Segment Information - Schedule of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 224,461	$ 163,214	$ 407,092	$ 303,161
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	165,466	122,103	311,960	233,330
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 58,995	$ 41,111	$ 95,132	$ 69,831