Stock-Based Compensation - Summary Stock Option Plan (Details) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jul. 31, 2021 USD ($) $ / shares shares	Jan. 31, 2021 USD ($) $ / shares shares
Number of Options
Outstanding, beginning of period (in shares)	37,231,191
Outstanding, end of period (in shares)	48,385,470	37,231,191
2013 Equity Incentive Plan
Number of Options
Outstanding, beginning of period (in shares)	37,231,191
Granted (in shares)	14,048,623
Exercised (in shares)	(3,296,747)
Forfeited (in shares)	(352,965)
Outstanding, end of period (in shares)	47,630,102	37,231,191
Expected to vest (in shares)	47,630,206
Options, vested and exercisable, number (in shares)	15,494,656
Weighted-Average Exercise Price
Outstanding, beginning of period (in USD per share) | $ / shares	$ 1.68
Granted (in USD per share) | $ / shares	9.66
Exercised (in USD per share) | $ / shares	1.24
Forfeited (in USD per share) | $ / shares	3.86
Outstanding, end of period (in USD per share) | $ / shares	4.04	$ 1.68
Expected to vest (in USD per shares) | $ / shares	4.04
Options, vested and exercisable, weighted average exercise price (in USD per share) | $ / shares	$ 1.51
Weighted-Average Remaining Contractual Term (in years)
Weighted-Average Remaining Contractual Term (in years), Outstanding	8 years 5 months 8 days	8 years 4 months 2 days
Expected to vest (in years)	8 years 5 months 8 days
Weighted-Average Remaining Contractual Term (in years), Vested and exercisable (in years)	7 years 3 months 10 days
Aggregate Intrinsic Value (in thousands)
Outstanding, beginning of period | $	$ 442,515
Outstanding, end of period | $	2,156,010	$ 442,515
Expected to vest | $	2,156,010
Vested and exerisable | $	$ 740,631