Balance Sheet Components - Schedule of Other Long-Term Assets (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Oct. 31, 2020	Oct. 31, 2020	Jan. 31, 2020
Property Plant And Equipment [Line Items]
Capitalized stock-based compensation expenses	$ 5.9	$ 5.9	$ 5.0
Accumulated amortization of capitalized software costs	8.3	8.3	$ 1.7
Amortization expense related to capitalized software	$ 2.7	$ 6.7
On-premises software | Maximum
Property Plant And Equipment [Line Items]
Finite-lived intangible asset, estimated useful life		4 years
On-premises software | Minimum
Property Plant And Equipment [Line Items]
Finite-lived intangible asset, estimated useful life		3 years