Segment Reporting - Company's Revenue by Geographic Region (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Revenue from External Customer [Line Items]
Total revenue	$ 37,710	$ 27,958	$ 71,651	$ 53,879
Operating Segment [Member] | Hong Kong [Member]
Revenue from External Customer [Line Items]
Total revenue	33,195	24,890	61,969	46,090
Operating Segment [Member] | Asia Pacific [Member]
Revenue from External Customer [Line Items]
Total revenue	446	74	702	251
Operating Segment [Member] | United States [Member]
Revenue from External Customer [Line Items]
Total revenue	1,242	1,368	3,847	4,404
Operating Segment [Member] | North America [Member]
Revenue from External Customer [Line Items]
Total revenue	1,071	328	2,033	648
Operating Segment [Member] | Europe [Member]
Revenue from External Customer [Line Items]
Total revenue	$ 1,756	$ 1,298	$ 3,100	$ 2,486