Segment Information - Schedule of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 727,977	$ 440,333	$ 174,451
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	561,352	343,625	134,920
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 166,625	$ 96,708	$ 39,531