Equity Incentive Plans and Stock-Based Compensation - Option Activity Under Stock Plans (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021
Stock Options (in thousands)
Outstanding, beginning balance (in shares)	23,013
Granted (in shares)	2,041
Exercised (in shares)	(10,048)
Forfeited (in shares)	(455)
Expired (in shares)	(7)
Outstanding, ending balance (in shares)	14,544	23,013
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 1.58
Granted (in dollars per share)	0.10
Exercised (in dollars per share)	1.16
Forfeited (in dollars per share)	2.55
Expired (in dollars per share)	2.40
Outstanding, ending balance (in dollars per share)	$ 1.64	$ 1.58
Outstanding, Weighted-Average Remaining Contractual Life (years)	7 years 7 months 6 days	7 years 10 months 24 days
Outstanding, Aggregate Intrinsic Value	$ 507,419	$ 1,207,831
Vested and exercisable, Number of Stock Options (in shares)	7,389
Vested and exercisable, Weighted-average exercise price (in dollars per share)	$ 1.54
Vested and exercisable, Weighted-Average Remaining Contractual Life (years)	6 years 10 months 24 days
Vested and exercisable, Aggregate Intrinsic Value	$ 258,486