Segment Information - Revenue by Geographic Area by Customer Location (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Revenues From External Customers And Long Lived Assets [Line Items]
Revenue	$ 31,772	$ 33,917	$ 96,993	$ 84,349
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Revenue	23,054	24,084	71,650	57,537
EMEA
Revenues From External Customers And Long Lived Assets [Line Items]
Revenue	4,882	4,659	14,020	12,756
Rest of the World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenue	$ 3,836	$ 5,174	$ 11,323	$ 14,056