Segment Information - Schedule of Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Revenues From External Customers And Long Lived Assets [Line Items]
Property and equipment, net	$ 125,353	$ 89,142	[1]
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Property and equipment, net	120,876	85,430
Rest of the world
Revenues From External Customers And Long Lived Assets [Line Items]
Property and equipment, net	$ 4,477	$ 3,712

[1] * As adjusted to reflect the impact of the full retrospective adoption of ASC 606