Equity Incentive Plans - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Apr. 30, 2020	Jan. 31, 2020
Number of Shares
Options outstanding, beginning balance (in shares)	41,935,173
Options granted (in shares)	0
Options exercised (in shares)	(5,184,632)
Options cancelled or expired (in shares)	(296,847)
Options outstanding, ending balance (in shares)	36,453,694	41,935,173
Options exercisable (in shares)	23,125,246
Average Exercise Price per Share
Options outstanding, beginning balance, average exercise price (in usd per share)	$ 5.47
Options granted, weighted average exercise price (in usd per share)	0
Options exercised, weighted average exercise price (in usd per share)	3.65
Options cancelled or expired, weighted average exercise price (in usd per share)	6.36
Options outstanding, ending balance, average exercise price (in usd per share)	5.72	$ 5.47
Options exercisable, average exercise price (in usd per share)	$ 5.25
Weighted average remaining contractual term, options outstanding	7 years 3 months 21 days	7 years 3 months 14 days
Weighted average remaining contractual term, options exercisable	6 years 9 months 14 days
Aggregate intrinsic value, options outstanding	$ 954,124
Aggregate intrinsic value, exercises in period	92,667
Aggregate intrinsic value, options outstanding	574,497	$ 954,124
Aggregate intrinsic value, options exercisable	$ 375,356