Stock-Based Compensation - Additional Information (Detail) $ in Millions	3 Months Ended
Apr. 30, 2020 USD ($)
New Accounting Pronouncement, Early Adoption [Line Items]
Unamortized share-based compensation expense	$ 420.8
Weighted-average period of total compensation costs to be recognized in years	2 years 4 months 24 days
ESPP
New Accounting Pronouncement, Early Adoption [Line Items]
Unamortized share-based compensation expense	$ 52.5
Weighted-average period of total compensation costs to be recognized in years	2 years

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

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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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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