Segment Information - Revenue by Geographic Area by Customer Location (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]
Revenue	$ 34,866	$ 27,556	$ 65,221	$ 50,432
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Revenue	25,934	18,868	48,597	33,453
EMEA
Revenues From External Customers And Long Lived Assets [Line Items]
Revenue	5,406	4,332	9,138	8,097
Rest of the World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenue	$ 3,526	$ 4,356	$ 7,486	$ 8,882