Information about Geographic Areas - Revenues by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Revenues by geography
Total revenues	$ 150,153	$ 142,779	$ 131,347	$ 119,764	$ 114,270	$ 106,921	$ 98,107	$ 89,923	$ 544,043	$ 409,221	$ 313,222
North America [Member]
Revenues by geography
Total revenues									297,014	225,483	173,261
Europe and other [Member]
Revenues by geography
Total revenues									160,666	111,923	81,782
Asia Pacific [Member]
Revenues by geography
Total revenues									$ 86,363	$ 71,815	$ 58,179