Revenue Recognition - Summary Disaggregation of Revenue by Region (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 145,826	$ 74,526	$ 267,814	$ 134,596
Percentage of revenue	100.00%	100.00%	100.00%	100.00%
Americas
Disaggregation of Revenue [Line Items]
Revenue	$ 117,098	$ 61,155	$ 215,258	$ 110,715
Percentage of revenue	80.00%	82.00%	80.00%	82.00%
Asia Pacific (APAC)
Disaggregation of Revenue [Line Items]
Revenue	$ 12,088	$ 6,078	$ 22,529	$ 10,820
Percentage of revenue	8.00%	8.00%	9.00%	8.00%
Europe, Middle East, and Africa (EMEA)
Disaggregation of Revenue [Line Items]
Revenue	$ 16,640	$ 7,293	$ 30,027	$ 13,061
Percentage of revenue	12.00%	10.00%	11.00%	10.00%