Significant Customers and Geographic Information - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues	$ 125,921	$ 95,139	$ 245,135	$ 176,483
United States
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues	78,658	59,605	157,374	110,385
Foreign Countries
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues	$ 47,263	$ 35,534	$ 87,761	$ 66,098