Basic and Diluted Net Loss per Share - Computation of Basic and Diluted Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Oct. 31, 2021	Jul. 31, 2021	Apr. 30, 2021	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Oct. 31, 2021	Oct. 31, 2020
Numerator:
Net loss	$ (69,442)	$ (84,938)	$ 82,289	$ (40,890)	$ (35,287)	$ (30,098)	$ (72,092)	$ (106,275)
Accretion of beneficial conversion feature of redeemable convertible preferred stock	0			(1,752)			0	(60,377)
Cumulative dividends on redeemable convertible preferred stock	0			(3,960)			(4,292)	(3,960)
Deemed dividends attributable to vested option holders	0			0			(51,855)	0
Deemed dividends attributable to common stock warrant holders	0			0			(110,635)	0
Net loss attributable to common stockholders - Basic	(69,442)			(46,602)			(238,874)	(170,612)
Gain attributable to earnout shares issued	0			0			(84,420)	0
Change in fair value of dilutive warrants	0			0			(51,106)	0
Net loss attributable to common stockholders - Diluted	$ (69,442)			$ (46,602)			$ (374,400)	$ (170,612)
Denominator:
Weighted average common shares outstanding (in shares)	325,223,132			15,102,625			286,272,045	13,550,552
Less: Weighted-average unvested restricted shares and shares subject to repurchase (in shares)	(188,212)			(111,759)			(246,562)	0
Weighted average shares outstanding - Basic (in shares)	325,034,920			14,990,866			286,025,483	13,550,552
Add: Earnout Shares under the treasury stock method (in shares)	0			0			4,948,794	0
Add: Public and Private Placement Warrants under the treasury stock method (in shares)	0			0			1,601,041	0
Weighted average shares outstanding - Diluted (in shares)	325,034,920			14,990,866			292,575,318	13,550,552
Net loss per share - Basic (USD per share)	$ (0.21)			$ (3.11)			$ (0.84)	$ (12.59)
Net loss per share - Diluted (USD per share)	$ (0.21)			$ (3.11)			$ (1.28)	$ (12.59)