Geographic Information - Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Revenues from External Customers and Long-Lived Assets
Revenue	$ 592,049	$ 264,748	$ 96,666
United States
Revenues from External Customers and Long-Lived Assets
Revenue	499,590	233,828	90,222
Other
Revenues from External Customers and Long-Lived Assets
Revenue	$ 92,459	$ 30,920	$ 6,444