Segment Reporting - Company's Revenue by Geographic Region (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Revenue from External Customer [Line Items]
Total revenue	$ 33,941	$ 25,921
Hong Kong [Member]
Revenue from External Customer [Line Items]
Total revenue	28,774	21,200
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Total revenue	256	177
United States [Member]
Revenue from External Customer [Line Items]
Total revenue	2,605	3,036
North America [Member]
Revenue from External Customer [Line Items]
Total revenue	962	320
Europe [Member]
Revenue from External Customer [Line Items]
Total revenue	$ 1,344	$ 1,188