Stockholders' Equity and Stock Based Compensation - Narrative (Details)		1 Months Ended				3 Months Ended		9 Months Ended
	Sep. 21, 2021 USD ($)	Sep. 30, 2021 USD ($) tranche target vote $ / shares shares	Aug. 31, 2021 shares	Feb. 28, 2021 shares	Jan. 31, 2020 USD ($)	Sep. 30, 2021 USD ($) vote $ / shares shares	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) vote $ / shares shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, authorized (in shares) | shares		10,000,000				10,000,000		10,000,000		0
Preferred stock, par value (in USD per share) | $ / shares		$ 0.00001				$ 0.00001		$ 0.00001		$ 0.00001
Total shares of common stock reserved for issuance (in shares) | shares		101,878,000				101,878,000		101,878,000		199,943,000
Contractual term								10 years
Stock-based compensation expense							$ 0	$ 124,259,000	$ 43,280,000
Unrecognized stock-based compensation expense		$ 612,100,000				$ 612,100,000		$ 612,100,000
Period for recognition								3 years 9 months 18 days
Secondary Transaction - Repurchase of Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense						6,100,000		$ 6,100,000	32,400,000
Secondary Transaction - Repurchase of Common Stock | Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense						2,600,000		$ 3,500,000	15,900,000
Secondary Transaction - Repurchase of Common Stock | General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense									16,500,000
Share-base compensation expense, excess value									10,800,000
Secondary transaction
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense									$ 43,200,000
Secondary transaction | General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense					$ 10,800,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period								4 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period								4 years
Contractual terms for restricted stock units								10 years
Number of shares approved for grant (in shares) | shares								26,376,000
Stock-based compensation expense	$ 0					124,259,000		$ 124,300,000
Performance Based Restricted Stock Units (PRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense						1,900,000		1,900,000
Performance Based Restricted Stock Units (PRSUs) | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares approved for grant (in shares) | shares		6,000,000		166,390
Number of threshold stock price targets | target		5
Number of threshold vesting tranches | tranche		5
Trading day period		60 days
Total grant date fair value		$ 131,000,000
Stock-based compensation expense						$ 1,400,000		$ 1,400,000
Performance Based Restricted Stock Units (PRSUs) | Chief Executive Officer | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Threshold stock price target (in USD per share) | $ / shares		$ 70.00
Performance Based Restricted Stock Units (PRSUs) | Chief Executive Officer | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Threshold stock price target (in USD per share) | $ / shares		$ 200.00
2021 Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for issuance (in shares) | shares		35,059,470	35,000,000			35,059,470		35,059,470
Percent of annual increase in capital shares reserved for future issuance			5.00%
Maximum amount of reduction to reserve (in shares) | shares						51,178,920
Shares cancelled and added to reserve (in shares) | shares		59,470				59,470		59,470
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for issuance (in shares) | shares		6,500,000				6,500,000		6,500,000		0
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, authorized (in shares) | shares		1,000,000,000				1,000,000,000		1,000,000,000		0
Common stock, number of votes per share | vote		1				1		1
Common stock, par value (in USD per share) | $ / shares		$ 0.00001				$ 0.00001		$ 0.00001		$ 0.00001
Class A Common Stock | 2021 Employee Stock Purchase Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for issuance (in shares) | shares			6,500,000
Purchase price of common stock in percent								85.00%
Class B Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, authorized (in shares) | shares		350,000,000				350,000,000		350,000,000		0
Common stock, number of votes per share | vote		10				10		10
Common stock, par value (in USD per share) | $ / shares		$ 0.00001				$ 0.00001		$ 0.00001		$ 0.00001