Stock-based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended			4 Months Ended	6 Months Ended		12 Months Ended
	Feb. 28, 2021	Feb. 28, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2017	Dec. 31, 2004
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares)			159,548,000			159,548,000	159,548,000		454,958,000
Share based payment arrangement, unvested award options, cost not yet recognized, amount			$ 200,000			$ 200,000	$ 200,000
Share based compensation by share based payment arrangement options granted (in shares)			0				0
Allocated share based compensation			$ 81,659		$ 7,409		$ 132,403	$ 49,666
Tender Offer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation									$ 35,200
Tender Offer | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares offered by existing shareholders to buy shares from employees and former employees (in shares)				31,100,000
Tender Offer | Series G Redeemable Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares offered by existing shareholders to buy shares from employees and former employees (in shares)				24,000,000.0
Two Thousand and Twenty Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to be granted price as a percentage of fair value									110.00%
Percentage of voting stock eligible for options									10.00%
Two Thousand and Twenty Equity Incentive Plan | Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares)			60,000,000.0			60,000,000.0	60,000,000.0
Two Thousand and Twenty Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share based compensation			$ 2,900				$ 3,400
Two Thousand and Twenty Employee Stock Purchase Plan | Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to be granted price as a percentage of fair value									85.00%
Common stock shares reserved for future issuance (in shares)									6,000,000
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares)			73,244,000			73,244,000	73,244,000		98,502,000
Share based payment arrangement, unvested award, period for recognition							3 years 1 month 6 days
Options | Two Thousand and Four Incentive Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement number of shares available for issuance (in shares)			0			0	0
Options | Two Thousand and Seventeen Amended and Restated Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of voting stock eligible for options										10.00%
Share based compensation by share based payment arrangement number of shares available for issuance (in shares)			0			0	0
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares)			10,092,000			10,092,000	10,092,000		3,061,000
Share based payment arrangement, unvested award, period for recognition							3 years 7 months 6 days
Unrecognized compensation, equity instruments other than options			$ 562,700			$ 562,700	$ 562,700
Allocated share based compensation				$ 21,300
Service period						4 years
Grant date fair value (in dollars per share)			$ 63.69			$ 63.69	$ 63.69		$ 31.55
Restricted Stock Units | Founder and CEO Long Term Performance Award | Founder CEO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation, equity instruments other than options	$ 232,200	$ 232,200	$ 214,800			$ 214,800	$ 214,800
Allocated share based compensation			12,200				$ 17,400
Share based compensation by share based payment arrangement maximum number of shares per employee (in shares)		11,500,000
Share-based compensation arrangement by share-based payment award, beginning Of award performance period, period after effective date		2 years
Number of consecutive trading days for the stock hurdle price to be achieved		90 days
Share price (in dollars per share)	$ 165.00	$ 165.00
Grant date fair value (in dollars per share)	$ 20.19	$ 20.19
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment arrangement, unvested award, period for recognition							2 years 4 months 24 days
Unrecognized compensation, equity instruments other than options			$ 7,500			$ 7,500	$ 7,500
Grant date fair value (in dollars per share)			$ 37.75			$ 37.75	$ 37.75		$ 37.75
Minimum | Options | Two Thousand and Four Incentive Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to be granted price as a percentage of fair value											85.00%
Minimum | Restricted Stock Units | Founder and CEO Long Term Performance Award | Founder CEO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment arrangement, unvested award, period for recognition	3 years 5 months 12 days
Maximum | Two Thousand and Twenty Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement contractual term of stock options									10 years
Maximum | Options | Two Thousand and Four Incentive Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement contractual term of stock options											10 years
Maximum | Options | Two Thousand and Seventeen Amended and Restated Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement contractual term of stock options										10 years
Maximum | Restricted Stock Units | Founder and CEO Long Term Performance Award | Founder CEO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment arrangement, unvested award, period for recognition	5 years 4 months 17 days
Holders of Ten Percent or More of The Voting Equity Capital | Two Thousand and Twenty Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement contractual term of stock options									5 years
Holders of Ten Percent or More of The Voting Equity Capital | Options | Two Thousand and Four Incentive Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of voting stock eligible for options											10.00%
Share based compensation by share based payment arrangement contractual term of stock options											5 years
Holders of Ten Percent or More of The Voting Equity Capital | Options | Two Thousand and Seventeen Amended and Restated Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement contractual term of stock options										5 years
Holders of Ten Percent or More of The Voting Equity Capital | Minimum | Two Thousand and Twenty Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to be granted price as a percentage of fair value									100.00%
Holders of Ten Percent or More of The Voting Equity Capital | Minimum | Options | Two Thousand and Four Incentive Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to be granted price as a percentage of fair value											110.00%
Holders of Ten Percent or More of The Voting Equity Capital | Minimum | Options | Two Thousand and Seventeen Amended and Restated Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options to be granted price as a percentage of fair value										110.00%