Stock-Based Compensation - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended									1 Months Ended	12 Months Ended
	Apr. 30, 2003 Person	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2014 ISOs [Member]	Jan. 31, 2014 NSOs [Member]	Jan. 31, 2014 Restricted Stock [Member]	Jan. 31, 2013 Restricted Stock [Member]	Jan. 31, 2012 Restricted Stock [Member]	Jan. 31, 2014 Employee Stock Option [Member]	Jun. 30, 2013 Stock Plan [Member]	Jan. 31, 2014 Stock Plan [Member]	Jan. 31, 2014 Stock Option Plan [Member]	Jan. 31, 2014 Two Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional common stock authorized for issuance											750,000
Number of common stock authorized for issuance											1,250,000
Expiration dates of stock incentive plans												2021-07	2011-07
Incentive stock option award maximum expiration period					10 years	10 years
Period to become exercisable					1 year	1 year	2 years
Number of shares of common stock reserved for issuance														1,448,650
Number of shares of common stock available for award at January 31, 2014												532,500
Intrinsic value of the stock options exercised		$ 3,158,000	$ 1,242,000	$ 238,000
Intrinsic value of outstanding stock options		10,124,000
Intrinsic value of exercisable stock options		7,977,000
Compensation expense		1,536,000	1,316,000	637,000
Unrecognized compensation cost		825,000
Compensation expense recognize, period										2014-12
Method used for fair value assumption		Black-Scholes option-pricing model
Volatility rate, minimum		0.73%	1.82%	1.98%
Volatility rate, maximum		1.52%	2.01%	3.42%
Stock options awarded, minimum		32.30%	34.50%	36.10%
Stock options awarded, maximum		34.30%	36.40%	57.60%
Market value of the shares amortized							10,000	25,000	15,000
Restricted stock awarded to employee									5,000
Warrants converted to shares of common stock			160,000
Conversion price for outstanding warrants			7.75
Number of individual to whom warrants issued	3
Aggregate fair value of the warrants	849,000
Company's expense for defined contribution savings plans		677,000	36,000	31,000
Defined contribution plan, profit-sharing contribution		$ 404,000