Stock-Based Compensation - Stock-Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	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]
Stock-based compensation	$ 2,635	$ 2,370	$ 8,726	$ 7,243
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	580	563	1,770	1,877
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,848	1,594	6,168	4,614
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 207	$ 213	$ 788	$ 752