Payment of withholding taxes and option costs on net share settlement of restricted stock units and stock options.

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- Definition

Amount of cost capitalized for award under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

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Stock-based Compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Capitalized website development and internal-use software costs excluded from stock-based compensation expense	$ 777	$ 656		$ 2,212	$ 1,323
Total payments for employees' tax obligations to taxing authorities due to net share settlements and cashless exercises of options	$ 3,106	$ 2,922		$ 11,314	$ 8,708
Class A Common Stock
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Employee tax withholding requirements and option costs due to net share settlement	114,973	111,370	119,009	404,626	337,313
2020 CO Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of shares authorized for issuances	485,714			485,714
2021 CO Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Number of shares authorized for issuances	228,571			228,571