Etsy (ETSY) 10-Q 4 Nov 21 2021 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-36911
Entity Registrant Name	ETSY, INC
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		126,780,745
Entity Central Index Key	0001370637
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 619,402	$ 1,244,099
Short-term Investments	197,430	425,119
Accounts receivable, net of expected credit losses of $9,402 and $9,757 as of September 30, 2021 and December 31, 2020, respectively	23,884	22,605
Prepaid and other current assets	68,936	56,152
Funds receivable and seller accounts	167,682	146,806
Total current assets	1,077,334	1,894,781
Restricted cash	5,341	5,341
Property and equipment, net of accumulated depreciation and amortization of $144,916 and $158,771 as of September 30, 2021 and December 31, 2020, respectively	198,902	112,495
Goodwill	1,385,214	140,810
Intangible assets, net of accumulated amortization of $42,598 and $25,705 as of September 30, 2021 and December 31, 2020, respectively	613,104	187,449
Deferred tax assets	103,809	115
Long-term Investments	90,350	39,094
Other assets	28,084	24,404
Total assets	3,502,138	2,404,489
Current liabilities:
Accounts payable	13,367	40,883
Accrued expenses	245,300	232,352
Finance lease obligations—current	8,757	8,537
Funds payable and amounts due to sellers	167,682	146,806
Deferred revenue	12,518	11,264
Other current liabilities	23,383	14,822
Total current liabilities	471,007	454,664
Finance lease obligations—net of current portion	38,700	44,979
Deferred tax liabilities	94,158	58,481
Long-term debt, net	2,274,351	1,062,299
Other liabilities	90,300	41,642
Total liabilities	2,968,516	1,662,065
Commitments and contingencies
Stockholders’ equity:
Common stock ($0.001 par value, 1,400,000,000 shares authorized as of September 30, 2021 and December 31, 2020; 126,503,754 and 125,835,931 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively)	127	126
Preferred stock ($0.001 par value, 25,000,000 shares authorized as of September 30, 2021 and December 31, 2020)	0	0
Additional paid-in capital	624,374	883,166
Accumulated deficit	(21,467)	(146,819)
Accumulated other comprehensive (loss) income	(69,412)	5,951
Total stockholders’ equity	533,622	742,424
Total liabilities and stockholders’ equity	$ 3,502,138	$ 2,404,489

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Accounts receivable, expected credit losses	$ 9,402	$ 9,757
Property and equipment, accumulated depreciation and amortization	144,916	158,771
Accumulated amortization	$ 42,598	$ 25,705
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)	126,503,754	125,835,931
Common stock, shares outstanding (in shares)	126,503,754	125,835,931
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 (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 532,429	$ 451,478	$ 1,611,975	$ 1,108,270
Cost of revenue	153,660	120,168	445,546	313,965
Gross profit	378,769	331,310	1,166,429	794,305
Operating expenses:
Marketing	131,928	126,779	450,606	289,991
Product development	73,521	45,908	188,980	128,923
General and administrative	89,579	40,454	203,360	112,717
Total operating expenses	295,028	213,141	842,946	531,631
Income from operations	83,741	118,169	323,483	262,674
Other income (expense):
Loss on extinguishment of debt	0	(16,855)	0	(16,855)
Interest expense	(2,779)	(10,615)	(6,346)	(30,608)
Interest and other income	139	1,158	1,921	6,503
Foreign exchange gain (loss)	2,698	(1,464)	8,223	(9,312)
Total other income (expense)	58	(27,776)	3,798	(50,272)
Income before income taxes	83,799	90,393	327,281	212,402
Benefit (provision) for income taxes	6,131	1,368	4,669	(11,694)
Net income	$ 89,930	$ 91,761	$ 331,950	$ 200,708
Net income per share attributable to common stockholders:
Basic (in dollars per share)	$ 0.71	$ 0.75	$ 2.62	$ 1.68
Diluted (in dollars per share)	$ 0.62	$ 0.70	$ 2.30	$ 1.59
Weighted-average common shares outstanding:
Basic (in shares)	126,633,789	121,978,272	126,753,641	119,666,841
Diluted (in shares)	147,413,915	137,560,385	145,866,797	134,376,695

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 89,930	$ 91,761	$ 331,950	$ 200,708
Other comprehensive (loss) income:
Cumulative translation adjustment	(66,709)	6,441	(75,059)	6,308
Unrealized (losses) gains on marketable securities, net of tax (benefit) expense of $(21), $(189), $(96) and $158, respectively	(67)	(630)	(304)	503
Total other comprehensive (loss) income	(66,776)	5,811	(75,363)	6,811
Comprehensive income	$ 23,154	$ 97,572	$ 256,587	$ 207,519

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Unrealized (losses) gains on marketable securities, tax expense (benefit)	$ (21)	$ (189)	$ (96)	$ 158

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Additional Paid-in CapitalCumulative Effect, Period of Adoption, Adjustment	Accumulated Deficit	Accumulated DeficitCumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2019			118,342,772
Beginning balance at Dec. 31, 2019	$ 406,634		$ 119	$ 642,628		$ (227,414)		$ (8,699)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	48,408			48,408
Exercise of vested options (in shares)			1,357,792
Exercise of vested options	18,486		$ 1	18,485
Issuance of convertible senior notes, net of issuance costs and taxes	102,131			102,131
Purchase of capped calls, net of taxes	(56,848)			(56,848)
Settlement of convertible senior notes, net of taxes (in shares)			7,271,632
Settlement of convertible senior notes, net of taxes	151,310		$ 7	151,303
Vesting of restricted stock units, net of shares withheld (in shares)			507,933
Vesting of restricted stock units, net of shares withheld	(19,811)		$ 1	(19,812)
Stock repurchase (in shares)			(1,819,696)
Stock repurchase	(191,162)		$ (2)			(191,160)
Other comprehensive income (loss)	6,811							6,811
Net income	200,708					200,708
Ending balance (in shares) at Sep. 30, 2020			125,660,433
Ending balance at Sep. 30, 2020	$ 666,667		$ 126	886,295		(217,866)		(1,888)
Accounting Standards Update [Extensible List]	Accounting Standards Update 2020-06
Beginning balance (in shares) at Dec. 31, 2019			118,342,772
Beginning balance at Dec. 31, 2019	$ 406,634		$ 119	642,628		(227,414)		(8,699)
Ending balance (in shares) at Dec. 31, 2020	125,835,931		125,835,931
Ending balance at Dec. 31, 2020	$ 742,424	$ (200,910)	$ 126	883,166	$ (228,738)	(146,819)	$ 27,828	5,951
Beginning balance (in shares) at Jun. 30, 2020			119,140,637
Beginning balance at Jun. 30, 2020	524,175		$ 119	675,213		(143,458)		(7,699)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	17,448			17,448
Exercise of vested options (in shares)			399,793
Exercise of vested options	6,309			6,309
Issuance of convertible senior notes, net of issuance costs and taxes	102,131			102,131
Purchase of capped calls, net of taxes	(56,848)			(56,848)
Settlement of convertible senior notes, net of taxes (in shares)			7,271,632
Settlement of convertible senior notes, net of taxes	151,310		$ 7	151,303
Vesting of restricted stock units, net of shares withheld (in shares)			124,961
Vesting of restricted stock units, net of shares withheld	(9,260)		$ 1	(9,261)
Stock repurchase (in shares)			(1,276,590)
Stock repurchase	(166,170)		$ (1)			(166,169)
Other comprehensive income (loss)	5,811							5,811
Net income	91,761					91,761
Ending balance (in shares) at Sep. 30, 2020			125,660,433
Ending balance at Sep. 30, 2020	$ 666,667		$ 126	886,295		(217,866)		(1,888)
Beginning balance (in shares) at Dec. 31, 2020	125,835,931		125,835,931
Beginning balance at Dec. 31, 2020	$ 742,424	$ (200,910)	$ 126	883,166	$ (228,738)	(146,819)	$ 27,828	5,951
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 95,062			95,062
Exercise of vested options (in shares)	493,932		493,932
Exercise of vested options	$ 10,867			10,867
Purchase of capped calls, net of taxes	(64,673)			(64,673)
Settlement of convertible senior notes, net of taxes (in shares)			985,081
Settlement of convertible senior notes, net of taxes	(422)		$ 1	(423)
Vesting of restricted stock units, net of shares withheld (in shares)			513,675
Vesting of restricted stock units, net of shares withheld	$ (70,886)		$ 1	(70,887)
Stock repurchase (in shares)	(267,350)		(1,324,865)
Stock repurchase	$ (234,427)		$ (1)			(234,426)
Other comprehensive income (loss)	(75,363)							(75,363)
Net income	$ 331,950					331,950
Ending balance (in shares) at Sep. 30, 2021	126,503,754		126,503,754
Ending balance at Sep. 30, 2021	$ 533,622		$ 127	624,374		(21,467)		(69,412)
Beginning balance (in shares) at Jun. 30, 2021			126,522,519
Beginning balance at Jun. 30, 2021	530,753		$ 127	590,232		(56,970)		(2,636)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	45,705			45,705
Exercise of vested options (in shares)			154,137
Exercise of vested options	2,830			2,830
Vesting of restricted stock units, net of shares withheld (in shares)			94,448
Vesting of restricted stock units, net of shares withheld	$ (14,393)			(14,393)
Stock repurchase (in shares)	(267,350)		(267,350)
Stock repurchase	$ (54,427)					(54,427)
Other comprehensive income (loss)	(66,776)							(66,776)
Net income	$ 89,930					89,930
Ending balance (in shares) at Sep. 30, 2021	126,503,754		126,503,754
Ending balance at Sep. 30, 2021	$ 533,622		$ 127	$ 624,374		$ (21,467)		$ (69,412)

Condensed Consolidated Statemen

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net income	$ 331,950	$ 200,708
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	90,047	47,664
Depreciation and amortization expense	49,276	45,088
Provision for expected credit losses	12,993	9,572
Foreign exchange (gain) loss	(7,159)	8,559
Non-cash interest expense	1,286	26,326
Deferred (benefit) provision for income taxes	(78,631)	5,755
Loss on extinguishment of debt	0	16,855
Other non-cash expense, net	4,324	3,231
Changes in operating assets and liabilities (net of impact of business combinations):
Current assets	(49,098)	(75,526)
Non-current assets	(4,067)	3,395
Current liabilities	(5,419)	146,634
Non-current liabilities	15,590	(2,972)
Net cash provided by operating activities	361,092	435,289
Cash flows from investing activities
Acquisition of businesses, net of cash acquired	(1,690,823)	0
Cash paid for intangible assets	(1,862)	0
Purchases of property and equipment	(5,740)	(388)
Development of internal-use software	(11,519)	(3,685)
Purchases of marketable securities	(343,902)	(300,880)
Sales and maturities of marketable securities	518,985	346,596
Net cash (used in) provided by investing activities	(1,534,861)	41,643
Cash flows from financing activities
Payment of tax obligations on vested equity awards	(69,147)	(19,811)
Repurchase of stock	(234,427)	(191,162)
Proceeds from exercise of stock options	10,867	18,486
Proceeds from issuance of convertible senior notes	1,000,000	650,000
Payment of debt issuance costs	(12,849)	(9,764)
Purchase of capped calls	(85,000)	(74,685)
Settlement of convertible senior notes	(43,863)	(137,166)
Payments on finance lease obligations	(7,321)	(7,056)
Other financing, net	(93)	(8,268)
Net cash provided by financing activities	558,167	220,574
Effect of exchange rate changes on cash	(9,095)	4,175
Net (decrease) increase in cash, cash equivalents, and restricted cash	(624,697)	701,681
Cash, cash equivalents, and restricted cash at beginning of period	1,249,440	448,634
Cash, cash equivalents, and restricted cash at end of period	624,743	1,150,315
Supplemental cash flow disclosures:
Cash paid for income taxes, net of refunds	66,105	8,309
Supplemental non-cash disclosures:
Replacement share-based awards issued in conjunction with acquisitions	5,686	0
Stock-based compensation capitalized in development of capitalized software and asset additions in exchange for liabilities	4,920	2,752
Right-of-use assets obtained in exchange for new lease liabilities	1,241	641
Debt issuance costs included in accounts payable and accrued expenses	476	795
Reconciliation of cash, cash equivalents, and restricted cash
Cash and cash equivalents	619,402	1,144,974
Restricted cash	5,341	5,341
Total cash, cash equivalents, and restricted cash	$ 624,743	$ 1,150,315

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - Convertible Senior Notes Due 2023 - Convertible Debt - shares shares in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2021	Mar. 31, 2018
Debt instrument conversion amount, shares (in shares)	7.3	1
Debt instrument, interest rate, stated percentage			0.00%

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
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”) operates a “House of Brands,” two-sided online marketplaces that connect millions of passionate and creative buyers and sellers. The Company’s primary marketplace, Etsy.com, is the global marketplace for unique and creative goods. The Company generates revenue primarily from transaction, listing, and payments processing fees, and on-site advertising and shipping label services. 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 July 2, 2021, Etsy acquired all the outstanding shares of Elo7 Serviços de Informática S.A. (“Elo7”) by means of a merger, and on July 12, 2021 Etsy acquired all of the issued share capital of Depop Limited (“Depop”) pursuant to a share purchase. The financial results of Elo7 and Depop have been included in Etsy’s Consolidated Financial Statements from the respective dates of acquisition. See “Note 5—Business Combinations.” Basis of Presentation The accompanying unaudited interim consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and pursuant to the applicable rules and regulations of the Securities and Exchange Commission (“SEC”). The Company has condensed or omitted certain information and notes normally included in complete annual financial statements prepared in accordance with GAAP. These unaudited interim consolidated financial statements should therefore be read in conjunction with the audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K filed with the SEC on February 26, 2021 (the “Annual Report”). In the opinion of management, all material adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for the periods presented have been reflected in the consolidated financial statements. The results of operations of any interim period are not necessarily indicative of the results of operations for the full annual period or any future period due to seasonal and other factors. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires the Company to make estimates and judgments that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates and judgments. The accounting estimates that require management’s most subjective judgments include: stock-based compensation; income taxes, including the estimate of the annual effective tax rate at interim periods and evaluation of uncertain tax positions; purchase price allocations for business combinations and valuation of acquired intangible assets, developed technology, and goodwill. As of September 30, 2021, the effects of the ongoing COVID-19 pandemic and progress towards its abatement on the Comp any’s business, results of operations, and financial condition continue to evolve. A s a result, many of the Company’s estimates and judgments required increased judgment and carry a higher degree of variability and volatility. As additional information becomes available, the Company’s estimates may change materially in future periods. Stock-Based Compensation Service based stock options, service based restricted stock units (“RSUs”), and performance based restricted stock units (“PBRSUs”) are awarded to employees, officers, and members of the Company’s Board of Directors. The PBRSUs include financial performance based restricted stock units (“Financial PBRSUs”) and total shareholder return performance based restricted stock units (“TSR PBRSUs”), both of which have performance and service vesting requirements. The Company recognizes forfeitures as they occur. The Company calculates the fair value of stock options on the date of grant using the Black-Scholes option-pricing model. The fair value of RSUs is measured using the closing price of the Company’s common stock on Nasdaq on the grant date. Additionally, the fair value of the Financial PBRSUs is determined using a probability assessment and the fair value of the TSR PBRSUs with market conditions are determined using a Monte-Carlo simulation model. For PBRSUs, the Company recognizes stock-based compensation expenses on a straight-line basis over the longer of the derived, explicit, or implicit service period. As of interim and annual reporting periods, the Financial PBRSUs stock-based compensation expense is adjusted based on expected achievement of performance targets, while TSR PBRSUs stock-based compensation expense is not adjusted. Recently Issued Accounting Pronouncements In October 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2021-08— Business Combinations (Topic 805)—Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , which requires contract assets and contract liabilities acquired in a business combination to be recognized and measured by the acquirer on the acquisition date in accordance with Accounting Standards Codification Topic 606— Revenue from Contracts with Customers (“ASC 606”). Under current GAAP, an acquirer generally recognizes assets acquired and liabilities assumed in a business combination, including contract assets and contract liabilities arising from revenue contracts with customers, at fair value on the acquisition date. This ASU will result in the acquirer recording acquired contract assets and liabilities on the same basis that would have been recorded by the acquiree before the acquisition under ASC 606. The amendments in this ASU do not affect the accounting for other assets or liabilities that may arise from revenue contracts with customers in accordance with ASC 606, such as refund liabilities, or in a business combination, such as customer-related intangible assets and contract-based intangible assets. The new guidance is effective for annual and interim periods beginning after December 15, 2022. Early adoption is permitted, including in interim periods, for any financial statements that have not yet been issued. This update should be applied prospectively to business combinations occurring on or after the effective date of the amendments. The Company is currently evaluating the impact that this new guidance may have on its consolidated financial statements. Recently Adopted Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06— Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity's Own Equity (Subtopic 815-40)—Accounting For Convertible Instruments and Contracts in an Entity's Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies accounting for convertible instruments by removing major separation models previously required under GAAP. Consequently, more convertible debt instruments will be reported as a single liability instrument with no separate accounting for embedded conversion features through equity. Without an initial allocation of proceeds to the conversion option, the debt will likely have a lower discount, thereby resulting in less non-cash interest expense through accretion. ASU 2020-06 removes certain settlement conditions that are required for equity contracts to qualify for the derivative scope exception, which will permit more equity contracts to qualify for it. ASU 2020-06 also simplifies the diluted net income per share calculation in certain areas. The new guidance is effective for annual and interim periods beginning after December 15, 2021, and early adoption is permitted for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. This update permits the use of either the modified retrospective or fully retrospective method of transition. The Company early adopted this standard, effective as of January 1, 2021, on a modified retrospective basis. The adoption of this standard had a material effect on the Company’s consolidated financial statements. The most significant effects related to the 0.125% Convertible Senior Notes due 2027 (the “2020 Notes”), 0.125% Convertible Senior Notes due 2026 (the “2019 Notes”), and 0% Convertible Senior Notes due 2023 (the “2018 Notes” and together with the 0.25% Convertible Senior Notes due 2028 (the “2021 Notes”), the 2020 Notes, and the 2019 Notes, the “Notes”), and included derecognition of the unamortized debt discount, which was recorded as a direct deduction from the Notes, resulting in an increase in long-term debt, net of approximately $264 million; derecognition of the equity component, which represents the value of the conversion option on the issuance date of the Notes outstanding, resulting in a reduction in additional paid-in capital of approximately $229 million, net of taxes; derecognition of deferred tax liabilities of approximately $63 million; and reversal of the cumulative debt discount recognized as interest expense in the Company’s Consolidated Statements of Operations since the date of issuance of each of the Notes to the period ending December 31, 2020, resulting in a decrease of accumulated deficit of approximately $28 million, net of taxes. The Company also had a reduction in interest expense due to the adoption of ASU 2020-06 as the debt discount has been derecognized and, effective January 1, 2021, there is no amortization of the debt discount. The Company did not incur any impact to liquidity or cash flows. When calculating net income per share of common stock attributable to common stockholders, the Company uses the if-converted method as required under ASU 2020-06 to determine the dilutive effect of the Notes.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Note 2—Revenue The following table summarizes revenue disaggregated by Marketplace revenue and optional Services revenue for the periods presented (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Marketplace revenue $ 395,503 $ 341,623 $ 1,204,608 $ 829,575 Services revenue 136,926 109,855 407,367 278,695 Revenue $ 532,429 $ 451,478 $ 1,611,975 $ 1,108,270 Etsy.com marketplace revenue is comprised of the fees a seller pays for marketplace activities. Marketplace activities include listing an item for sale, completing sales transactions, and using the Company’s payments platforms to process payments. Across the Company’s “House of Brands,” Reverb, Depop, and Elo7 marketplace revenue is comprised of seller transaction fees and payments fees, similar to Etsy.com, but these marketplaces do not charge a listing fee to their sellers. Etsy.com services revenue is comprised of the fees a seller pays for the Company’s optional other services, which primarily include on-site advertising services and shipping labels. Similar services revenue is recognized across the Company’s “House of Brands,” including from Reverb’s Bump on-site advertising and Reverb, Depop, and Elo7’s shipping labels. For more information on the Company’s critical accounting policies related to Etsy.com revenue recognition, see “Note 1—Basis of Presentation and Summary of Significant Accounting Policies” in the Notes to Consolidated Financial Statements of the Company’s Annual Report, which is incorporated herein by reference. Contract balances Deferred revenues The amount of revenue recognized in the nine months ended September 30, 2021 that was included in the deferred balance at January 1, 2021 was $11.3 million.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 3—Income Taxes The Company’s provision or benefit from income taxes in interim periods is determined using an estimate of the annual effective tax rate, adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter the Company updates its estimate of the annual effective tax rate, and if its estimated tax rate changes, the Company makes a cumulative adjustment. The estimate of the annual effective income tax rate for the full year is applied to the respective interim period, taking into account year-to-date amounts and projected results for the full year. The Company’s quarterly tax provision, and its quarterly estimate of the annual effective tax rate, is subject to significant variation due to several factors, including variability in accurately predicting its income or loss before tax and the mix of jurisdictions to which they relate, taxable income or loss in each jurisdiction, changes in its stock price, audit-related developments, acquisitions, changes in its deferred tax assets and liabilities and their valuation, foreign currency gains (losses), changes in statutes, regulations, case law, and administrative practices, principles, and interpretations related to tax, including changes to the global tax framework, competition, and other laws and accounting rules in various jurisdictions, and relative changes of expenses or losses for which tax benefits are not recognized. Additionally, the effective tax rate can be more or less volatile based on the amount of income or loss before tax. For example, the impact of discrete items and non-deductible expenses on the effective tax rate is greater when income before income taxes is lower. For the nine months ended September 30, 2021, the Company’s effective income tax rate was (1.4)% representing an income tax benefit recorded on net income before tax. The effective tax rate for the nine months ended September 30, 2021 was lower than the U.S. statutory rate of 21% primarily due to excess tax benefits from employee stock-based compensation, the impact from foreign operations that are subject to lower tax rates, and a benefit related to a research and development tax credit, partially offset by state income taxes. Although management believes its tax positions and related provisions reflected in the consolidated financial statements are fully supportable, it recognizes that these tax positions and related provisions may be challenged by various tax authorities. These tax positions and related provisions are reviewed on an ongoing basis and are adjusted as additional facts and information become available, including progress on tax audits, changes in interpretation of tax laws, developments in case law and closing of statute of limitations. To the extent that the ultimate results differ from the original or adjusted estimates of the Company, the effect will be recorded in the provision for income taxes. 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. The amount of unrecognized tax benefits included in the Consolidated Balance Sheets increased $2.9 million in the nine months ended September 30, 2021, from $23.7 million as of December 31, 2020 to $26.6 million as of September 30, 2021. The total amount of unrecognized tax benefits that, if recognized, would favorably affect the effective tax rate is $25.6 million as of September 30, 2021. Although the timing of the resolution and/or closure of audits is highly uncertain, it is reasonably possible that the balance of gross unrecognized tax benefits could significantly change in the next 12 months. Given the number of years remaining subject to examination and the number of matters being examined, at this time, the Company is unable to estimate the full range of possible adjustments to the balance of gross unrecognized tax benefits.

Net Income Per Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Income Per Share	Note 4—Net Income Per Share The following table presents the method used when calculating the impact of the Company’s Notes on earnings per share for the periods presented: Three Months Ended Nine Months Ended 2021 2020 2021 2020 2021 Notes If-Converted N/A If-Converted N/A 2020 Notes If-Converted Treasury Stock If-Converted Treasury Stock 2019 Notes If-Converted If-Converted If-Converted If-Converted 2018 Notes If-Converted If-Converted If-Converted If-Converted The Notes were dilutive for the three and nine months ended September 30, 2021. The following table presents the calculation of basic and diluted net income per share for the periods presented (in thousands, except share and per share amounts): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Numerator: Net income attributable to common stockholders—basic $ 89,930 $ 91,761 $ 331,950 $ 200,708 Add back interest expense, net of tax attributable to assumed conversion of convertible senior notes 1,594 4,494 3,312 13,348 Net income attributable to common stockholders—diluted $ 91,524 $ 96,255 $ 335,262 $ 214,056 Denominator: Weighted-average common shares outstanding—basic 126,633,789 121,978,272 126,753,641 119,666,841 Dilutive effect of assumed conversion of options to purchase common stock 4,126,970 4,533,426 4,229,632 4,380,663 Dilutive effect of assumed conversion of restricted stock units 1,936,390 2,425,214 2,042,745 1,705,718 Dilutive effect of assumed conversion of convertible senior notes 14,716,766 8,623,473 12,840,779 8,623,473 Weighted-average common shares outstanding—diluted 147,413,915 137,560,385 145,866,797 134,376,695 Net income per share attributable to common stockholders—basic $ 0.71 $ 0.75 $ 2.62 $ 1.68 Net income per share attributable to common stockholders—diluted $ 0.62 $ 0.70 $ 2.30 $ 1.59 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: Three Months Ended Nine Months Ended 2021 2020 2021 2020 Stock options 193,919 5,769 135,179 341,109 Restricted stock units 54,189 36,260 475,475 66,231 Convertible senior notes — 8,213,081 — 10,430,621 Total anti-dilutive securities 248,108 8,255,110 610,654 10,837,961

Business Combinations

Business Combinations	9 Months Ended
	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Business Combinations	Note 5—Business Combinations Depop Acquisition On July 12, 2021, the Company acquired all of the outstanding capital stock of Depop, an online global peer-to-peer fashion resale marketplace. The Company believes Depop extends its market opportunity in the high frequency apparel sector, specifically in the fast-growing resale space, and deepens the Company’s reach into the Gen Z consumer. The fair value of consideration transferred of $1.493 billion consisted of: (1) cash consideration paid of $1.479 billion, net of cash acquired, (2) non-cash consideration of $4.8 million representing the portion of the replacement equity awards issued in connection with the acquisition that was associated with services rendered through the date of the acquisition, and (3) $9.2 million holdback pending the finalization of certain purchase price items which were resolved and paid in the fourth quarter of 2021. The portion of the replacement equity awards associated with services rendered post-acquisition will be recorded as post-combination expense on a straight-line basis over the remaining vesting period of the awards. Additionally, deferred consideration awards will be issued to certain Depop executives, which will also be recorded as post-combination expense on a straight-line basis over the three-year mandatory service period associated with the deferred consideration. Neither of these awards was included in the fair value of the consideration transferred. For more information on these awards, see Note 11—Stock-Based Compensation. 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 assembled workforce, expanded market opportunities, and value creation across the Company’s businesses. The resulting goodwill is not expected to be deductible for tax purposes. The allocation of the purchase price has been prepared on a preliminary basis and changes to the allocation to certain assets and liabilities, including tax estimates, may be revised as additional information becomes available. The Company will finalize the acquisition accounting within the required measurement period of one year. Depop Purchase Price Allocation The following table summarizes the allocation of the purchase price (at fair value) to the assets acquired and liabilities of Depop assumed as of July 12, 2021 (the date of acquisition) (in thousands, except years): Preliminary Purchase Price Allocation Estimated Useful Life (in years) Current assets $ 4,249 Property and equipment other 1,299 2-5 Developed technology 84,661 5 Trademark 245,657 20 Customer relationships 147,116 13 Goodwill 1,131,099 Indefinite Current liabilities (18,878) Non-current liabilities (1) (28,097) Deferred tax liability, net (74,283) Total purchase price $ 1,492,823 (1) Non-current liabilities are primarily related to non-income tax related contingency reserves. Elo7 Acquisition On July 2, 2021, the Company acquired all the outstanding shares of Elo7 (including Elo7, Ltd. and related subsidiaries entities), by means of a merger, an e-commerce marketplace in Brazil focused on unique, handmade items. The Company sees significant potential in Brazil's e-commerce sector, which is still in early stages of development and fueled by one of the largest economies in the world. The Company believes having a well known local brand will help Etsy, Inc. to better capitalize on this opportunity. The fair value of consideration transferred of $212.1 million consisted of: (1) cash consideration paid of $211.3 million, net of cash acquired, and (2) non-cash consideration of $0.8 million representing the portion of the replacement equity awards issued in connection with the acquisition that was associated with services rendered through the date of the acquisition. The portion of the replacement equity awards associated with services rendered post-acquisition will be recorded as post-combination expense on a straight-line basis over the remaining vesting period of the awards, and were therefore not included in the fair value of the consideration transferred. For more information on these awards, see Note 11—Stock-Based Compensation. 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 assembled workforce, expanded market opportunities, and value creation across the Company’s businesses. The resulting goodwill is not expected to be deductible for tax purposes. The allocation of the purchase price has been prepared on a preliminary basis and changes to the allocation to certain assets and liabilities, including tax estimates, may be revised as additional information becomes available. The Company will finalize the acquisition accounting within the required measurement period of one year. Elo7 Purchase Price Allocation The following table summarizes the allocation of the purchase price (at fair value) to the assets acquired and liabilities assumed of Elo7 as of July 2, 2021 (the date of acquisition) (in thousands): Preliminary Purchase Price Allocation Estimated Useful Life (in years) Current assets $ 2,721 Developed technology 12,084 5 Trademark 22,187 15 Customer relationships 44,374 15 Goodwill 159,009 Indefinite Non-current assets 590 Current liabilities (3,406) Non-current liabilities (2,691) Deferred tax liability, net (22,727) Total purchase price $ 212,141 Revenue and Earnings Revenue and net loss were $17.4 million and $26.8 million, respectively, for Depop and Elo7, in the aggregate, from their respective dates of acquisition through September 30, 2021. Acquisition-related expenses are expensed as incurred. They were recorded in general and administrative expenses and were $25.0 million and $35.0 million for the three and nine months ended September 30, 2021, respectively. 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, including Depop and Elo7, as if the business combinations had occurred on January 1, 2020, the earliest period presented herein (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Revenue $ 534,395 $ 474,910 $ 1,656,452 $ 1,162,420 Net income 108,781 89,040 332,246 184,423 The pro forma financial information includes adjustments that are directly attributable to the business combinations and are factually supportable. The pro forma adjustments include incremental amortization of intangible and developed technology assets, based on preliminary values of each asset, and remove non-recurring transaction costs directly associated with the acquisition, such as legal and other professional service fees, and the pro forma tax impact for such adjustments. Cost savings or operating synergies expected to result from the acquisition are not included in the pro forma results. For the three and nine months ended September 30, 2021, the pro forma financial information excludes $44.2 million and $58.4 million, respectively, of non-recurring acquisition-related expenses incurred prior to the effective dates of the business combinations. For the nine months ended September 30, 2020, the pro forma financial information includes $1.1 million of non-recurring acquisition-related expenses incurred post effective dates of the business combinations. These pro forma results are illustrative only and not indicative of the actual results of operations that would have been achieved nor are they indicative of future results of operations. Goodwill The change in the carrying amount of goodwill from December 31, 2020 to September 30, 2021 is as follows, with the addition primarily due to the acquisitions of Depop and Elo7 (in thousands): Net Book Value Balance as of December 31, 2020 $ 140,810 Business combinations 1,290,108 Foreign currency translation adjustments (45,704) Balance as of September 30, 2021 $ 1,385,214 The Company has determined it has four operating segments, Etsy, Reverb, Depop, and Elo7, which qualify for aggregation as one reportable segment, for purposes of allocating resources and evaluating financial performance. The Company has determined it has four reporting units and will perform the annual goodwill impairment test for each reporting unit during the fourth quarter. With respect to the goodwill generated as a result of the above purchase price allocations, the Company determined that the estimated fair value of the two newly acquired reporting units was not substantially in excess of its carrying value, due to the proximity of the acquisition dates. Intangible Assets As of September 30, 2021, the gross book value and accumulated amortization of acquired intangible assets from the acquisitions of Depop and Elo7 were as follows (in thousands): As of September 30, 2021 Gross book Accumulated Net book Customer relationships $ 183,956 $ (2,974) $ 180,982 Trademark 258,886 (2,826) 256,060 Total acquired intangible assets $ 442,842 $ (5,800) $ 437,042 Amortization expense for customer relationships and trademarks from the acquisitions of Depop and Elo7 was $5.8 million for the period ended September 30, 2021 and was recorded in marketing expense. Based on amounts recorded at September 30, 2021, the Company will recognize acquired intangible asset amortization expense for the three months ending December 31, 2021 and years ending December 31, 2022, 2023, 2024, 2025, and thereafter as follows (in thousands): Remainder of 2021 $ 6,754 2022 27,015 2023 27,015 2024 27,015 2025 27,015 Thereafter 322,228 Total amortization expense $ 437,042 Developed Technology As of September 30, 2021, the gross book value and accumulated amortization of acquired developed technology from the acquisitions of Depop and Elo7, classified in property and equipment, net, were as follows (in thousands): As of September 30, 2021 Gross book value Accumulated amortization Net book value Developed technology $ 93,348 $ (3,983) $ 89,365 Amortization expense for developed technology from the acquisitions of Depop and Elo7 was $4.0 million for the period ended September 30, 2021 and was recorded in cost of revenue.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 6—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 Company did not have any Level 3 instruments as of September 30, 2021 and December 31, 2020. Short- and long-term investments and certain cash equivalents consist of investments in debt securities that are available-for-sale. The following table sets forth the cost, gross unrealized losses, gross unrealized gains, and fair values of the Company’s investments as of the dates indicated (in thousands): Cost Gross Gross Fair Value Cash and Cash Equivalents Short-term Investments Long-term Investments September 30, 2021 Cash $ 175,615 $ — $ — $ 175,615 $ 175,615 $ — $ — Level 1 U.S. Government and agency securities 67,480 (2) 40 67,518 — 59,220 8,298 Money market funds (1) 440,380 — — 440,380 439,787 — — 507,860 (2) 40 507,898 439,787 59,220 8,298 Level 2 Certificate of deposit 22,898 — 3 22,901 — 22,901 — Commercial paper 27,326 (1) 5 27,330 4,000 23,330 — Corporate bonds 174,008 (80) 103 174,031 — 91,979 82,052 224,232 (81) 111 224,262 4,000 138,210 82,052 $ 907,707 $ (83) $ 151 $ 907,775 $ 619,402 $ 197,430 $ 90,350 December 31, 2020 Cash $ 346,136 $ — $ — $ 346,136 $ 346,136 $ — $ — Level 1 U.S. Government and agency securities 410,371 (3) 358 410,726 — 376,089 34,637 Money market funds (1) 920,643 — — 920,643 881,465 — — 1,331,014 (3) 358 1,331,369 881,465 376,089 34,637 Level 2 Certificate of deposit 12,746 — 5 12,751 6,000 6,751 — Commercial paper 14,494 — 4 14,498 10,498 4,000 — Corporate bonds 42,632 (7) 111 42,736 — 38,279 4,457 69,872 (7) 120 69,985 16,498 49,030 4,457 $ 1,747,022 $ (10) $ 478 $ 1,747,490 $ 1,244,099 $ 425,119 $ 39,094 (1) $0.6 million and $39.2 million of money market funds were classified as funds receivable and seller accounts as of September 30, 2021 and December 31, 2020, respectively. The Company evaluates fair value for each individual security in the investment portfolio. All investments in an unrealized loss position have been in an unrealized loss position for less than 12 months as of September 30, 2021. The Company typically invests in short- and long-term instruments, including fixed-income funds and U.S. Government and agency securities aligned with the Company’s investment strategy. The maturities of the Company’s non-current marketable debt securities generally range from greater than 12 and up to 37 months. Disclosure of Fair Values The Company’s financial instruments that are not measured at fair value in the Consolidated Balance Sheets include the Notes, see “Note 8—Debt.” The Company estimates the fair value of the Notes through inputs that are observable in the market, classified as Level 2 as described above. The following table presents the carrying value and estimated fair value of the Notes as of the dates indicated (in thousands): As of September 30, 2021 As of December 31, 2020 Carrying Value Fair Value Carrying Value Fair Value 2021 Notes $ 987,254 $ 1,138,800 $ — $ — 2020 Notes (1) 642,939 802,555 511,733 536,126 2019 Notes (1) 644,126 1,554,771 514,035 566,399 2018 Notes (1) 68 390 39,166 42,157 $ 2,274,387 $ 3,496,516 $ 1,064,934 $ 1,144,682 (1) Upon adoption of ASU 2020-06 as of January 1, 2021, the carrying value of the Notes increased due to the derecognition of the unamortized debt discount, as described in “Note 1—Basis of Presentation and Summary of Significant Accounting Policies—Recently Adopted Accounting Pronouncements.” The increase in the carrying value of the 2018 Notes was offset by the conversion of $43.9 million of the 2018 Notes in the nine months ended September 30, 2021 (see “Note 8—Debt”). 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.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Accrued Expenses	Note 7—Accrued Expenses Accrued expenses consisted of the following as of the dates indicated (in thousands): As of September 30, As of December 31, Pass-through marketplace tax collection obligation $ 107,906 $ 109,662 Vendor accruals 74,038 73,437 Employee compensation-related liabilities 44,955 43,879 Income tax payable 18,401 5,374 Total accrued expenses $ 245,300 $ 232,352

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	Note 8—Debt 2021 Convertible Debt In June 2021, the Company issued $1.0 billion aggregate principal amount of the 2021 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 2021 Notes were approximately $986.7 million after deducting the initial purchasers’ discount and offering expenses and before the 2021 Capped Call Transactions, as described below, and the repurchase of stock, as described in “Note 10—Stockholders’ Equity.” The 2021 Notes are convertible into shares of the Company’s common stock based upon an initial conversion rate of 4.0518 shares of the Company’s common stock per $1,000 principal amount of 2021 Notes (equivalent to an initial conversion price of approximately $246.80 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. Based on the terms of the 2021 Notes, 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 2021 Notes in cash and, therefore, the 2021 Notes are classified as long-term debt as of September 30, 2021. The 2021 Notes will mature on June 15, 2028, unless earlier converted, redeemed, or repurchased. Prior to the close of business on the business day immediately preceding February 15, 2028, holders may convert all or a portion of their 2021 Notes only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on September 30, 2021 (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 2021 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) if the Company calls the 2021 Notes for redemption at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date, but only with respect to the 2021 Notes called (or deemed called) for redemption; or (4) upon the occurrence of specified corporate events. On and after February 15, 2028 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2021 Notes at any time, regardless of the foregoing circumstances. The Company may redeem all or any portion of the 2021 Notes, at the Company’s option, subject to partial redemption limitations, on or after June 20, 2025, if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive), including the trading day immediately preceding the date on which the Company provides notice of redemption, during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. If a fundamental change occurs prior to the maturity date, holders may require the Company to repurchase all or a portion of their 2021 Notes for cash at a price equal to 100% of the principal amount of the 2021 Notes to be repurchased. Holders of 2021 Notes who convert their 2021 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 2021 Notes. As of September 30, 2021, none of the conditions permitting the holders of the 2021 Notes to early convert have been met. In accounting for the issuance of the 2021 Notes, the Company recorded the 2021 Notes as a liability at face value. Transaction costs attributable to the liability were recorded as a direct deduction from the related debt liability in the Consolidated Balance Sheet and are amortized to interest expense over the term of the 2021 Notes. 2021 Capped Call Transactions The Company used $85.0 million of the net proceeds from the 2021 Notes to enter into privately negotiated capped call instruments (“2021 Capped Call Transactions”) with certain financial institutions. The 2021 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 2021 Notes upon conversion of the 2021 Notes in the event that the market price per share of the Company’s common stock is greater than the strike price of the 2021 Capped Call Transactions with such reduction and/or offset subject to a cap. The 2021 Capped Call Transactions have an initial cap price of $340.42 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 June 8, 2021, and is subject to certain adjustments under the terms of the 2021 Capped Call Transactions. Collectively, the 2021 Capped Call Transactions cover, initially, the number of shares of the Company’s common stock underlying the 2021 Notes, subject to anti-dilution adjustments substantially similar to those applicable to the 2021 Notes. The 2021 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 2021 Capped Call Transactions have been included as a net reduction to additional paid-in capital within stockholders’ equity. 2020 Convertible Debt In August 2020, the Company issued $650.0 million aggregate principal amount of the 2020 Notes in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act. The net proceeds from the sale of the 2020 Notes were approximately $639.5 million after deducting the offering expenses. The 2020 Notes are convertible into shares of the Company’s common stock based upon an initial conversion rate of 5.0007 shares of the Company’s common stock per $1,000 principal amount of 2020 Notes (equivalent to an initial conversion price of approximately $199.97 per share). The Company used $74.7 million of the net proceeds from the 2020 Notes offering to enter into separate capped call instruments (“2020 Capped Call Transactions”) with the initial purchasers and/or their respective affiliates. During any calendar quarter preceding May 1, 2027 in which the closing price of the Company’s common stock exceeds 130% of the applicable conversion price of the 2020 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 2020 Notes. Based on the daily closing prices of the Company’s stock during the quarter ended September 30, 2021, holders of the 2020 Notes are not eligible to convert their 2020 Notes during the fourth quarter of 2021. Based on the terms of the 2020 Notes, 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 2020 Notes in cash and, therefore, the 2020 Notes are classified as long-term debt as of September 30, 2021. 2019 Convertible Debt In September 2019, the Company issued $650.0 million aggregate principal amount of the 2019 Notes in a private placement to qualified institutional buyers pursuant to Rule 144A under 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 Company used $76.2 million of the net proceeds from the 2019 Notes offering to enter into separate capped call instruments (“2019 Capped Call Transactions”) with the initial purchasers and/or their respective affiliates. During any calendar quarter preceding June 1, 2026 in which the closing price of the Company’s common stock exceeds 130% of the applicable conversion price of the 2019 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 2019 Notes. Based on the daily closing prices of the Company’s stock during the quarter ended September 30, 2021, holders of the 2019 Notes are eligible to convert their 2019 Notes during the fourth quarter of 2021. Based on the terms of the 2019 Notes, 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 2019 Notes in cash and, therefore, the 2019 Notes are classified as long-term debt as of September 30, 2021. 2018 Convertible Debt In March 2018, the Company issued $345.0 million aggregate principal amount of the 2018 Notes in a private placement to qualified institutional buyers pursuant to Rule 144A under 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 Company used $34.2 million of the net proceeds from the 2018 Notes offering to enter into separate capped call instruments (“2018 Capped Call Transactions”) with the initial purchasers and/or their respective affiliates. During the third quarter of 2020, the Company paid $137.2 million in cash and issued approximately 7.3 million shares of Etsy’s common stock to repurchase $301.1 million aggregate principal amount of its outstanding 2018 Notes through privately negotiated transactions. Concurrently, the Company repurchased 1.3 million shares of Etsy’s common stock for $166.2 million, in order to effectively complete the partial repurchase of 2018 Notes principal value in cash, and the conversion premium in shares. The equity component impact associated with the conversion premium on the 2018 Notes was a net increase to additional paid-in capital of $143.2 million. This transaction was accounted for as an extinguishment of debt and recorded in accordance with the applicable accounting standard in the year ended December 31, 2020. The Company recognized a non-cash loss on extinguishment of $16.9 million. This loss was calculated by comparing the carrying value of the debt component with the fair value of a similar liability that does not have an associated convertible feature immediately prior to extinguishment as well as writing off any remaining unamortized deferred debt issuance costs at the time of extinguishment. During the nine months ended September 30, 2021, the Company paid $43.9 million in cash and issued approximately 1.0 million shares of Etsy’s common stock to settle conversion notices of $43.8 million aggregate principal amount of the outstanding 2018 Notes. The debt conversion transactions were accounted for in accordance with ASU 2020-06, which was adopted in the first quarter of 2021. See “Note 1—Basis of Presentation and Summary of Significant Accounting Policies—Recently Adopted Accounting Pronouncements” for additional information. 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 September 30, 2021, holders of the remaining 2018 Notes are eligible to convert their 2018 Notes during the fourth quarter of 2021. Based on the terms of the 2018 Notes, 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 remaining 2018 Notes are classified as long-term debt as of September 30, 2021. The following table presents the outstanding principal amount and carrying value of the Notes as of the dates indicated (in thousands): As of September 30, 2021 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Principal $ 1,000,000 $ 650,000 $ 649,988 $ 68 $ 2,300,056 Unamortized debt issuance costs 12,746 7,061 5,862 — 25,669 Net carrying value (1) $ 987,254 $ 642,939 $ 644,126 $ 68 $ 2,274,387 As of December 31, 2020 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Principal $ — $ 650,000 $ 650,000 $ 43,915 $ 1,343,915 Unamortized debt discount (1) — 130,308 129,224 4,286 263,818 Unamortized debt issuance costs — 7,959 6,741 463 15,163 Net carrying value $ — $ 511,733 $ 514,035 $ 39,166 $ 1,064,934 (1) Upon adoption of ASU 2020-06 as of January 1, 2021, the unamortized debt discount balance was derecognized, as described in “Note 1—Basis of Presentation and Summary of Significant Accounting Policies—Recently Adopted Accounting Pronouncements.” The annual effective interest rate for the 2021 Notes, 2020 Notes, 2019 Notes, and 2018 Notes was approximately 0.4%, 0.3%, 0.3%, and 0.4%, respectively. Interest expense related to each of the Notes for the periods presented below was as follows (in thousands): Three Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Total interest expense (1) $ 1,100 $ 502 $ 497 $ — $ 2,099 Three Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Coupon interest and amortization of debt issuance costs $ — $ 191 $ 462 $ 251 $ 904 Amortization of debt discount — 1,761 4,925 2,328 9,014 Total interest expense $ — $ 1,952 $ 5,387 $ 2,579 $ 9,918 Nine Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Total interest expense (1) $ 1,318 $ 1,505 $ 1,489 $ 44 $ 4,356 Nine Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Coupon interest and amortization of debt issuance costs $ — $ 191 $ 1,377 $ 1,020 $ 2,588 Amortization of debt discount — 1,761 14,626 9,450 25,837 Total interest expense $ — $ 1,952 $ 16,003 $ 10,470 $ 28,425 (1) Total interest expense for the three and nine months ended September 30, 2021 consisted of coupon interest and amortization of debt issuance costs, as there is no amortization of the debt discount in the current year due to the adoption of ASU 2020-06 as of January 1, 2021, as described in “Note 1—Basis of Presentation and Summary of Significant Accounting Policies—Recently Adopted Accounting Pronouncements.” The estimated fair value of each of the Notes was determined through inputs that are observable in the market, and are classified as Level 2. See “Note 6—Fair Value Measurements” for more information regarding the fair value of the Notes. The Notes are general unsecured obligations of the Company. The 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 the Company’s liabilities that are not so subordinated; 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. 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 12-month period consisting of the preceding four fiscal quarter periods. 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.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 9—Commitments and Contingencies In June 2021, the Company issued the 2021 Notes, see “Note 8—Debt” for more information. Additionally, in June 2021 the Company entered into a 5-year contractual commitment for cloud-based services with an aggregate future minimum payment obligation of $525.0 million, which includes escalating commitments each contract year. Commitments did not materially change during the nine months ended September 30, 2021 except for this activity. 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 could have an adverse effect on the Company’s results of operations, cash flows, or business and financial condition in the period the claims or litigation are resolved. Although the results of litigation and claims cannot be predicted with certainty, the Company currently believes that the final outcome of these ordinary course matters will not have a material adverse effect on its business.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Stockholders' Equity	Note 10—Stockholders’ Equity In December 2020, the Board of Directors approved a stock repurchase program that enables the Company to repurchase up to $250 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. Under the stock repurchase program, 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 could 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. In June 2021 the Company repurchased approximately 1.1 million shares of its common stock for approximately $180.0 million concurrently with the issuance of the 2021 Notes, see “Note 8—Debt.” This repurchase was separate from the stock repurchase plan approved by the Board of Directors in December 2020. The following table summarizes the Company’s cumulative share repurchase activity under the program noted above, excluding shares withheld to satisfy tax withholding obligations in connection with the vesting of employee RSUs and excluding the 1.1 million shares repurchased in June 2021 (in thousands, except share and per share amounts): Shares Repurchased Average Price Paid per Share (1) Value of Shares Repurchased (1) Remaining Amount Authorized Balance as of January 1, 2021 $ 250,000 Repurchases of common stock for the three months ended: March 31, 2021 — $ — $ — — June 30 2021 — — — — September 30, 2021 267,350 203.58 54,431 (54,431) Balance as of September 30, 2021 267,350 $ 203.58 $ 54,431 $ 195,569 (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	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Note 11—Stock-Based Compensation During the three and nine months ended September 30, 2021, the Company granted stock options and RSUs, including Financial PBRSUs and TSR PBRSUs, under its 2015 Equity Incentive Plan (“2015 Plan”) and, pursuant to the evergreen increase provision of the 2015 Plan, 6,291,797 additional shares were added to the total number of shares available for issuance under the 2015 Plan effective as of January 4, 2021. At September 30, 2021, 44,040,744 shares were authorized under the 2015 Plan and 29,533,786 shares were available for future grant. Starting in the second quarter of 2021, the Company updated certain assumptions used to determine the fair value of its stock options under the Black-Scholes option-pricing model, including the expected volatility and expected term assumptions. Given Etsy’s sufficient trading history as of the second quarter of 2021, the Company calculates expected volatility based solely on the historical volatility of Etsy’s stock price observations over a period equivalent to the expected term of the stock option grants. Prior to the second quarter of 2021, the Company estimated expected volatility by taking the average historical price volatility for Etsy and certain industry peers. Further, given that the Company has sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term of its stock options, beginning in the second quarter, the Company estimates its expected term using historical option exercise behavior and expected post-vest cancellation data, averaged with an assumption that recently granted options will be exercised ratably from vesting to the expiration of the stock option. Prior to the second quarter of 2021, the Company used the simplified method to calculate the expected term for awards issued to employees or members of the Company’s Board of Directors. These updated assumptions have been applied prospectively to option awards granted in or after the second quarter of 2021. The Company does not expect these changes to have a material impact on the Consolidated Statements of Operations. The fair value of options granted in the periods presented below using the Black-Scholes pricing model has been based on the following assumptions: Three Months Ended Nine Months Ended 2021 2020 2021 2020 Volatility 56.0% 41.7% 43.4% - 56.1% 38.9% - 41.7% Risk-free interest rate 0.9% 0.3% 0.8% - 1.1% 0.3% - 1.7% Expected term (in years) 5.12 6.12 - 6.16 4.86 - 6.15 5.52 - 6.16 The following table summarizes the activity for the Company’s options during the nine months ended September 30, 2021 (in thousands, except share and per share amounts): Shares Weighted-Average Exercise Price Weighted-Average Remaining Contract Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2020 5,099,952 $ 20.97 6.81 $ 800,453 Granted 194,148 219.12 Exercised (493,932) 22.00 Forfeited/Canceled (29,964) 47.86 Outstanding at September 30, 2021 4,770,204 28.75 6.20 857,569 Total exercisable at September 30, 2021 3,813,551 15.25 5.68 734,923 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 during the three and nine months ended September 30, 2021 and 2020 (in thousands, except per share amounts): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Weighted-average grant date fair value of options granted $ 96.83 $ 50.68 $ 94.88 $ 18.18 Intrinsic value of options exercised 29,247 42,278 92,489 94,737 Fair value of awards vested 13,561 8,855 49,296 35,262 The total unrecognized compensation expense at September 30, 2021 related to the Company’s options was $27.9 million, which will be recognized over an estimated weighted-average amortization period of 2.84 years. Service-based RSUs and, beginning in the first quarter of 2021, Financial PBRSUs and TSR PBRSUs, are awarded at fixed dollar amounts. The target number of shares underlying the awards is determined based on Etsy’s 30-day average share price leading up to and including the grant date. For the Financial PBRSUs, the number of RSUs received will depend on the achievement of financial metrics relative to the approved performance targets. Depending on the actual financial metrics achieved relative to the target financial metrics, throughout the defined performance period of the award, the number of PBRSUs that vest could range from 0% to 200% of the target amount, and are subject to the Compensation Committee’s approval of the level of achievement against the approved performance targets. For the TSR PBRSUs, the number of RSUs received will depend on the Company’s total shareholder return relative to that of the Nasdaq Composite Index over a three-year measurement period. In connection with the acquisitions of Depop and Elo7 in July 2021, outstanding, unvested options held by continuing employees of each acquired entity as of the respective acquisition dates were replaced with Etsy RSU awards with the same aggregate fair value, with a total dollar value of $78.8 million, $5.6 million of which relates to pre-combination service and was included as a component of the purchase price. These RSUs generally follow the original vesting schedule of the replaced options, which provided that they will vest 25% on the first anniversary of their original vesting commencement date with the remaining 75% vesting ratably each month thereafter until the fourth anniversary of their original vesting commencement date. The following table summarizes the activity for the Company’s unvested RSUs, which includes Financial PBRSUs and TSR PBRSUs, during the nine months ended September 30, 2021: Shares Weighted-Average Unvested at December 31, 2020 3,085,987 $ 50.28 Granted (1) 1,984,463 207.28 Vested (864,588) 48.06 Forfeited/Canceled (218,795) 86.94 Unvested at September 30, 2021 3,987,067 126.90 (1) Includes RSU awards issued to Depop and Elo7 employees in connection with the acquisitions in the third quarter of 2021. The total unrecognized compensation expense at September 30, 2021 related to the Company’s unvested RSUs, including the Financial PBRSUs and TSR PBRSUs, was $449.2 million, which will be recognized over an estimated weighted-average amortization period of 3.11 years. In connection with the acquisition of Depop, certain Depop executives are eligible to receive deferred consideration of $44.0 million in Etsy shares over the three years following the acquisition date, subject to certain service-based vesting conditions during the vesting period. These awards will be settled by issuing Etsy shares on or shortly following the applicable vesting date, with the number of shares to be determined based on the Company’s stock price on the applicable vesting date, and will therefore be recognized as post-combination service stock-based compensation expense over a three-year vesting period, with a corresponding liability included within Other liabilities on the Company’s Consolidated Balance Sheets until the service-based vesting criteria are met and the awards are settled in Etsy shares. The unrecognized compensation expense at September 30, 2021 related to these awards was $40.8 million, which will be recognized over a remaining term of 2.78 years. These amounts are excluded from the unrecognized compensation expense associated with the Company’s unvested RSUs noted above. Stock-based compensation expense included in the Consolidated Statements of Operations for the periods presented below is as follows (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Cost of revenue $ 3,587 $ 2,032 $ 8,985 $ 5,559 Marketing 4,102 1,360 7,639 3,941 Product development 17,345 8,668 40,588 23,941 General and administrative 17,222 5,068 32,835 14,223 Stock-based compensation expense $ 42,256 $ 17,128 $ 90,047 $ 47,664

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Event	Note 12—Subsequent Event In October 2021, the Company entered into a First Amendment to Lease (the "First Amendment") related to the Company's corporate headquarters located at 117 Adams Street and 55 Prospect Street, Brooklyn, NY. The First Amendment extends the expiration of the term of the current lease from July 31, 2026 to July 31, 2039 with an incremental future minimum payment obligation of approximately $163 million, $38 million of which relates to payments under the Company’s operating lease commitments, and $125 million of which relates to payments under the Company’s finance lease commitments. This aggregate increase to the Company’s minimum payment obligations includes a tenant allowance, a portion of which becomes available beginning in April 2022, rent concessions that become available in 2026, and escalating commitments each contract year between 2028 and 2038. The First Amendment is expected to result in increases to the Company’s right of use assets and lease liabilities related to the Company's operating and finance leases, which will result in the following changes within the Company's Consolidated Balance Sheets (in thousands): Property, plant and equipment, net $ 66,413 Other assets 20,391 Finance lease obligations—current portion (3,823) Finance lease obligations—net of current portion 70,236 Other liabilities 20,391

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Consolidation	Basis of ConsolidationThe consolidated financial statements include the accounts of Etsy and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. On July 2, 2021, Etsy acquired all the outstanding shares of Elo7 Serviços de Informática S.A. (“Elo7”) by means of a merger, and on July 12, 2021 Etsy acquired all of the issued share capital of Depop Limited (“Depop”) pursuant to a share purchase. The financial results of Elo7 and Depop have been included in Etsy’s Consolidated Financial Statements from the respective dates of acquisition.
Basis of Presentation	Basis of Presentation The accompanying unaudited interim consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and pursuant to the applicable rules and regulations of the Securities and Exchange Commission (“SEC”). The Company has condensed or omitted certain information and notes normally included in complete annual financial statements prepared in accordance with GAAP. These unaudited interim consolidated financial statements should therefore be read in conjunction with the audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K filed with the SEC on February 26, 2021 (the “Annual Report”). In the opinion of management, all material adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for the periods presented have been reflected in the consolidated financial statements. The results of operations of any interim period are not necessarily indicative of the results of operations for the full annual period or any future period due to seasonal and other factors.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires the Company to make estimates and judgments that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates and judgments. The accounting estimates that require management’s most subjective judgments include: stock-based compensation; income taxes, including the estimate of the annual effective tax rate at interim periods and evaluation of uncertain tax positions; purchase price allocations for business combinations and valuation of acquired intangible assets, developed technology, and goodwill. As of September 30, 2021, the effects of the ongoing COVID-19 pandemic and progress towards its abatement on the Comp any’s business, results of operations, and financial condition continue to evolve. A s a result, many of the Company’s estimates and judgments required increased judgment and carry a higher degree of variability and volatility. As additional information becomes available, the Company’s estimates may change materially in future periods.
Stock-Based Compensation	Stock-Based Compensation Service based stock options, service based restricted stock units (“RSUs”), and performance based restricted stock units (“PBRSUs”) are awarded to employees, officers, and members of the Company’s Board of Directors. The PBRSUs include financial performance based restricted stock units (“Financial PBRSUs”) and total shareholder return performance based restricted stock units (“TSR PBRSUs”), both of which have performance and service vesting requirements. The Company recognizes forfeitures as they occur. The Company calculates the fair value of stock options on the date of grant using the Black-Scholes option-pricing model. The fair value of RSUs is measured using the closing price of the Company’s common stock on Nasdaq on the grant date. Additionally, the fair value of the Financial PBRSUs is determined using a probability assessment and the fair value of the TSR PBRSUs with market conditions are determined using a Monte-Carlo simulation model.
Recently Issued Accounting Pronouncements and Recently Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements In October 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2021-08— Business Combinations (Topic 805)—Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , which requires contract assets and contract liabilities acquired in a business combination to be recognized and measured by the acquirer on the acquisition date in accordance with Accounting Standards Codification Topic 606— Revenue from Contracts with Customers (“ASC 606”). Under current GAAP, an acquirer generally recognizes assets acquired and liabilities assumed in a business combination, including contract assets and contract liabilities arising from revenue contracts with customers, at fair value on the acquisition date. This ASU will result in the acquirer recording acquired contract assets and liabilities on the same basis that would have been recorded by the acquiree before the acquisition under ASC 606. The amendments in this ASU do not affect the accounting for other assets or liabilities that may arise from revenue contracts with customers in accordance with ASC 606, such as refund liabilities, or in a business combination, such as customer-related intangible assets and contract-based intangible assets. The new guidance is effective for annual and interim periods beginning after December 15, 2022. Early adoption is permitted, including in interim periods, for any financial statements that have not yet been issued. This update should be applied prospectively to business combinations occurring on or after the effective date of the amendments. The Company is currently evaluating the impact that this new guidance may have on its consolidated financial statements. Recently Adopted Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06— Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity's Own Equity (Subtopic 815-40)—Accounting For Convertible Instruments and Contracts in an Entity's Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies accounting for convertible instruments by removing major separation models previously required under GAAP. Consequently, more convertible debt instruments will be reported as a single liability instrument with no separate accounting for embedded conversion features through equity. Without an initial allocation of proceeds to the conversion option, the debt will likely have a lower discount, thereby resulting in less non-cash interest expense through accretion. ASU 2020-06 removes certain settlement conditions that are required for equity contracts to qualify for the derivative scope exception, which will permit more equity contracts to qualify for it. ASU 2020-06 also simplifies the diluted net income per share calculation in certain areas. The new guidance is effective for annual and interim periods beginning after December 15, 2021, and early adoption is permitted for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. This update permits the use of either the modified retrospective or fully retrospective method of transition. The Company early adopted this standard, effective as of January 1, 2021, on a modified retrospective basis. The adoption of this standard had a material effect on the Company’s consolidated financial statements. The most significant effects related to the 0.125% Convertible Senior Notes due 2027 (the “2020 Notes”), 0.125% Convertible Senior Notes due 2026 (the “2019 Notes”), and 0% Convertible Senior Notes due 2023 (the “2018 Notes” and together with the 0.25% Convertible Senior Notes due 2028 (the “2021 Notes”), the 2020 Notes, and the 2019 Notes, the “Notes”), and included derecognition of the unamortized debt discount, which was recorded as a direct deduction from the Notes, resulting in an increase in long-term debt, net of approximately $264 million; derecognition of the equity component, which represents the value of the conversion option on the issuance date of the Notes outstanding, resulting in a reduction in additional paid-in capital of approximately $229 million, net of taxes; derecognition of deferred tax liabilities of approximately $63 million; and reversal of the cumulative debt discount recognized as interest expense in the Company’s Consolidated Statements of Operations since the date of issuance of each of the Notes to the period ending December 31, 2020, resulting in a decrease of accumulated deficit of approximately $28 million, net of taxes. The Company also had a reduction in interest expense due to the adoption of ASU 2020-06 as the debt discount has been derecognized and, effective January 1, 2021, there is no amortization of the debt discount. The Company did not incur any impact to liquidity or cash flows. When calculating net income per share of common stock attributable to common stockholders, the Company uses the if-converted method as required under ASU 2020-06 to determine the dilutive effect of the Notes.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table summarizes revenue disaggregated by Marketplace revenue and optional Services revenue for the periods presented (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Marketplace revenue $ 395,503 $ 341,623 $ 1,204,608 $ 829,575 Services revenue 136,926 109,855 407,367 278,695 Revenue $ 532,429 $ 451,478 $ 1,611,975 $ 1,108,270

Net Income Per Share (Tables)

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Method Used to Calculate Impact from Convertible Senior Notes on Net Income Per Share	The following table presents the method used when calculating the impact of the Company’s Notes on earnings per share for the periods presented: Three Months Ended Nine Months Ended 2021 2020 2021 2020 2021 Notes If-Converted N/A If-Converted N/A 2020 Notes If-Converted Treasury Stock If-Converted Treasury Stock 2019 Notes If-Converted If-Converted If-Converted If-Converted 2018 Notes If-Converted If-Converted If-Converted If-Converted
Schedule of Calculation of Basic and Diluted Net Income Per Share	The following table presents the calculation of basic and diluted net income per share for the periods presented (in thousands, except share and per share amounts): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Numerator: Net income attributable to common stockholders—basic $ 89,930 $ 91,761 $ 331,950 $ 200,708 Add back interest expense, net of tax attributable to assumed conversion of convertible senior notes 1,594 4,494 3,312 13,348 Net income attributable to common stockholders—diluted $ 91,524 $ 96,255 $ 335,262 $ 214,056 Denominator: Weighted-average common shares outstanding—basic 126,633,789 121,978,272 126,753,641 119,666,841 Dilutive effect of assumed conversion of options to purchase common stock 4,126,970 4,533,426 4,229,632 4,380,663 Dilutive effect of assumed conversion of restricted stock units 1,936,390 2,425,214 2,042,745 1,705,718 Dilutive effect of assumed conversion of convertible senior notes 14,716,766 8,623,473 12,840,779 8,623,473 Weighted-average common shares outstanding—diluted 147,413,915 137,560,385 145,866,797 134,376,695 Net income per share attributable to common stockholders—basic $ 0.71 $ 0.75 $ 2.62 $ 1.68 Net income per share attributable to common stockholders—diluted $ 0.62 $ 0.70 $ 2.30 $ 1.59
Schedule of Anti-Dilutive Securities Excluded from Computation of Net Income 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: Three Months Ended Nine Months Ended 2021 2020 2021 2020 Stock options 193,919 5,769 135,179 341,109 Restricted stock units 54,189 36,260 475,475 66,231 Convertible senior notes — 8,213,081 — 10,430,621 Total anti-dilutive securities 248,108 8,255,110 610,654 10,837,961

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Sep. 30, 2021
Business Combination and Asset Acquisition [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 of Depop assumed as of July 12, 2021 (the date of acquisition) (in thousands, except years): Preliminary Purchase Price Allocation Estimated Useful Life (in years) Current assets $ 4,249 Property and equipment other 1,299 2-5 Developed technology 84,661 5 Trademark 245,657 20 Customer relationships 147,116 13 Goodwill 1,131,099 Indefinite Current liabilities (18,878) Non-current liabilities (1) (28,097) Deferred tax liability, net (74,283) Total purchase price $ 1,492,823 (1) Non-current liabilities are primarily related to non-income tax related contingency reserves. The following table summarizes the allocation of the purchase price (at fair value) to the assets acquired and liabilities assumed of Elo7 as of July 2, 2021 (the date of acquisition) (in thousands): Preliminary Purchase Price Allocation Estimated Useful Life (in years) Current assets $ 2,721 Developed technology 12,084 5 Trademark 22,187 15 Customer relationships 44,374 15 Goodwill 159,009 Indefinite Non-current assets 590 Current liabilities (3,406) Non-current liabilities (2,691) Deferred tax liability, net (22,727) Total purchase price $ 212,141
Schedule of Unaudited Supplemental Pro Forma Information	The following unaudited pro forma summary presents consolidated information of the Company, including Depop and Elo7, as if the business combinations had occurred on January 1, 2020, the earliest period presented herein (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Revenue $ 534,395 $ 474,910 $ 1,656,452 $ 1,162,420 Net income 108,781 89,040 332,246 184,423
Schedule of Goodwill	The change in the carrying amount of goodwill from December 31, 2020 to September 30, 2021 is as follows, with the addition primarily due to the acquisitions of Depop and Elo7 (in thousands): Net Book Value Balance as of December 31, 2020 $ 140,810 Business combinations 1,290,108 Foreign currency translation adjustments (45,704) Balance as of September 30, 2021 $ 1,385,214
Schedule of Finite-Lived Intangible Assets	As of September 30, 2021, the gross book value and accumulated amortization of acquired intangible assets from the acquisitions of Depop and Elo7 were as follows (in thousands): As of September 30, 2021 Gross book Accumulated Net book Customer relationships $ 183,956 $ (2,974) $ 180,982 Trademark 258,886 (2,826) 256,060 Total acquired intangible assets $ 442,842 $ (5,800) $ 437,042
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Based on amounts recorded at September 30, 2021, the Company will recognize acquired intangible asset amortization expense for the three months ending December 31, 2021 and years ending December 31, 2022, 2023, 2024, 2025, and thereafter as follows (in thousands): Remainder of 2021 $ 6,754 2022 27,015 2023 27,015 2024 27,015 2025 27,015 Thereafter 322,228 Total amortization expense $ 437,042
Schedule of Property and Equipment	As of September 30, 2021, the gross book value and accumulated amortization of acquired developed technology from the acquisitions of Depop and Elo7, classified in property and equipment, net, were as follows (in thousands): As of September 30, 2021 Gross book value Accumulated amortization Net book value Developed technology $ 93,348 $ (3,983) $ 89,365

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Fair Values Company’s Investments	The following table sets forth the cost, gross unrealized losses, gross unrealized gains, and fair values of the Company’s investments as of the dates indicated (in thousands): Cost Gross Gross Fair Value Cash and Cash Equivalents Short-term Investments Long-term Investments September 30, 2021 Cash $ 175,615 $ — $ — $ 175,615 $ 175,615 $ — $ — Level 1 U.S. Government and agency securities 67,480 (2) 40 67,518 — 59,220 8,298 Money market funds (1) 440,380 — — 440,380 439,787 — — 507,860 (2) 40 507,898 439,787 59,220 8,298 Level 2 Certificate of deposit 22,898 — 3 22,901 — 22,901 — Commercial paper 27,326 (1) 5 27,330 4,000 23,330 — Corporate bonds 174,008 (80) 103 174,031 — 91,979 82,052 224,232 (81) 111 224,262 4,000 138,210 82,052 $ 907,707 $ (83) $ 151 $ 907,775 $ 619,402 $ 197,430 $ 90,350 December 31, 2020 Cash $ 346,136 $ — $ — $ 346,136 $ 346,136 $ — $ — Level 1 U.S. Government and agency securities 410,371 (3) 358 410,726 — 376,089 34,637 Money market funds (1) 920,643 — — 920,643 881,465 — — 1,331,014 (3) 358 1,331,369 881,465 376,089 34,637 Level 2 Certificate of deposit 12,746 — 5 12,751 6,000 6,751 — Commercial paper 14,494 — 4 14,498 10,498 4,000 — Corporate bonds 42,632 (7) 111 42,736 — 38,279 4,457 69,872 (7) 120 69,985 16,498 49,030 4,457 $ 1,747,022 $ (10) $ 478 $ 1,747,490 $ 1,244,099 $ 425,119 $ 39,094
Schedule of Estimated Fair Value Liability Component	The following table presents the carrying value and estimated fair value of the Notes as of the dates indicated (in thousands): As of September 30, 2021 As of December 31, 2020 Carrying Value Fair Value Carrying Value Fair Value 2021 Notes $ 987,254 $ 1,138,800 $ — $ — 2020 Notes (1) 642,939 802,555 511,733 536,126 2019 Notes (1) 644,126 1,554,771 514,035 566,399 2018 Notes (1) 68 390 39,166 42,157 $ 2,274,387 $ 3,496,516 $ 1,064,934 $ 1,144,682 (1) Upon adoption of ASU 2020-06 as of January 1, 2021, the carrying value of the Notes increased due to the derecognition of the unamortized debt discount, as described in “Note 1—Basis of Presentation and Summary of Significant Accounting Policies—Recently Adopted Accounting Pronouncements.” The increase in the carrying value of the 2018 Notes was offset by the conversion of $43.9 million of the 2018 Notes in the nine months ended September 30, 2021 (see “Note 8—Debt”).

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued expenses consisted of the following as of the dates indicated (in thousands): As of September 30, As of December 31, Pass-through marketplace tax collection obligation $ 107,906 $ 109,662 Vendor accruals 74,038 73,437 Employee compensation-related liabilities 44,955 43,879 Income tax payable 18,401 5,374 Total accrued expenses $ 245,300 $ 232,352

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Debt	The following table presents the outstanding principal amount and carrying value of the Notes as of the dates indicated (in thousands): As of September 30, 2021 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Principal $ 1,000,000 $ 650,000 $ 649,988 $ 68 $ 2,300,056 Unamortized debt issuance costs 12,746 7,061 5,862 — 25,669 Net carrying value (1) $ 987,254 $ 642,939 $ 644,126 $ 68 $ 2,274,387 As of December 31, 2020 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Principal $ — $ 650,000 $ 650,000 $ 43,915 $ 1,343,915 Unamortized debt discount (1) — 130,308 129,224 4,286 263,818 Unamortized debt issuance costs — 7,959 6,741 463 15,163 Net carrying value $ — $ 511,733 $ 514,035 $ 39,166 $ 1,064,934 (1) Upon adoption of ASU 2020-06 as of January 1, 2021, the unamortized debt discount balance was derecognized, as described in “Note 1—Basis of Presentation and Summary of Significant Accounting Policies—Recently Adopted Accounting Pronouncements.”
Schedule of Interest Expense	Interest expense related to each of the Notes for the periods presented below was as follows (in thousands): Three Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Total interest expense (1) $ 1,100 $ 502 $ 497 $ — $ 2,099 Three Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Coupon interest and amortization of debt issuance costs $ — $ 191 $ 462 $ 251 $ 904 Amortization of debt discount — 1,761 4,925 2,328 9,014 Total interest expense $ — $ 1,952 $ 5,387 $ 2,579 $ 9,918 Nine Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Total interest expense (1) $ 1,318 $ 1,505 $ 1,489 $ 44 $ 4,356 Nine Months Ended 2021 Notes 2020 Notes 2019 Notes 2018 Notes Total Coupon interest and amortization of debt issuance costs $ — $ 191 $ 1,377 $ 1,020 $ 2,588 Amortization of debt discount — 1,761 14,626 9,450 25,837 Total interest expense $ — $ 1,952 $ 16,003 $ 10,470 $ 28,425

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Class of Treasury Stock	The following table summarizes the Company’s cumulative share repurchase activity under the program noted above, excluding shares withheld to satisfy tax withholding obligations in connection with the vesting of employee RSUs and excluding the 1.1 million shares repurchased in June 2021 (in thousands, except share and per share amounts): Shares Repurchased Average Price Paid per Share (1) Value of Shares Repurchased (1) Remaining Amount Authorized Balance as of January 1, 2021 $ 250,000 Repurchases of common stock for the three months ended: March 31, 2021 — $ — $ — — June 30 2021 — — — — September 30, 2021 267,350 203.58 54,431 (54,431) Balance as of September 30, 2021 267,350 $ 203.58 $ 54,431 $ 195,569 (1) Average price paid per share excludes broker commissions. Value of shares repurchased includes broker commissions.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Black-Scholes Valuation Assumptions Used to Determine Fair Value of Options Granted	The fair value of options granted in the periods presented below using the Black-Scholes pricing model has been based on the following assumptions: Three Months Ended Nine Months Ended 2021 2020 2021 2020 Volatility 56.0% 41.7% 43.4% - 56.1% 38.9% - 41.7% Risk-free interest rate 0.9% 0.3% 0.8% - 1.1% 0.3% - 1.7% Expected term (in years) 5.12 6.12 - 6.16 4.86 - 6.15 5.52 - 6.16
Summary of Stock Option Activity	The following table summarizes the activity for the Company’s options during the nine months ended September 30, 2021 (in thousands, except share and per share amounts): Shares Weighted-Average Exercise Price Weighted-Average Remaining Contract Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2020 5,099,952 $ 20.97 6.81 $ 800,453 Granted 194,148 219.12 Exercised (493,932) 22.00 Forfeited/Canceled (29,964) 47.86 Outstanding at September 30, 2021 4,770,204 28.75 6.20 857,569 Total exercisable at September 30, 2021 3,813,551 15.25 5.68 734,923
Summary of Weighted Average Grant Date Fair Value and Fair Value of Awards Vested	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 during the three and nine months ended September 30, 2021 and 2020 (in thousands, except per share amounts): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Weighted-average grant date fair value of options granted $ 96.83 $ 50.68 $ 94.88 $ 18.18 Intrinsic value of options exercised 29,247 42,278 92,489 94,737 Fair value of awards vested 13,561 8,855 49,296 35,262
Summary of Unvested RSU Activity	The following table summarizes the activity for the Company’s unvested RSUs, which includes Financial PBRSUs and TSR PBRSUs, during the nine months ended September 30, 2021: Shares Weighted-Average Unvested at December 31, 2020 3,085,987 $ 50.28 Granted (1) 1,984,463 207.28 Vested (864,588) 48.06 Forfeited/Canceled (218,795) 86.94 Unvested at September 30, 2021 3,987,067 126.90 (1) Includes RSU awards issued to Depop and Elo7 employees in connection with the acquisitions in the third quarter of 2021.
Schedule of Stock-based Compensation Expense	Stock-based compensation expense included in the Consolidated Statements of Operations for the periods presented below is as follows (in thousands): Three Months Ended Nine Months Ended 2021 2020 2021 2020 Cost of revenue $ 3,587 $ 2,032 $ 8,985 $ 5,559 Marketing 4,102 1,360 7,639 3,941 Product development 17,345 8,668 40,588 23,941 General and administrative 17,222 5,068 32,835 14,223 Stock-based compensation expense $ 42,256 $ 17,128 $ 90,047 $ 47,664

Subsequent Event (Tables)

Subsequent Event (Tables)	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Schedule of Changes in Company's Consolidated Balance Sheets	The First Amendment is expected to result in increases to the Company’s right of use assets and lease liabilities related to the Company's operating and finance leases, which will result in the following changes within the Company's Consolidated Balance Sheets (in thousands): Property, plant and equipment, net $ 66,413 Other assets 20,391 Finance lease obligations—current portion (3,823) Finance lease obligations—net of current portion 70,236 Other liabilities 20,391

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Jan. 01, 2021	Dec. 31, 2020	Aug. 31, 2020	Sep. 30, 2019	Mar. 31, 2018
Reclassification [Line Items]
Increase in long-term debt, net	$ 2,274,351			$ 1,062,299
Additional paid-in capital	624,374			883,166
Reduction in deferred tax liabilities	(94,158)			(58,481)
Decrease in accumulated deficit	(21,467)			(146,819)
Accounting Standards Update 2020-06
Reclassification [Line Items]
Increase in long-term debt, net			$ 264,000
Additional paid-in capital			229,000
Reduction in deferred tax liabilities			63,000
Decrease in accumulated deficit			$ 28,000
Convertible Debt
Reclassification [Line Items]
Increase in long-term debt, net	2,274,387			1,064,934
Convertible Senior Notes Due 2027 | Convertible Debt
Reclassification [Line Items]
Debt instrument, interest rate, stated percentage					0.125%
Increase in long-term debt, net	642,939			511,733
Convertible Senior Notes Due 2026 | Convertible Debt
Reclassification [Line Items]
Debt instrument, interest rate, stated percentage						0.125%
Increase in long-term debt, net	644,126			514,035
Convertible Senior Notes Due 2023 | Convertible Debt
Reclassification [Line Items]
Debt instrument, interest rate, stated percentage							0.00%
Increase in long-term debt, net	68			39,166
Convertible Senior Notes Due 2028 | Convertible Debt
Reclassification [Line Items]
Debt instrument, interest rate, stated percentage		0.25%
Increase in long-term debt, net	$ 987,254			$ 0

Revenue - Summary of Revenue by

Revenue - Summary of Revenue by Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 532,429	$ 451,478	$ 1,611,975	$ 1,108,270
Marketplace revenue
Disaggregation of Revenue [Line Items]
Revenue	395,503	341,623	1,204,608	829,575
Services revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 136,926	$ 109,855	$ 407,367	$ 278,695

Revenue - Narrative (Details)

Revenue - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Revenue recognized in the period	$ 11.3

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate	(1.40%)
Unrecognized tax benefits, period increase	$ 2.9
Unrecognized tax benefits	26.6	$ 23.7
Unrecognized tax benefits that would impact effective tax rate favorably	$ 25.6

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	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income attributable to common stockholders—basic	$ 89,930	$ 91,761	$ 331,950	$ 200,708
Add back interest expense, net of tax attributable to assumed conversion of convertible senior notes	1,594	4,494	3,312	13,348
Net income attributable to common stockholders—diluted	$ 91,524	$ 96,255	$ 335,262	$ 214,056
Denominator:
Weighted average common shares outstanding—basic (in shares)	126,633,789	121,978,272	126,753,641	119,666,841
Dilutive effect of assumed conversion of convertible senior notes (in shares)	14,716,766	8,623,473	12,840,779	8,623,473
Weighted average common shares outstanding - diluted (in shares)	147,413,915	137,560,385	145,866,797	134,376,695
Net income per share attributable to common stockholders—basic (in dollars per shares)	$ 0.71	$ 0.75	$ 2.62	$ 1.68
Net income per share attributable to common stockholders—diluted (in dollars per share)	$ 0.62	$ 0.70	$ 2.30	$ 1.59
Stock Options
Denominator:
Dilutive effect of assumed conversion (in shares)	4,126,970	4,533,426	4,229,632	4,380,663
Restricted stock units
Denominator:
Dilutive effect of assumed conversion (in shares)	1,936,390	2,425,214	2,042,745	1,705,718

Net Income Per Share - Summary

Net Income Per Share - Summary of Shares Excluded from the Calculation of Diluted Net Income Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per share (in shares)	248,108	8,255,110	610,654	10,837,961
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)	193,919	5,769	135,179	341,109
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)	54,189	36,260	475,475	66,231
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)	0	8,213,081	0	10,430,621

Business Combinations - Narrati

Business Combinations - Narrative (Details) $ in Thousands	Jul. 12, 2021USD ($)	Jul. 02, 2021USD ($)	Dec. 31, 2021USD ($)	Sep. 30, 2021USD ($)reporting_unitsegment	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)
Business Acquisition [Line Items]
Cash consideration paid							$ 1,690,823	$ 0
Revenue				$ 532,429		$ 451,478	1,611,975	1,108,270
Net loss				$ (89,930)		(91,761)	(331,950)	(200,708)
Number of operating segments | segment				4
Number of reportable segments | segment				1
Number of reporting units | reporting_unit				4
Depop
Business Acquisition [Line Items]
Fair value of consideration transferred	$ 1,493,000
Cash consideration paid	1,479,000
Non-cash consideration, replacement equity awards	$ 4,800
Depop | Forecast
Business Acquisition [Line Items]
Businesses acquire due to payment			$ 9,200
Elo7
Business Acquisition [Line Items]
Fair value of consideration transferred		$ 212,100
Cash consideration paid		211,300
Non-cash consideration, replacement equity awards		$ 800
Depop and Elo7
Business Acquisition [Line Items]
Revenue					$ 17,400
Net loss					$ 26,800
Acquisition-related expenses				$ 25,000			35,000
Non-recurring acquisition-related expenses				$ 108,781		$ 89,040	332,246	184,423
Number of reporting units | reporting_unit				2
Amortization of intangible assets				$ 5,800
Depop and Elo7 | Developed technology
Business Acquisition [Line Items]
Depreciation				4,000
Depop and Elo7 | Acquisition-related Costs
Business Acquisition [Line Items]
Non-recurring acquisition-related expenses				$ 44,200			$ 58,400	$ 1,100

Business Combinations - Purchas

Business Combinations - Purchase Price Allocation (Details) - USD ($) $ in Thousands	Jul. 12, 2021	Jul. 02, 2021	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill			$ 1,385,214	$ 140,810
Depop
Business Acquisition [Line Items]
Current assets	$ 4,249
Goodwill	1,131,099
Current liabilities	(18,878)
Non-current liabilities	(28,097)
Deferred tax liability, net	(74,283)
Total purchase price	1,492,823
Depop | Trademark
Business Acquisition [Line Items]
Finite-lived intangibles	$ 245,657
Estimated Useful Life (in years)	20 years
Depop | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangibles	$ 147,116
Estimated Useful Life (in years)	13 years
Depop | Property and equipment other
Business Acquisition [Line Items]
Property and equipment	$ 1,299
Depop | Property and equipment other | Minimum
Business Acquisition [Line Items]
Estimated Useful Life (in years)	2 years
Depop | Property and equipment other | Maximum
Business Acquisition [Line Items]
Estimated Useful Life (in years)	5 years
Depop | Developed technology
Business Acquisition [Line Items]
Property and equipment	$ 84,661
Estimated Useful Life (in years)	5 years
Elo7
Business Acquisition [Line Items]
Current assets		$ 2,721
Goodwill		159,009
Non-current assets		590
Current liabilities		(3,406)
Non-current liabilities		(2,691)
Deferred tax liability, net		(22,727)
Total purchase price		212,141
Elo7 | Trademark
Business Acquisition [Line Items]
Finite-lived intangibles		$ 22,187
Estimated Useful Life (in years)		15 years
Elo7 | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangibles		$ 44,374
Estimated Useful Life (in years)		15 years
Elo7 | Developed technology
Business Acquisition [Line Items]
Property and equipment		$ 12,084
Estimated Useful Life (in years)		5 years

Business Combinations - Unaudit

Business Combinations - Unaudited Supplemental Pro Forma Information (Details) - Depop and Elo7 - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Business Acquisition [Line Items]
Revenue	$ 534,395	$ 474,910	$ 1,656,452	$ 1,162,420
Net income	$ 108,781	$ 89,040	$ 332,246	$ 184,423

Business Combinations - Goodwil

Business Combinations - Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 140,810
Business combinations	1,290,108
Foreign currency translation adjustments	(45,704)
Ending balance	$ 1,385,214

Business Combinations - Intangi

Business Combinations - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (42,598)	$ (25,705)
Net book value	613,104	$ 187,449
Depop and Elo7
Acquired Finite-Lived Intangible Assets [Line Items]
Gross book value	442,842
Accumulated amortization	(5,800)
Net book value	437,042
Customer relationships | Depop and Elo7
Acquired Finite-Lived Intangible Assets [Line Items]
Gross book value	183,956
Accumulated amortization	(2,974)
Net book value	180,982
Trademark | Depop and Elo7
Acquired Finite-Lived Intangible Assets [Line Items]
Gross book value	258,886
Accumulated amortization	(2,826)
Net book value	$ 256,060

Business Combinations - Future

Business Combinations - Future Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Net book value	$ 613,104	$ 187,449
Depop and Elo7
Business Acquisition [Line Items]
Remainder of 2021	6,754
2022	27,015
2023	27,015
2024	27,015
2025	27,015
Thereafter	322,228
Net book value	$ 437,042

Business Combinations - Develop

Business Combinations - Developed Technology (Details) - Developed technology - Depop and Elo7 $ in Thousands	Sep. 30, 2021USD ($)
Business Acquisition [Line Items]
Gross book value	$ 93,348
Accumulated amortization	(3,983)
Net book value	$ 89,365

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Values Company’s Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	$ 907,707	$ 1,747,022
Gross Unrealized Holding Loss	(83)	(10)
Gross Unrealized Holding Gain	151	478
Fair Value	907,775	1,747,490
Cash and Cash Equivalents	619,402	1,244,099
Short-term Investments	197,430	425,119
Long-term Investments	90,350	39,094
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	175,615	346,136
Gross Unrealized Holding Loss	0	0
Gross Unrealized Holding Gain	0	0
Fair Value	175,615	346,136
Cash and Cash Equivalents	175,615	346,136
Short-term Investments	0	0
Long-term Investments	0	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	507,860	1,331,014
Gross Unrealized Holding Loss	(2)	(3)
Gross Unrealized Holding Gain	40	358
Fair Value	507,898	1,331,369
Cash and Cash Equivalents	439,787	881,465
Short-term Investments	59,220	376,089
Long-term Investments	8,298	34,637
Level 1 | U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	67,480	410,371
Gross Unrealized Holding Loss	(2)	(3)
Gross Unrealized Holding Gain	40	358
Fair Value	67,518	410,726
Cash and Cash Equivalents	0	0
Short-term Investments	59,220	376,089
Long-term Investments	8,298	34,637
Level 1 | Money market funds (1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	440,380	920,643
Gross Unrealized Holding Loss	0	0
Gross Unrealized Holding Gain	0	0
Fair Value	440,380	920,643
Cash and Cash Equivalents	439,787	881,465
Short-term Investments	0	0
Long-term Investments	0	0
Funds receivable and seller accounts	600	39,200
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	224,232	69,872
Gross Unrealized Holding Loss	(81)	(7)
Gross Unrealized Holding Gain	111	120
Fair Value	224,262	69,985
Cash and Cash Equivalents	4,000	16,498
Short-term Investments	138,210	49,030
Long-term Investments	82,052	4,457
Level 2 | Certificate of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	22,898	12,746
Gross Unrealized Holding Loss	0	0
Gross Unrealized Holding Gain	3	5
Fair Value	22,901	12,751
Cash and Cash Equivalents	0	6,000
Short-term Investments	22,901	6,751
Long-term Investments	0	0
Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	27,326	14,494
Gross Unrealized Holding Loss	(1)	0
Gross Unrealized Holding Gain	5	4
Fair Value	27,330	14,498
Cash and Cash Equivalents	4,000	10,498
Short-term Investments	23,330	4,000
Long-term Investments	0	0
Level 2 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost	174,008	42,632
Gross Unrealized Holding Loss	(80)	(7)
Gross Unrealized Holding Gain	103	111
Fair Value	174,031	42,736
Cash and Cash Equivalents	0	0
Short-term Investments	91,979	38,279
Long-term Investments	$ 82,052	$ 4,457

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details)	Sep. 30, 2021
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities, investment maturity	12 months
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities, investment maturity	37 months

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Estimated Fair Value Liability Component (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Repayment of convertible senior notes		$ 43,863	$ 137,166
Convertible Debt | 2018 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Repayment of convertible senior notes	$ 137,200	43,900
Level 2 | Convertible Debt | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		2,274,387		$ 1,064,934
Level 2 | Convertible Debt | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		3,496,516		1,144,682
Level 2 | Convertible Debt | 2021 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		987,254		0
Level 2 | Convertible Debt | 2021 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		1,138,800		0
Level 2 | Convertible Debt | 2020 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		642,939		511,733
Level 2 | Convertible Debt | 2020 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		802,555		536,126
Level 2 | Convertible Debt | 2019 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		644,126		514,035
Level 2 | Convertible Debt | 2019 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		1,554,771		566,399
Level 2 | Convertible Debt | 2018 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		68		39,166
Level 2 | Convertible Debt | 2018 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value		$ 390		$ 42,157

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Pass-through marketplace tax collection obligation	$ 107,906	$ 109,662
Vendor accruals	74,038	73,437
Employee compensation-related liabilities	44,955	43,879
Income tax payable	18,401	5,374
Total accrued expenses	$ 245,300	$ 232,352

Debt - 2021 Convertible Debt (D

Debt - 2021 Convertible Debt (Details) - Convertible Debt $ / shares in Units, $ in Thousands	1 Months Ended
	Jun. 30, 2021USD ($)day$ / shares	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Principal | $		$ 2,300,056	$ 1,343,915
Convertible Senior Notes Due 2028
Debt Instrument [Line Items]
Principal | $	$ 1,000,000	$ 1,000,000	$ 0
Proceeds from issuance of convertible senior notes | $	$ 986,700
Conversion ratio	0.0040518
Conversion price (in dollars per share) | $ / shares	$ 246.80
Convertible Senior Notes Due 2028 | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Threshold trading days	20
Threshold consecutive trading days	30
Threshold percentage of stock price trigger	130.00%
Convertible Senior Notes Due 2028 | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Threshold trading days	5
Threshold consecutive trading days	10
Threshold percentage of stock price trigger	98.00%
Convertible Senior Notes Due 2028 | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price percent	100.00%

Debt - 2021 Capped Call Transac

Debt - 2021 Capped Call Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 08, 2021	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Purchase of capped calls		$ 85,000	$ 74,685
Convertible Debt | 2021 Capped Call Transactions
Debt Instrument [Line Items]
Purchase of capped calls	$ 85,000
Transaction price cap (in dollars per share)	$ 340.42
Cap premium percentage over reported sales price	100.00%

Debt - 2020 Convertible Debt (D

Debt - 2020 Convertible Debt (Details) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Aug. 31, 2020USD ($)day$ / shares	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Purchase of capped calls		$ 85,000	$ 74,685
Convertible Debt
Debt Instrument [Line Items]
Debt instrument		2,300,056		$ 1,343,915
Convertible Debt | Convertible Senior Notes Due 2027
Debt Instrument [Line Items]
Debt instrument	$ 650,000	$ 650,000		$ 650,000
Proceeds from issuance of convertible senior notes	$ 639,500
Conversion ratio	0.0050007
Conversion price (in dollars per share) | $ / shares	$ 199.97
Purchase of capped calls	$ 74,700
Convertible Debt | Convertible Senior Notes Due 2027 | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Threshold percentage of stock price trigger	130.00%
Threshold trading days | day	20
Threshold consecutive trading days | day	30

Debt - 2019 Convertible Debt (D

Debt - 2019 Convertible Debt (Details) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)day$ / shares	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Purchase of capped calls		$ 85,000	$ 74,685
Convertible Debt
Debt Instrument [Line Items]
Debt instrument		2,300,056		$ 1,343,915
Convertible Debt | Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Debt instrument	$ 650,000	$ 649,988		$ 650,000
Proceeds from issuance of convertible senior notes	$ 639,500
Conversion ratio	0.0114040
Conversion price (in dollars per share) | $ / shares	$ 87.69
Purchase of capped calls	$ 76,200
Convertible Debt | Convertible Senior Notes Due 2026 | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Threshold percentage of stock price trigger	130.00%
Threshold trading days | day	20
Threshold consecutive trading days | day	30

Debt - 2018 Convertible Debt (D

Debt - 2018 Convertible Debt (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended				9 Months Ended
	Mar. 31, 2018USD ($)day$ / shares	Sep. 30, 2021USD ($)shares	Jun. 30, 2021shares	Mar. 31, 2021shares	Sep. 30, 2020USD ($)shares	Sep. 30, 2021USD ($)shares	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Purchase of capped calls						$ 85,000	$ 74,685
Repayment of convertible senior notes						$ 43,863	137,166
Shares repurchased (in shares) | shares		267,350	0	0		267,350
Shares repurchased		$ 54,427			$ 166,170	$ 234,427	191,162
Issuance of convertible senior notes, net of issuance costs and taxes					102,131		102,131
Loss on extinguishment of debt		0			(16,855)	0	$ (16,855)
Convertible Debt
Debt Instrument [Line Items]
Debt instrument		2,300,056				2,300,056		$ 1,343,915
Convertible Debt | Convertible Senior Notes Due 2023
Debt Instrument [Line Items]
Debt instrument	$ 345,000	$ 68				68		$ 43,915
Proceeds from issuance of convertible senior notes	$ 335,000
Conversion ratio	0.0275691
Conversion price (in dollars per share) | $ / shares	$ 36.27
Purchase of capped calls	$ 34,200
Repayment of convertible senior notes					$ 137,200	$ 43,900
Debt instrument conversion amount, shares (in shares) | shares					7,300,000	1,000,000
Debt instrument conversion amount					$ 301,100	$ 43,800
Shares repurchased (in shares) | shares					1,300,000
Shares repurchased					$ 166,200
Issuance of convertible senior notes, net of issuance costs and taxes					143,200
Loss on extinguishment of debt					$ 16,900
Threshold percentage of stock price trigger	130.00%
Threshold trading days | day	20
Threshold consecutive trading days | day	30

Debt - Convertible Debt, Schedu

Debt - Convertible Debt, Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Aug. 31, 2020	Sep. 30, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Long-term debt, net	$ 2,274,351		$ 1,062,299
Convertible Debt
Debt Instrument [Line Items]
Principal	2,300,056		1,343,915
Unamortized debt discount			263,818
Unamortized debt issuance costs	25,669		15,163
Long-term debt, net	2,274,387		1,064,934
2021 Notes | Convertible Debt
Debt Instrument [Line Items]
Principal	1,000,000	$ 1,000,000	0
Unamortized debt discount			0
Unamortized debt issuance costs	12,746		0
Long-term debt, net	987,254		0
2020 Notes | Convertible Debt
Debt Instrument [Line Items]
Principal	650,000		650,000	$ 650,000
Unamortized debt discount			130,308
Unamortized debt issuance costs	7,061		7,959
Long-term debt, net	642,939		511,733
2019 Notes | Convertible Debt
Debt Instrument [Line Items]
Principal	649,988		650,000		$ 650,000
Unamortized debt discount			129,224
Unamortized debt issuance costs	5,862		6,741
Long-term debt, net	644,126		514,035
2018 Notes | Convertible Debt
Debt Instrument [Line Items]
Principal	68		43,915			$ 345,000
Unamortized debt discount			4,286
Unamortized debt issuance costs	0		463
Long-term debt, net	$ 68		$ 39,166

Debt - Convertible Debt, Sche_2

Debt - Convertible Debt, Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Total interest expense			$ 4,356	$ 28,425
Convertible Debt
Debt Instrument [Line Items]
Coupon interest and amortization of debt issuance costs		$ 904		2,588
Amortization of debt discount		9,014		25,837
Total interest expense	$ 2,099	9,918
2021 Notes
Debt Instrument [Line Items]
Total interest expense			$ 1,318	0
2021 Notes | Convertible Debt
Debt Instrument [Line Items]
Effective interest rate	0.40%		0.40%
Coupon interest and amortization of debt issuance costs		0		0
Amortization of debt discount		0		0
Total interest expense	$ 1,100	0
2020 Notes
Debt Instrument [Line Items]
Total interest expense			$ 1,505	1,952
2020 Notes | Convertible Debt
Debt Instrument [Line Items]
Effective interest rate	0.30%		0.30%
Coupon interest and amortization of debt issuance costs		191		191
Amortization of debt discount		1,761		1,761
Total interest expense	$ 502	1,952
2019 Notes
Debt Instrument [Line Items]
Total interest expense			$ 1,489	16,003
2019 Notes | Convertible Debt
Debt Instrument [Line Items]
Effective interest rate	0.30%		0.30%
Coupon interest and amortization of debt issuance costs		462		1,377
Amortization of debt discount		4,925		14,626
Total interest expense	$ 497	5,387
2018 Notes
Debt Instrument [Line Items]
Total interest expense			$ 44	10,470
2018 Notes | Convertible Debt
Debt Instrument [Line Items]
Effective interest rate	0.40%		0.40%
Coupon interest and amortization of debt issuance costs		251		1,020
Amortization of debt discount		2,328		$ 9,450
Total interest expense	$ 0	$ 2,579

Debt - 2019 Credit Agreement (D

Debt - 2019 Credit Agreement (Details) - USD ($)	Feb. 25, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Line of Credit Facility [Line Items]
Non-cash interest expense				$ 4,356,000	$ 28,425,000
Credit Agreement
Line of Credit Facility [Line Items]
Capitalization of debt issuance costs	$ 1,400,000
Unamortized debt issuance costs		$ 700,000		700,000		$ 900,000
Non-cash interest expense		100,000	$ 100,000	200,000	$ 200,000
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
Line of credit facility, amount outstanding		$ 0		$ 0		$ 0
Credit Agreement | Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Commitment fee amount	0.20%
Credit Agreement | Revolving Credit Facility | Maximum
Line of Credit Facility [Line Items]
Commitment fee amount	0.35%
Credit Agreement | Revolving Credit Facility | Federal Funds Effective Swap Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
Credit Agreement | Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
Credit Agreement | Revolving Credit Facility | One-Month London Interbank Offered Rate (LIBOR) Plus 1% | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.25%
Credit Agreement | Revolving Credit Facility | One-Month London Interbank Offered Rate (LIBOR) Plus 1% | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%
Credit Agreement | Revolving Credit Facility | London Interbank Offered Rate (LIBOR), Adjusted | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%
Credit Agreement | Revolving Credit Facility | London Interbank Offered Rate (LIBOR), Adjusted | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.875%
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

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	1 Months Ended
	Jun. 30, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Contractual commitment period	5 years
Contractual commitment	$ 525

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended				9 Months Ended
	Jun. 30, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Stock repurchase program, authorized amount								$ 250,000,000
Shares repurchased (in shares)		267,350	0	0		267,350
Shares repurchased		$ 54,427,000			$ 166,170,000	$ 234,427,000	$ 191,162,000
2021 Notes | Convertible Debt
Debt Instrument [Line Items]
Shares repurchased (in shares)	1,100,000
Shares repurchased	$ 180,000,000

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Activity of Shares Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2021	Jan. 01, 2021
Equity [Abstract]
Shares Repurchased (in shares)	267,350	0	0	267,350
Average Price Paid per Share (in dollars per share)	$ 203.58	$ 0	$ 0	$ 203.58
Stock repurchased and retired during period, value, including broker fees	$ (54,431)	$ 0	$ 0	$ (54,431)
Remaining Amount Authorized	$ 195,569			$ 195,569	$ 250,000

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions	Jul. 12, 2021	Jan. 04, 2021	Jul. 31, 2021	Sep. 30, 2021
Depop
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation, period of recognition				2 years 9 months 10 days
Precombination service awards, replacement awards	$ 4.8
Total unrecognized compensation				$ 40.8
Vesting period	3 years
Deferred purchase price for post-combination share-based service arrangement	$ 44
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation				$ 27.9
Total unrecognized compensation, period of recognition				2 years 10 months 2 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation, period of recognition				3 years 1 month 9 days
Average share price period				30 days
Total unrecognized compensation				$ 449.2
RSUs | Depop and Elo7
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate fair value of awards granted			$ 78.8
Precombination service awards, replacement awards			$ 5.6
RSUs | Depop and Elo7 | First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
RSUs | Depop and Elo7 | Ratably Each Month Thereafter
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			75.00%
Financial Performance Based Restricted Stock Units (RSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of awards that may be issued				0.00%
Financial Performance Based Restricted Stock Units (RSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of awards that may be issued				200.00%
Total Shareholder Return Performance Based Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period				3 years
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of additional shares issued annually (in shares)		6,291,797
Number of shares authorized (in shares)				44,040,744
Number of shares available for grant (in shares)				29,533,786

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Options Granted Using the Black-Scholes Pricing Model (Details) - Stock options	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	56.00%	41.70%
Risk-free interest rate	0.90%	0.30%
Expected term (in years)	5 years 1 month 13 days
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility			43.40%	38.90%
Risk-free interest rate			0.80%	0.30%
Expected term (in years)		6 years 1 month 13 days	4 years 10 months 9 days	5 years 6 months 7 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility			56.10%	41.70%
Risk-free interest rate			1.10%	1.70%
Expected term (in years)		6 years 1 month 28 days	6 years 1 month 24 days	6 years 1 month 28 days

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares
Shares
Outstanding, beginning balance (in shares)	5,099,952
Granted (in shares)	194,148
Exercised (in shares)	(493,932)
Forfeited/Canceled (in shares)	(29,964)
Outstanding, ending balance (in shares)	4,770,204	5,099,952
Total exercisable (in shares)	3,813,551
Weighted-Average Exercise Price
Outstanding, balance (in dollars per share) | $ / shares	$ 28.75	$ 20.97
Granted (in dollars per share) | $ / shares	219.12
Exercised (in dollars per share) | $ / shares	22
Forfeited/Canceled (in dollars per share) | $ / shares	47.86
Total exercisable (in dollars per share) | $ / shares	$ 15.25
Weighted-Average Remaining Contract Term (in years)
Outstanding, Weighted-Average Remaining Contractual Term	6 years 2 months 12 days	6 years 9 months 21 days
Total exercisable, Weighted-Average Remaining Contract Term	5 years 8 months 4 days
Aggregate Intrinsic Value
Outstanding, Aggregate Intrinsic Value | $	$ 857,569	$ 800,453
Total exercisable, Aggregate Intrinsic Value | $	$ 734,923

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Grant Date Fair Value of Options Granted, Intrinsic Value of Options Exercised and Fair Value of Awards Vested (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Weighted average grant date fair value of options granted (in dollars per share)	$ 96.83	$ 50.68	$ 94.88	$ 18.18
Intrinsic value of options exercised	$ 29,247	$ 42,278	$ 92,489	$ 94,737
Fair value of awards vested	$ 13,561	$ 8,855	$ 49,296	$ 35,262

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Unvested RSUs (Details) - RSUs - $ / shares	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Shares
Beginning balance, Unvested (in shares)	3,085,987
Granted (in shares)	1,984,463
Vested (in shares)	(864,588)
Forfeited/Cancelled (in shares)	(218,795)
Ending balance, Unvested (in shares)	3,987,067
Weighted-Average Grant Date Fair Value
Unvested, balance (in dollars per share)	$ 126.90	$ 50.28
Granted (in dollars per share)	207.28
Vested (in dollars per share)	48.06
Forfeited/Cancelled (in dollars per share)	$ 86.94

Stock-Based Compensation - Allo

Stock-Based Compensation - Allocated Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 42,256	$ 17,128	$ 90,047	$ 47,664
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3,587	2,032	8,985	5,559
Marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	4,102	1,360	7,639	3,941
Product development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	17,345	8,668	40,588	23,941
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 17,222	$ 5,068	$ 32,835	$ 14,223

Subsequent Event - Narrative (D

Subsequent Event - Narrative (Details) - Subsequent Event - First Amendment To Lease $ in Millions	Oct. 31, 2021USD ($)
Subsequent Event [Line Items]
Incremental future minimum payment obligation	$ 163
Incremental future minimum payment obligation, operating lease	38
Incremental future minimum payment obligation, finance lease	$ 125

Subsequent Event - Consolidated

Subsequent Event - Consolidated Balance Sheets (Details) - Subsequent Event - First Amendment To Lease $ in Thousands	1 Months Ended
	Oct. 31, 2021USD ($)
Subsequent Event [Line Items]
Property, plant and equipment, net	$ 66,413
Other assets	20,391
Finance lease obligations—current portion	(3,823)
Finance lease obligations—net of current portion	70,236
Other liabilities	$ 20,391