Revenue Recognition - Summary Disaggregation of Revenue by Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 166,593	$ 90,121	$ 434,407	$ 224,717
Percentage of revenue	100.00%	100.00%	100.00%	100.00%
Americas
Disaggregation of Revenue [Line Items]
Revenue	$ 133,864	$ 73,619	$ 349,122	$ 184,334
Percentage of revenue	81.00%	82.00%	81.00%	82.00%
Asia Pacific (“APAC”)
Disaggregation of Revenue [Line Items]
Revenue	$ 13,661	$ 7,646	$ 36,189	$ 18,466
Percentage of revenue	8.00%	8.00%	8.00%	8.00%
Europe, Middle East, and Africa (“EMEA”)
Disaggregation of Revenue [Line Items]
Revenue	$ 19,068	$ 8,856	$ 49,096	$ 21,917
Percentage of revenue	11.00%	10.00%	11.00%	10.00%