Segment Reporting - Company's Revenue by Geographic Region (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Revenue from External Customer [Line Items]
Total revenue	$ 45,990	$ 35,669	$ 117,641	$ 89,548
Hong Kong [Member]
Revenue from External Customer [Line Items]
Total revenue	39,502	31,036	101,471	77,126
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Total revenue	942	63	1,644	314
United States [Member]
Revenue from External Customer [Line Items]
Total revenue	1,710	1,931	5,557	6,335
North America [Member]
Revenue from External Customer [Line Items]
Total revenue	1,369	783	3,402	1,431
Europe [Member]
Revenue from External Customer [Line Items]
Total revenue	$ 2,467	$ 1,856	$ 5,567	$ 4,342