Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Class A and Class B Common Stock	Class B Common Stock	Common Stock Class A and Class B Common Stock	Common Stock Class B Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Shares, beginning of period (in shares) at Jan. 31, 2020	113,523,948
Balance, beginning of period at Jan. 31, 2020	$ 201,826
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series E Preferred Stock, net of issuance costs (in shares)	31,405,183
Issuance of Series E Preferred Stock, net of issuance costs of $0.1 million	$ 152,539
Shares, end of period (in shares) at Jul. 31, 2020	144,929,131
Balance, end of period at Jul. 31, 2020	$ 354,365
Shares, beginning of period (in shares) at Jan. 31, 2020					33,550,809
Balance, beginning of period at Jan. 31, 2020	(224,213)				$ 1	$ 8,986	$ (201)	$ (232,999)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of options (in shares)					1,177,407
Issuance of common stock upon exercise of options	907					907
Vesting of early exercised options	29					29
Stock based compensation expense	5,258					5,258
Foreign currency translation adjustments	304						304
Net loss	(49,576)	$ (49,576)						(49,576)
Shares, end of period (in shares) at Jul. 31, 2020					34,728,216
Balance, end of period at Jul. 31, 2020	$ (267,291)				$ 1	15,180	103	(282,575)
Shares, beginning of period (in shares) at Apr. 30, 2020	144,929,131
Balance, beginning of period at Apr. 30, 2020	$ 354,365
Shares, end of period (in shares) at Jul. 31, 2020	144,929,131
Balance, end of period at Jul. 31, 2020	$ 354,365
Shares, beginning of period (in shares) at Apr. 30, 2020					34,416,477
Balance, beginning of period at Apr. 30, 2020	(246,171)				$ 1	13,305	160	(259,637)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of options (in shares)					311,739
Issuance of common stock upon exercise of options	267					267
Vesting of early exercised options	11					11
Stock based compensation expense	1,597					1,597
Foreign currency translation adjustments	(57)						(57)
Net loss	(22,938)	(22,938)						(22,938)
Shares, end of period (in shares) at Jul. 31, 2020					34,728,216
Balance, end of period at Jul. 31, 2020	$ (267,291)				$ 1	15,180	103	(282,575)
Shares, beginning of period (in shares) at Jan. 31, 2021	167,058,113
Balance, beginning of period at Jan. 31, 2021	$ 621,139
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)	(167,058,113)
Conversion of redeemable convertible preferred stock to common stock upon initial public offering	$ (621,139)
Shares, end of period (in shares) at Jul. 31, 2021	0
Balance, end of period at Jul. 31, 2021	$ 0
Shares, beginning of period (in shares) at Jan. 31, 2021				39,242,316
Balance, beginning of period at Jan. 31, 2021	(320,536)			$ 2		29,869	165	(350,572)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)				169,787,200
Conversion of redeemable convertible preferred stock to common stock upon initial public offering	621,139			$ 10		621,129
Issuance of common stock upon initial public offering and private placement, net of underwriting discounts and commissions (in shares)				41,678,568
Issuance of common stock upon initial public offering and private placement, net of underwriting discounts and commissions	1,380,960			$ 4		1,380,956
Issuance of common stock upon exercise of options (in shares)				4,625,342
Issuance of common stock upon exercise of options	5,827					5,827
Issuance of common stock upon exercise of warrants (in shares)				940,953
Vesting of early exercised options	554					554
Issuance of common stock and awards assumed in connection with acquisition (in shares)				7,277,214
Issuance of common stock and awards assumed in connection with acquisition	120,319			$ 1		120,318
Issuance of restricted stock awards (in shares)				1,315,099
Stock based compensation expense	37,712					37,712
Issuance of restricted stock for services provided (in shares)				20,000
Issuance of restricted stock for services provided	500					500
Foreign currency translation adjustments	290
Net loss	(130,797)	(130,797)						(130,797)
Shares, end of period (in shares) at Jul. 31, 2021				264,886,692
Balance, end of period at Jul. 31, 2021	$ 1,715,968			$ 17		2,196,865	455	(481,369)
Shares, beginning of period (in shares) at Apr. 30, 2021	167,058,113
Balance, beginning of period at Apr. 30, 2021	$ 621,139
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)	(167,058,113)
Conversion of redeemable convertible preferred stock to common stock upon initial public offering	$ (621,139)
Shares, end of period (in shares) at Jul. 31, 2021	0
Balance, end of period at Jul. 31, 2021	$ 0
Shares, beginning of period (in shares) at Apr. 30, 2021				50,504,590
Balance, beginning of period at Apr. 30, 2021	(245,874)			$ 3		166,974	355	(413,206)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)				169,787,200
Conversion of redeemable convertible preferred stock to common stock upon initial public offering	621,139			$ 10		621,129
Issuance of common stock upon initial public offering and private placement, net of underwriting discounts and commissions (in shares)				41,678,568
Issuance of common stock upon initial public offering and private placement, net of underwriting discounts and commissions	1,380,960			$ 4		1,380,956
Issuance of common stock upon exercise of options (in shares)				1,975,381
Issuance of common stock upon exercise of options	2,617					2,617
Issuance of common stock upon exercise of warrants (in shares)			940,953	940,953
Vesting of early exercised options	537					537
Stock based compensation expense	24,152					24,152
Issuance of restricted stock for services provided	500					500
Foreign currency translation adjustments	100
Net loss	(68,163)	$ (68,163)						(68,163)
Shares, end of period (in shares) at Jul. 31, 2021				264,886,692
Balance, end of period at Jul. 31, 2021	$ 1,715,968			$ 17		$ 2,196,865	$ 455	$ (481,369)