Redeemable Convertible Preferred Stock - Summary of Redeemable Convertible Preferred Stock (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)	0	154,055,430
Redeemable convertible preferred stock, outstanding (in shares)	0	153,937,730	153,938,000	142,662,000
Liquidation Preference	$ 0	$ 326,559,000
Carrying Value	$ 0	$ 2,895,096,000	$ 1,334,572,000	$ 631,413,000
Series A
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		21,428,000
Redeemable convertible preferred stock, outstanding (in shares)		21,311,000
Original issuance price (in dollars per share)		$ 0.05
Liquidation Preference		$ 1,059,000
Carrying Value		$ 397,172,000
Series B
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		36,229,000
Redeemable convertible preferred stock, outstanding (in shares)		36,229,000
Original issuance price (in dollars per share)		$ 0.14
Liquidation Preference		$ 5,000,000
Carrying Value		$ 675,223,000
Series C
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		15,307,000
Redeemable convertible preferred stock, outstanding (in shares)		15,307,000
Original issuance price (in dollars per share)		$ 0.46
Liquidation Preference		$ 7,000,000
Carrying Value		$ 285,280,000
Series D
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		30,663,000
Redeemable convertible preferred stock, outstanding (in shares)		30,663,000
Original issuance price (in dollars per share)		$ 1.01
Liquidation Preference		$ 31,000,000
Carrying Value		$ 571,476,000
Series E
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		21,292,000
Redeemable convertible preferred stock, outstanding (in shares)		21,292,000
Original issuance price (in dollars per share)		$ 2.35
Liquidation Preference		$ 50,000,000
Carrying Value		$ 396,927,000
Series F
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		8,709,000
Redeemable convertible preferred stock, outstanding (in shares)		8,709,000
Original issuance price (in dollars per share)		$ 3.16
Liquidation Preference		$ 27,500,000
Carrying Value		$ 162,439,000
Series G
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		9,151,000
Redeemable convertible preferred stock, outstanding (in shares)		9,151,000
Original issuance price (in dollars per share)		$ 6.01
Liquidation Preference		$ 55,000,000
Carrying Value		$ 172,344,000
Series H
Temporary Equity [Line Items]
Redeemable convertible preferred stock, authorized (in shares)		11,276,000
Redeemable convertible preferred stock, outstanding (in shares)		11,276,000
Original issuance price (in dollars per share)		$ 13.30
Liquidation Preference		$ 150,000,000
Carrying Value		$ 234,235,000