Information about Geographic Areas - Revenues by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Revenues by geography
Total revenues	$ 87,012	$ 83,825	$ 75,664	$ 66,721	$ 62,803	$ 54,979	$ 49,581	$ 42,788	$ 313,222	$ 210,151	$ 129,548
North America [Member]
Revenues by geography
Total revenues									173,261	124,451	84,546
Europe and other [Member]
Revenues by geography
Total revenues									81,782	49,944	29,036
Asia Pacific [Member]
Revenues by geography
Total revenues									$ 58,179	$ 35,756	$ 15,966