Stock Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended						1 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2014 Common Stock [Member]	Jan. 31, 2012 Common Stock [Member]	Jan. 31, 2014 Incentive Stock Option [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member]
Schedule Of Stock Options [Line Items]
Stock options exercise price as a percentage of fair market value	100.00%					110.00%
Stock options, duration						5 years
Stock options, duration						10 years
Stock options, expiration period	10 years
Dividend yield	0.00%	0.00%	0.00%
Cashless exercise options exercised	4,170
Common stock options exercised	73,167			68,997	5,356
Restricted stock units granted							5,224
Total unrecognized compensation cost	$ 2.4
Weighted-average period	2 years 8 months 12 days