Intangible Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	$ 270	$ 540	$ 1,040
Intangible assets estimated useful life	3 years	3 years	3 years