Equity Incentive Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
Jul. 31, 2020	Jul. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value, options granted in period (in usd per share)	$ 0	$ 5.38
Fair value of options vested during period	$ 12.7	$ 13.4
Unrecognized stock based compensation expense	$ 31.8
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognition period, unrecognized stock based compensation expense	2 years
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognition period, unrecognized stock based compensation expense	2 years 3 months 18 days
Unrecognized compensation expense	$ 131.7
Weighted average grant date fair value, stock units granted (in usd per share)	$ 22.84
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognition period, unrecognized stock based compensation expense	1 month 6 days
Unrecognized compensation expense	$ 0.7
Weighted average grant date fair value, stock units granted (in usd per share)	$ 5.48
Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value, stock units granted (in usd per share)	$ 22.30

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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