Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Income Statement [Abstract]
Revenue	$ 56,018	$ 24,557	$ 139,163	$ 63,188
Cost of revenue	20,357	10,341	57,428	25,497
Gross profit	35,661	14,216	81,735	37,691
Operating expenses:
Research and development	34,773	14,925	93,630	42,266
Sales and marketing	41,311	19,974	118,461	54,027
General and administrative	26,951	9,003	65,785	19,874
Total operating expenses	103,035	43,902	277,876	116,167
Loss from operations	(67,374)	(29,686)	(196,141)	(78,476)
Interest income	99	10	143	206
Interest expense	(3)	(312)	(785)	(1,089)
Other income (expense), net	(1,055)	(111)	(2,021)	(122)
Loss before provision for income taxes	(68,333)	(30,099)	(198,804)	(79,481)
Provision for income taxes	262	57	588	251
Net loss	$ (68,595)	$ (30,156)	$ (199,392)	$ (79,732)
Net loss per share attributable to Class A and Class B common stockholders, basic (in USD per share)	$ (0.26)	$ (0.85)	$ (1.39)	$ (2.30)
Net loss per share attributable to Class A and Class B common stockholders, diluted (in USD per share)	$ (0.26)	$ (0.85)	$ (1.39)	$ (2.30)
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders, basic (in shares)	262,999,535	35,646,513	143,199,215	34,705,426
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders, diluted (in shares)	262,999,535	35,646,513	143,199,215	34,705,426