Summary of Business and Significant Accounting Policies - Activity Related to Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Receivables [Abstract]
Balance at beginning of period	$ 413	$ 305	$ 305
Add: charges (credits) to costs and expenses	201	227	(35)
Less: recoveries (write-offs)	(72)	(119)	35
Balance at end of period	$ 542	$ 413	$ 305