Equity Incentive Plans - Schedule of Stock Option Valuation Assumptions (Details) - Employee Stock Option	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	44.60%	41.40%	41.90%	41.40%
Expected volatility, maximum	45.70%	41.50%	45.70%	42.50%
Risk-free interest rate, minimum (as a percent)	1.80%	1.40%	1.80%	1.20%
Risk-free interest rate, maximum (as a percent)	2.10%	1.40%	2.10%	1.50%
Dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 11 months 19 days	5 years 10 months 28 days	5 years 10 months 6 days	5 years 9 months 7 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 10 days	6 years 29 days	6 years 2 months 12 days	6 years 11 months 27 days