Summary of Business and Significant Accounting Policies - Activity Related to Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Receivables [Abstract]
Balance at beginning of period	$ 305	$ 305	$ 300
Add: charges (credits) to costs and expenses	227	(35)	317
Less: recoveries (write-offs)	(119)	35	(312)
Balance at end of period	$ 413	$ 305	$ 305