Stock Option Plans - Summary of Company's Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding, beginning shares	1,427
Granted, shares	100
Exercised, shares	(91)
Forfeited, shares
Expired, shares
Outstanding, ending shares	1,436	1,427
Exercisable, shares	1,304
Vested and expected to vest, shares	1,429
Weighted Average Exercise Price, Outstanding beginning	$ 11.37
Weighted Average Exercise Price, Granted	$ 14.63	$ 8.10	$ 6.44
Weighted Average Exercise Price, Exercised	$ 5.61
Weighted Average Exercise Price, Forfeited
Weighted Average Exercise Price, Expired
Weighted Average Exercise Price, Outstanding ending	$ 12.04	$ 11.37
Weighted Average Exercise Price, Exercisable	$ 11.65
Weighted Average Exercise Price, Vested and expected to vest	$ 12.03
Weighted Average Remaining Contractual Term, outstanding	4 years 8 months 27 days
Weighted Average Remaining Contractual Term, exercisable	4 years 3 months 7 days
Weighted Average Remaining Contractual Term, Vested and expected to vest	4 years 8 months 19 days
Aggregate Intrinsic Value, Outstanding	$ 5,630
Aggregate Intrinsic Value, Exercisable	5,583
Aggregate Intrinsic Value, Vested and expected to vest	$ 5,628