Net Loss Per Share - Exercise Prices of Common Shares above Market Price of Common Stock (Detail) (Stock Options [Member]) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issuable upon the exercise of stock options that are anti-dilutive	691	1,225	634	670