Stock-Based Compensation - Summary of Stock Option Activity Under Equity Incentive Plans and Related Information (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Oct. 31, 2017	Jan. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Subject to Options Outstanding, Beginning balance	12,318,800
Shares Subject to Options Outstanding, Options granted	1,533,056
Shares Subject to Options Outstanding, Options exercised	(1,561,172)
Shares Subject to Options Outstanding, Options forfeited/cancelled	(852,990)
Shares Subject to Options Outstanding, Ending balance	11,437,694	12,318,800
Shares Subject to Options Outstanding, Vested and expected to vest	11,330,158
Shares Subject to Options Outstanding, Exercisable	8,939,286
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Beginning Balance	$ 7.44
Weighted Average Exercise Price, Options granted	17.46
Weighted Average Exercise Price, Options exercised	6.36
Weighted Average Exercise Price, Options forfeited/cancelled	15.05
Weighted Average Exercise Price, Ending Balance	8.37	$ 7.44
Weighted Average Exercise Price, Vested and expected to vest	8.30
Weighted Average Exercise Price, Exercisable	$ 6.36
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Life (Years)	5 years 11 months 26 days	6 years 5 months 1 day
Weighted Average Remaining Contractual Life (Years), Vested and expected to vest	5 years 11 months 19 days
Weighted Average Remaining Contractual Life (Years), Exercisable	5 years 3 months 19 days
Aggregate Intrinsic Value, Balance	$ 155,364	$ 119,606
Aggregate Intrinsic Value, Vested and expected to vest	154,675
Aggregate Intrinsic Value, Exercisable	$ 139,342