specific identification method. Unrealized gains and losses are excluded from earnings and reported as a component of other comprehensive income (loss), net of related estimated income tax provisions or benefits. The following table provides cash and cash equivalents, and short- and long-term investments within the Consolidated Balance Sheets as of the dates indicated (in thousands): As of December 31, 2019 2018 Cash and cash equivalents $ 443,293 $ 366,985 Short-term investments 373,959 257,302 Long-term investments 89,343 — Total cash, cash equivalents, and short- and long-term investments $ 906,595 $ 624,287 Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash and cash equivalents, short- and long-term investments, and funds receivable and seller accounts. The Company reduces credit risk by placing its cash and cash equivalents with major financial institutions with high credit ratings. At times, to the extent eligible, such amounts may exceed federally insured limits. The Company believes that minimal credit risk exists with respect to these investments due to the credit ratings of the financial institutions that hold its short- and long-term investments. In addition, funds receivable settle relatively quickly, and the Company’s historical experience of losses has not been significant. Fair Value of Financial Instruments Management believes that the fair value of financial instruments, consisting of cash and cash equivalents, short- and long-term investments, accounts receivable, funds receivable and seller accounts, accounts payable, and funds payable and seller accounts approximates carrying value due to the immediate or short-term maturity associated with these instruments. In accounting for the issuance of the Notes discussed in “ Note 13—Debt ,” management used estimates and assumptions to calculate the carrying amounts of the liability and equity components by measuring the fair value of similar securities. Accounts Receivable and Allowance for Doubtful Accounts The Company’s trade accounts receivable are recorded at amounts billed to sellers and are presented on the Consolidated Balance Sheets net of the allowance for doubtful accounts. The allowance is determined by a number of factors, including age of the receivable, current economic conditions, historical losses, and management’s assessment of the financial condition of sellers. Receivables are written off once they are deemed uncollectible. Estimates of uncollectible accounts receivable are recorded to general and administrative expense. See “ Note 2—Revenue ” for additional information on payment terms related to the Company’s accounts receivable balances. The following table summarizes the allowance activity during the periods indicated (in thousands): Year Ended 2019 2018 2017 Balance as of the beginning of period $ 4,720 $ 2,687 $ 1,999 Bad debt expense 10,963 4,124 2,497 Write-offs, net of recoveries and other adjustments (10,650 ) (2,091 ) (1,809 ) Balance as of the end of period $ 5,033 $ 4,720 $ 2,687 Funds Receivable and Seller Accounts and Funds Payable and Amounts due to Sellers The Company records funds receivable and seller accounts and funds payable and amounts due to sellers as current assets and liabilities, respectively, on the Consolidated Balance Sheets. Funds receivable and seller accounts represent amounts received or expected to be received from buyers via third-party credit card processors, which flow through a bank account for payment to sellers. This cash and related receivable represent the total amount due to sellers, and as such a liability for the same amount is recorded to funds payable and amounts due to sellers. Property and Equipment Property and equipment, consisting principally of capitalized website development and internal-use software, building, leasehold improvements, and computer equipment, are recorded at cost. Depreciation and amortization begin at the time the asset is placed into service and are recognized using the straight-line method in amounts sufficient to relate the cost of depreciable and amortizable assets to the Consolidated Statements of Operations over their estimated useful lives. Repairs and maintenance are charged to the Consolidated Statements of Operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation or amortization are removed from the balance sheet and the resulting gain or loss is reflected in the Consolidated Statements of Operations. When events or changes in circumstances require, the Company assesses the likelihood of recovering the cost of tangible long-lived assets based on its expectations of future profitability, undiscounted cash flows, and management’s plans with respect to operations to determine if the asset is impaired and subject to write-off. Measurement of any impairment loss is based on the excess of the carrying value of the asset over the fair value. See “ Recently Adopted Accounting Pronouncements ” below for information on the impact of ASU 2016-02 —Leases on property and equipment balances. Website Development and Internal-use Software Costs Costs incurred to develop the Company’s website and software for internal-use are capitalized and amortized over the estimated useful life of the software, generally three to five years . In accordance with authoritative accounting guidance, capitalization of costs to develop software begin 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. Costs related to the design or maintenance of website development and internal-use software are expensed as incurred. The Company periodically reviews capitalized website development and internal-use software costs to determine whether the projects will be completed, placed in service, removed from service, or replaced by other internally-developed or third-party software. If an asset is not expected to provide any future use, the asset is retired and any unamortized cost is expensed. If an asset will continue to be used, but the net book value is not expected to be fully recoverable, the asset is impaired to its fair value. When events or changes in circumstances require, the Company assesses the likelihood of recovering the cost of website development and internal-use software costs based on its expectations of future profitability, undiscounted cash flows, and our plans with respect to operations to determine if the asset is impaired and subject to write-off. Measurement of any impairment loss is based on the excess of the carrying value of the asset over the fair value. No impairment of capitalized website development and internal-use software assets was recorded during the years ended December 31, 2019 and 2018 . The Company recognized an asset impairment charge of $3.2 million related to capitalized web development and internal-use software assets in the year ended December 31, 2017 as a result of its decision to discontinue certain product offerings, including Etsy Studio and Etsy Manufacturing. Capitalized website development and internal-use software costs are included in property and equipment within the Consolidated Balance Sheets. Business Combinations In accordance with the guidance for business combinations, we determine whether a transaction is a business combination, which requires that the assets acquired and liabilities assumed constitute a business. The Company accounts for business combinations using the acquisition method of accounting. If the assets acquired are not a business, we account for the transaction as an asset acquisition. Under both methods, the purchase price is allocated to the assets acquired and liabilities assumed using the fair values determined by management as of the acquisition date. The results of businesses acquired in a business combination are included in the Company’s Consolidated Financial Statements from the date of acquisition. Determining the fair value of assets acquired and liabilities assumed requires management to use significant judgment and estimates, including estimates of future revenue and adjusted earnings before interest and taxes and discount rates. Our estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and unpredictable and, as a result, actual results may differ materially from estimates. Our estimates associated with the accounting for business combinations may change as additional information becomes available regarding the assets acquired and liabilities assumed. Any change in facts and circumstances that existed as of the acquisition date and impacts our preliminary estimates is recorded to goodwill if identified within the measurement period. Subsequent to the measurement period or our final determination of fair value of assets and liabilities whichever is earlier the adjustments will affect our earnings. Acquisition-related expenses incurred by the Company in a business combination are not included as a component of consideration transferred, but are accounted for as an expense in the period in which the costs are incurred. Goodwill Goodwill represents the excess of the aggregate fair value of the consideration transferred in a business combination over the fair value of the assets acquired, net of liabilities assumed. Goodwill is not amortized, but is subject to an annual impairment test. Management has determined that the Company has two operating segments, which qualify for aggregation as one reportable segment, for purposes of allocating resources and evaluating financial performance. As a result, the Company has determined it has two reporting units. The Company performs its annual goodwill impairment test during the fourth quarter or more frequently if events or changes in circumstances indicate that the goodwill may be impaired. The Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of the reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, the Company determines it is not more likely than not that the fair value of the reporting unit is less than its carrying amount, then additional impairment testing is not required. However, if the Company concludes otherwise, then it is required to perform a quantitative assessment for impairment. The quantitative assessment involves comparing the estimated fair value of the reporting unit with its respective book value, including goodwill. If the estimated fair value exceeds book value, goodwill is considered not to be impaired. If, however, the book value of the reporting unit exceeds the fair value, an impairment loss is recognized in an amount equal to the excess, not to exceed the total amount of goodwill allocated to that reporting unit. The Company completed a qualitative analysis for the Etsy reporting unit and a quantitative analysis for the Reverb reporting unit during the fourth quarter of 2019 . No impairment of goodwill was recorded during the three years ended December 31, 2019, 2018, and 2017 . Intangible Assets Finite intangible assets are amortized over the estimated useful life of the asset. The estimated useful life of acquired technology is three years . The estimated useful lives of acquired customer relationships and trademarks are fifteen years and the estimated useful life of th

Revenue

Revenue	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue	Note 2—Revenue The following table summarizes revenue by type of service for the periods presented (in thousands): Year Ended December 31, 2019 2018 2017 Marketplace revenue (1) $ 593,646 $ 444,765 $ 329,362 Services revenue 224,733 158,928 111,869 Revenue $ 818,379 $ 603,693 $ 441,231 (1) Other revenue for the years ended December 31, 2019, 2018, and 2017 has been reclassified and presented within Marketplace revenue. Comparative periods have been reclassified to conform to current period presentation. See “ Note 1—Basis of Presentation and Summary of Significant Accounting Policies —Revenue Recognition” for additional information on recognition. Payment terms Etsy As of November 13, 2018, for Etsy sellers using Etsy Payments, all charges, including listing fees, transaction fees, Etsy Payments fees, advertising services fees, and Etsy Shipping Labels fees, are deducted from the funds credited to the seller’s shop payment account in the seller’s ledger currency prior to settlement of those funds to the seller’s bank account. Etsy sellers receive a statement electronically on the first day of each month outlining the previous month’s charges and any remaining amount due after the Company’s fees are deducted from the seller’s shop payment account. Etsy sellers who do not use Etsy Payments receive a statement electronically on the first day of each month for the previous month’s charges in U.S. Dollars, including all listing fees, transactions fees, advertising services fees, and Etsy Shipping Labels fees. Payment is due by the 15th of every month. Prior to November 13, 2018, Etsy sellers would receive a statement electronically on the first day of each month for the previous month’s charges in U.S. Dollars, including all listing fees, transactions fees, advertising services fees, and Etsy Shipping Labels fees. Payment was due by the 15th of every month. Prior to November 13, 2018 only Etsy Payments fees were deducted from the funds credited to the seller’s shop payment account in the seller’s ledger currency prior to settlement of those funds to the seller’s bank account. Reverb For most transactions, Reverb buyers use a credit card to pay for the merchandise or service, when the order is placed. For these transactions, the Company collects the total amount due on the order, retains its fees due from the Reverb seller, and remits the net proceeds to the Reverb seller. Contract balances Deferred revenues The Company records deferred revenues when cash payments are received or due in advance of the completion of the listing period, which represents the value of the Company’s unsatisfied performance obligations. Deferred listing revenue is recognized ratably over the remainder of the four -month listing period, unless the item is sold or the seller re-lists it, at which time any remaining listing fee is recognized. The amount of revenue recognized in the year ended December 31, 2019 that was included in the deferred balance at the beginning of the period was $7.5 million .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 3—Income Taxes The following are the domestic and foreign components of the Company’s income before income taxes (in thousands): Year Ended 2019 2018 2017 Domestic $ 14,544 $ 36,157 $ (16,583 ) Foreign 66,102 18,921 48,848 Income before income taxes $ 80,646 $ 55,078 $ 32,265 The income tax benefit is comprised of the following (in thousands): Year Ended 2019 2018 2017 Current: Federal $ (3,967 ) $ 709 $ (6,397 ) State 1,053 (578 ) 79 Foreign 352 600 476 Total current (2,562 ) 731 (5,842 ) Deferred: Federal (19,734 ) (3,343 ) (34,948 ) State (1,564 ) 3,496 (8,778 ) Foreign 8,612 (23,297 ) 33 Total deferred (12,686 ) (23,144 ) (43,693 ) Total income tax benefit $ (15,248 ) $ (22,413 ) $ (49,535 ) For the years ended December 31, 2019 , 2018 and 2017 , the Company recorded a benefit for income taxes of $15.2 million , $22.4 million , and $49.5 million or an effective tax rate of (18.9)% , (40.7)% and (153.5)% , respectively. A reconciliation of the income tax benefit at the U.S. federal statutory income tax rate to the Company’s total income tax benefit is as follows (in thousands): Year Ended 2019 2018 2017 Income tax provision at the federal statutory rate (a) $ 16,936 $ 11,566 $ 11,308 State and local income taxes net of federal benefit 973 3,839 (691 ) Foreign income tax rate differential (5,454 ) (298 ) (11,878 ) Stock-based compensation (16,281 ) (11,717 ) (12,584 ) Research and development credit (9,864 ) (4,115 ) (1,098 ) U.S. tax reform (b) (4,197 ) 3,897 (31,063 ) Non-deductible expenses 1,784 (329 ) 168 Uncertain tax positions 380 382 789 Change in valuation allowance (c) — (28,733 ) (4,673 ) Return to provision adjustment 500 3,293 167 Other (25 ) (198 ) 20 Total income tax benefit $ (15,248 ) $ (22,413 ) $ (49,535 ) (a) The income tax provision at the U.S. federal statutory rate is computed using 21% in 2019 and 2018 and 35% in 2017. Refer to footnote (b) below. (b) On December 22, 2017, the U.S. government enacted the TCJA, as described above, which includes significant changes to the taxation of business entities. These changes include, among others, (1) a permanent reduction to the corporate income tax rate, (2) Global Intangible Low-Taxed Income (“GILTI”), a new tax on worldwide income, and (3) Foreign Derived Intangible Income (“FDII”) a deduction provided with respect to certain foreign earned income. Effective January 1, 2018, the Company is subject to several provisions of the TCJA including computations under GILTI and FDII. For the year ended December 31, 2017, primarily as a result of the permanent change in U.S. corporate income tax rate, the Company recognized a net income tax benefit of $31.1 million associated with the TCJA. For the years ended December 31, 2019 and 2018, the Company has accounted for the impact of the new TCJA provisions, as well as any adjustments with respect to the re-measurement of its deferred taxes, as part of its income tax benefit using the currently available regulations and technical guidance on the interpretations of the TCJA. The Company has elected to account for GILTI as a period cost. The Company is not currently subject to the Base Erosion and Anti-Abuse Tax (“BEAT”) or Section 163(j) Interest Limitation. The Company will continue to monitor the forthcoming regulations and additional guidance of the GILTI, FDII, and BEAT provisions under the TCJA, which are complex and subject to continuing regulatory interpretation by the Internal Revenue Service (“IRS”). (c) For the year ended December 31, 2018, the Company released valuation allowance recorded against deferred tax assets in certain foreign jurisdictions as it had achieved three years of cumulative pre-tax income. Deferred income taxes reflect the net tax effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets (liabilities) are as follows (in thousands): As of December 31, 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 19,599 $ 13,347 Research and development credit carryforwards 13,133 7,567 Lease liability (a) 18,666 — Stock-based compensation expense 7,642 6,623 Excess tax basis in intangible assets 3,572 12,109 Accrued bonus 4,065 1,049 Deferred rent (a) — 529 Other deferred tax assets 3,944 1,858 Total deferred tax assets 70,621 43,082 Less: valuation allowance 883 1,673 Total net deferred tax asset 69,738 41,409 Deferred tax liabilities: Excess book basis in intangible assets (39,500 ) (362 ) Restructuring liability (29,635 ) (33,730 ) Convertible debt (22,839 ) (7,283 ) Right-of-use asset (a) (17,596 ) — Depreciation (a) (10,328 ) (6,933 ) Other deferred tax liabilities (80 ) (92 ) Total deferred tax liabilities (119,978 ) (48,400 ) Net deferred tax liabilities $ (50,240 ) $ (6,991 ) (a) As part of the Company’s adoption of ASC 842 beginning in 2019, the Company recorded adjustments to the GAAP basis of certain assets and liabilities and established other assets and liabilities (i.e., right-of-use asset and lease liability). The net adjustment was recorded as a retrospective adjustment to retained earnings. The adoption of ASC 842 does not change the Company’s tax basis in these assets and liabilities. However, as a result of the adoption, an adjustment was recorded to the historic deferred taxes, through retained earnings, to account for the change in GAAP basis as well as establishing deferred taxes on the newly established right-of-use assets and lease liabilities. The Company has not recorded deferred income taxes and withholding taxes with respect to undistributed earnings from its non-U.S. subsidiaries as such earnings are intended to be reinvested indefinitely. The amount of undistributed earnings of non-U.S. subsidiaries at December 31, 2019 , as well as the related deferred income tax, if any, is not material. As of December 31, 2019 , the Company had the following operating loss and tax credit carryforwards available to offset taxable income in future years: December 31, 2019 Expiration Period U.S. Federal net operating loss carryforwards $ 30,403 2035-Unlimited U.S. Federal credit carryforwards 13,054 2035-2039 U.S. State net operating loss carryforwards 21,150 2027-2039 U.S. State credit carryforwards 184 2020-2024 Non-U.S. net operating loss carryforwards 91,440 Unlimited Utilization of the net operating losses (“NOLs”) is dependent on generating sufficient taxable income from our operations in each of the respective jurisdictions to which the NOLs relate, while taking into account tax filing methodologies and limitations and/or restrictions on our ability to use them. The Company’s U.S. federal NOLs were acquired as part of the acquisition of Reverb and are subject to limitations as promulgated under Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”). Section 382 of the Code limits the amount of NOLs that we can use on an annual basis to offset consolidated U.S. taxable income. The NOLs are also subject to review by relevant tax authorities in the jurisdictions to which they relate. The NOL deferred tax asset balance additionally includes losses in certain foreign jurisdictions that are currently subject to a valuation allowance. The Company assesses the likelihood of its ability to realize the benefit of its deferred tax assets in each jurisdiction by evaluating all relevant positive and negative evidence at each reporting date. To the extent the Company determines that some or all of its deferred tax assets are not more likely than not to be realized, it establishes a valuation allowance. For the year ended December 31, 2018 , the Company achieved three years of cumulative pre-tax income in certain of its foreign jurisdictions, management determined that sufficient positive evidence existed as of December 31, 2018 , to conclude that was more likely than not that deferred tax assets of $23.4 million will be utilized in those jurisdictions. The following table summarizes the valuation allowance activity for the periods indicated (in thousands): Year Ended 2019 2018 2017 Balance as of the beginning of period $ 1,673 $ 32,455 $ 13,839 Additions charged to expense 504 — 16,743 Deletions credited to expense (4 ) (28,733 ) — Currency translation and other balance sheet activity (1,290 ) (2,049 ) 1,873 Balance as of the end of period $ 883 $ 1,673 $ 32,455 Unrecognized tax benefits The following table summarizes the unrecognized tax benefit activity for the periods indicated (in thousands): As of December 31, 2019 2018 2017 Balance as of the beginning of period $ 18,819 $ 17,013 $ 23,574 Additions based on tax positions related to the current year 1,847 921 732 Additions for tax positions of prior years 3,620 946 118 Reductions for tax provisions of prior years (2,423 ) (61 ) (7,411 ) Lapse of Statute of Limitation (184 ) — — Additions recorded through goodwill as part of business combination 1,334 — — Settlements (3,080 ) — — Balance as of the end of period $ 19,933 $ 18,819 $ 17,013 The amount of unrecognized tax benefits included on the Consolidated Balance Sheets as of December 31, 2019, 2018, and 2017 are $19.9 million , $18.8 million , and $17.0 million , respectively. The total amount of unrecognized tax benefits that, if recognized, would favorably affect the effective tax rate is $19.4 million at December 31, 2019 . We recognize interest and/or penalties related to uncertain tax positions in income tax expense. For the years ended 2019 and 2018 , $(0.1) million and $0.3 million , respectively, was included in income tax (benefit)/expense for interest and penalties. The amount of interest and penalties accrued as of December 31, 2019 and 2018 was approximately $0.2 million and $0.5 million , respectively. The total amount of unrecognized tax benefits relating to the Company's tax positions is subject to change based on future events including, but not limited to, the settlements of ongoing audits and/or the expiration of applicable statutes of limitations. The outcomes and timing of such events are highly uncertain and a reasonable estimate of the range of gross unrecognized tax benefits, excluding interest and penalties, that could potentially be reduced during the next 12 months cannot be made. The Company is subject to taxation in the United States, New York, and various other states and foreign jurisdictions. As of December 31, 2019 , tax year 2014 and later remain open to examination. The Company is under examination, or may be subject to examination, by the IRS for calendar year 2014 and thereafter. These examinations may result in proposed adjustments to the Company’s income tax liability or tax attributes with respect to years under examination as well as subsequent periods. The provision for income taxes involves a significant amount of management judgment regarding interpretation of relevant facts and laws in the jurisdictions in which the Company operates. Future changes in applicable laws, projected levels of taxable income and tax planning could change the effective tax rate and tax balances recorded by the Company. In addition, tax authorities periodically review income tax returns filed by the Company and can raise issues regarding its filing positions, timing and amount of income and deductions, and the allocation of income among the jurisdictions in which the Company operates. A significant period of time may elapse between the filing of an income tax return and the ultimate resolution of an issue raised by a revenue authority with respect to that return. Any adjustments as a result of any examination may result in additional taxes or penalties against the Company. If the ultimate result of these audits differ from original or adjusted estimates, they could have a material impact on the Company’s tax provision.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Income Per Share	Note 4—Net Income Per Share The following table presents the calculation of basic and diluted net income per share for periods presented (in thousands, except share and per share amounts): Year Ended 2019 2018 2017 Numerator: Net income $ 95,894 $ 77,491 $ 81,800 Net income allocated to participating securities under the two-class method — (37 ) (80 ) Net income attributable to common stockholders—basic 95,894 77,454 81,720 Dilutive effect of net income allocated to participating securities under the two-class method — 37 80 Change in fair value of liability classified restricted stock — — 771 Net income attributable to common stockholders—diluted $ 95,894 $ 77,491 $ 82,571 Denominator: Weighted average common shares outstanding—basic (1) 119,665,248 120,146,076 118,538,687 Dilutive effect of assumed conversion of options to purchase common stock 4,516,413 4,238,622 2,498,448 Dilutive effect of assumed conversion of restricted stock units 1,521,719 1,721,658 1,177,799 Dilutive effect of assumed conversion of convertible debt (2) — 900,580 — Diluted effective of assumed conversion of restricted stock from acquisition 16,693 77,849 52,739 Weighted average common shares outstanding—diluted 125,720,073 127,084,785 122,267,673 Net income per share attributable to common stockholders—basic $ 0.80 $ 0.64 $ 0.69 Net income per share attributable to common stockholders—diluted $ 0.76 $ 0.61 $ 0.68 (1) 57,482 , and 114,963 shares of unvested stock are considered participating securities and are excluded from basic shares outstanding for the year ended December 31, 2018 and 2017 , respectively. (2) Since the Company expects to settle in cash the principal outstanding under the 2019 Notes (see “ Note 13—Debt ”), it uses the treasury stock method when calculating the potential dilutive effect of the conversion spread on diluted net income per share, if applicable. The Company uses the if-converted method when calculating the dilutive effect of the 2018 Notes for the year ended December 31, 2019 and used the treasury stock method for the year ended December 31, 2018 . The following potential common shares were excluded from the calculation of diluted net income per share attributable to common stockholders because their effect would have been anti-dilutive for the periods presented: Year Ended 2019 2018 2017 Stock options 317,401 475,238 4,902,664 Restricted stock units 706,234 136,998 435,358 Convertible senior notes 9,511,993 — — Total anti-dilutive securities 10,535,628 612,236 5,338,022

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Business Combinations	Note 5—Business Combinations On August 15, 2019 , the Company acquired all of the outstanding capital stock of Reverb, a leading online marketplace dedicated to buying and selling new, used, and vintage musical instruments. The acquisition enables the Company to expand into a new vertical, with a company that has a similar strategy and business model. The total cash consideration paid was $270.4 million , net of cash acquired. The acquisition was accounted for under the acquisition method of accounting. Accordingly, the purchase price was allocated to the assets acquired and liabilities assumed based upon their estimated fair values as of the date of the acquisition. The excess of the purchase price over the estimated fair value of the net assets acquired was recorded as goodwill, which consists largely of synergies and acquisition of workforce. The resulting goodwill is not expected to be deductible for tax purposes. The Company has finalized the valuation of assets acquired and liabilities assumed for the acquisition of Reverb. The Company recognized certain measurement period adjustments as disclosed below during the three months ended December 31, 2019 . The measurement period is closed as of December 31, 2019 . Purchase Price Allocation The following table summarizes the allocation of the purchase price (at fair value) to the assets acquired and liabilities assumed of Reverb as of August 15, 2019 (the date of acquisition) (in thousands): Initial Fair Value Estimate (1) Measurement Period Adjustments (2) Final Fair Value as Adjusted Short-term investments $ 1,028 $ — $ 1,028 Other current assets (3) 6,442 (3,540 ) 2,902 Funds receivable and seller accounts 5,578 — 5,578 Property and equipment other 1,543 — 1,543 Developed technology 30,300 — 30,300 Trademark 79,400 — 79,400 Customer relationships 93,500 — 93,500 Goodwill 102,039 (336 ) 101,703 Other assets (3) 3,225 3,518 6,743 Other net working capital (208 ) — (208 ) Funds payable and amounts due to sellers (5,578 ) — (5,578 ) Other current liabilities (3) (8,520 ) 4,836 (3,684 ) Other liabilities (3) (2,497 ) (4,836 ) (7,333 ) Deferred tax liability, net (34,898 ) (587 ) (35,485 ) Total purchase price $ 271,354 $ (945 ) $ 270,409 (1) As previously reported in the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2019 . This was the quarter in which the business combination was completed. (2) The Company recorded measurement period adjustments in the fourth quarter of fiscal 2019 due to the final working capital adjustment as well as new facts and circumstances related to assets and liabilities which existed at the acquisition date. The adjustments included an increase in deferred tax liability of $0.6 million and a decrease in goodwill of $0.3 million . Other adjustments are related to the classification of certain assets and liabilities within the balance sheet. (3) Other current liabilities and other liabilities are primarily related to non-income tax related contingency reserves, which are wholly offset by an indemnification asset and a deferred tax asset. Revenue and net loss of Reverb from August 15, 2019 (the date of acquisition) through December 31, 2019 were $19.1 million and $9.9 million , respectively. Acquisition-related expenses are expensed as incurred. They were recorded in general and administrative expenses and were $3.9 million for the year ended December 31, 2019 . They primarily related to advisory, legal, valuation and other professional fees. Unaudited Supplemental Pro Forma Information The following unaudited pro forma summary presents consolidated information of the Company as if the business combination had occurred on January 1, 2018 (in thousands): Year Ended December 31, 2019 2018 Revenue $ 847,154 $ 639,743 Net income 88,595 53,587 The pro forma financial information includes adjustments that are directly attributable to the business combination and are factually supportable. The pro forma adjustments include incremental amortization of intangible and developed technology assets, based on final values of each asset and acquisition-related expenses and are tax-effected. For the year ended December 31, 2019 , the pro forma financial information excludes $6.1 million of non-recurring acquisition-related expenses. For the year ended December 31, 2018 , the pro forma financial information includes $2.0 million

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Note 6—Goodwill and Intangible Assets The following table summarizes the changes in the carrying amount of goodwill for the periods indicated (in thousands): Year Ended 2019 2018 Balance as of the beginning of the period $ 37,482 $ 38,541 Business combination 101,703 — Foreign currency translation adjustments (454 ) (1,059 ) Balance as of the end of the period $ 138,731 $ 37,482 The Company has determined it has two operating segments, Etsy and Reverb, which qualify for aggregation as one reportable segment, for purposes of allocating resources and evaluating financial performance. As a result, the Company has determined it has two reporting units to test for goodwill impairment during the fourth quarter. The Company did no t recognize any goodwill impairments during the years ended December 31, 2019, 2018, and 2017 . At December 31, 2019 and 2018 , the gross book value and accumulated amortization of intangible assets were as follows (in thousands): As of December 31, 2019 As of December 31, 2018 Gross book Accumulated Foreign currency translation Net book Gross book Accumulated Foreign currency translation Net book Customer relationships $ 93,500 $ (2,338 ) $ — $ 91,162 $ — $ — $ — $ — Trademark 79,400 (1,985 ) — 77,415 — — — — Referral agreement 37,127 (5,417 ) (1,356 ) 30,354 35,323 (1,890 ) (712 ) 32,721 Technology 7,200 (7,200 ) — — 7,200 (5,500 ) — 1,700 Patent licenses 332 (27 ) — 305 172 (4 ) — 168 Intangible assets, net $ 217,559 $ (16,967 ) $ (1,356 ) $ 199,236 $ 42,695 $ (7,394 ) $ (712 ) $ 34,589 The Company acquired intangible assets valued at $172.9 million in the Reverb acquisition on August 15, 2019 . As part of the acquisition, the Company recorded acquired intangible assets for customer relationships and trademark. These are both amortized on a straight-line basis over a period of 15 years . See “ Note 5—Business Combinations ” for additional information on the acquisition of Reverb. On June 15, 2018, the Company entered into a referral agreement with DaWanda GmbH (“DaWanda”), a privately held Germany-based marketplace for gifts and handmade items. As part of this agreement, DaWanda agreed to encourage its community of buyers and sellers to migrate to the Etsy platform. DaWanda wound down its operations and shut down its site on August 30, 2018. Etsy did not acquire any of DaWanda’s assets, liabilities, or employees as part of this agreement. The Company accounted for the agreement as an asset acquisition and the referral agreement intangible asset is amortized on a straight-line basis over a period of 10 years . Amortization expense for the years ended December 31, 2019, 2018, and 2017 was $9.6 million , $4.3 million , and $3.4 million , respectively. The Company did no t recognize any intangible asset impairment losses in the years ended December 31, 2019 , 2018 , and 2017 . Based on amounts recorded at December 31, 2019 , the Company estimates intangible asset amortization expense in each of the years ending December 31 as follows (in thousands): 2020 $ 15,148 2021 15,148 2022 15,148 2023 15,148 2024 15,148 Thereafter 123,496 Total amortization expense $ 199,236

Segment and Geographic Informat

Segment and Geographic Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment and Geographic Information	Note 7—Segment and Geographic Information The Company has determined it has two operating segments, Etsy and Reverb, which qualify for aggregation as one reportable segment, for purposes of allocating resources and evaluating financial performance. Revenue by country is based on the billing address of the seller. The following table summarizes revenue, (loss) income before income taxes and net income by geographic area (in thousands): Year Ended 2019 2018 2017 United States $ 550,257 $ 422,523 $ 317,755 International 268,122 181,170 123,476 Revenue $ 818,379 $ 603,693 $ 441,231 United States (1)(2) $ (23,702 ) $ 7,460 $ (43,014 ) International 104,348 47,618 75,279 (Loss) income before income taxes $ 80,646 $ 55,078 $ 32,265 United States $ 510 $ 7,175 $ 7,029 International 95,384 70,316 74,771 Net income $ 95,894 $ 77,491 $ 81,800 (1) The United States loss before income taxes in the year ended December 31, 2019 was primarily driven by a majority of operating expenses being incurred in the United States. (2) The United States loss before income taxes in the year ended December 31, 2017 was primarily driven by a foreign exchange loss, interest associated with the build-to-suit lease accounting related to our corporate headquarters, restructuring and other exit costs, and asset impairment charges. See “ Note 17—Restructuring and Other Exit Costs (Income) ” and “ Note 10—Property and Equipment ” for additional information on restructuring and other exit costs and asset impairment charges, respectively. No individual international country’s revenue exceeded 10% of total revenue. All significant long-lived assets are located in the United States.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 8—Fair Value Measurements The Company has characterized its investments in marketable securities, based on the priority of the inputs used to value the investments, into a three-level fair value hierarchy. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1), and lowest priority to unobservable inputs (Level 3). If the inputs used to measure the investments fall within different levels of the hierarchy, the categorization is based on the lowest level input that is significant to the fair value measurement of the investment. Investments recorded in the accompanying Consolidated Balance Sheets are categorized based on the inputs to valuation techniques as follows: Level 1—These are investments where values are based on unadjusted quoted prices for identical assets in an active market that the Company has the ability to access. Level 2—These are investments where values are based on quoted market prices in markets that are not active or model derived valuations in which all significant inputs are observable in active markets. Level 3—These are financial instruments where values are derived from techniques in which one or more significant inputs are unobservable. The following are the major categories of assets measured at fair value on a recurring basis as of the dates indicated (in thousands): As of December 31, 2019 Level 1 Level 2 Level 3 Total Asset Cash equivalents: Commercial paper $ — $ 5,794 $ — $ 5,794 Certificate of deposit — 2,959 — 2,959 Money market funds 228,859 — — 228,859 228,859 8,753 — 237,612 Short-term investments: Commercial paper — 29,320 — 29,320 Certificate of deposit — 26,132 — 26,132 Corporate bonds — 114,202 — 114,202 U.S. Government and agency securities 204,305 — — 204,305 204,305 169,654 — 373,959 Funds receivable and seller accounts: Money market funds 18,168 — — 18,168 18,168 — — 18,168 Long-term investments: Certificate of deposit — 4,729 — 4,729 Corporate bonds — 38,563 — 38,563 U.S. Government and agency securities 46,051 — — 46,051 46,051 43,292 — 89,343 $ 497,383 $ 221,699 $ — $ 719,082 As of December 31, 2018 Level 1 Level 2 Level 3 Total Asset Cash equivalents: Commercial paper $ — $ 7,775 $ — $ 7,775 Money market funds 244,856 — — 244,856 244,856 7,775 — 252,631 Short-term investments: Commercial paper — 147,860 — 147,860 Corporate bonds — 46,801 — 46,801 U.S. Government and agency securities 62,641 — — 62,641 62,641 194,661 — 257,302 Funds receivable and seller accounts: Money market funds 9,229 — — 9,229 9,229 — — 9,229 $ 316,726 $ 202,436 $ — $ 519,162 Level 1 instruments include investments in debt securities including money market funds and U.S. Government and agency securities, which are valued based on inputs including quotes from broker-dealers or recently executed transactions in the same or similar securities. Level 2 instruments include investments in debt securities, including fixed-income funds consisting of investments in commercial paper, corporate bonds, and certificates of deposit, which are valued based on quoted market prices in markets that are not active or model derived valuations in which all significant inputs are observable in active markets. The Company did not have any Level 3 instruments as of December 31, 2019 and December 31, 2018 . See “ Note 9—Marketable Securities ” for additional information on the Company’s marketable securities measured at fair value. Disclosure of Fair Values The Company’s financial instruments that are not remeasured at fair value include the 2018 Notes and the 2019 Notes (see “ Note 13—Debt ”). The Company estimates the fair value of the 2018 Notes and 2019 Notes through consideration of quoted market prices of similar instruments, classified as Level 2 as described above. The estimated fair value of the 2018 Notes was $310.3 million and $279.1 million as of December 31, 2019 and December 31, 2018 , respectively. The estimated fair value of the 2019 Notes was $522.2 million as of December 31, 2019 . The carrying value of other financial instruments, including cash, accounts receivable, accounts payable, funds receivable and seller accounts, and funds payable and amounts due to sellers approximate fair value due to the immediate or short-term maturity associated with these instruments.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Note 9—Marketable Securities Short- and long-term investments and certain cash equivalents consist of investments in debt securities that are available-for-sale. The cost and fair value of available-for-sale securities were as follows as of the dates indicated (in thousands): Cost Gross Gross Fair Value December 31, 2019 Cash equivalents: Commercial paper $ 5,794 $ — $ — $ 5,794 Certificate of deposit 2,958 — 1 2,959 8,752 — 1 8,753 Short-term investments: Commercial paper 29,319 (1 ) 2 29,320 Certificate of deposit 26,129 (3 ) 6 26,132 Corporate bonds 114,068 (22 ) 156 114,202 U.S. Government and agency securities 204,246 (8 ) 67 204,305 373,762 (34 ) 231 373,959 Long-term investments: Certificate of deposit 4,727 — 2 4,729 Corporate bonds 38,582 (35 ) 16 38,563 U.S. Government and agency securities 46,017 (2 ) 36 46,051 89,326 (37 ) 54 89,343 $ 471,840 $ (71 ) $ 286 $ 472,055 December 31, 2018 Cash equivalents: Commercial paper $ 7,775 $ — $ — $ 7,775 7,775 — — 7,775 Short-term investments: Commercial paper 147,860 — — 147,860 Corporate bonds 46,836 (35 ) — 46,801 U.S. Government and agency securities 62,638 (9 ) 12 62,641 257,334 (44 ) 12 257,302 $ 265,109 $ (44 ) $ 12 $ 265,077 The Company’s investments in marketable securities consist primarily of investments in commercial paper, certificates of deposit, and debt securities, including U.S. Government and agency securities and fixed-income funds. When evaluating investments for other-than-temporary impairment, the Company reviews factors such as length of time and extent to which fair value has been below cost basis, the financial condition of the issuer and the Company’s ability, and intent to hold the investment for a period of time, which may be sufficient for anticipated recovery in market value. The Company evaluates fair values for each individual security in the investment portfolio. See “ Note 8—Fair Value Measurements ” for additional information on the Company’s marketable securities measured at fair value.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment	Note 10—Property and Equipment Property and equipment consisted of the following as of the dates indicated (in thousands): As of Estimated useful lives 2019 2018 Computer equipment (1) 3 years $ 35,190 $ 36,670 Furniture and equipment 2 - 4 years 7,999 6,574 Leasehold improvements (2) Shorter of life of asset or lease term 48,688 10,731 Construction in progress Not applicable 206 551 Building (2) 25 years 66,650 81,892 Website development and internal-use software (3) 3 - 5 years 106,215 69,201 264,948 205,619 Less: Accumulated depreciation and amortization 120,084 85,440 $ 144,864 $ 120,179 (1) Computer equipment includes leased equipment which are accounted for as finance leases since the adoption of ASU 2016-02— Leases in the first quarter of 2019. These leases were previously accounted for as capital leases. (2) In 2014 the Company applied build-to-suit accounting treatment to its headquarters lease in Brooklyn, New York. Upon adoption of ASU 2016-02— Leases in the first quarter of 2019, the Company derecognized the existing facility financing obligation and existing building asset for sale-leaseback transactions that currently do not qualify for sale accounting of $60.0 million and $51.1 million , respectively, and $22.1 million was reclassified from building to leasehold improvements and the Company recognized a new ROU asset of $66.7 million for the associated lease. For more information on the adoption of ASU 2016-02— Leases see “ Note 1—Basis of Presentation and Summary of Significant Accounting Policies .” (3) On August 15, 2019 , the Company acquired Reverb in a business combination, including the developed technology which was recognized at fair value. This amount is included in website development and internal-use software and is amortized on a straight-line basis over a period of 3 years . Depreciation and amortization expense on property and equipment was $38.4 million , $22.4 million , and $23.8 million for the years ended December 31, 2019, 2018, and 2017 , respectively, which includes amortization expense for equipment acquired under finance leases of $4.3 million for the year ended December 31, 2019 and under capital leases of $5.9 million and $7.7 million for the years ended December 31, 2018 and 2017 , respectively. The gross balance of leased equipment as of December 31, 2019 and 2018 was $30.4 million and $29.7 million , respectively. The related accumulated amortization of equipment under finance leases was $28.5 million at December 31, 2019 and under capital leases was $24.4 million at December 31, 2018 . The following table summarizes capitalized website development and internal-use software activities during the periods indicated (in thousands): Year Ended 2019 2018 Balance as of the beginning of the period $ 69,201 $ 48,333 Additions to website development 8,687 22,068 Acquisition of developed technology 30,300 — Less: Retirements 1,973 1,200 106,215 69,201 Less: Accumulated amortization balance as of the beginning of the period 38,418 29,991 Amortization Expense 18,737 9,519 Less: Retirements 340 1,092 Accumulated amortization balance as of the end of the period 56,815 38,418 $ 49,400 $ 30,783 For the years ended December 31, 2019, 2018, and 2017 , the Company recorded amortization expense relating to capitalized website development and internal-use software of $18.7 million , $9.5 million , and $8.2 million , respectively. The loss on write-off for capitalized website development and internal-use software assets that were retired during the years ended December 31, 2019, 2018, and 2017 was $1.6 million , $0.1 million , and $0.3 million , respectively. On August 15, 2019 , the Company acquired Reverb in a business combination, including the developed technology which was recognized at fair value. As of December 31, 2019 , the gross book value and accumulated amortization of the acquired developed technology classified in property and equipment, net was $30.3 million and $3.8 million , respectively. The developed technology is amortized on a straight-line basis over a period of 3 years . Amortization expense from the developed technology of Reverb was $3.8 million for the period ended December 31, 2019 and was recorded in cost of revenue. The Company recognized a $3.2 million impairment loss related to capitalized website development and internal-use software during the year ended December 31, 2017 , included in asset impairment charges. During the fourth quarter of 2017, the Company made the decision to discontinue certain product offerings, including Etsy Studio and Etsy Manufacturing, which was an indicator that the carrying amount of certain capitalized website development and internal-use software assets may not be recoverable. The Company prepared an undiscounted cash flow analysis and determined that the values for these assets exceeded the expected future cash flows and impaired the remaining book values based on a negative present value of projected undiscounted cash flows.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Note 11—Leases As the lessee, the Company currently leases 225,135 square feet of real estate space for its corporate headquarters located in Brooklyn, New York, under a noncancelable lease that expires in 2026. The Company uses these facilities for its principal administration, technology and development, and engineering activities. The Company also leases office space for its offices in San Francisco, Hudson (New York), Chicago, Dublin, and London. Additionally, the Company has short-term leases in other locations around the world that meet short-term lease criteria and are not recognized on the Consolidated Balance Sheets. Most leases include one or more options to renew, and the exercise of these options is at the Company’s sole discretion. The Company determined that its options to break or renew would not be reasonably certain in determining the expected lease term, and therefore are not included as part of its ROU assets and lease liabilities. The Company entered into financing lease agreements with Dell Financial Services, LLC. (“DFS”) and ePlus Group, Inc. (“ePlus”) for hosting and computer equipment leases. The leases through DFS have a 36 -month term, zero interest, and are payable in equal monthly installments with a buy-out option of $1 at the end of the lease term. The leases through ePlus have a 36 -month term, interest rate of 3.71% - 6.94% , and are payable in equal monthly installments with a fair market value or a $1 buy-out option at the end of the lease term depending on the equipment. In calculating the present value of the lease payments, the Company has elected to utilize its estimated incremental borrowing rate based on the remaining lease term and not the original lease term. The depreciable life of assets and leasehold improvements are limited by the expected lease term. The elements of lease expense were as follows (in thousands): Year Ended December 31, 2019 Operating lease cost $ 5,405 Finance lease cost: Amortization of right-of-use assets 13,124 Interest on lease liabilities 3,205 Total finance lease cost 16,329 Other lease cost, net (1) 1,149 Total lease cost $ 22,883 (1) Other lease cost, net includes short-term sublease income, short-term lease costs, and variable lease costs, which are immaterial. The following table presents the lease-related assets and liabilities recorded on the Consolidated Balance Sheet (in thousands): As of December 31, 2019 Operating leases: Other assets $ 24,362 Other current liabilities $ 4,134 Other liabilities 22,322 Total operating lease liabilities $ 26,456 Finance leases: Property and equipment, net $ 59,696 Finance lease obligations—current $ 8,275 Finance lease obligations—net of current portion 53,611 Total finance lease liabilities $ 61,886 The following table summarizes the weighted average remaining lease term and weighted average discount rate as of December 31, 2019 : As of December 31, 2019 Weighted average remaining lease term: Operating leases 5.94 years Finance leases 6.37 years Weighted average discount rate: Operating leases 4.26 % Finance leases 4.31 % Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used in operating leases $ (4,889 ) Operating cash flows used in finance leases (3,181 ) Finance cash flows used in finance leases (10,833 ) Future minimum lease payments under non-cancelable leases for the years ending December 31, 2020 , 2021 , 2022 , 2023 , 2024 and thereafter are as follows (in thousands): Operating Leases Finance Leases 2020 $ 5,152 $ 10,805 2021 4,928 11,152 2022 4,942 10,677 2023 4,981 10,599 2024 4,298 10,678 Thereafter 5,688 17,037 Total future minimum lease payments 29,989 70,948 Less imputed interest 3,533 9,062 Total $ 26,456 $ 61,886 The following table represents the Company’s commitments under its previous presentation of its capital, operating, and build-to-suit lease agreements as of December 31, 2018 (in thousands): Capital Lease Operating Build-to-Suit Periods ending 2019 $ 4,392 $ 4,904 $ 9,451 2020 1,754 4,783 9,522 2021 481 4,185 10,354 2022 — 4,180 10,520 2023 — 4,205 10,599 Thereafter — 9,760 27,715 Total minimum payments required $ 6,627 $ 32,017 $ 78,161 Amounts representing interest 648 Present value of net minimum payments 5,979 Current maturities 3,884 Long-term payment obligations $ 2,095
Leases	Note 11—Leases As the lessee, the Company currently leases 225,135 square feet of real estate space for its corporate headquarters located in Brooklyn, New York, under a noncancelable lease that expires in 2026. The Company uses these facilities for its principal administration, technology and development, and engineering activities. The Company also leases office space for its offices in San Francisco, Hudson (New York), Chicago, Dublin, and London. Additionally, the Company has short-term leases in other locations around the world that meet short-term lease criteria and are not recognized on the Consolidated Balance Sheets. Most leases include one or more options to renew, and the exercise of these options is at the Company’s sole discretion. The Company determined that its options to break or renew would not be reasonably certain in determining the expected lease term, and therefore are not included as part of its ROU assets and lease liabilities. The Company entered into financing lease agreements with Dell Financial Services, LLC. (“DFS”) and ePlus Group, Inc. (“ePlus”) for hosting and computer equipment leases. The leases through DFS have a 36 -month term, zero interest, and are payable in equal monthly installments with a buy-out option of $1 at the end of the lease term. The leases through ePlus have a 36 -month term, interest rate of 3.71% - 6.94% , and are payable in equal monthly installments with a fair market value or a $1 buy-out option at the end of the lease term depending on the equipment. In calculating the present value of the lease payments, the Company has elected to utilize its estimated incremental borrowing rate based on the remaining lease term and not the original lease term. The depreciable life of assets and leasehold improvements are limited by the expected lease term. The elements of lease expense were as follows (in thousands): Year Ended December 31, 2019 Operating lease cost $ 5,405 Finance lease cost: Amortization of right-of-use assets 13,124 Interest on lease liabilities 3,205 Total finance lease cost 16,329 Other lease cost, net (1) 1,149 Total lease cost $ 22,883 (1) Other lease cost, net includes short-term sublease income, short-term lease costs, and variable lease costs, which are immaterial. The following table presents the lease-related assets and liabilities recorded on the Consolidated Balance Sheet (in thousands): As of December 31, 2019 Operating leases: Other assets $ 24,362 Other current liabilities $ 4,134 Other liabilities 22,322 Total operating lease liabilities $ 26,456 Finance leases: Property and equipment, net $ 59,696 Finance lease obligations—current $ 8,275 Finance lease obligations—net of current portion 53,611 Total finance lease liabilities $ 61,886 The following table summarizes the weighted average remaining lease term and weighted average discount rate as of December 31, 2019 : As of December 31, 2019 Weighted average remaining lease term: Operating leases 5.94 years Finance leases 6.37 years Weighted average discount rate: Operating leases 4.26 % Finance leases 4.31 % Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used in operating leases $ (4,889 ) Operating cash flows used in finance leases (3,181 ) Finance cash flows used in finance leases (10,833 ) Future minimum lease payments under non-cancelable leases for the years ending December 31, 2020 , 2021 , 2022 , 2023 , 2024 and thereafter are as follows (in thousands): Operating Leases Finance Leases 2020 $ 5,152 $ 10,805 2021 4,928 11,152 2022 4,942 10,677 2023 4,981 10,599 2024 4,298 10,678 Thereafter 5,688 17,037 Total future minimum lease payments 29,989 70,948 Less imputed interest 3,533 9,062 Total $ 26,456 $ 61,886 The following table represents the Company’s commitments under its previous presentation of its capital, operating, and build-to-suit lease agreements as of December 31, 2018 (in thousands): Capital Lease Operating Build-to-Suit Periods ending 2019 $ 4,392 $ 4,904 $ 9,451 2020 1,754 4,783 9,522 2021 481 4,185 10,354 2022 — 4,180 10,520 2023 — 4,205 10,599 Thereafter — 9,760 27,715 Total minimum payments required $ 6,627 $ 32,017 $ 78,161 Amounts representing interest 648 Present value of net minimum payments 5,979 Current maturities 3,884 Long-term payment obligations $ 2,095

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued Expenses	Note 12—Accrued Expenses Accrued expenses consisted of the following as of the dates indicated (in thousands): As of December 31, 2019 2018 Sales and use tax payable $ 39,250 $ 12,242 Vendor accruals 25,760 17,817 Accrued bonus 19,561 12,906 Payroll-related liabilities 3,172 2,406 Accrued vacation 602 3,787 Total accrued expenses $ 88,345 $ 49,158

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Note 13—Debt 2019 Convertible Debt In September 2019 , the Company issued $650.0 million aggregate principal amount of 0.125% Convertible Senior Notes due 2026 (the “ 2019 Notes ”) in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”). The net proceeds from the sale of the 2019 Notes were $639.5 million after deducting the initial purchasers’ discount and offering expenses. The 2019 Notes are convertible based upon an initial conversion rate of 11.4040 shares of the Company’s common stock per $1,000 principal amount of 2019 Notes (equivalent to an initial conversion price of approximately $87.69 per share). The conversion rate will be subject to adjustment upon the occurrence of certain specified events, including certain distributions and dividends to all or substantially all of the holders of the Company’s common stock. The Company will settle any conversions of the 2019 Notes in cash, shares of the Company’s common stock, or a combination thereof, with the form of consideration determined at the Company’s election. The 2019 Notes will mature on October 1, 2026 , unless earlier converted or repurchased. Prior to the close of business on the business day immediately preceding June 1, 2026 , holders may convert all or a portion of their 2019 Notes only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2019 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the 5 business day period after any 10 consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of 2019 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; (3) with respect to any or all of the 2019 Notes called for redemption by the Company prior to the close of business on the business day immediately preceding June 1, 2026 , holders may convert all or any portion of their 2019 Notes at any time prior to the close of business on the second scheduled trading day prior to the redemption date, even if the 2019 Notes are not otherwise convertible at such time; and (4) upon the occurrence of specified corporate events. On and after June 1, 2026 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2019 Notes at any time, regardless of the foregoing circumstances. As of December 31, 2019 , the if-converted value of the 2019 Notes was approximately $321.6 million lower than the aggregate principal amount, or $328.4 million . If a fundamental change occurs prior to the maturity date, holders may require the Company to repurchase all or a portion of their 2019 Notes for cash at a price equal to 100% of the principal amount of the 2019 Notes to be repurchased. Holders of 2019 Notes who convert their 2019 Notes in connection with a notice of a redemption or a make-whole fundamental change may be entitled to a premium in the form of an increase in the conversion rate of the 2019 Notes . As of December 31, 2019 , none of the conditions permitting the holders of the 2019 Notes to early convert have been met. The 2019 Notes are general unsecured obligations of the Company. The 2019 Notes rank senior in right of payment to all of the Company’s future indebtedness that is expressly subordinated in right of payment to the 2019 Notes ; rank equal in right of payment with all of our liabilities that are not so subordinated, including our 0% Convertible Senior Notes due 2023 (the “ 2018 Notes ”); are effectively junior to any of the Company’s secured indebtedness; and are structurally junior to all indebtedness and liabilities (including trade payables) of the Company’s subsidiaries. In accounting for the issuance of the 2019 Notes , the Company separated the 2019 Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar liability that does not have an associated convertible feature. The carrying amount of the equity component, representing the conversion option, which does not meet the criteria for separate accounting as a derivative as it is indexed to the Company’s own stock, was determined by deducting the fair value of the liability component from the par value of the 2019 Notes . The difference between the principal amount of the 2019 Notes and the liability component represents the debt discount, which is recorded as a direct deduction from the related debt liability in the Consolidated Balance Sheet and accreted over the period from the date of issuance to the contractual maturity date, resulting in the recognition of non-cash interest expense. The equity component of the 2019 Notes of approximately $154.0 million is included in additional paid-in capital in the Consolidated Balance Sheet and is not remeasured as long as it continues to meet the conditions for equity classification. Transaction costs were allocated to the liability and equity components in the same proportion as the allocation of the proceeds. Transaction costs attributable to the liability component were recorded as a direct deduction from the related debt liability in the Consolidated Balance Sheet and are amortized to interest expense using the effective interest method over the term of the 2019 Notes , and transaction costs attributable to the equity component were netted with the equity component in stockholders’ equity. The Company capitalized $10.5 million of debt issuance costs in connection with the 2019 Notes . Non-cash interest expense, including amortization of debt issuance costs, related to the 2019 Notes for the year ended December 31, 2019 was $5.6 million . Total unamortized debt issuance costs were $7.8 million as of December 31, 2019 . The estimated fair value of the 2019 Notes was $522.2 million as of December 31, 2019 . The estimated fair value of the 2019 Notes was determined through consideration of quoted market prices for similar instruments. The fair value is classified as Level 2, as defined in “ Note 8—Fair Value Measurements .” 2019 Capped Call Transactions The Company used $76.2 million of the net proceeds from the 2019 Notes offering to enter into separate capped call transactions (“2019 Capped Call Transactions”) with the initial purchasers and/or their respective affiliates. The 2019 Capped Call Transactions are expected generally to reduce the potential dilution and/or offset the cash payments the Company is required to make in excess of the principal amount of the 2019 Notes upon conversion of the 2019 Notes in the event that the market price per share of the Company’s common stock is greater than the strike price of the 2019 Capped Call Transactions with such reduction and/or offset subject to a cap. The 2019 Capped Call Transactions have an initial cap price of $148.63 per share of the Company’s common stock, which represents a premium of 150% over the last reported sale price of the Company’s common stock on September 18, 2019, and is subject to certain adjustments under the terms of the 2019 Capped Call Transactions. Collectively, the 2019 Capped Call Transactions cover, initially, the number of shares of the Company’s common stock underlying the 2019 Notes , subject to anti-dilution adjustments substantially similar to those applicable to the 2019 Notes . The 2019 Capped Call Transactions do not meet the criteria for separate accounting as a derivative as they are indexed to the Company’s stock. The premiums paid for the 2019 Capped Call Transactions have been included as a net reduction to additional paid-in capital within stockholders’ equity. 2018 Convertible Debt In March 2018 , the Company issued the 2018 Notes , $345.0 million aggregate principal amount of 0% Convertible Senior Notes due 2023 , in a private placement to qualified institutional buyers pursuant to the Securities Act. The net proceeds from the sale of the 2018 Notes were $335.0 million after deducting the initial purchasers’ discount and offering expenses. The 2018 Notes are convertible based upon an initial conversion rate of 27.5691 shares of the Company’s common stock per $1,000 principal amount of 2018 Notes (equivalent to an initial conversion price of approximately $36.27 per share). The conversion rate will be subject to adjustment upon the occurrence of certain specified events, including certain distributions and dividends to all or substantially all of the holders of the Company’s common stock. The Company will settle any conversions of the 2018 Notes in cash, shares of the Company’s common stock, or a combination thereof, with the form of consideration determined at the Company’s election. The 2018 Notes will mature on March 1, 2023 , unless earlier converted or repurchased. Prior to the close of business on the business day immediately preceding November 1, 2022 , holders may convert all or a portion of their 2018 Notes only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2018 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the 5 business day period after any 10 consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of 2018 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; (3) with respect to any or all of the 2018 Notes called for redemption by the Company prior to the close of business on the business day immediately preceding November 1, 2022 , holders may convert all or any portion of their 2018 Notes at any time prior to the close of business on the second scheduled trading day prior to the redemption date, even if the 2018 Notes are not otherwise convertible at such time; (4) upon the occurrence of specified corporate events. On and after November 1, 2022 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their Notes at any time, regardless of the foregoing circumstances. If a fundamental change occurs prior to the maturity date, holders may require the Company to repurchase all or a portion of their 2018 Notes for cash at a price equal to 100% of the principal amount of the 2018 Notes to be repurchased. Holders of 2018 Notes who convert their 2018 Notes in connection with a notice of a redemption or a make-whole fundamental change may be entitled to a premium in the form of an increase in the conversion rate of the 2018 Notes . During any calendar quarter preceding November 1, 2022 in which the closing price of the Company’s common stock exceeds 130% of the applicable conversion price of the 2018 Notes on at least 20 of the last 30 consecutive trading days of the quarter, holders may in the immediate quarter following convert all or a portion of their 2018 Notes . Based on the daily closing prices of the Company’s stock during the quarter ended December 31, 2019 , holders of the 2018 Notes are not eligible to convert their 2018 Notes during the first quarter of 2020. When a conversion notice is received, the Company has the option to pay or deliver cash, shares of the Company’s common stock, or a combination thereof. Accordingly, the Company cannot be required to settle the 2018 Notes in cash and, therefore, the 2018 Notes are classified as long-term debt as of December 31, 2019 . As of December 31, 2019 , the if-converted value of the 2018 Notes was approximately $76.4 million higher than the aggregate principal amount, or $421.4 million . The 2018 Notes are general unsecured obligations of the Company. The 2018 Notes rank senior in right of payment to all of the Company’s future indebtedness that is expressly subordinated in right of payment to the Notes; rank equal in right of payment with all of our liabilities that are not so subordinated, including our 2019 Notes ; are effectively junior to any of the Company’s secured indebtedness; and are structurally junior to all indebtedness and liabilities (including trade payables) of the Company’s subsidiaries. In accounting for the issuance of the 2018 Notes , the Company separated the 2018 Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar liability that does not have an associated convertible feature. The carrying amount of the equity component, representing the conversion option, which does not meet the criteria for separate accounting as a derivative as it is indexed to the Company’s own stock, was determined by deducting the fair value of the liability component from the par value of the 2018 Notes . The difference between the principal amount of the 2018 Notes and the liability component represents the debt discount, which is recorded as a direct deduction from the related debt liability in the Consolidated Balance Sheets and accreted over the period from the date of issuance to the contractual maturity date, resulting in the recognition of non-cash interest expense. The equity component of the 2018 Notes of approximately $72.8 million is included in additional paid-in capital in the Consolidated Balance Sheets and is not remeasured as long as it continues to meet the conditions for equity classification. Transaction costs were allocated to the liability and equity components in the same proportion as the allocation of the proceeds. Transaction costs attributable to the liability component were recorded as a direct deduction from the related debt liability in the Consolidated Balance Sheets and are amortized to interest expense using the effective interest method over the term of the 2018 Notes , and transaction costs attributable to the equity component were netted with the equity component in stockholders’ equity. The Company capitalized $10.0 million of debt issuance costs in connection with the 2018 Notes . Non-cash interest expense, including amortization of debt issuance costs, related to the 2018 Notes for the year ended December 31, 2019 and 2018 was $15.2 million and $12.2 million , respectively. Total unamortized debt issuance costs related to the 2018 Notes were $5.2 million and $6.7 million as of December 31, 2019 and 2018 , respectively. The estimated fair value of the 2018 Notes was $310.3 million and $279.1 million as of December 31, 2019 and 2018 , respectively. The estimated fair value of the 2018 Notes was determined through consideration of quoted market prices for similar instruments. The fair value is classified as Level 2, as defined in “ Note 8—Fair Value Measurements .” 2018 Capped Call Transactions The Company used $34.2 million of the net proceeds from the 2018 Notes offering to enter into separate capped call transactions (“ 2018 Capped Call Transactions ”) with the initial purchasers and/or their respective affiliates. The 2018 Capped Call Transactions are expected generally to reduce the potential dilution and/or offset the cash payments the Company is required to make in excess of the principal amount of the 2018 Notes upon conversion of the 2018 Notes in the event that the market price per share of the Company’s common stock is greater than the strike price of the 2018 Capped Call Transactions with such reduction and/or offset subject to a cap. The 2018 Capped Call Transactions have an initial cap price of $52.76 per share of the Company’s common stock, which represents a premium of 100% over the last reported sale price of the Company’s common stock on March 8, 2018, and is subject to certain adjustments under the terms of the 2018 Capped Call Transactions . Collectively, the 2018 Capped Call Transactions cover, initially, the number of shares of the Company’s common stock underlying the 2018 Notes , subject to anti-dilution adjustments substantially similar to those applicable to the 2018 Notes . The Capped Call Transactions do not meet the criteria for separate accounting as a derivative as they are indexed to the Company’s stock. The premiums paid for the 2018 Capped Call Transactions have been included as a net reduction to additional paid-in capital within stockholders’ equity. 2019 Credit Agreement On February 25, 2019 , the Company entered into a $200.0 million senior secured revolving credit facility pursuant to a Credit Agreement (the “ 2019 Credit Agreement ”) with lenders party thereto from time to time, and Citibank N.A., as administrative Agent. The 2019 Credit Agreement will mature in February 2024 . The 2019 Credit Agreement includes a letter of credit sublimit of $30.0 million and a swingline loan sublimit of $10.0 million . Borrowings under the 2019 Credit Agreement (other than swingline loans) bear interest, at the Company’s option, at (i) a base rate equal to the highest of (a) the prime rate, (b) the federal funds rate plus 0.50% , and (c) an adjusted LIBOR rate for a one-month interest period plus 1.00% , in each case plus a margin ranging from 0.25% to 0.875% or (ii) an adjusted LIBOR rate plus a margin ranging from 1.25% to 1.875% . Swingline loans under the 2019 Credit Agreement bear interest at the same base rate (plus the margin applicable to borrowings bearing interest at the base rate). These margins are determined based on the senior secured net leverage ratio (defined as secured funded debt, net of unrestricted cash up to $100 million , to EBITDA) for the preceding four fiscal quarter period. The Company is also obligated to pay other customary fees for a credit facility of this size and type, including an unused commitment fee, ranging from 0.20% to 0.35% depending on the Company’s senior secured net leverage ratio, and fees associated with letters of credit. The 2019 Credit Agreement also permits the Company, in certain circumstances, to request an increase in the facility by an amount of up to $100.0 million at the same maturity, pricing and other terms and to request an extension of the maturity date for the facility. In connection with the 2019 Credit Agreement , the Company also paid the lenders certain upfront fees. The 2019 Credit Agreement contains customary representations and warranties applicable to the Company and its subsidiaries and customary affirmative and negative covenants applicable to the Company and its restricted subsidiaries. The negative covenants include restrictions on, among other things, indebtedness, liens, certain fundamental changes (including mergers), investments, dispositions, restricted payments (including dividends and stock repurchases), prepayments of junior debt, and transactions with affiliates. These restrictions do not prohibit a subsidiary of the Company from making pro rata payments to the Company or any other person that owns an equity interest in such subsidiary. The 2019 Credit Agreement contains financial covenants, that require the Company and its subsidiaries to maintain (i) a secured net leverage ratio not to exceed 3.00 to 1.00 , subject to an increase, at the option of the Company, to 3.50 to 1.00 for a specified period of time in the event of certain material acquisitions, tested as of the last day of each fiscal quarter and (ii) an interest coverage ratio (defined as the ratio of EBITDA to cash interest expense) of not less than 2.50 to 1.00 , tested for each fiscal quarter. The 2019 Credit Agreement includes customary events of default, including, but not limited to, nonpayment of principal or interest, breaches of representations and warranties, failure to perform or observe covenants, cross-defaults with certain other indebtedness, final judgments or orders, certain change of control events, and certain bankruptcy-related events or proceedings. Upon the occurrence of an event of default (subject to notice and grace periods), obligations under the 2019 Credit Agreement could be accelerated. Subject to certain exceptions, to the extent the Company has any material domestic subsidiaries, the obligations under the 2019 Credit Agreement would be required to be guaranteed by such material domestic subsidiaries. The obligations under the 2019 Credit Agreement are secured by all or substantially all of the assets of the Company and any such subsidiary guarantors. The Company capitalized $1.4 million of debt issuance costs in connection with the 2019 Credit Agreement . Non-cash interest expense related to debt issuance costs on the 2019 Credit Agreement for the year ended December 31, 2019 was $0.3 million . Total unamortized debt issuance costs related to the 2019 Credit Agreement were $1.1 million as of December 31, 2019 . At December 31, 2019 , the Company did no t have any borrowings under the 2019 Credit Agreement

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 14—Commitments and Contingencies Lease Commitments Finance Leases The Company adopted ASU 2016-02 —Leases (Topic 842) in the first quarter of 2019. Prior to the adoption of this standard, the Company applied build-to-suit accounting treatment to its headquarters lease in Brooklyn, New York and accounted for leased computer equipment as capital leases. The Company now accounts for these as finance leases under the requirements of the standard. For more information on the adoption of ASU 2016-02— Leases see “ Note 1—Basis of Presentation and Summary of Significant Accounting Policies .” In May 2014, the Company entered into a 10 -year lease agreement for approximately 199,000 rentable square feet of office space in Brooklyn, New York for the Company’s headquarters, which commenced in 2015 . For the year ended December 31, 2019 , approximately 172,000 rentable square feet was accounted for as a finance lease and approximately 53,000 rentable square feet located in an adjacent building was accounted for as an operating lease. In connection with the lease agreement, the Company established a $5.3 million collateral account, reflected in the restricted cash balance on the Consolidated Balance Sheets. The Company entered into a credit agreement with Dell Financial Services, LLC. (“DFS”) on February 17, 2016, which provided the Company with a credit line of up to $6.0 million for hosting equipment leases (the “DFS Line”), which was increased to $9.0 million during 2017. This credit line was reduced to $6.0 million in 2019. The DFS Line allows the Company to lease hosting equipment from DFS. The leases have a 36 -month term, zero interest and are payable in equal monthly installments with a buy-out option of $1 at the end of the lease term. As of December 31, 2019 , the Company has lease obligations of approximately $0.8 million related to leased hosting equipment using the previously active DFS Line. The Company entered into a credit agreement with ePlus Group, Inc. (“ePlus”) on January 3, 2014, which provided the Company with a credit line of up to $8.0 million for computer equipment leases (the “ePlus Line”), which was increased to $18.0 million during 2015. The ePlus Line allows the Company to order equipment from any approved vendor. ePlus purchases the equipment on behalf of the Company and leases it back to the Company. The leases have a 36 -month term, interest rate of 3.71 - 6.94% and are payable in equal monthly installments with a fair market value or a $1 buy-out option at the end of the lease term depending on the equipment. As of December 31, 2019 , the Company has lease obligations of approximately $2.0 million related to leased computer equipment using the ePlus Line. For the years ended December 31, 2019, 2018, and 2017 , the accompanying Consolidated Statement of Operations includes charges of approximately $0.5 million , $1.0 million , and $1.6 million for interest expense, respectively, related to the equipment leased using the DFS and ePlus Lines. Operating Leases The Company did not enter into any material operating leases or extensions in 2019 , 2018 , or 2017 . Rent expense for the Company’s operating leases is recognized over the term of each respective lease on a straight-line basis. In addition, the Company leases other office facilities under shorter terms and cancelable leases. Total rent expense for the years ended December 31, 2019, 2018, and 2017 was $5.4 million , $3.8 million , and $4.1 million , respectively. Purchase Obligations The Company has $97.7 million of non-cancelable contractual commitments as of December 31, 2019 , primarily related to cloud computing, as well as other support services. These commitments are due within four years. The following table represents the Company’s commitments under its purchase obligations as of December 31, 2019 (in thousands): Purchase Obligations Periods ending 2020 $ 34,153 2021 30,735 2022 32,122 2023 700 2024 — Thereafter — Total purchase obligations $ 97,710 Long-Term Debt In September 2019 , the Company issued the 2019 Notes in a private placement to qualified institutional buyers pursuant to the Securities Act. The 2019 Notes will mature on October 1, 2026 , unless earlier converted or repurchased. In March 2018 , the Company issued the 2018 Notes in a private placement to qualified institutional buyers pursuant to the Securities Act. The 2018 Notes will mature on March 1, 2023 , unless earlier converted or repurchased, and there are no contractual payments required until maturity. For more information on the 2019 and 2018 Notes, see “ Note 13—Debt .” Non-Income Tax Contingencies The Company had reserves of $7.2 million and $0.9 million at December 31, 2019 and 2018 , respectively, for certain non-income tax obligations, representing management’s best estimate of its potential liability. The 2019 reserve includes $4.8 million due to the acquisition of Reverb, which is wholly offset by an indemnification asset of $3.7 million and a deferred tax asset of $1.1 million . The Company could also be subject to examination in various jurisdictions related to income tax and non-income tax matters. The resolution of these types of matters, if in excess of the recorded reserve, could have an adverse impact on the Company’s business. Legal Proceedings From time to time in the normal course of business, various other claims and litigation have been asserted or commenced against the Company. Due to uncertainties inherent in litigation and other claims, the Company can give no assurance that it will prevail in any such matters, which could subject the Company to significant liability for damages. Any claims or litigation, regardless of their success, could have an adverse effect on the Company’s Consolidated Results of Operations or Cash Flows in the period the claims or litigation are resolved. Although the results of litigation and claims cannot be predicted with certainty, we currently believe that the final outcome of these ordinary course matters will not have a material adverse effect on our business.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	Note 15—Stockholders’ Equity At December 31, 2019 and 2018 , the authorized capital stock of the Company included 1,400,000,000 shares of common stock. At December 31, 2019 and 2018 there were 25,000,000 shares of preferred stock authorized. Common Stock At December 31, 2019 and 2018 there were 118,342,772 and 119,771,702 shares of common stock issued and outstanding, respectively. Holders of common stock are entitled to one vote per share. Holders of common stock are not entitled to receive dividends unless declared by the Board of Directors. No dividends have been declared through December 31, 2019 . The common stock has a $0.001 par value. Convertible Preferred Stock Upon the closing of the IPO on April 21, 2015, all outstanding shares of convertible preferred stock were converted into 53,448,243 shares of common stock. As of December 31, 2019, 2018, and 2017 , there was no convertible preferred stock outstanding. Share Repurchases In September 2019 , the Board of Directors approved a concurrent stock repurchase with the pricing of the 2019 Notes , pursuant to which the Company repurchased $124.5 million , or 2,094,196 shares of its common stock. This authorization was only applicable concurrent with the issuance of the 2019 Notes and, therefore, there are no further purchases authorized under this approval. On November 1, 2018, the Board of Directors approved a stock repurchase program that enables the Company to repurchase up to $200 million of its common stock. The program does not have a time limit and may be modified, suspended, or terminated at any time by the Board of Directors. The number of shares repurchased and the timing of repurchases will depend on a number of factors, including, but not limited to, stock price, trading volume and general market conditions, along with Etsy’s working capital requirements, general business conditions and other factors. In November 2017, the Board of Directors approved a stock repurchase program that enabled the Company to repurchase up to $100 million of its common stock. The program was completed in the second quarter of 2018. Under the stock repurchase programs, the Company may purchase shares of its common stock through various means, including open market transactions, privately negotiated transactions, tender offers or any combination thereof. In addition, open market repurchases of common stock may be made pursuant to trading plans established pursuant to Rule 10b5-1 under the Securities Exchange Act of 1934, as amended, which would permit common stock to be repurchased at a time that the Company might otherwise be precluded from doing so under insider trading laws or self-imposed trading restrictions. The following table summarizes the Company’s cumulative share repurchase activity of the programs noted above, excluding shares withheld to satisfy tax withholding obligations in connection with the vesting of employee restricted stock units and excluding the concurrent stock repurchase with the pricing of the 2019 Notes (in thousands, except share and per share amounts): Shares Repurchased Average Price Paid per Share (1) Value of Shares Repurchased (1) Remaining Amount Authorized New Authorization on November 17, 2017 of $100 million — $ — $ — $ 100,000 Repurchases of common stock for the three months ended: December 31, 2017 586,231 17.57 10,301 (10,301 ) Balance as of December 31, 2017 586,231 17.57 10,301 89,699 Repurchases of common stock for the three months ended: March 31, 2018 2,807,393 24.43 68,586 (68,586 ) June 30, 2018 722,941 29.15 21,113 (21,113 ) September 30, 2018 — — — — New Authorization on November 1, 2018 of $200 million — — — 200,000 Repurchases of common stock for the three months ended: December 31, 2018 916,083 49.11 45,000 (45,000 ) Balance as of December 31, 2018 5,032,648 28.80 145,000 155,000 Repurchases of common stock for the three months ended: March 31, 2019 532,412 51.64 27,500 (27,500 ) June 30, 2019 — — — — September 30, 2019 50,721 55.16 2,798 (2,798 ) December 31, 2019 425,078 52.21 22,202 (22,202 ) Balance as of December 31, 2019 6,040,859 $ 32.68 $ 197,500 $ 102,500 (1) Average price paid per share excludes broker commissions. Value of shares repurchased includes broker commissions. All repurchases were made using cash resources and all repurchased shares of common stock have been retired.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-based Compensation	Note 16—Stock-based Compensation The Company’s 2015 Equity Incentive Plan (the “2015 Plan”) was adopted by its Board of Directors and approved by stockholders in March 2015. The 2015 Plan became effective immediately upon adoption although no awards were made under it until the effective date of the IPO. The 2015 Plan replaced the 2006 Stock Plan, and no further grants were made under the 2006 Stock Plan as of the effective date of the IPO. Under the 2006 Stock Plan, incentive and nonqualified stock options or rights to purchase common stock were granted to eligible participants. Options were generally granted for a term of 10 years and generally vested 25% after the first year of service and ratably each month over the remaining 36-month period contingent on continued employment with the Company on each vesting date. The 2015 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units (“RSUs”), and performance cash awards to employees, directors, and consultants. Beginning in 2016, the number of shares available for issuance under the 2015 Plan may be increased annually by an amount equal to the lesser of 7,050,000 shares of common stock, 5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year, or such other amount as determined by the Company’s Board of Directors. The Board of Directors approved an increase of 5,917,139 , 2,395,434 , and 6,088,461 shares available for issuance under the 2015 Plan as of January 2, 2020, January 2, 2019, and January 2, 2018, respectively. Any awards issued under the 2015 Plan that are forfeited by the participant will become available for future grant under the 2015 Plan. The number of shares of the Company’s common stock initially reserved for issuance under the 2015 Plan equaled the sum of 14,100,000 shares plus up to 12,653,075 shares reserved for issuance or subject to outstanding awards under the 2006 Stock Plan. At December 31, 2019 , 31,831,808 shares were authorized under the 2015 Plan and 20,494,369 shares were available for future grant. In the year ended December 31, 2019 , the Company granted nonqualified stock options and RSUs to eligible participants. Options were generally granted for a term of 10 years . For both options and RSUs, vesting is typically over a four -year period and is contingent upon continued employment with the Company on each vesting date. In general, options granted to newly-hired employees prior to July 2018 vest 25% after the first year of service and ratably each month over the remaining 36 -month period. In general, RSUs granted to newly-hired employees prior to July 2018 vest 25% after the first year following the vesting commencement date, which is the first day of the fiscal quarter closest to the date of grant, and then vest ratably each quarter over the remaining 12-quarter period. In general, for current employees who received an additional grant prior to March 2018, options vest ratably each month over a 48 -month period. In general, for current employees who received an additional grant prior to March 2018, RSUs vest ratably each quarter over a 16-quarter period following the vesting commencement date, which is the first day of the fiscal quarter closest to the date of grant. The Company recognizes forfeitures as they occur. Beginning in July 2018, in general , for newly-hired employees, both options and RSUs vest 25% after the first year of service and ratably each six -month period over a four -year period following the vesting commencement date, which is the first day of the month following the date of grant. Beginning in March 2018, in general, for current employees who receive an additional grant, both options and RSUs vest ratably each six -month period over a four -year period following the vesting commencement date . The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model using the inputs below. Prior to the IPO, the Company utilized equity valuations based on comparable publicly-traded companies, discounted free cash flows, an analysis of the Company’s enterprise value, and other factors deemed relevant in estimating the fair value of its common stock. Subsequent to the IPO, the Company has used the closing price of its common stock on Nasdaq as the fair value of its common stock. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant for time periods that approximate the expected life of the option awards. Expected volatilities are based on implied volatilities from Etsy and market comparisons of certain publicly traded companies and other factors. The expected term of stock options granted has been determined using the simplified method, which uses the midpoint between the vesting date and the contractual term. The fair value of RSUs is determined based on the closing price of the Company’s common stock on Nasdaq (rounded to the nearest hundredth) for the 30 trading days immediately prior to and including the date of grant. The requisite service period for stock options and RSUs is generally four years from the date of grant. The fair value of options granted in each year using the Black-Scholes pricing model has been based on the following assumptions: Year Ended 2019 2018 2017 Volatility 39.1% - 39.5% 38.6% - 47.8% 41.7% - 44.2% Risk-free interest rate 1.6% - 2.5% 2.6% - 2.9% 1.9% - 2.2% Expected term (in years) 5.5 - 6.2 5.5 - 6.3 5.5 - 6.3 Dividend rate —% —% —% The following table summarizes the activity for the Company’s options (in thousands, except share and per share amounts): Shares Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2016 9,339,567 $ 7.89 6.64 $ 43,613 Granted 5,887,183 11.04 Exercised (5,760,263 ) 5.87 Forfeited/Canceled (1,518,548 ) 11.36 Outstanding at December 31, 2017 7,947,939 11.02 7.93 74,996 Granted 797,201 29.87 Exercised (1,588,779 ) 11.49 Forfeited/Canceled (265,367 ) 15.68 Outstanding at December 31, 2018 6,890,994 12.91 7.94 239,177 Granted 462,563 64.29 Exercised (840,835 ) 11.64 Forfeited/Canceled (217,803 ) 30.11 Outstanding at December 31, 2019 6,294,919 16.26 7.24 185,900 Total exercisable at December 31, 2019 3,835,279 12.30 6.88 123,671 The following table summarizes the weighted-average grant date fair value of options granted, intrinsic value of options exercised and fair value of awards vested in periods indicated (in thousands, except per share amounts): Year Ended December 31, 2019 2018 2017 Weighted average grant date fair value of options granted $ 26.75 $ 13.33 $ 4.85 Intrinsic value of options exercised 42,758 34,268 52,693 Fair value of awards vested 41,997 32,717 19,826 The total unrecognized compensation expense at December 31, 2019 was $22.6 million , which will be recognized over a weighted-average period of 2.47 years . The following table summarizes the activity for the Company’s unvested RSUs: Shares Weighted-Average Unvested at December 31, 2016 3,135,181 $ 10.70 Granted 2,360,315 12.17 Vested (1,072,321 ) 10.44 Forfeited/Canceled (1,348,928 ) 10.56 Unvested at December 31, 2017 3,074,247 11.98 Granted 2,448,169 28.22 Vested (1,496,906 ) 13.80 Forfeited/Canceled (545,142 ) 18.47 Unvested at December 31, 2018 3,480,368 22.87 Granted 1,464,785 61.92 Vested (1,392,295 ) 22.67 Forfeited/Canceled (592,445 ) 31.25 Unvested at December 31, 2019 2,960,413 40.61 The total unrecognized compensation at December 31, 2019 was $107.4 million , which will be recognized over a weighted-average period of 2.98 years . Total stock-based compensation expense included in the Consolidated Statements of Operations is as follows (in thousands): Year Ended 2019 2018 2017 Cost of revenue $ 5,787 $ 3,357 $ 1,739 Marketing 3,774 2,507 1,933 Product development 21,085 21,234 8,274 General and administrative 13,749 11,133 14,613 Total stock-based compensation expense $ 44,395 $ 38,231 $ 26,559 The total stock-based compensation expense in the years ended December 31, 2019, 2018, and 2017 includes $1.3 million , $3.8 million , and $3.9 million , in acquisition-related stock-based compensation expense, respectively. During the year ended December 31, 2018 , the Company incurred non-cash stock-based compensation expense of $7.0 million resulting from the modification of stock options and RSUs to accelerate vesting of certain stock-based compensation in connection with the departure of two employees. See “ Note 17—Restructuring and Other Exit Costs (Income) ” for information on stock modifications incurred in 2017 related to restructuring.

Restructuring and Other Exit Co

Restructuring and Other Exit Costs (Income)	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Other Exit Costs (Income)	Note 17—Restructuring and Other Exit Costs (Income) On April 30, 2017, the Board of Directors approved a plan to increase efficiency and streamline the Company’s cost structure through headcount reductions and a reduction in internal program expenses (the “May Actions”). On June 16, 2017, the Board of Directors approved additional initiatives designed to improve focus on key strategic growth opportunities (together with the May Actions, the “Actions”). The Actions included total headcount reductions of 245 positions or 23% of the total workforce as of December 31, 2016 , closing ALM, a marketplace in France, and closing or consolidating certain international offices. In connection with the Actions, the Company incurred $13.9 million of restructuring and other exit costs in the year ended December 31, 2017 , comprised of employee severance, stock compensation modifications, and other exit costs, largely made up of cash expenditures. The Company generated $0.2 million of income in the year ended December 31, 2018 due to changes in estimated severance costs. The following table displays restructuring and other exit costs (income) recorded related to the Actions and a rollforward of the charges to the accrued expenses balance as of December 31, 2019 (in thousands): Severance Charge Stock-Based Compensation Other Exit Costs Total Balance, December 31, 2016 $ — $ — $ — $ — Total restructuring and other exit costs 10,204 2,701 992 13,897 Costs charged against equity/assets — (2,701 ) (286 ) (2,987 ) Cash payments (8,896 ) — (672 ) (9,568 ) Balance, December 31, 2017 1,308 — 34 1,342 Total restructuring and other exit income (244 ) — (5 ) (249 ) Cash payments (1,064 ) — (29 ) (1,093 ) Balance, December 31, 2018 — — — — Balance, December 31, 2019 $ — $ — $ — $ — Total restructuring and other exit costs (income) included in the Consolidated Statements of Operations are as follows (in thousands): Year Ended 2019 2018 2017 Cost of revenue $ — $ (19 ) $ 738 Marketing — (82 ) 2,950 Product development — (110 ) 3,232 General and administrative — (38 ) 6,977 Total restructuring and other exit costs (income) $ — $ (249 ) $ 13,897

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Consolidation	Basis of Consolidation
Use of Estimates	Use of Estimates The preparation of the Company’s Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets, liabilities, and equity at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. The accounting estimates that require management’s most difficult and subjective judgments include: leases, including determining the incremental borrowing rate; income taxes, including the accounting for uncertain tax positions; purchase price allocations for business combinations, valuation of the acquired intangibles purchased in a business combination; valuation of goodwill and intangible assets; stock-based compensation; and fair value of financial instruments. The Company evaluates its estimates and judgments on an ongoing basis and revises them when necessary. Actual results may differ from the original or revised estimates.
Revenue Recognition	Revenue Recognition The Company’s revenue is diversified; generated from a mix of marketplace activities and other optional services to help sellers to generate more sales and scale their businesses. Revenues are recognized as the Company transfers control of promised goods or services to sellers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company evaluates whether it is appropriate to recognize revenue on a gross or net basis based upon its evaluation of whether the Company obtains control of the specified goods or services by considering if it is primarily responsible for fulfillment of the promise, has inventory risk, and has the latitude in establishing pricing and selecting suppliers, among other factors. Based on its evaluation of these factors, revenue is recorded either gross or net of costs associated with the transaction. With the exception of shipping labels, the Company’s revenues are recognized on a gross basis. Sales and usage-based taxes are excluded from revenues. Etsy Marketplace revenue: As members of the Etsy marketplace, Etsy sellers receive the benefit of marketplace activities, including listing items for sale, completing sales transactions, and payments processing, which represents a single stand-ready performance obligation. Etsy sellers pay a fixed listing fee of $0.20 for each item listed on Etsy.com for a period of four months or, if earlier, until a sale occurs. Variable fees include the 5% transaction fee that an Etsy seller pays for each completed transaction, inclusive of shipping fees charged, and Etsy Payments fees for processing payments, including foreign currency payments. On July 16, 2018 , the Company increased the seller transaction fee from 3.5% to 5% of each completed transaction, and now applies it to the cost of shipping in addition to the cost of the item. Etsy Payments processing fees vary between 3.0% to 4.5% of an item’s total sale price, including shipping, plus a flat fee per order, depending on the country in which a seller’s bank account is located. The Company earns additional fees on transactions in which currency conversions are performed. The listing fee is recognized ratably over a four -month listing period, unless the item is sold or the seller re-lists it, at which time any remaining listing fee is recognized. The transaction fee and Etsy Payments fees are recognized when the corresponding transaction is consummated. Listing fees are nonrefundable while transaction fees and Etsy Payments fees are recorded net of refunds. Marketplace revenue also includes revenue generated through our commercial partnerships, which was recorded in its own Other revenue line prior to the fourth quarter of 2019. Reverb Marketplace revenue: The Reverb seller transaction fee is a variable fee, which is 3.5% of each completed transaction, including both the cost of the item and the shipping. There are no Reverb listing fees. Variable fees also include payments fees for processing payments, including foreign currency payments. Payments processing fees vary between 2.5% - 2.7% of an item’s total sale price, including shipping, plus a flat fee per order, depending on the currency in which a listing is denominated. Etsy Services revenue: Services revenue is derived from optional services offered to Etsy sellers, which primarily include advertising services and Etsy Shipping Labels. Each service below represents an individual obligation that the Company must perform when an Etsy seller chooses to use the service. • Revenue from Promoted Listings, Etsy.com’s on-site advertising service, consists of cost-per-click fees an Etsy seller pays for prominent placement of the seller’s listings in search results in the Etsy.com marketplace. Promoted Listings fees are based on an auction system, which utilizes the budget that each Etsy seller sets when using Promoted Listings to determine the cost-per-click fee. Promoted Listing fees are nonrefundable and are charged to a seller’s Etsy bill when the Promoted Listing is clicked, at which time revenue is recognized. In the third quarter of 2019, Etsy streamlined Promoted Listings and Google Shopping, an off-site marketing tool for Etsy sellers, into one unified ad platform called Etsy Ads, where Etsy sellers can set a budget, which allows Etsy to allocate that budget between channels, targeting optimal return on seller spend. Due to this new offering, Etsy no longer offered its Promoted Listings service as a standalone advertising service after September 30, 2019. Revenue from Etsy Ads consists of cost-per-click fees, which are nonrefundable and are charged to a seller’s Etsy bill when the ad is clicked, at which time revenue is recognized. The revenue the Company recognizes related to Etsy Ads is recorded on a gross basis in Services revenue with an offsetting expense recorded in cost of revenue. • Revenue from Etsy Shipping Labels consists of fees an Etsy seller pays the Company when she purchases shipping labels through its platform, net of the cost the Company incurs in purchasing those shipping labels. The Company provides its sellers access to purchase shipping labels from the United States Postal Service, FedEx, Canada Post, Royal Mail, and DAI Post at discounted pricing due to the volume of purchases through its platform. The Company recognizes Etsy Shipping Label revenue when an Etsy seller purchases a shipping label. The Company recognizes Etsy Shipping Label revenue on a net basis as it is an agent in this arrangement and does not take control of shipping labels prior to transferring the labels to the Etsy Seller. Etsy Shipping Label revenue is recorded net of refunds. Reverb Services revenue : Reverb has its own on-site advertising service called Bump advertising. Reverb sellers have the ability to determine their own ad rate as a percentage of their item’s final sale price. Revenue from Bump advertising is recognized at the time the item is sold. Reverb also provides its sellers access to purchase shipping labels at discounted pricing due to the volume of purchases through its platform. Revenue from shipping labels consists of fees a Reverb seller pays when they purchase shipping labels directly through the Reverb platform, net of the cost we incur in purchasing those shipping labels. Reverb recognizes shipping label revenue when a Reverb seller purchases a shipping label. Reverb recognizes shipping label revenue on a net basis as it is an agent in this arrangement and does not take control of shipping labels prior to transferring the labels to the Reverb seller. Shipping label revenue is recorded net of refunds. Cost of Revenue Cost of revenue primarily consists of the cost of interchange and other fees for credit card processing services, credit card verification service fees, and credit card chargebacks to support payments revenue, and costs of refunds made to buyers that the Company is not able to collect from sellers. Cost of revenue also includes expenses associated with the operation and maintenance of the Company’s platform and its data centers, including employee-related costs, hosting and bandwidth costs, and depreciation and amortization. With the shift to Etsy Ads in the third quarter of 2019, amounts spent on Google Shopping, which were previously recorded on a net basis in Other revenue, are recorded on a gross basis in Services revenue with an offsetting expense recorded in cost of revenue.
Marketing	Marketing
Advertising	Advertising expenses are recognized as incurred, with the exception of certain production expenses related to television and display advertising which are deferred until the first time an advertisement airs or is published. If such advertising is not expected to occur, costs are expensed immediately.
Product Development	Product Development Product development expenses consist primarily of employee-related expenses for engineering, product management, product design, and product research activities. Additional expenses include consulting costs related to the development, quality assurance, and testing of new technology and enhancement of our existing technology.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for its stock-based compensation awards in accordance with ASC Topic 718 —Compensation—Stock Compensation (“ASC 718”). Stock options and restricted stock units (“RSUs”) are awarded to employees and members of the Company’s Board of Directors and are measured at fair value at each grant date. The Company calculates the fair value of stock options on the date of grant using the Black-Scholes option-pricing model and the expense is recognized over the requisite service period. Prior to the IPO, the Company utilized equity valuations based on comparable publicly-traded companies, discounted free cash flows, an analysis of the Company’s enterprise value, and other factors deemed relevant in estimating the fair value of its common stock. Subsequent to the IPO, the Company has used the closing price of its common stock on Nasdaq as the fair value of its common stock. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. Expected volatilities are based on implied volatilities from market comparisons of Etsy and certain publicly traded companies, and other factors. The expected term of stock options granted has been determined using the simplified method, which uses the midpoint between the vesting date and the contractual term. The fair value of RSUs is determined based on the closing price of the Company’s common stock on Nasdaq on the grant date. The requisite service period for stock options and RSUs is generally four years from the date of grant. The Company recognizes forfeitures as they occur. The Company accounted for stock-based compensation arrangements related to the A Little Market (“ALM”) acquisition in restricted shares, subject to a put option that allows the holder of the shares to put the shares back to the Company for cash, as liability-classified stock awards. These awards were re-measured at fair value each reporting period, with changes in fair value being charged to the Consolidated Statement of Operations. Compensation expense was recognized using a graded vesting methodology for each separately vesting tranche as though the award were, in substance, multiple awards. Unless the put option was exercised, the restricted shares were to be reclassified from a liability to an equity classified award upon the termination of the put option at the vesting of each separate tranche. In 2017, all outstanding restricted shares subject to a put option became fully vested and the Company is no longer required to remeasure these awards at fair value going forward.
Foreign Currency	Foreign Currency The Company has determined that the functional currency for each of its foreign operations is the currency of the primary cash flow of the operations, which is generally the local currency in which the operation is located. All assets and liabilities are translated into U.S. dollars using exchange rates in effect at the balance sheet date. Revenue and expenses are translated using average exchange rates during the period. Foreign currency translation adjustments are reflected in stockholders’ equity as a component of other comprehensive income (loss). Transaction gains and losses including intercompany balances denominated in a currency other than the functional currency of the entity involved are included in foreign exchange gain (loss) within other income (expense) in the Consolidated Statement of Operations.
Income Taxes	Income Taxes The income tax benefit is based on income before income taxes and is accounted for under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to settle. The Company recognizes future tax benefits, such as net operating losses and tax credits, to the extent that realizing these benefits is considered in its judgment to be more likely than not. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income or expense in the period that includes the enactment date. The Company regularly reviews the recoverability of its deferred tax assets by considering its historic profitability, projected future taxable income, timing of the reversals of existing temporary differences and the feasibility of its tax planning strategies. Where appropriate the Company records a valuation allowance against deferred tax assets that are deemed more likely than not to be realizable. On December 22, 2017 the Tax Cuts and Jobs Act of 2017 (the “TCJA”) was signed into law. The TCJA requires the Company to make an accounting policy election of either (1) treating taxes due on future U.S. inclusions in taxable income related to Global Intangible Low Taxed Income ("GILTI") as a current period expense when incurred (the “period cost method”) or (2) factoring such amounts into the Company’s measurement of its deferred taxes (the “deferred method”). The Company has recorded tax expense related to GILTI in its effective tax rate beginning in 2018, and has elected to treat taxes due on future U.S. inclusions in taxable income related to GILTI as a current period expense when incurred using the period cost method. The Company accounts for uncertainty in income taxes using a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by the taxing authorities. The amount recognized is measured as the largest amount of benefit that has a greater than 50% likelihood of being realized upon ultimate audit settlement. The Company recognizes interest and penalties, if any, associated with income tax matters as part of the income tax provision and includes accrued interest and penalties with the related income tax liability in the Consolidated Balance Sheets.
Net Income (Loss) Per Share	Net Income (Loss) Per Share Basic net income per share attributable to common stockholders is computed by dividing the net income attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted net income per share is computed by dividing net income for the period by the weighted-average number of shares of common stock and potentially dilutive common stock outstanding during the period. Net income in the diluted net income per share calculation is adjusted for income or loss from fair value adjustments on instruments accounted for as liabilities, but which may be settled in shares. The dilutive effect of outstanding options and stock-based compensation awards is reflected in diluted net income per share by application of the treasury stock and if-converted methods. Since the Company expects to settle in cash the principal outstanding under the 0.125% Convertible Senior Notes due 2026 (the “ 2019 Notes ”) (see “ Note 13—Debt ”), it uses the treasury stock method when calculating the potential dilutive effect of the conversion spread on diluted net income per share, if applicable. The Company uses the if-converted method when calculating the dilutive effect of the 0% Convertible Senior Notes due 2023 (the “ 2018 Notes ”) for the reporting periods starting in the third quarter of 2019, and used the treasury stock method for previous reporting periods. The calculation of diluted net income (loss) per share excludes all anti-dilutive common shares. For periods in which the Company has reported net losses, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, because dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Segment Data	Segment Data The Company identifies operating segments as components of an entity for which discrete financial information is available and is regularly reviewed by the chief operating decision maker in making decisions regarding resource allocation and performance assessment. The Company defines the term “chief operating decision maker” to be its chief executive officer. The Company has determined it has two operating segments, Etsy and Reverb, which qualify for aggregation as one reportable segment, for purposes of allocating resources and evaluating financial performance.
Cash and Cash Equivalents	Cash and Cash Equivalents, and Short- and Long-term Investments
Short- and Long-term Investments	Short-term investments, consisting of U.S. Government and agency securities, corporate bonds, commercial paper, and certificates of deposit with original maturities of greater than three months but less than one year when purchased, are classified as available-for-sale and are reported at fair value using the specific identification method. Long-term investments, consisting of U.S. Government and agency securities, corporate bonds, and certificates of deposit with original maturities of greater than twelve months but less than 37 months when purchased, are classified as available-for-sale and are reported at fair value using the specific identification method. Unrealized gains and losses are excluded from earnings and reported as a component of other comprehensive income (loss), net of related estimated income tax provisions or benefits.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash and cash equivalents, short- and long-term investments, and funds receivable and seller accounts. The Company reduces credit risk by placing its cash and cash equivalents with major financial institutions with high credit ratings. At times, to the extent eligible, such amounts may exceed federally insured limits. The Company believes that minimal credit risk exists with respect to these investments due to the credit ratings of the financial institutions that hold its short- and long-term investments. In addition, funds receivable settle relatively quickly, and the Company’s historical experience of losses has not been significant.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Management believes that the fair value of financial instruments, consisting of cash and cash equivalents, short- and long-term investments, accounts receivable, funds receivable and seller accounts, accounts payable, and funds payable and seller accounts approximates carrying value due to the immediate or short-term maturity associated with these instruments.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts
Funds Receivable and Seller Accounts and Funds Payable and Amounts Due to Sellers	Funds Receivable and Seller Accounts and Funds Payable and Amounts due to Sellers The Company records funds receivable and seller accounts and funds payable and amounts due to sellers as current assets and liabilities, respectively, on the Consolidated Balance Sheets. Funds receivable and seller accounts represent amounts received or expected to be received from buyers via third-party credit card processors, which flow through a bank account for payment to sellers. This cash and related receivable represent the total amount due to sellers, and as such a liability for the same amount is recorded to funds payable and amounts due to sellers.
Property and Equipment	Property and Equipment Property and equipment, consisting principally of capitalized website development and internal-use software, building, leasehold improvements, and computer equipment, are recorded at cost. Depreciation and amortization begin at the time the asset is placed into service and are recognized using the straight-line method in amounts sufficient to relate the cost of depreciable and amortizable assets to the Consolidated Statements of Operations over their estimated useful lives. Repairs and maintenance are charged to the Consolidated Statements of Operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation or amortization are removed from the balance sheet and the resulting gain or loss is reflected in the Consolidated Statements of Operations.
Website Development and Internal-use Software Costs	Website Development and Internal-use Software Costs Costs incurred to develop the Company’s website and software for internal-use are capitalized and amortized over the estimated useful life of the software, generally three to five years . In accordance with authoritative accounting guidance, capitalization of costs to develop software begin 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. Costs related to the design or maintenance of website development and internal-use software are expensed as incurred. The Company periodically reviews capitalized website development and internal-use software costs to determine whether the projects will be completed, placed in service, removed from service, or replaced by other internally-developed or third-party software. If an asset is not expected to provide any future use, the asset is retired and any unamortized cost is expensed. If an asset will continue to be used, but the net book value is not expected to be fully recoverable, the asset is impaired to its fair value. When events or changes in circumstances require, the Company assesses the likelihood of recovering the cost of website development and internal-use software costs based on its expectations of future profitability, undiscounted cash flows, and our plans with respect to operations to determine if the asset is impaired and subject to write-off. Measurement of any impairment loss is based on the excess of the carrying value of the asset over the fair value. No impairment of capitalized website development and internal-use software assets was recorded during the years ended December 31, 2019 and 2018 . The Company recognized an asset impairment charge of $3.2 million related to capitalized web development and internal-use software assets in the year ended December 31, 2017 as a result of its decision to discontinue certain product offerings, including Etsy Studio and Etsy Manufacturing. Capitalized website development and internal-use software costs are included in property and equipment within the Consolidated Balance Sheets.
Business Combinations	Business Combinations In accordance with the guidance for business combinations, we determine whether a transaction is a business combination, which requires that the assets acquired and liabilities assumed constitute a business. The Company accounts for business combinations using the acquisition method of accounting. If the assets acquired are not a business, we account for the transaction as an asset acquisition. Under both methods, the purchase price is allocated to the assets acquired and liabilities assumed using the fair values determined by management as of the acquisition date. The results of businesses acquired in a business combination are included in the Company’s Consolidated Financial Statements from the date of acquisition. Determining the fair value of assets acquired and liabilities assumed requires management to use significant judgment and estimates, including estimates of future revenue and adjusted earnings before interest and taxes and discount rates. Our estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and unpredictable and, as a result, actual results may differ materially from estimates. Our estimates associated with the accounting for business combinations may change as additional information becomes available regarding the assets acquired and liabilities assumed. Any change in facts and circumstances that existed as of the acquisition date and impacts our preliminary estimates is recorded to goodwill if identified within the measurement period. Subsequent to the measurement period or our final determination of fair value of assets and liabilities whichever is earlier the adjustments will affect our earnings. Acquisition-related expenses incurred by the Company in a business combination are not included as a component of consideration transferred, but are accounted for as an expense in the period in which the costs are incurred.
Goodwill	Goodwill Goodwill represents the excess of the aggregate fair value of the consideration transferred in a business combination over the fair value of the assets acquired, net of liabilities assumed. Goodwill is not amortized, but is subject to an annual impairment test. Management has determined that the Company has two operating segments, which qualify for aggregation as one reportable segment, for purposes of allocating resources and evaluating financial performance. As a result, the Company has determined it has two reporting units. The Company performs its annual goodwill impairment test during the fourth quarter or more frequently if events or changes in circumstances indicate that the goodwill may be impaired. The Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of the reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, the Company determines it is not more likely than not that the fair value of the reporting unit is less than its carrying amount, then additional impairment testing is not required. However, if the Company concludes otherwise, then it is required to perform a quantitative assessment for impairment. The quantitative assessment involves comparing the estimated fair value of the reporting unit with its respective book value, including goodwill. If the estimated fair value exceeds book value, goodwill is considered not to be impaired. If, however, the book value of the reporting unit exceeds the fair value, an impairment loss is recognized in an amount equal to the excess, not to exceed the total amount of goodwill allocated to that reporting unit.
Intangible Assets	Intangible Assets Finite intangible assets are amortized over the estimated useful life of the asset. The estimated useful life of acquired technology is three years . The estimated useful lives of acquired customer relationships and trademarks are fifteen years and the estimated useful life of the referral agreement is ten years
Leases	Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating leases are included in other assets, other current liabilities, and other liabilities on the Company’s Consolidated Balance Sheets. Finance leases are included in property and equipment, net, finance lease obligations, current, and finance lease obligations, net of current portion on the Company’s Consolidated Balance Sheets. Leases with a term greater than one year are recognized on the Consolidated Balance Sheet as right-of-use (“ROU”) assets, lease obligations and, if applicable, long-term lease obligations in the financial statement line items cited above. The Company has elected not to recognize leases with terms of one year or less on the Consolidated Balance Sheet. Lease obligations and their corresponding ROU assets are recorded based on the present value of lease payments over the expected lease term. As the interest rate implicit in lease contracts is typically not readily determinable, the Company utilizes the appropriate incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Certain adjustments to the ROU asset may be required for items such as initial direct costs paid or incentives received. The lease term may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. The components of a lease should be split into three categories: lease components, including land, building, or other similar components; non-lease components, including common area maintenance, maintenance, consumables, or other similar components; and non-components, including property taxes, insurance, or other similar components. However, the Company has elected to combine lease and non-lease components as a single component. The lease expense is recognized over the expected term on a straight-line basis.
Contingencies	Contingencies The Company accrues for loss contingencies when losses become probable and are reasonably estimable. If the reasonable estimate of the loss is a range and no amount within the range is a better estimate, the minimum amount of the range is recorded as a liability. The Company does not accrue for contingent losses that, in its judgment, are considered to be reasonably possible, but not probable; however, it discloses the range of such reasonably possible losses.
Recently Issued Accounting Pronouncements and Recently Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13 —Financial Instruments—Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments , and additional changes, modifications, clarifications, or interpretations related to this guidance thereafter, which require a reporting entity to estimate credit losses on certain types of financial instruments, and present assets held at amortized cost and available-for-sale debt securities at the amount expected to be collected. The new guidance is effective for annual and interim periods beginning after December 15, 2019, and early adoption is permitted. The Company will adopt this standard in the first quarter of 2020, and the adoption is not expected to have a significant impact on its Consolidated Financial Statements. In August 2018, the FASB issued ASU 2018-15 —Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40)—Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The new guidance is effective for annual and interim periods beginning after December 15, 2019, and early adoption is permitted. The Company will adopt this standard in the first quarter of 2020. Upon adoption of the standard, the Company’s Consolidated Financial Statements will be impacted by the timing of amortization of the integration costs related to cloud computing arrangements. In December 2019, the FASB issued ASU 2019-12 —Income Taxes (Topic 740)—Simplifying the Accounting for Income Taxes , which enhances and simplifies various aspects of the income tax accounting guidance, including requirements such as tax basis step-up in goodwill obtained in a transaction that is not a business combination, ownership changes in investments, and interim-period accounting for enacted changes in tax law. The standard will be effective for the Company in the first quarter of 2021, although early adoption is permitted. The Company is currently considering the date it will adopt this standard, and the adoption is not expected to have a significant impact on its Consolidated Financial Statements. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 —Leases (Topic 842), and additional changes, modifications, clarifications, or interpretations related to this guidance thereafter, which require a reporting entity to recognize ROU assets and lease liabilities on the balance sheet for operating leases to increase the transparency and comparability. Disclosure requirements have been enhanced with the objective of enabling financial statement users to assess the amount, timing, and uncertainty of cash flows arising from leases. The Company adopted this standard in the first quarter of 2019, effective as of January 1, 2019, using the modified retrospective approach utilizing transition guidance introduced in ASU 2018-11— Leases: Targeted Improvements , and elected the ‘package of practical expedients’ permitted under the transition guidance within the new standard, which among other things, allowed the Company to carry forward the historical lease identification, classification, and initial direct costs. The Company did not elect the hindsight practical expedient which permits entities to use hindsight in determining the lease term and assessing impairment. The Company also elected to continue to recognize lease payments related to short-term leases as an expense on a straight-line basis over the lease term. Upon adoption, the Company recognized new ROU assets and lease obligations on the Consolidated Balance Sheet for its operating leases of $25.4 million and $27.8 million , respectively. Additionally, upon adoption the Company renamed its capital lease obligations, current and capital lease obligations, net of current to finance lease obligations, current and finance lease obligations, net of current portion, respectively, in the Consolidated Balance Sheets. In 2014 the Company applied build-to-suit accounting treatment to its headquarters lease in Brooklyn, New York, as the Company was deemed the accounting owner of the construction project because of the Company’s involvement in the build-out of the space. Upon transition, the Company derecognized the facility financing obligation and related building assets recorded as a result of the failed sale and leaseback transactions and recorded any difference as a cumulative-effect adjustment to accumulated deficit. The adoption of this standard had a material impact on the Company’s financial position but did not and is not expected to significantly affect the Company’s results of operations. The Company has derecognized the existing facility financing obligation and existing building asset for sale-leaseback transactions that currently do not qualify for sale accounting of $60.0 million and $51.1 million , respectively, and $22.1 million was reclassified from building to leasehold improvements and will be amortized over the remaining term of the lease. The Company recognized a gain of $9.3 million , offset by a tax impact of $2.2 million associated with this change through accumulated deficit as of January 1, 2019, with a net decrease to accumulated deficit of $7.1 million , and recognized a new ROU asset of $66.7 million

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash, Cash Equivalents and Investments	The following table provides cash and cash equivalents, and short- and long-term investments within the Consolidated Balance Sheets as of the dates indicated (in thousands): As of December 31, 2019 2018 Cash and cash equivalents $ 443,293 $ 366,985 Short-term investments 373,959 257,302 Long-term investments 89,343 — Total cash, cash equivalents, and short- and long-term investments $ 906,595 $ 624,287
Schedule of Allowance Activity	The following table summarizes the allowance activity during the periods indicated (in thousands): Year Ended 2019 2018 2017 Balance as of the beginning of period $ 4,720 $ 2,687 $ 1,999 Bad debt expense 10,963 4,124 2,497 Write-offs, net of recoveries and other adjustments (10,650 ) (2,091 ) (1,809 ) Balance as of the end of period $ 5,033 $ 4,720 $ 2,687

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table summarizes revenue by type of service for the periods presented (in thousands): Year Ended December 31, 2019 2018 2017 Marketplace revenue (1) $ 593,646 $ 444,765 $ 329,362 Services revenue 224,733 158,928 111,869 Revenue $ 818,379 $ 603,693 $ 441,231 (1) Other revenue for the years ended December 31, 2019, 2018, and 2017 has been reclassified and presented within Marketplace revenue. Comparative periods have been reclassified to conform to current period presentation.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The following are the domestic and foreign components of the Company’s income before income taxes (in thousands): Year Ended 2019 2018 2017 Domestic $ 14,544 $ 36,157 $ (16,583 ) Foreign 66,102 18,921 48,848 Income before income taxes $ 80,646 $ 55,078 $ 32,265
Income Tax Benefit	The income tax benefit is comprised of the following (in thousands): Year Ended 2019 2018 2017 Current: Federal $ (3,967 ) $ 709 $ (6,397 ) State 1,053 (578 ) 79 Foreign 352 600 476 Total current (2,562 ) 731 (5,842 ) Deferred: Federal (19,734 ) (3,343 ) (34,948 ) State (1,564 ) 3,496 (8,778 ) Foreign 8,612 (23,297 ) 33 Total deferred (12,686 ) (23,144 ) (43,693 ) Total income tax benefit $ (15,248 ) $ (22,413 ) $ (49,535 )
Reconciliation of the Income Tax Benefit	A reconciliation of the income tax benefit at the U.S. federal statutory income tax rate to the Company’s total income tax benefit is as follows (in thousands): Year Ended 2019 2018 2017 Income tax provision at the federal statutory rate (a) $ 16,936 $ 11,566 $ 11,308 State and local income taxes net of federal benefit 973 3,839 (691 ) Foreign income tax rate differential (5,454 ) (298 ) (11,878 ) Stock-based compensation (16,281 ) (11,717 ) (12,584 ) Research and development credit (9,864 ) (4,115 ) (1,098 ) U.S. tax reform (b) (4,197 ) 3,897 (31,063 ) Non-deductible expenses 1,784 (329 ) 168 Uncertain tax positions 380 382 789 Change in valuation allowance (c) — (28,733 ) (4,673 ) Return to provision adjustment 500 3,293 167 Other (25 ) (198 ) 20 Total income tax benefit $ (15,248 ) $ (22,413 ) $ (49,535 ) (a) The income tax provision at the U.S. federal statutory rate is computed using 21% in 2019 and 2018 and 35% in 2017. Refer to footnote (b) below. (b) On December 22, 2017, the U.S. government enacted the TCJA, as described above, which includes significant changes to the taxation of business entities. These changes include, among others, (1) a permanent reduction to the corporate income tax rate, (2) Global Intangible Low-Taxed Income (“GILTI”), a new tax on worldwide income, and (3) Foreign Derived Intangible Income (“FDII”) a deduction provided with respect to certain foreign earned income. Effective January 1, 2018, the Company is subject to several provisions of the TCJA including computations under GILTI and FDII. For the year ended December 31, 2017, primarily as a result of the permanent change in U.S. corporate income tax rate, the Company recognized a net income tax benefit of $31.1 million associated with the TCJA. For the years ended December 31, 2019 and 2018, the Company has accounted for the impact of the new TCJA provisions, as well as any adjustments with respect to the re-measurement of its deferred taxes, as part of its income tax benefit using the currently available regulations and technical guidance on the interpretations of the TCJA. The Company has elected to account for GILTI as a period cost. The Company is not currently subject to the Base Erosion and Anti-Abuse Tax (“BEAT”) or Section 163(j) Interest Limitation. The Company will continue to monitor the forthcoming regulations and additional guidance of the GILTI, FDII, and BEAT provisions under the TCJA, which are complex and subject to continuing regulatory interpretation by the Internal Revenue Service (“IRS”).
Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets (liabilities) are as follows (in thousands): As of December 31, 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 19,599 $ 13,347 Research and development credit carryforwards 13,133 7,567 Lease liability (a) 18,666 — Stock-based compensation expense 7,642 6,623 Excess tax basis in intangible assets 3,572 12,109 Accrued bonus 4,065 1,049 Deferred rent (a) — 529 Other deferred tax assets 3,944 1,858 Total deferred tax assets 70,621 43,082 Less: valuation allowance 883 1,673 Total net deferred tax asset 69,738 41,409 Deferred tax liabilities: Excess book basis in intangible assets (39,500 ) (362 ) Restructuring liability (29,635 ) (33,730 ) Convertible debt (22,839 ) (7,283 ) Right-of-use asset (a) (17,596 ) — Depreciation (a) (10,328 ) (6,933 ) Other deferred tax liabilities (80 ) (92 ) Total deferred tax liabilities (119,978 ) (48,400 ) Net deferred tax liabilities $ (50,240 ) $ (6,991 ) (a) As part of the Company’s adoption of ASC 842 beginning in 2019, the Company recorded adjustments to the GAAP basis of certain assets and liabilities and established other assets and liabilities (i.e., right-of-use asset and lease liability). The net adjustment was recorded as a retrospective adjustment to retained earnings. The adoption of ASC 842 does not change the Company’s tax basis in these assets and liabilities. However, as a result of the adoption, an adjustment was recorded to the historic deferred taxes, through retained earnings, to account for the change in GAAP basis as well as establishing deferred taxes on the newly established right-of-use assets and lease liabilities.
Summary of Tax Credit Carryforwards	As of December 31, 2019 , the Company had the following operating loss and tax credit carryforwards available to offset taxable income in future years: December 31, 2019 Expiration Period U.S. Federal net operating loss carryforwards $ 30,403 2035-Unlimited U.S. Federal credit carryforwards 13,054 2035-2039 U.S. State net operating loss carryforwards 21,150 2027-2039 U.S. State credit carryforwards 184 2020-2024 Non-U.S. net operating loss carryforwards 91,440 Unlimited
Summary of Operating Loss Carryforwards	As of December 31, 2019 , the Company had the following operating loss and tax credit carryforwards available to offset taxable income in future years: December 31, 2019 Expiration Period U.S. Federal net operating loss carryforwards $ 30,403 2035-Unlimited U.S. Federal credit carryforwards 13,054 2035-2039 U.S. State net operating loss carryforwards 21,150 2027-2039 U.S. State credit carryforwards 184 2020-2024 Non-U.S. net operating loss carryforwards 91,440 Unlimited
Summary of Valuation Allowance	The following table summarizes the valuation allowance activity for the periods indicated (in thousands): Year Ended 2019 2018 2017 Balance as of the beginning of period $ 1,673 $ 32,455 $ 13,839 Additions charged to expense 504 — 16,743 Deletions credited to expense (4 ) (28,733 ) — Currency translation and other balance sheet activity (1,290 ) (2,049 ) 1,873 Balance as of the end of period $ 883 $ 1,673 $ 32,455
Schedule of Unrecognized Tax Benefits Activity	The following table summarizes the unrecognized tax benefit activity for the periods indicated (in thousands): As of December 31, 2019 2018 2017 Balance as of the beginning of period $ 18,819 $ 17,013 $ 23,574 Additions based on tax positions related to the current year 1,847 921 732 Additions for tax positions of prior years 3,620 946 118 Reductions for tax provisions of prior years (2,423 ) (61 ) (7,411 ) Lapse of Statute of Limitation (184 ) — — Additions recorded through goodwill as part of business combination 1,334 — — Settlements (3,080 ) — — Balance as of the end of period $ 19,933 $ 18,819 $ 17,013

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents the calculation of basic and diluted net income per share for periods presented (in thousands, except share and per share amounts): Year Ended 2019 2018 2017 Numerator: Net income $ 95,894 $ 77,491 $ 81,800 Net income allocated to participating securities under the two-class method — (37 ) (80 ) Net income attributable to common stockholders—basic 95,894 77,454 81,720 Dilutive effect of net income allocated to participating securities under the two-class method — 37 80 Change in fair value of liability classified restricted stock — — 771 Net income attributable to common stockholders—diluted $ 95,894 $ 77,491 $ 82,571 Denominator: Weighted average common shares outstanding—basic (1) 119,665,248 120,146,076 118,538,687 Dilutive effect of assumed conversion of options to purchase common stock 4,516,413 4,238,622 2,498,448 Dilutive effect of assumed conversion of restricted stock units 1,521,719 1,721,658 1,177,799 Dilutive effect of assumed conversion of convertible debt (2) — 900,580 — Diluted effective of assumed conversion of restricted stock from acquisition 16,693 77,849 52,739 Weighted average common shares outstanding—diluted 125,720,073 127,084,785 122,267,673 Net income per share attributable to common stockholders—basic $ 0.80 $ 0.64 $ 0.69 Net income per share attributable to common stockholders—diluted $ 0.76 $ 0.61 $ 0.68 (1) 57,482 , and 114,963 shares of unvested stock are considered participating securities and are excluded from basic shares outstanding for the year ended December 31, 2018 and 2017 , respectively. (2) Since the Company expects to settle in cash the principal outstanding under the 2019 Notes (see “ Note 13—Debt ”), it uses the treasury stock method when calculating the potential dilutive effect of the conversion spread on diluted net income per share, if applicable. The Company uses the if-converted method when calculating the dilutive effect of the 2018 Notes for the year ended December 31, 2019 and used the treasury stock method for the year ended December 31, 2018
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potential common shares were excluded from the calculation of diluted net income per share attributable to common stockholders because their effect would have been anti-dilutive for the periods presented: Year Ended 2019 2018 2017 Stock options 317,401 475,238 4,902,664 Restricted stock units 706,234 136,998 435,358 Convertible senior notes 9,511,993 — — Total anti-dilutive securities 10,535,628 612,236 5,338,022

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Schedule of Purchase Price Allocation	The following table summarizes the allocation of the purchase price (at fair value) to the assets acquired and liabilities assumed of Reverb as of August 15, 2019 (the date of acquisition) (in thousands): Initial Fair Value Estimate (1) Measurement Period Adjustments (2) Final Fair Value as Adjusted Short-term investments $ 1,028 $ — $ 1,028 Other current assets (3) 6,442 (3,540 ) 2,902 Funds receivable and seller accounts 5,578 — 5,578 Property and equipment other 1,543 — 1,543 Developed technology 30,300 — 30,300 Trademark 79,400 — 79,400 Customer relationships 93,500 — 93,500 Goodwill 102,039 (336 ) 101,703 Other assets (3) 3,225 3,518 6,743 Other net working capital (208 ) — (208 ) Funds payable and amounts due to sellers (5,578 ) — (5,578 ) Other current liabilities (3) (8,520 ) 4,836 (3,684 ) Other liabilities (3) (2,497 ) (4,836 ) (7,333 ) Deferred tax liability, net (34,898 ) (587 ) (35,485 ) Total purchase price $ 271,354 $ (945 ) $ 270,409 (1) As previously reported in the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2019 . This was the quarter in which the business combination was completed. (2) The Company recorded measurement period adjustments in the fourth quarter of fiscal 2019 due to the final working capital adjustment as well as new facts and circumstances related to assets and liabilities which existed at the acquisition date. The adjustments included an increase in deferred tax liability of $0.6 million and a decrease in goodwill of $0.3 million . Other adjustments are related to the classification of certain assets and liabilities within the balance sheet. (3) Other current liabilities and other liabilities are primarily related to non-income tax related contingency reserves, which are wholly offset by an indemnification asset and a deferred tax asset.
Schedule of Unaudited Supplemental Pro Forma Information	The following unaudited pro forma summary presents consolidated information of the Company as if the business combination had occurred on January 1, 2018 (in thousands): Year Ended December 31, 2019 2018 Revenue $ 847,154 $ 639,743 Net income 88,595 53,587

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table summarizes the changes in the carrying amount of goodwill for the periods indicated (in thousands): Year Ended 2019 2018 Balance as of the beginning of the period $ 37,482 $ 38,541 Business combination 101,703 — Foreign currency translation adjustments (454 ) (1,059 ) Balance as of the end of the period $ 138,731 $ 37,482
Schedule of Finite-Lived Intangible Assets	At December 31, 2019 and 2018 , the gross book value and accumulated amortization of intangible assets were as follows (in thousands): As of December 31, 2019 As of December 31, 2018 Gross book Accumulated Foreign currency translation Net book Gross book Accumulated Foreign currency translation Net book Customer relationships $ 93,500 $ (2,338 ) $ — $ 91,162 $ — $ — $ — $ — Trademark 79,400 (1,985 ) — 77,415 — — — — Referral agreement 37,127 (5,417 ) (1,356 ) 30,354 35,323 (1,890 ) (712 ) 32,721 Technology 7,200 (7,200 ) — — 7,200 (5,500 ) — 1,700 Patent licenses 332 (27 ) — 305 172 (4 ) — 168 Intangible assets, net $ 217,559 $ (16,967 ) $ (1,356 ) $ 199,236 $ 42,695 $ (7,394 ) $ (712 ) $ 34,589
Schedule of Future Amortization Expense	Based on amounts recorded at December 31, 2019 , the Company estimates intangible asset amortization expense in each of the years ending December 31 as follows (in thousands): 2020 $ 15,148 2021 15,148 2022 15,148 2023 15,148 2024 15,148 Thereafter 123,496 Total amortization expense $ 199,236

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Revenue from External Customers by Geographic Areas	The following table summarizes revenue, (loss) income before income taxes and net income by geographic area (in thousands): Year Ended 2019 2018 2017 United States $ 550,257 $ 422,523 $ 317,755 International 268,122 181,170 123,476 Revenue $ 818,379 $ 603,693 $ 441,231 United States (1)(2) $ (23,702 ) $ 7,460 $ (43,014 ) International 104,348 47,618 75,279 (Loss) income before income taxes $ 80,646 $ 55,078 $ 32,265 United States $ 510 $ 7,175 $ 7,029 International 95,384 70,316 74,771 Net income $ 95,894 $ 77,491 $ 81,800 (1) The United States loss before income taxes in the year ended December 31, 2019 was primarily driven by a majority of operating expenses being incurred in the United States. (2) The United States loss before income taxes in the year ended December 31, 2017 was primarily driven by a foreign exchange loss, interest associated with the build-to-suit lease accounting related to our corporate headquarters, restructuring and other exit costs, and asset impairment charges. See “ Note 17—Restructuring and Other Exit Costs (Income) ” and “ Note 10—Property and Equipment ” for additional information on restructuring and other exit costs and asset impairment charges, respectively.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring	The following are the major categories of assets measured at fair value on a recurring basis as of the dates indicated (in thousands): As of December 31, 2019 Level 1 Level 2 Level 3 Total Asset Cash equivalents: Commercial paper $ — $ 5,794 $ — $ 5,794 Certificate of deposit — 2,959 — 2,959 Money market funds 228,859 — — 228,859 228,859 8,753 — 237,612 Short-term investments: Commercial paper — 29,320 — 29,320 Certificate of deposit — 26,132 — 26,132 Corporate bonds — 114,202 — 114,202 U.S. Government and agency securities 204,305 — — 204,305 204,305 169,654 — 373,959 Funds receivable and seller accounts: Money market funds 18,168 — — 18,168 18,168 — — 18,168 Long-term investments: Certificate of deposit — 4,729 — 4,729 Corporate bonds — 38,563 — 38,563 U.S. Government and agency securities 46,051 — — 46,051 46,051 43,292 — 89,343 $ 497,383 $ 221,699 $ — $ 719,082 As of December 31, 2018 Level 1 Level 2 Level 3 Total Asset Cash equivalents: Commercial paper $ — $ 7,775 $ — $ 7,775 Money market funds 244,856 — — 244,856 244,856 7,775 — 252,631 Short-term investments: Commercial paper — 147,860 — 147,860 Corporate bonds — 46,801 — 46,801 U.S. Government and agency securities 62,641 — — 62,641 62,641 194,661 — 257,302 Funds receivable and seller accounts: Money market funds 9,229 — — 9,229 9,229 — — 9,229 $ 316,726 $ 202,436 $ — $ 519,162

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Summary of Cost and Fair Value of Available-For-Sale Securities	The cost and fair value of available-for-sale securities were as follows as of the dates indicated (in thousands): Cost Gross Gross Fair Value December 31, 2019 Cash equivalents: Commercial paper $ 5,794 $ — $ — $ 5,794 Certificate of deposit 2,958 — 1 2,959 8,752 — 1 8,753 Short-term investments: Commercial paper 29,319 (1 ) 2 29,320 Certificate of deposit 26,129 (3 ) 6 26,132 Corporate bonds 114,068 (22 ) 156 114,202 U.S. Government and agency securities 204,246 (8 ) 67 204,305 373,762 (34 ) 231 373,959 Long-term investments: Certificate of deposit 4,727 — 2 4,729 Corporate bonds 38,582 (35 ) 16 38,563 U.S. Government and agency securities 46,017 (2 ) 36 46,051 89,326 (37 ) 54 89,343 $ 471,840 $ (71 ) $ 286 $ 472,055 December 31, 2018 Cash equivalents: Commercial paper $ 7,775 $ — $ — $ 7,775 7,775 — — 7,775 Short-term investments: Commercial paper 147,860 — — 147,860 Corporate bonds 46,836 (35 ) — 46,801 U.S. Government and agency securities 62,638 (9 ) 12 62,641 257,334 (44 ) 12 257,302 $ 265,109 $ (44 ) $ 12 $ 265,077

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following as of the dates indicated (in thousands): As of Estimated useful lives 2019 2018 Computer equipment (1) 3 years $ 35,190 $ 36,670 Furniture and equipment 2 - 4 years 7,999 6,574 Leasehold improvements (2) Shorter of life of asset or lease term 48,688 10,731 Construction in progress Not applicable 206 551 Building (2) 25 years 66,650 81,892 Website development and internal-use software (3) 3 - 5 years 106,215 69,201 264,948 205,619 Less: Accumulated depreciation and amortization 120,084 85,440 $ 144,864 $ 120,179 (1) Computer equipment includes leased equipment which are accounted for as finance leases since the adoption of ASU 2016-02— Leases in the first quarter of 2019. These leases were previously accounted for as capital leases. (2) In 2014 the Company applied build-to-suit accounting treatment to its headquarters lease in Brooklyn, New York. Upon adoption of ASU 2016-02— Leases in the first quarter of 2019, the Company derecognized the existing facility financing obligation and existing building asset for sale-leaseback transactions that currently do not qualify for sale accounting of $60.0 million and $51.1 million , respectively, and $22.1 million was reclassified from building to leasehold improvements and the Company recognized a new ROU asset of $66.7 million for the associated lease. For more information on the adoption of ASU 2016-02— Leases see “ Note 1—Basis of Presentation and Summary of Significant Accounting Policies .” (3) On August 15, 2019 , the Company acquired Reverb in a business combination, including the developed technology which was recognized at fair value. This amount is included in website development and internal-use software and is amortized on a straight-line basis over a period of 3 years .
Schedule of Capitalized Software Development	The following table summarizes capitalized website development and internal-use software activities during the periods indicated (in thousands): Year Ended 2019 2018 Balance as of the beginning of the period $ 69,201 $ 48,333 Additions to website development 8,687 22,068 Acquisition of developed technology 30,300 — Less: Retirements 1,973 1,200 106,215 69,201 Less: Accumulated amortization balance as of the beginning of the period 38,418 29,991 Amortization Expense 18,737 9,519 Less: Retirements 340 1,092 Accumulated amortization balance as of the end of the period 56,815 38,418 $ 49,400 $ 30,783

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Schedule of Lease Expense, Weighted Averages and Supplemental Cash Flow Information	The elements of lease expense were as follows (in thousands): Year Ended December 31, 2019 Operating lease cost $ 5,405 Finance lease cost: Amortization of right-of-use assets 13,124 Interest on lease liabilities 3,205 Total finance lease cost 16,329 Other lease cost, net (1) 1,149 Total lease cost $ 22,883 (1) Other lease cost, net includes short-term sublease income, short-term lease costs, and variable lease costs, which are immaterial. The following table presents the lease-related assets and liabilities recorded on the Consolidated Balance Sheet (in thousands): As of December 31, 2019 Operating leases: Other assets $ 24,362 Other current liabilities $ 4,134 Other liabilities 22,322 Total operating lease liabilities $ 26,456 Finance leases: Property and equipment, net $ 59,696 Finance lease obligations—current $ 8,275 Finance lease obligations—net of current portion 53,611 Total finance lease liabilities $ 61,886 The following table summarizes the weighted average remaining lease term and weighted average discount rate as of December 31, 2019 : As of December 31, 2019 Weighted average remaining lease term: Operating leases 5.94 years Finance leases 6.37 years Weighted average discount rate: Operating leases 4.26 % Finance leases 4.31 %
Schedule of Cash Flow Activities, Lessee	Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used in operating leases $ (4,889 ) Operating cash flows used in finance leases (3,181 ) Finance cash flows used in finance leases (10,833 )
Schedule of Future Minimum Operating Lease Payments	Future minimum lease payments under non-cancelable leases for the years ending December 31, 2020 , 2021 , 2022 , 2023 , 2024 and thereafter are as follows (in thousands): Operating Leases Finance Leases 2020 $ 5,152 $ 10,805 2021 4,928 11,152 2022 4,942 10,677 2023 4,981 10,599 2024 4,298 10,678 Thereafter 5,688 17,037 Total future minimum lease payments 29,989 70,948 Less imputed interest 3,533 9,062 Total $ 26,456 $ 61,886
Schedule of Future Minimum Finance Lease Payments	Future minimum lease payments under non-cancelable leases for the years ending December 31, 2020 , 2021 , 2022 , 2023 , 2024 and thereafter are as follows (in thousands): Operating Leases Finance Leases 2020 $ 5,152 $ 10,805 2021 4,928 11,152 2022 4,942 10,677 2023 4,981 10,599 2024 4,298 10,678 Thereafter 5,688 17,037 Total future minimum lease payments 29,989 70,948 Less imputed interest 3,533 9,062 Total $ 26,456 $ 61,886
Schedule of Commitments Under Previous Presentation	The following table represents the Company’s commitments under its previous presentation of its capital, operating, and build-to-suit lease agreements as of December 31, 2018 (in thousands): Capital Lease Operating Build-to-Suit Periods ending 2019 $ 4,392 $ 4,904 $ 9,451 2020 1,754 4,783 9,522 2021 481 4,185 10,354 2022 — 4,180 10,520 2023 — 4,205 10,599 Thereafter — 9,760 27,715 Total minimum payments required $ 6,627 $ 32,017 $ 78,161 Amounts representing interest 648 Present value of net minimum payments 5,979 Current maturities 3,884 Long-term payment obligations $ 2,095 December 31, 2019 (in thousands): Purchase Obligations Periods ending 2020 $ 34,153 2021 30,735 2022 32,122 2023 700 2024 — Thereafter — Total purchase obligations $ 97,710

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued expenses consisted of the following as of the dates indicated (in thousands): As of December 31, 2019 2018 Sales and use tax payable $ 39,250 $ 12,242 Vendor accruals 25,760 17,817 Accrued bonus 19,561 12,906 Payroll-related liabilities 3,172 2,406 Accrued vacation 602 3,787 Total accrued expenses $ 88,345 $ 49,158

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Summary of Purchase Obligations	The following table represents the Company’s commitments under its previous presentation of its capital, operating, and build-to-suit lease agreements as of December 31, 2018 (in thousands): Capital Lease Operating Build-to-Suit Periods ending 2019 $ 4,392 $ 4,904 $ 9,451 2020 1,754 4,783 9,522 2021 481 4,185 10,354 2022 — 4,180 10,520 2023 — 4,205 10,599 Thereafter — 9,760 27,715 Total minimum payments required $ 6,627 $ 32,017 $ 78,161 Amounts representing interest 648 Present value of net minimum payments 5,979 Current maturities 3,884 Long-term payment obligations $ 2,095 December 31, 2019 (in thousands): Purchase Obligations Periods ending 2020 $ 34,153 2021 30,735 2022 32,122 2023 700 2024 — Thereafter — Total purchase obligations $ 97,710

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Summary of Activity of Shares Repurchases	The following table summarizes the Company’s cumulative share repurchase activity of the programs noted above, excluding shares withheld to satisfy tax withholding obligations in connection with the vesting of employee restricted stock units and excluding the concurrent stock repurchase with the pricing of the 2019 Notes (in thousands, except share and per share amounts): Shares Repurchased Average Price Paid per Share (1) Value of Shares Repurchased (1) Remaining Amount Authorized New Authorization on November 17, 2017 of $100 million — $ — $ — $ 100,000 Repurchases of common stock for the three months ended: December 31, 2017 586,231 17.57 10,301 (10,301 ) Balance as of December 31, 2017 586,231 17.57 10,301 89,699 Repurchases of common stock for the three months ended: March 31, 2018 2,807,393 24.43 68,586 (68,586 ) June 30, 2018 722,941 29.15 21,113 (21,113 ) September 30, 2018 — — — — New Authorization on November 1, 2018 of $200 million — — — 200,000 Repurchases of common stock for the three months ended: December 31, 2018 916,083 49.11 45,000 (45,000 ) Balance as of December 31, 2018 5,032,648 28.80 145,000 155,000 Repurchases of common stock for the three months ended: March 31, 2019 532,412 51.64 27,500 (27,500 ) June 30, 2019 — — — — September 30, 2019 50,721 55.16 2,798 (2,798 ) December 31, 2019 425,078 52.21 22,202 (22,202 ) Balance as of December 31, 2019 6,040,859 $ 32.68 $ 197,500 $ 102,500 (1) Average price paid per share excludes broker commissions. Value of shares repurchased includes broker commissions.

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The fair value of options granted in each year using the Black-Scholes pricing model has been based on the following assumptions: Year Ended 2019 2018 2017 Volatility 39.1% - 39.5% 38.6% - 47.8% 41.7% - 44.2% Risk-free interest rate 1.6% - 2.5% 2.6% - 2.9% 1.9% - 2.2% Expected term (in years) 5.5 - 6.2 5.5 - 6.3 5.5 - 6.3 Dividend rate —% —% —%
Schedule of Share-based Compensation, Stock Options, Activity	The following table summarizes the activity for the Company’s options (in thousands, except share and per share amounts): Shares Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2016 9,339,567 $ 7.89 6.64 $ 43,613 Granted 5,887,183 11.04 Exercised (5,760,263 ) 5.87 Forfeited/Canceled (1,518,548 ) 11.36 Outstanding at December 31, 2017 7,947,939 11.02 7.93 74,996 Granted 797,201 29.87 Exercised (1,588,779 ) 11.49 Forfeited/Canceled (265,367 ) 15.68 Outstanding at December 31, 2018 6,890,994 12.91 7.94 239,177 Granted 462,563 64.29 Exercised (840,835 ) 11.64 Forfeited/Canceled (217,803 ) 30.11 Outstanding at December 31, 2019 6,294,919 16.26 7.24 185,900 Total exercisable at December 31, 2019 3,835,279 12.30 6.88 123,671
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	The following table summarizes the weighted-average grant date fair value of options granted, intrinsic value of options exercised and fair value of awards vested in periods indicated (in thousands, except per share amounts): Year Ended December 31, 2019 2018 2017 Weighted average grant date fair value of options granted $ 26.75 $ 13.33 $ 4.85 Intrinsic value of options exercised 42,758 34,268 52,693 Fair value of awards vested 41,997 32,717 19,826
Summary of the Activity of Unvested RSUs	The following table summarizes the activity for the Company’s unvested RSUs: Shares Weighted-Average Unvested at December 31, 2016 3,135,181 $ 10.70 Granted 2,360,315 12.17 Vested (1,072,321 ) 10.44 Forfeited/Canceled (1,348,928 ) 10.56 Unvested at December 31, 2017 3,074,247 11.98 Granted 2,448,169 28.22 Vested (1,496,906 ) 13.80 Forfeited/Canceled (545,142 ) 18.47 Unvested at December 31, 2018 3,480,368 22.87 Granted 1,464,785 61.92 Vested (1,392,295 ) 22.67 Forfeited/Canceled (592,445 ) 31.25 Unvested at December 31, 2019 2,960,413 40.61
Schedule of Share-based Compensation, Allocation of Recognized Period Costs	Total stock-based compensation expense included in the Consolidated Statements of Operations is as follows (in thousands): Year Ended 2019 2018 2017 Cost of revenue $ 5,787 $ 3,357 $ 1,739 Marketing 3,774 2,507 1,933 Product development 21,085 21,234 8,274 General and administrative 13,749 11,133 14,613 Total stock-based compensation expense $ 44,395 $ 38,231 $ 26,559

Restructuring and Other Exit _2

Restructuring and Other Exit Costs (Income) (Tables)	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Reserve by Type of Cost	The following table displays restructuring and other exit costs (income) recorded related to the Actions and a rollforward of the charges to the accrued expenses balance as of December 31, 2019 (in thousands): Severance Charge Stock-Based Compensation Other Exit Costs Total Balance, December 31, 2016 $ — $ — $ — $ — Total restructuring and other exit costs 10,204 2,701 992 13,897 Costs charged against equity/assets — (2,701 ) (286 ) (2,987 ) Cash payments (8,896 ) — (672 ) (9,568 ) Balance, December 31, 2017 1,308 — 34 1,342 Total restructuring and other exit income (244 ) — (5 ) (249 ) Cash payments (1,064 ) — (29 ) (1,093 ) Balance, December 31, 2018 — — — — Balance, December 31, 2019 $ — $ — $ — $ —
Restructuring and Related Costs	Total restructuring and other exit costs (income) included in the Consolidated Statements of Operations are as follows (in thousands): Year Ended 2019 2018 2017 Cost of revenue $ — $ (19 ) $ 738 Marketing — (82 ) 2,950 Product development — (110 ) 3,232 General and administrative — (38 ) 6,977 Total restructuring and other exit costs (income) $ — $ (249 ) $ 13,897

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Reclassifications (Details) - Revenue - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other revenue
Disaggregation of Revenue [Line Items]
Prior period reclassification adjustment	$ 4	$ 3.3
Marketplace revenue
Disaggregation of Revenue [Line Items]
Prior period reclassification adjustment	$ (4)	$ (3.3)

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details)	5 Months Ended	12 Months Ended	18 Months Ended
	Dec. 31, 2019platform	Dec. 31, 2019USD ($)platform	Dec. 31, 2019platform	Jul. 15, 2018
Marketplace Revenue
Disaggregation of Revenue [Line Items]
Listing fee per item | $		$ 0.20
Period over which listing fee is recognized		4 months
Fee for each completed transaction, percent			5.00%	3.50%
Services
Disaggregation of Revenue [Line Items]
Number of unified ad platforms | platform	1	1	1
Minimum | Marketplace Revenue
Disaggregation of Revenue [Line Items]
Direct checkout fees, percent		3.00%
Maximum | Marketplace Revenue
Disaggregation of Revenue [Line Items]
Direct checkout fees, percent		4.50%
Reverb Holdings Inc. | Marketplace Revenue
Disaggregation of Revenue [Line Items]
Fee for each completed transaction, percent	3.50%
Reverb Holdings Inc. | Minimum | Marketplace Revenue
Disaggregation of Revenue [Line Items]
Direct checkout fees, percent		2.50%
Reverb Holdings Inc. | Maximum | Marketplace Revenue
Disaggregation of Revenue [Line Items]
Direct checkout fees, percent		2.70%

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Marketing (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Advertising expense	$ 175.2	$ 129.1	$ 78.4

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies - Stock-Based Compensation (Details)	12 Months Ended
	Dec. 31, 2019
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award requisite service period	4 years
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award requisite service period	4 years

Basis of Presentation and Sum_8

Basis of Presentation and Summary of Significant Accounting Policies - Net Income (Loss) Per Share (Details) - Convertible Debt	Sep. 30, 2019	Mar. 31, 2018
Convertible Senior Notes due 2026
Debt Instrument [Line Items]
Interest rate percentage	0.125%
Convertible Senior Notes due 2023
Debt Instrument [Line Items]
Interest rate percentage		0.00%

Basis of Presentation and Sum_9

Basis of Presentation and Summary of Significant Accounting Policies - Segment Data (Details)	12 Months Ended
	Dec. 31, 2019segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	2
Number of reportable segments	1

Basis of Presentation and Su_10

Basis of Presentation and Summary of Significant Accounting Policies - Cash, Cash Equivalents and Short- and Long-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 443,293	$ 366,985	$ 315,442	$ 181,592
Short-term investments	373,959	257,302
Long-term investments	89,343	0
Total cash, cash equivalents, and short- and long-term investments	$ 906,595	$ 624,287

Basis of Presentation and Su_11

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Allowance Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of the beginning of period	$ 4,720	$ 2,687	$ 1,999
Bad debt expense	10,963	4,124	2,497
Write-offs, net of recoveries and other adjustments	(10,650)	(2,091)	(1,809)
Balance as of the end of period	$ 5,033	$ 4,720	$ 2,687

Basis of Presentation and Su_12

Basis of Presentation and Summary of Significant Accounting Policies - Website Development and Internal-use Software Costs (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Asset impairment charges	$ 0	$ 0	$ 3,162,000
Developed technology
Property, Plant and Equipment [Line Items]
Asset impairment charges	$ 0	$ 0	$ 3,200,000
Developed technology | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Developed technology | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years

Basis of Presentation and Su_13

Basis of Presentation and Summary of Significant Accounting Policies - Goodwill (Details)	12 Months Ended
	Dec. 31, 2019USD ($)unitsegment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	2
Number of reportable segments	1
Number of reporting units | unit	2
Goodwill impairment | $	$ 0	$ 0	$ 0

Basis of Presentation and Su_14

Basis of Presentation and Summary of Significant Accounting Policies - Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 0	$ 0	$ 0
Technology
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life	3 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life	15 years
Trademark
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life	15 years
Referral Agreement
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life	10 years

Basis of Presentation and Su_15

Basis of Presentation and Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset		$ 24,362
Operating lease, liability		26,456
Derecognized existing facility financing obligation		0	$ (59,991)
Property and equipment, net reclassified			$ (120,179)
Property and equipment, net		59,696
Finance lease, liability		$ 61,886
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	$ 25,400
Operating lease, liability	27,800
Derecognized existing facility financing obligation	60,000
Property and equipment, net reclassified	51,100
Cumulative effect of new accounting principle in period of adoption, gain recognized	9,300
Cumulative effect of new accounting principle in period of adoption, tax impact	(2,200)
Cumulative effect adjustment related to the adoption of the leasing standard	7,116
Property and equipment, net	66,700
Accounting Standards Update 2016-02 | Building
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property and equipment, net reclassified	22,100
Accounting Standards Update 2016-02 | Leasehold improvements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property and equipment, net reclassified	(22,100)
Finance lease, liability	66,700
Accumulated Deficit | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment related to the adoption of the leasing standard	$ 7,116

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 818,379	$ 603,693	$ 441,231
Marketplace revenue
Disaggregation of Revenue [Line Items]
Revenue	593,646	444,765	329,362
Services revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 224,733	$ 158,928	$ 111,869

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 7,617	$ 7,478
Revenue recognized in the period	$ 7,500
Marketplace Revenue
Disaggregation of Revenue [Line Items]
Period over which listing fee is recognized	4 months

Income Taxes - Domestic and For

Income Taxes - Domestic and Foreign Components of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Domestic	$ 14,544	$ 36,157	$ (16,583)
Foreign	66,102	18,921	48,848
Income before income taxes	$ 80,646	$ 55,078	$ 32,265

Income Taxes - Income Tax Benef

Income Taxes - Income Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ (3,967)	$ 709	$ (6,397)
State	1,053	(578)	79
Foreign	352	600	476
Total current	(2,562)	731	(5,842)
Deferred:
Federal	(19,734)	(3,343)	(34,948)
State	(1,564)	3,496	(8,778)
Foreign	8,612	(23,297)	33
Total deferred	(12,686)	(23,144)	(43,693)
Total income tax benefit	$ (15,248)	$ (22,413)	$ (49,535)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax benefit	$ 15,248	$ 22,413	$ 49,535
Effective income tax rate	(18.90%)	(40.70%)	(153.50%)
Effective income tax rate reconciliation, at federal statutory income tax rate, percent	21.00%	21.00%	35.00%
Net provisional income tax benefit associated with TCJA	$ (4,197)	$ 3,897	$ (31,063)
Net operating loss carryforwards	19,599	13,347
Research and development credit carryforwards	13,133	7,567
Deferred tax assets valuation allowance	883	1,673
Deferred tax assets considered realizable	69,738	41,409
Deferred tax assets, more likely than not to be utilized		23,400
Unrecognized tax benefits	19,933	18,819	$ 17,013	$ 23,574
Unrecognized tax benefits that would impact effective tax rate favorably	19,400
Income tax penalties and interest expense	(100)	300
Income tax penalties and interest accrued	$ 200	$ 500

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of the Income Tax Benefit at the U.S. Federal Statutory Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax provision at the federal statutory rate	$ 16,936	$ 11,566	$ 11,308
State and local income taxes net of federal benefit	973	3,839	(691)
Foreign income tax rate differential	(5,454)	(298)	(11,878)
Stock-based compensation	(16,281)	(11,717)	(12,584)
Research and development credit	(9,864)	(4,115)	(1,098)
U.S. tax reform	(4,197)	3,897	(31,063)
Non-deductible expenses	1,784	(329)	168
Uncertain tax positions	380	382	789
Change in valuation allowance	0	(28,733)	(4,673)
Return to provision adjustment	500	3,293	167
Other	(25)	(198)	20
Total income tax benefit	$ (15,248)	$ (22,413)	$ (49,535)

Income Taxes - Significant Comp

Income Taxes - Significant Component of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 19,599	$ 13,347
Research and development credit carryforwards	13,133	7,567
Lease liability	18,666	0
Stock-based compensation expense	7,642	6,623
Excess tax basis in intangible assets	3,572	12,109
Accrued bonus	4,065	1,049
Deferred rent	0	529
Other deferred tax assets	3,944	1,858
Total deferred tax assets	70,621	43,082
Less: valuation allowance	883	1,673
Total net deferred tax asset	69,738	41,409
Deferred tax liabilities:
Excess book basis in intangible assets	(39,500)	(362)
Restructuring liability	(29,635)	(33,730)
Convertible debt	(22,839)	(7,283)
Right-of-use asset	(17,596)	0
Depreciation	(10,328)	(6,933)
Other deferred tax liabilities	(80)	(92)
Total deferred tax liabilities	(119,978)	(48,400)
Net deferred tax liabilities	$ (50,240)	$ (6,991)

Income Taxes - Summary of Tax C

Income Taxes - Summary of Tax Credit Carryforwards and Operating Loss Carryforwards (Details) $ in Thousands	Dec. 31, 2019USD ($)
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 30,403
Tax credit carryforwards	13,054
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	21,150
Tax credit carryforwards	184
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 91,440

Income Taxes - Summary of Valua

Income Taxes - Summary of Valuation Allowance Activity (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance as of the beginning of period	$ 1,673	$ 32,455	$ 13,839
Additions charged to expense	504	0	16,743
Deletions credited to expense	(4)	(28,733)	0
Currency translation and other balance sheet activity	(1,290)	(2,049)	1,873
Balance as of the end of period	$ 883	$ 1,673	$ 32,455

Income Taxes - Summary of Unrec

Income Taxes - Summary of Unrecognized Tax Benefits Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of the beginning of period	$ 18,819	$ 17,013	$ 23,574
Additions based on tax positions related to the current year	1,847	921	732
Additions for tax positions of prior years	3,620	946	118
Reductions for tax provisions of prior years	(2,423)	(61)	(7,411)
Lapse of Statute of Limitation	(184)	0	0
Additions recorded through goodwill as part of business combination	1,334	0	0
Settlements	(3,080)	0	0
Balance as of the end of period	$ 19,933	$ 18,819	$ 17,013

Net Income Per Share - Calculat

Net Income Per Share - Calculation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net income	$ 95,894	$ 77,491	$ 81,800
Net income allocated to participating securities under the two-class method	0	(37)	(80)
Net income attributable to common stockholders—basic	95,894	77,454	81,720
Dilutive effect of net income allocated to participating securities under the two-class method	0	37	80
Change in fair value of liability classified restricted stock	0	0	771
Net income attributable to common stockholders—diluted	$ 95,894	$ 77,491	$ 82,571
Denominator:
Weighted average common shares outstanding—basic (in shares)	119,665,248	120,146,076	118,538,687
Weighted average common shares outstanding—diluted (in shares)	125,720,073	127,084,785	122,267,673
Net (loss) income per share attributable to common stockholders—basic (in shares)	$ 0.80	$ 0.64	$ 0.69
Net (loss) income per share attributable to common stockholders—diluted (in shares)	$ 0.76	$ 0.61	$ 0.68
Anti-dilutive securities excluded from computation of earnings per share (in shares)	10,535,628	612,236	5,338,022
Common Stock
Denominator:
Dilutive effect of assumed conversion (in shares)	4,516,413	4,238,622	2,498,448
Restricted stock units
Denominator:
Dilutive effect of assumed conversion (in shares)	1,521,719	1,721,658	1,177,799
Convertible senior notes
Denominator:
Dilutive effect of assumed conversion of convertible debt (2)	0	900,580	0
Restricted Stock
Denominator:
Dilutive effect of assumed conversion (in shares)	16,693	77,849	52,739
Participating Securities
Denominator:
Anti-dilutive securities excluded from computation of earnings per share (in shares)		57,482	114,963

Net Income Per Share - Summary

Net Income Per Share - Summary of Shares Excluded from the Calculation of Diluted Net Income Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share (in shares)	10,535,628	612,236	5,338,022
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share (in shares)	317,401	475,238	4,902,664
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share (in shares)	706,234	136,998	435,358
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share (in shares)	9,511,993	0	0

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($) $ in Thousands	Aug. 15, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired			$ 270,409	$ 0	$ 0
Revenue			818,379	603,693	441,231
Net loss			(95,894)	(77,491)	$ (81,800)
Reverb Holdings Inc.
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired	$ 270,400
Revenue		$ 19,100
Net loss		$ 9,900
Acquisition-related expenses			3,900
Non-recurring acquisition-related expenses			88,595	53,587
Acquisition-related Costs | Reverb Holdings Inc.
Business Acquisition [Line Items]
Non-recurring acquisition-related expenses			$ 6,100	$ 2,000

Business Combinations - Purchas

Business Combinations - Purchase Price Allocation (Details) - USD ($) $ in Thousands	5 Months Ended
	Dec. 31, 2019	Aug. 15, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value Estimate
Goodwill	$ 138,731		$ 37,482	$ 38,541
Reverb Holdings Inc.
Fair Value Estimate
Short-term investments	1,028	$ 1,028
Other current assets	2,902	6,442
Funds receivable and seller accounts	5,578	5,578
Finite-lived intangibles		172,900
Goodwill	101,703	102,039
Other assets	6,743	3,225
Other net working capital	(208)	(208)
Funds payable and amounts due to sellers	(5,578)	(5,578)
Other current liabilities	(3,684)	(8,520)
Other liabilities	(7,333)	(2,497)
Deferred tax liability, net	(35,485)	(34,898)
Total purchase price	270,409	271,354
Measurement Period Adjustments
Short-term investments	0
Other current assets	(3,540)
Funds receivable and seller accounts	0
Goodwill	(336)
Other assets	3,518
Other net working capital	0
Funds payable and amounts due to sellers	0
Other current liabilities	4,836
Other liabilities	(4,836)
Deferred tax liability, net	(587)
Total purchase price	(945)
Reverb Holdings Inc. | Trademark
Fair Value Estimate
Finite-lived intangibles	79,400	79,400
Measurement Period Adjustments
Finite-lived intangibles	0
Reverb Holdings Inc. | Customer relationships
Fair Value Estimate
Finite-lived intangibles	93,500	93,500
Measurement Period Adjustments
Finite-lived intangibles	0
Property and equipment other | Reverb Holdings Inc.
Fair Value Estimate
Property and equipment	1,543	1,543
Measurement Period Adjustments
Property and equipment other	0
Developed technology | Reverb Holdings Inc.
Fair Value Estimate
Property and equipment	30,300	$ 30,300
Measurement Period Adjustments
Property and equipment other	$ 0

Business Combinations - Unaudit

Business Combinations - Unaudited Supplemental Pro Forma Information (Details) - Reverb Holdings Inc. - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Revenue	$ 847,154	$ 639,743
Net income	$ 88,595	$ 53,587

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Summary of Changes in the Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Balance as of the beginning of the period	$ 37,482	$ 38,541
Business combination	101,703	0
Foreign currency translation adjustments	(454)	(1,059)
Balance as of the end of the period	$ 138,731	$ 37,482

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details)	5 Months Ended	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2019USD ($)unitsegment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Aug. 15, 2019USD ($)
Finite-Lived Intangible Assets [Line Items]
Number of operating segments | segment		2
Number of reportable segments | segment		1
Number of reporting units | unit		2
Goodwill impairment		$ 0	$ 0	$ 0
Amortization expense of intangible assets		9,600,000	4,300,000	3,400,000
Impairment of intangible assets		$ 0	$ 0	$ 0
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life		15 years
Trademark
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life		15 years
Referral agreement
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life		10 years
Reverb Holdings Inc.
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles					$ 172,900,000
Reverb Holdings Inc. | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles	$ 93,500,000	$ 93,500,000			93,500,000
Acquired intangible asset, useful life	15 years
Reverb Holdings Inc. | Trademark
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles	$ 79,400,000	$ 79,400,000			$ 79,400,000
Acquired intangible asset, useful life	15 years

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross book value	$ 217,559	$ 42,695
Accumulated amortization	(16,967)	(7,394)
Foreign currency translation	(1,356)	(712)
Net book value	199,236	34,589
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross book value	93,500	0
Accumulated amortization	(2,338)	0
Foreign currency translation	0	0
Net book value	91,162	0
Trademark
Finite-Lived Intangible Assets [Line Items]
Gross book value	79,400	0
Accumulated amortization	(1,985)	0
Foreign currency translation	0	0
Net book value	77,415	0
Referral agreement
Finite-Lived Intangible Assets [Line Items]
Gross book value	37,127	35,323
Accumulated amortization	(5,417)	(1,890)
Foreign currency translation	(1,356)	(712)
Net book value	30,354	32,721
Technology
Finite-Lived Intangible Assets [Line Items]
Gross book value	7,200	7,200
Accumulated amortization	(7,200)	(5,500)
Foreign currency translation	0	0
Net book value	0	1,700
Patent licenses
Finite-Lived Intangible Assets [Line Items]
Gross book value	332	172
Accumulated amortization	(27)	(4)
Foreign currency translation	0	0
Net book value	$ 305	$ 168

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Summary of Future Amortization Expense for Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 15,148
2021	15,148
2022	15,148
2023	15,148
2024	15,148
Thereafter	123,496
Net book value	$ 199,236	$ 34,589

Segment and Geographic Inform_3

Segment and Geographic Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment	2
Number of reportable segments | segment	1
Revenue, Major Customer [Line Items]
Revenue	$ 818,379	$ 603,693	$ 441,231
(Loss) income before income taxes	80,646	55,078	32,265
Net income	95,894	77,491	81,800
United States
Revenue, Major Customer [Line Items]
Revenue	550,257	422,523	317,755
(Loss) income before income taxes	(23,702)	7,460	(43,014)
Net income	510	7,175	7,029
International
Revenue, Major Customer [Line Items]
Revenue	268,122	181,170	123,476
(Loss) income before income taxes	104,348	47,618	75,279
Net income	$ 95,384	$ 70,316	$ 74,771

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Major Categories of Assets and Liabilities Measured at Fair Value 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]
Short-term investments	$ 373,959	$ 257,302
Long-term investments	89,343	0
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	237,612	252,631
Short-term investments	373,959	257,302
Funds receivable and seller accounts	18,168	9,229
Long-term investments	89,343
Asset	719,082	519,162
Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	5,794	7,775
Short-term investments	29,320	147,860
Recurring | Certificate of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,959
Short-term investments	26,132
Long-term investments	4,729
Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	228,859	244,856
Funds receivable and seller accounts	18,168	9,229
Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	114,202	46,801
Long-term investments	38,563
Recurring | U.S. Government and agency bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	204,305	62,641
Long-term investments	46,051
Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	228,859	244,856
Short-term investments	204,305	62,641
Funds receivable and seller accounts	18,168	9,229
Long-term investments	46,051
Asset	497,383	316,726
Level 1 | Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term investments	0	0
Level 1 | Recurring | Certificate of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
Short-term investments	0
Long-term investments	0
Level 1 | Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	228,859	244,856
Funds receivable and seller accounts	18,168	9,229
Level 1 | Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0
Level 1 | Recurring | U.S. Government and agency bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	204,305	62,641
Long-term investments	46,051
Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	8,753	7,775
Short-term investments	169,654	194,661
Funds receivable and seller accounts	0	0
Long-term investments	43,292
Asset	221,699	202,436
Level 2 | Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	5,794	7,775
Short-term investments	29,320	147,860
Level 2 | Recurring | Certificate of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,959
Short-term investments	26,132
Long-term investments	4,729
Level 2 | Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Funds receivable and seller accounts	0	0
Level 2 | Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	114,202	46,801
Long-term investments	38,563
Level 2 | Recurring | U.S. Government and agency bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0
Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term investments	0	0
Funds receivable and seller accounts	0	0
Long-term investments	0
Asset	0	0
Level 3 | Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term investments	0	0
Level 3 | Recurring | Certificate of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
Short-term investments	0
Long-term investments	0
Level 3 | Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Funds receivable and seller accounts	0	0
Level 3 | Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Long-term investments	0
Level 3 | Recurring | U.S. Government and agency bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	$ 0
Long-term investments	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - Reported Value Measurement - Convertible Debt - Level 2 - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Convertible Senior Notes due 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value	$ 310.3	$ 279.1
Convertible Senior Notes due 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value	$ 522.2

Marketable Securities (Details)

Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Cost	$ 471,840	$ 265,109
Gross Unrealized Holding Loss	(71)	(44)
Gross Unrealized Holding Gain	286	12
Fair Value	472,055	265,077
Short-term Investments
Debt Securities, Available-for-sale [Line Items]
Cost	373,762	257,334
Gross Unrealized Holding Loss	(34)	(44)
Gross Unrealized Holding Gain	231	12
Fair Value	373,959	257,302
Short-term Investments | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cost	29,319	147,860
Gross Unrealized Holding Loss	(1)	0
Gross Unrealized Holding Gain	2	0
Fair Value	29,320	147,860
Short-term Investments | Certificate of deposit
Debt Securities, Available-for-sale [Line Items]
Cost	26,129
Gross Unrealized Holding Loss	(3)
Gross Unrealized Holding Gain	6
Fair Value	26,132
Short-term Investments | Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Cost	114,068	46,836
Gross Unrealized Holding Loss	(22)	(35)
Gross Unrealized Holding Gain	156	0
Fair Value	114,202	46,801
Short-term Investments | U.S. Government and agency securities
Debt Securities, Available-for-sale [Line Items]
Cost	204,246	62,638
Gross Unrealized Holding Loss	(8)	(9)
Gross Unrealized Holding Gain	67	12
Fair Value	204,305	62,641
Long-term Investments
Debt Securities, Available-for-sale [Line Items]
Cost	89,326
Gross Unrealized Holding Loss	(37)
Gross Unrealized Holding Gain	54
Fair Value	89,343
Long-term Investments | Certificate of deposit
Debt Securities, Available-for-sale [Line Items]
Cost	4,727
Gross Unrealized Holding Loss	0
Gross Unrealized Holding Gain	2
Fair Value	4,729
Long-term Investments | Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Cost	38,582
Gross Unrealized Holding Loss	(35)
Gross Unrealized Holding Gain	16
Fair Value	38,563
Long-term Investments | U.S. Government and agency securities
Debt Securities, Available-for-sale [Line Items]
Cost	46,017
Gross Unrealized Holding Loss	(2)
Gross Unrealized Holding Gain	36
Fair Value	46,051
Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Cost	8,752	7,775
Gross Unrealized Holding Loss	0	0
Gross Unrealized Holding Gain	1	0
Fair Value	8,753	7,775
Cash Equivalents | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Cost	5,794	7,775
Gross Unrealized Holding Loss	0	0
Gross Unrealized Holding Gain	0	0
Fair Value	5,794	$ 7,775
Cash Equivalents | Certificate of deposit
Debt Securities, Available-for-sale [Line Items]
Cost	2,958
Gross Unrealized Holding Loss	0
Gross Unrealized Holding Gain	1
Fair Value	$ 2,959

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	5 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 264,948	$ 264,948
Property and equipment, gross				$ 205,619
Less: Accumulated depreciation and amortization	120,084	120,084
Less: Accumulated depreciation and amortization				85,440
Property and equipment, net	144,864	144,864
Property and equipment, net				120,179
Derecognized existing facility financing obligation	0	0		(59,991)
Property and equipment, net	$ 59,696	$ 59,696
Computer equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives		3 years
Lessee, finance lease, term of contract	3 years	3 years
Property and equipment, gross	$ 35,190	$ 35,190
Property and equipment, gross				36,670
Property and equipment, net	30,400	30,400
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,999	$ 7,999
Property and equipment, gross				6,574
Furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives		2 years
Furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives		4 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	48,688	$ 48,688
Property and equipment, gross				10,731
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 206	$ 206
Property and equipment, gross				551
Building
Property, Plant and Equipment [Line Items]
Lessee, finance lease, term of contract	25 years	25 years
Property and equipment, gross	$ 66,650	$ 66,650
Property and equipment, gross				81,892
Website development and internal-use software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	106,215	106,215
Property and equipment, gross	106,215	106,215		69,201	$ 48,333
Less: Accumulated depreciation and amortization	56,815	56,815		38,418	$ 29,991
Property and equipment, net	$ 49,400	$ 49,400		$ 30,783
Website development and internal-use software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives		3 years
Website development and internal-use software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives		5 years
Accounting Standards Update 2016-02
Property, Plant and Equipment [Line Items]
Property and equipment, net			$ (51,100)
Derecognized existing facility financing obligation			60,000
Property and equipment, net			66,700
Accounting Standards Update 2016-02 | Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, net			22,100
Accounting Standards Update 2016-02 | Building
Property, Plant and Equipment [Line Items]
Property and equipment, net			$ (22,100)
Reverb Holdings Inc. | Website development and internal-use software
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Property and equipment, gross	$ 30,300	$ 30,300
Less: Accumulated depreciation and amortization	$ 3,800	$ 3,800
Acquired intangible asset, useful life	3 years

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($)	5 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation		$ 38,400,000	$ 22,400,000	$ 23,800,000
Amortization expense for equipment acquired under finance leases		13,124,000
Gross balance of leased equipment	$ 59,696,000	59,696,000
Property and equipment, gross			205,619,000
Accumulated amortization			85,440,000
Asset impairment charges		0	0	3,162,000
Developed technology
Property, Plant and Equipment [Line Items]
Amortization expense		18,737,000	9,519,000	8,200,000
Loss on write-off of retired website development and internal-use software		1,600,000	100,000	300,000
Property and equipment, gross	106,215,000	106,215,000	69,201,000	48,333,000
Accumulated amortization	56,815,000	56,815,000	38,418,000	29,991,000
Asset impairment charges		0	0	3,200,000
Computer equipment
Property, Plant and Equipment [Line Items]
Amortization expense for equipment acquired under finance leases		4,300,000
Amortization expense for equipment acquired under capital leases			5,900,000	$ 7,700,000
Gross balance of leased equipment	30,400,000	30,400,000
Gross balance of leased equipment			29,700,000
Accumulated amortization of equipment under finance leases	28,500,000	$ 28,500,000
Accumulated amortization of equipment under capital leases			24,400,000
Property and equipment, gross			$ 36,670,000
Estimated useful lives		3 years
Reverb Holdings Inc. | Developed technology
Property, Plant and Equipment [Line Items]
Amortization expense		$ 3,800,000
Property and equipment, gross	30,300,000	30,300,000
Accumulated amortization	$ 3,800,000	$ 3,800,000
Estimated useful lives	3 years

Property and Equipment - Summ_2

Property and Equipment - Summary of Capitalized Website Development and Internal-Use Software Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement in Capitalized Computer Software, Net [Roll Forward]
Balance as of the beginning of the period	$ 205,619
Balance as of the end of the period		$ 205,619
Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]
Accumulated amortization balance as of the beginning of the period	85,440
Accumulated amortization balance as of the end of the period		85,440
Property and equipment, net		120,179
Developed technology
Movement in Capitalized Computer Software, Net [Roll Forward]
Balance as of the beginning of the period	69,201	48,333
Additions to website development	8,687	22,068
Acquisition of developed technology	30,300	0
Less: Retirements	1,973	1,200
Balance as of the end of the period	106,215	69,201	$ 48,333
Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]
Accumulated amortization balance as of the beginning of the period	38,418	29,991
Amortization Expense	18,737	9,519	8,200
Less: Retirements	340	1,092
Accumulated amortization balance as of the end of the period	56,815	38,418	$ 29,991
Property and equipment, net	$ 49,400	$ 30,783

Leases - Narrative (Details)

Leases - Narrative (Details)	Dec. 31, 2019USD ($)ft²
Corporate Headquarters
Lessee, Lease, Description [Line Items]
Area of real estate property (in sqft) | ft²	225,135
Lessee, finance lease, term of contract	25 years
Lease Arrangements, Hosting | DFS
Lessee, Lease, Description [Line Items]
Lessee, finance lease, term of contract	36 months
Lessee, finance lease, discount rate	0.00%
Lessee, finance lease, buy-out option, amount	$ 1
Lease Arrangements, Hosting and Computer Equipment | ePlus
Lessee, Lease, Description [Line Items]
Lessee, finance lease, term of contract	36 months
Lessee, finance lease, buy-out option, amount	$ 1
Lease Arrangements, Hosting and Computer Equipment | ePlus | Minimum
Lessee, Lease, Description [Line Items]
Lessee, finance lease, discount rate	3.71%
Lease Arrangements, Hosting and Computer Equipment | ePlus | Maximum
Lessee, Lease, Description [Line Items]
Lessee, finance lease, discount rate	6.94%

Leases - Elements of Lease Expe

Leases - Elements of Lease Expense (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 5,405
Finance lease cost:
Amortization of right-of-use assets	13,124
Interest on lease liabilities	3,205
Total finance lease cost	16,329
Other lease income, net	1,149
Total lease cost	$ 22,883

Leases - Lease-related Assets a

Leases - Lease-related Assets and Liabilities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Operating leases:
Other assets	$ 24,362
Other current liabilities	4,134
Other liabilities	22,322
Total operating lease liabilities	26,456
Finance leases:
Property and equipment, net	59,696
Finance lease obligations—current	8,275
Finance lease obligations—net of current portion	53,611
Total finance lease liabilities	$ 61,886

Leases - Weighted Average Remai

Leases - Weighted Average Remaining Lease Term and Weighted Average Discount Rate (Details)	Dec. 31, 2019
Leases [Abstract]
Weighted average remaining lease term, operating leases	5 years 11 months 8 days
Weighted average remaining lease term, finance leases	6 years 4 months 13 days
Weighted average discount rate, operating leases	4.26%
Weighted average discount rate, finance leases	4.31%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating cash flows used in operating leases	$ (4,889)
Operating cash flows used in finance leases	(3,181)
Finance cash flows used in finance leases	$ (10,833)

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments Under Non-cancelable Leases (Details) $ in Thousands	Dec. 31, 2019USD ($)
Operating Leases
2020	$ 5,152
2021	4,928
2022	4,942
2023	4,981
2024	4,298
Thereafter	5,688
Total future minimum lease payments	29,989
Less imputed interest	3,533
Total operating lease liabilities	26,456
Finance Leases
2020	10,805
2021	11,152
2022	10,677
2023	10,599
2024	10,678
Thereafter	17,037
Total future minimum lease payments	70,948
Less imputed interest	9,062
Total finance lease liabilities	$ 61,886

Leases - Commitments Under Prev

Leases - Commitments Under Previous Presentation (Details) $ in Thousands	Dec. 31, 2018USD ($)
Capital Lease Obligations
2019	$ 4,392
2020	1,754
2021	481
2022	0
2023	0
Thereafter	0
Total minimum payments required	6,627
Amounts representing interest	648
Present value of net minimum payments	5,979
Current maturities	3,884
Long-term payment obligations	2,095
Operating Leases
2019	4,904
2020	4,783
2021	4,185
2022	4,180
2023	4,205
Thereafter	9,760
Total minimum payments required	32,017
Build-to-Suit Lease
2019	9,451
2020	9,522
2021	10,354
2022	10,520
2023	10,599
Thereafter	27,715
Total minimum payments required	$ 78,161

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Sales and use tax payable	$ 39,250	$ 12,242
Vendor accruals	25,760	17,817
Accrued bonus	19,561	12,906
Payroll-related liabilities	3,172	2,406
Accrued vacation	602	3,787
Total accrued expenses	$ 88,345	$ 49,158

Debt - 2019 Convertible Debt (D

Debt - 2019 Convertible Debt (Details)	1 Months Ended		12 Months Ended
	Sep. 30, 2019USD ($)day$ / shares	Mar. 31, 2018USD ($)day$ / shares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Non-cash interest expense			$ 19,108,000	$ 10,968,000	$ 3,117,000
Convertible Debt | Convertible Senior Notes due 2026
Debt Instrument [Line Items]
Debt instrument	$ 650,000,000
Interest rate, stated percentage	0.125%
Proceeds from issuance of convertible senior notes	$ 639,500,000
Conversion ratio	0.0114040
Conversion price (in dollars per share) | $ / shares	$ 87.69
If-converted value lower than principal			321,600,000
If-converted value			328,400,000
Redemption price, percentage	100.00%
Carrying amount of equity component			154,000,000
Capitalization of debt issuance costs			10,500,000
Non-cash interest expense			5,600,000
Unamortized debt issuance expense			7,800,000
Convertible Debt | Convertible Senior Notes due 2023
Debt Instrument [Line Items]
Debt instrument		$ 345,000,000
Interest rate, stated percentage		0.00%
Proceeds from issuance of convertible senior notes		$ 335,000,000
Conversion ratio		27.5691
Conversion price (in dollars per share) | $ / shares		$ 36.27
Redemption price, percentage		100.00%
Carrying amount of equity component			72,800,000
Capitalization of debt issuance costs		$ 10,000,000
Non-cash interest expense			15,200,000	12,200,000
Unamortized debt issuance expense			5,200,000	6,700,000
Reported Value Measurement | Level 2 | Convertible Debt | Convertible Senior Notes due 2026
Debt Instrument [Line Items]
Long-term debt, fair value			522,200,000
Reported Value Measurement | Level 2 | Convertible Debt | Convertible Senior Notes due 2023
Debt Instrument [Line Items]
Long-term debt, fair value			$ 310,300,000	$ 279,100,000
Debt Instrument, Redemption, Period One | Convertible Debt | Convertible Senior Notes due 2026
Debt Instrument [Line Items]
Threshold trading days | day	20
Threshold consecutive trading days | day	30
Threshold percentage of stock price trigger	130.00%
Debt Instrument, Redemption, Period One | Convertible Debt | Convertible Senior Notes due 2023
Debt Instrument [Line Items]
Threshold trading days | day		20
Threshold consecutive trading days | day		30
Threshold percentage of stock price trigger		130.00%
Debt Instrument, Redemption, Period Two | Convertible Debt | Convertible Senior Notes due 2026
Debt Instrument [Line Items]
Threshold consecutive trading days | day	10
Threshold percentage of stock price trigger	98.00%
Threshold business days | day	5
Debt Instrument, Redemption, Period Two | Convertible Debt | Convertible Senior Notes due 2023
Debt Instrument [Line Items]
Threshold consecutive trading days | day		10
Threshold percentage of stock price trigger		98.00%

Debt - 2019 Capped Call Transac

Debt - 2019 Capped Call Transactions (Details) - Convertible Debt - Capped Call Transaction - USD ($) $ / shares in Units, $ in Millions	Sep. 18, 2019	Mar. 08, 2018	Sep. 30, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes			$ 76.2	$ 34.2
Transaction price cap (in dollars per share)			$ 148.63	$ 52.76
Cap premium percentage over reported sales price	150.00%	100.00%

Debt - 2018 Convertible Debt (D

Debt - 2018 Convertible Debt (Details)	Dec. 31, 2019USD ($)	Mar. 31, 2018USD ($)day$ / shares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Non-cash interest expense			$ 19,108,000	$ 10,968,000	$ 3,117,000
Convertible Senior Notes due 2023 | Convertible Debt
Debt Instrument [Line Items]
Debt instrument		$ 345,000,000
Interest rate, stated percentage		0.00%
Proceeds from issuance of convertible senior notes		$ 335,000,000
Conversion ratio		27.5691
Conversion price (in dollars per share) | $ / shares		$ 36.27
Redemption price, percentage		100.00%
If-converted value in excess of principal	$ 76,400,000
If-converted value	421,400,000
Carrying amount of equity component	72,800,000		72,800,000
Capitalization of debt issuance costs		$ 10,000,000
Non-cash interest expense			15,200,000	12,200,000
Unamortized debt issuance expense	5,200,000		5,200,000	6,700,000
Level 2 | Reported Value Measurement | Convertible Senior Notes due 2023 | Convertible Debt
Debt Instrument [Line Items]
Long-term debt, fair value	$ 310,300,000		$ 310,300,000	$ 279,100,000
Debt Instrument, Redemption, Period One | Convertible Senior Notes due 2023 | Convertible Debt
Debt Instrument [Line Items]
Threshold trading days | day		20
Threshold consecutive trading days | day		30
Threshold percentage of stock price trigger		130.00%
Debt Instrument, Redemption, Period Two | Convertible Senior Notes due 2023 | Convertible Debt
Debt Instrument [Line Items]
Threshold consecutive trading days | day		10
Threshold percentage of stock price trigger		98.00%
Days after threshold consecutive trading days | day		5

Debt - 2018 Capped Call Transac

Debt - 2018 Capped Call Transactions (Details) - Convertible Debt - Capped Call Transaction - USD ($) $ / shares in Units, $ in Millions	Sep. 18, 2019	Mar. 08, 2018	Sep. 30, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes			$ 76.2	$ 34.2
Transaction price cap (in dollars per share)			$ 148.63	$ 52.76
Cap premium percentage over reported sales price	150.00%	100.00%

Debt - 2019 Credit Agreement (D

Debt - 2019 Credit Agreement (Details) - USD ($)	Feb. 25, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Non-cash interest expense		$ 19,108,000	$ 10,968,000	$ 3,117,000
Credit Agreement
Line of Credit Facility [Line Items]
Maximum required secured net leverage ratio	300.00%
Maximum required secured net leverage ratio, certain material acquisitions	350.00%
Minimum required interest coverage ratio	250.00%
Capitalization of debt issuance costs	$ 1,400,000
Non-cash interest expense		300,000
Unamortized debt issuance expense		1,100,000
Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	200,000,000
Maximum unrestricted cash	100,000,000
Contingent right to increase maximum borrowing capacity amount	100,000,000
Line of credit facility, amount outstanding		$ 0
Credit Agreement | Letter of Credit
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	30,000,000
Credit Agreement | Bridge Loan
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	$ 10,000,000
Federal Funds Effective Swap Rate | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
London Interbank Offered Rate (LIBOR) | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
Minimum | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee amount	0.20%
Minimum | One-Month London Interbank Offered Rate (LIBOR) Plus 1% | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.25%
Minimum | London Interbank Offered Rate (LIBOR), Adjusted | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%
Maximum | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee amount	0.35%
Maximum | One-Month London Interbank Offered Rate (LIBOR) Plus 1% | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%
Maximum | London Interbank Offered Rate (LIBOR), Adjusted | Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.875%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) ft² in Thousands	Feb. 17, 2016USD ($)	Jan. 03, 2014USD ($)	May 31, 2014USD ($)ft²	Dec. 31, 2019USD ($)ft²	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Feb. 17, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Loss Contingencies [Line Items]
Collateral account				$ 5,341,000	$ 5,341,000	$ 5,341,000		$ 5,341,000
Gross balance of leased equipment				70,948,000
Finance lease, interest expense				3,205,000
Operating leases, rent expense				5,400,000
Operating leases, rent expense					3,800,000	4,100,000
Purchase obligation				97,710,000
Non-income Tax Obligations
Loss Contingencies [Line Items]
Non-income tax obligation reserve				7,200,000	900,000
Capital Lease Obligations | Dell Financial Services, LLC
Loss Contingencies [Line Items]
Line of credit, maximum borrowing capacity						9,000,000	$ 6,000,000
Term of lease	36 months
Interest rate percentage	0.00%
Buyout option	$ 1
Capital Lease Obligations | ePlus Group, Inc
Loss Contingencies [Line Items]
Line of credit, maximum borrowing capacity		$ 8,000,000							$ 18,000,000
Term of lease		36 months
Buyout option		$ 1
Finance Lease Obligations | Dell Financial Services, LLC
Loss Contingencies [Line Items]
Line of credit, maximum borrowing capacity				6,000,000
Office Building
Loss Contingencies [Line Items]
Build-to-suit leases, term of contract			10 years
Area of real estate property (in sqft) | ft²			199
Computer equipment
Loss Contingencies [Line Items]
Finance lease, interest expense				500,000
Capital leases, interest expense					$ 1,000,000	$ 1,600,000
Computer equipment | Dell Financial Services, LLC
Loss Contingencies [Line Items]
Gross balance of leased equipment				800,000
Computer equipment | ePlus Group, Inc
Loss Contingencies [Line Items]
Gross balance of leased equipment				$ 2,000,000
Minimum | Capital Lease Obligations | ePlus Group, Inc
Loss Contingencies [Line Items]
Interest rate percentage		3.71%
Maximum | Capital Lease Obligations | ePlus Group, Inc
Loss Contingencies [Line Items]
Interest rate percentage		6.94%
Finance Lease | Office Building
Loss Contingencies [Line Items]
Area of real estate property (in sqft) | ft²				172
Collateral account			$ 5,300,000
Operating Lease | Office Building
Loss Contingencies [Line Items]
Area of real estate property (in sqft) | ft²				53
Reverb Holdings Inc. | Non-income Tax Obligations
Loss Contingencies [Line Items]
Non-income tax obligation reserve				$ 4,800,000
Indemnification asset				3,700,000
Deferred tax asset				$ 1,100,000

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Purchase Obligations (Details) $ in Thousands	Dec. 31, 2019USD ($)
Purchase Obligations
2020	$ 34,153
2021	30,735
2022	32,122
2023	700
2024	0
Thereafter	0
Total purchase obligations	$ 97,710

Stockholders' Equity - Common a

Stockholders' Equity - Common and Convertible Preferred Stock (Details)	Apr. 21, 2015shares	Dec. 31, 2019USD ($)vote$ / sharesshares	Dec. 31, 2018$ / sharesshares	Dec. 31, 2017shares	Dec. 31, 2016shares
Class of Stock [Line Items]
Common stock, shares authorized (in shares)		1,400,000,000	1,400,000,000
Preferred stock, shares authorized (in shares)		25,000,000	25,000,000
Common stock, shares outstanding (in shares)		118,342,772	119,771,702
Common stock, shares issued (in shares)		118,342,772	119,771,702
Common stock, votes per share of stock held | vote		1
Dividends declared for common stock | $		$ 0
Common stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Common Stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)		118,342,772	119,771,702	121,769,238	115,973,039
Conversion of preferred stock upon public offering (in shares)	53,448,243
Convertible senior notes
Class of Stock [Line Items]
Convertible preferred stock outstanding (in shares)		0	0	0

Stockholders' Equity - Share Re

Stockholders' Equity - Share Repurchases Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended									12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Nov. 01, 2018	Nov. 30, 2017	Nov. 17, 2017
Class of Stock [Line Items]
Stock repurchased	$ 124,500,000										$ 176,985,000	$ 134,647,000	$ 10,301,000
Stock repurchased (in shares)	2,094,196	425,078	50,721	0	532,412	916,083	0	722,941	2,807,393	586,231	6,040,859	5,032,648	586,231
Remaining number of shares authorized to be repurchased (in shares)		0									0
Authorized repurchase amount														$ 200,000,000	$ 100,000,000	$ 100,000,000
Common Stock
Class of Stock [Line Items]
Stock repurchased											$ 3,000	$ 4,000	$ 1,000
Stock repurchased (in shares)											3,102,407	4,446,417	586,231

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Activity of Shares Repurchases (Details) - USD ($)	1 Months Ended	3 Months Ended									12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Nov. 01, 2018	Nov. 30, 2017	Nov. 17, 2017
Equity [Abstract]
Shares Repurchased (in shares)	2,094,196	425,078	50,721	0	532,412	916,083	0	722,941	2,807,393	586,231	6,040,859	5,032,648	586,231
Average Price Paid Per Share (in dollars per share)		$ 52.21	$ 55.16	$ 0	$ 51.64	$ 49.11	$ 0	$ 29.15	$ 24.43	$ 17.57	$ 32.68	$ 28.80	$ 17.57
Value of shares repurchased during period, including broker fees		$ (22,202,000)	$ (2,798,000)	$ 0	$ (27,500,000)	$ (45,000,000)	$ 0	$ (21,113,000)	$ (68,586,000)	$ (10,301,000)	$ (197,500,000)	$ (145,000,000)	$ (10,301,000)
Value of Shares Repurchased	$ 124,500,000										176,985,000	134,647,000	10,301,000
New Authorization														$ 200,000,000	$ 100,000,000	$ 100,000,000
Remaining Amount Authorized		$ 102,500,000				$ 155,000,000				$ 89,699,000	$ 102,500,000	$ 155,000,000	$ 89,699,000

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($) $ in Millions	Jan. 02, 2020	Jan. 02, 2019	Jan. 02, 2018	Mar. 31, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation						$ 22.6
Stock-based compensation expense, acquisitions						$ 1.3	$ 3.8	$ 3.9
Plan modification, incremental compensation cost							$ 7
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period						10 years
Award vesting rights, percentage					25.00%	25.00%
Award vesting period				48 months	4 years	4 years
Award requisite service period						4 years
Trading period immediately prior to and including the date of grant						30 days
Weighted-average period for unrecognized compensation						2 years 5 months 19 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period				4 years	4 years
Award vesting rights, percentage					25.00%
Award vesting period						4 years
Interval vesting period						6 months
Award requisite service period						4 years
Weighted-average period for unrecognized compensation						2 years 11 months 23 days
Unrecognized compensation						$ 107.4
2006 Stock Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period						10 years
Award vesting rights, percentage						25.00%
Award vesting period						4 years
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential annual share increase (in shares)						7,050,000
Percentage of outstanding stock						5.00%
Maximum number of additional shares issued annually (in shares)		2,395,434	6,088,461
Shares reserved for future issuance (in shares)						14,100,000
Number of shares authorized (in shares)						31,831,808
Number of shares available for grant (in shares)						20,494,369
2006 Plan Eligible for 2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)						12,653,075
Subsequent Event [Member] | 2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of additional shares issued annually (in shares)	5,917,139

Stock-based Compensation - Fair

Stock-based Compensation - Fair Value of Options Granted Using the Black-Scholes Pricing Model (Details) - Stock options	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum	39.10%	38.60%	41.70%
Volatility, maximum	39.50%	47.80%	44.20%
Risk-free interest rate, minimum	1.60%	2.60%	1.90%
Risk-free interest rate, maximum	2.50%	2.90%	2.20%
Dividend rate	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	5 years 6 months	5 years 6 months	5 years 6 months
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	6 years 2 months 12 days	6 years 3 months 18 days	6 years 3 months 18 days

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Shares
Outstanding, beginning balance (in shares)	6,890,994	7,947,939	9,339,567
Granted (in shares)	462,563	797,201	5,887,183
Exercised (in shares)	(840,835)	(1,588,779)	(5,760,263)
Forfeited/Cancelled (in shares)	(217,803)	(265,367)	(1,518,548)
Outstanding, ending balance (in shares)	6,294,919	6,890,994	7,947,939	9,339,567
Total exercisable at December 31, 2019, Shares (in shares)	3,835,279
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 12.91	$ 11.02	$ 7.89
Granted (in dollars per share)	64.29	29.87	11.04
Exercised (in dollars per share)	11.64	11.49	5.87
Forfeited/Cancelled (in dollars per share)	30.11	15.68	11.36
Outstanding, ending balance (in dollars per share)	16.26	$ 12.91	$ 11.02	$ 7.89
Total exercisable at December 31, 2019, Weighted-Average Exercise Price (in dollars per share)	$ 12.30
Weighted-Average Remaining Contract Term (in years)
Outstanding at December 31, 2019	7 years 2 months 26 days	7 years 11 months 8 days	7 years 11 months 4 days	6 years 7 months 20 days
Total exercisable at December 31, 2019	6 years 10 months 17 days
Aggregate Intrinsic Value
Outstanding at December 31, 2019	$ 185,900	$ 239,177	$ 74,996	$ 43,613
Total exercisable at December 31, 2019	$ 123,671

Stock-based Compensation - Weig

Stock-based Compensation - Weighted Average Grant Date Fair Value Options Granted and Awards Vested and Intrinsic Value of Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement [Abstract]
Weighted average grant date fair value of options granted (in shares)	$ 26.75	$ 13.33	$ 4.85
Intrinsic value of options exercised	$ 42,758	$ 34,268	$ 52,693
Fair value of awards vested	$ 41,997	$ 32,717	$ 19,826

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of the Unvested RSUs (Details) - RSUs - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shares
Unvested at beginning of period (in shares)	3,480,368	3,074,247	3,135,181
Granted (in shares)	1,464,785	2,448,169	2,360,315
Vested (in shares)	(1,392,295)	(1,496,906)	(1,072,321)
Forfeited/Canceled (in shares)	(592,445)	(545,142)	(1,348,928)
Unvested at period end (in shares)	2,960,413	3,480,368	3,074,247
Weighted-Average Fair Value
Unvested at beginning of period (in dollars per share)	$ 22.87	$ 11.98	$ 10.70
Granted (in dollars per share)	61.92	28.22	12.17
Vested (in dollars per share)	22.67	13.80	10.44
Forfeited/Canceled (in dollars per share)	31.25	18.47	10.56
Unvested at period end (in dollars per share)	$ 40.61	$ 22.87	$ 11.98

Stock-based Compensation - Allo

Stock-based Compensation - Allocated 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 [Line Items]
Share-based compensation expense	$ 44,395	$ 38,231	$ 26,559
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	5,787	3,357	1,739
Marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3,774	2,507	1,933
Product development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	21,085	21,234	8,274
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 13,749	$ 11,133	$ 14,613

Restructuring and Other Exit _3

Restructuring and Other Exit Costs (Income) - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016position
Restructuring and Related Activities [Abstract]
Expected number of positions eliminated | position				245
Number of positions eliminated				23.00%
Restructuring costs (income) | $	$ 0	$ (249)	$ 13,897

Restructuring and Other Exit _4

Restructuring and Other Exit Costs (Income) - Schedule of Restructuring Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Restructuring reserve at period start	$ 1,342	$ 0
Total restructuring and other exit costs	(249)	13,897
Costs charged against equity/assets		(2,987)
Cash payments	(1,093)	(9,568)
Restructuring reserve	0	1,342	$ 0
Restructuring reserve at period end	0	1,342
Severance Charge
Restructuring Reserve [Roll Forward]
Restructuring reserve at period start	1,308	0
Total restructuring and other exit costs	(244)	10,204
Costs charged against equity/assets		0
Cash payments	(1,064)	(8,896)
Restructuring reserve	0	1,308	0
Restructuring reserve at period end	0	1,308
Stock-Based Compensation
Restructuring Reserve [Roll Forward]
Restructuring reserve at period start	0	0
Total restructuring and other exit costs	0	2,701
Costs charged against equity/assets		(2,701)
Cash payments	0	0
Restructuring reserve	0	0	0
Restructuring reserve at period end	0	0
Other Exit Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve at period start	34	0
Total restructuring and other exit costs	(5)	992
Costs charged against equity/assets		(286)
Cash payments	(29)	(672)
Restructuring reserve	0	34	$ 0
Restructuring reserve at period end	$ 0	$ 34

Restructuring and Other Exit _5

Restructuring and Other Exit Costs (Income) - Restructuring and Other Related Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0	$ (249)	$ 13,897
Cost of revenue
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	(19)	738
Marketing
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	(82)	2,950
Product development
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	(110)	3,232
General and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0	$ (38)	$ 6,977

Uncategorized Items - etsy12312

Label	Element	Value
Accounting Standards Update 2016-16 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (51,364,000)
Accounting Standards Update 2016-16 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(51,449,000)
Accounting Standards Update 2016-16 [Member] | Additional Paid-in Capital [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 85,000