Income Taxes - Components of Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Current provision:
Federal									$ 13,837	$ 9,211	$ 1,603
State									1,186	1,138	124
Foreign									1,644	600	165
Total									16,667	10,949	1,892
Deferred provision:
Federal									(1,360)	(616)	289
State									(94)	(23)	242
Foreign									(328)
Total									(1,781)	(639)	530
Provision for income taxes	$ 4,696	$ 3,585	$ 3,775	$ 2,829	$ 3,075	$ 3,109	$ 2,454	$ 1,672	$ 14,885	$ 10,310	$ 2,423