Income Taxes - Loss before Income Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Income Tax Disclosure [Abstract]
Domestic	$ (212.6)	$ (171.4)	$ (154.1)
Foreign	0.5	0.3	0.0
Net loss before income tax benefit / (expense)	$ (212.1)	$ (171.1)	$ (154.1)