Equity Incentive Plans - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Apr. 30, 2020 USD ($) $ / shares shares	Oct. 31, 2020 USD ($) $ / shares shares
Number of Shares
Options outstanding, beginning balance (in shares) | shares	41,935,173	41,935,173
Options exercised (in shares) | shares		(12,710,980)
Options cancelled or expired (in shares) | shares		(722,413)
Options outstanding, ending balance (in shares) | shares		28,501,780
Options exercisable (in shares) | shares		18,985,268
Average Exercise Price per Share
Options outstanding, beginning balance, average exercise price (in usd per share) | $ / shares	$ 5.47	$ 5.47
Options exercised, weighted average exercise price (in usd per share) | $ / shares		4.52
Options cancelled or expired, weighted average exercise price (in usd per share) | $ / shares		6.69
Options outstanding, ending balance, average exercise price (in usd per share) | $ / shares		5.86
Options exercisable, average exercise price (in usd per share) | $ / shares		$ 5.51
Weighted average remaining contractual term, options outstanding	7 years 3 months 14 days	6 years 11 months 15 days
Weighted average remaining contractual term, options exercisable		6 years 6 months 18 days
Aggregate intrinsic value, options outstanding | $	$ 954,124	$ 954,124
Aggregate intrinsic value, exercises in period | $		304,448
Aggregate intrinsic value, options outstanding | $		643,884
Aggregate intrinsic value, options exercisable | $		$ 435,592