Stock-Based Compensation - Components of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total	$ 21,393	$ 1,588	$ 34,830	$ 5,239
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total	840	65	1,223	135
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total	8,823	261	15,962	3,024
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total	3,905	606	5,952	1,067
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total	$ 7,825	$ 656	$ 11,693	$ 1,013