Stock Based Compensation - Stock-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Stock Based Compensation [Line Items]
Stock-based compensation expense	$ 1,210	$ 924	$ 636
Cost of Revenues [Member]
Stock Based Compensation [Line Items]
Stock-based compensation expense	137	111	79
Sales and Marketing [Member]
Stock Based Compensation [Line Items]
Stock-based compensation expense	239	190	119
Research and Development [Member]
Stock Based Compensation [Line Items]
Stock-based compensation expense	376	308	227
General and Administrative [Member]
Stock Based Compensation [Line Items]
Stock-based compensation expense	$ 458	$ 315	$ 211