Information about Geographic Areas - Revenues by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Revenues by geography
Total revenues	$ 114,270	$ 106,921	$ 98,107	$ 89,923	$ 87,012	$ 83,825	$ 75,664	$ 66,721	$ 409,221	$ 313,222	$ 210,151
North America [Member]
Revenues by geography
Total revenues									225,483	173,261	124,451
Europe and other [Member]
Revenues by geography
Total revenues									111,923	81,782	49,944
Asia Pacific [Member]
Revenues by geography
Total revenues									$ 71,815	$ 58,179	$ 35,756