Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Tax Credit Carryforward [Line Items]
Increase (decrease) of valuation allowance	$ 298,700,000	$ 35,500,000	$ (2,300,000)
Unrecognized tax benefits, if recognized, would impact effective tax rate	2,000,000.0	2,000,000.0	1,000,000.0
Interest and penalties	100,000	300,000	$ 0
Interest and penalties, cumulative liability	200,000	$ 300,000
Federal Income Tax
Tax Credit Carryforward [Line Items]
Operating loss carryforward	1,264,300,000
Federal Income Tax | Research and Development Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	13,600,000
State Income Tax
Tax Credit Carryforward [Line Items]
Operating loss carryforward	797,000,000.0
State Income Tax | Research and Development Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	11,400,000
Foreign Tax
Tax Credit Carryforward [Line Items]
Operating loss carryforward	$ 34,100,000