Net Loss per Share Attributable to Common Stockholders - Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share (Details) - $ / shares		3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share Basic [Line Items]
Net loss per share, basic and diluted		$ (0.04)	$ (0.38)	$ (0.20)	$ (0.76)
Class A Common Stock [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				93,278,289	18,095,111
Net loss per share, basic and diluted		(0.04)	(0.38)	$ (0.20)	$ (0.76)
Class A Common Stock [Member] | Stock Option Activity [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				64,701,181	18,095,111
Class A Common Stock [Member] | Redeemable Convertible Preferred Stock [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				0	0
Class A Common Stock [Member] | Issuance Of Common Stock Upon Early Exercise Of Options Unvested [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				0	0
Class A Common Stock [Member] | Restricted Stock Units [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				3,511,500	0
Class A Common Stock [Member] | Warrant [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				25,065,608	0
Class B Common Stock [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				0	277,847,992
Net loss per share, basic and diluted		$ (0.04)	$ (0.38)	$ (0.20)	$ (0.76)
Class B Common Stock [Member] | Stock Option Activity [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options	0				65,643,621
Class B Common Stock [Member] | Redeemable Convertible Preferred Stock [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				0	198,274,933
Class B Common Stock [Member] | Issuance Of Common Stock Upon Early Exercise Of Options Unvested [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				0	13,929,438
Class B Common Stock [Member] | Restricted Stock Units [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				0	0
Class B Common Stock [Member] | Warrant [Member]
Earnings Per Share Basic [Line Items]
Outstanding stock options				0	0