Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

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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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- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130556-203045

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Revenue from Contracts with Customers - Deferred Revenue (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jul. 31, 2019	Apr. 30, 2019	Jul. 31, 2018	Apr. 30, 2018	Jul. 31, 2019	Jul. 31, 2018
Revenue from External Customer [Line Items]
Revenue expected to be recognized from performance obligations	$ 129.4				$ 129.4
Subscription
Revenue from External Customer [Line Items]
Revenue recognized included in deferred revenue	45.3		$ 27.8		68.5	$ 41.2
Revenue expected to be recognized from performance obligations	126.4				126.4
Professional services
Revenue from External Customer [Line Items]
Revenue recognized included in deferred revenue		$ 1.9		$ 1.3	1.9	$ 1.0
Revenue expected to be recognized from performance obligations	$ 2.9				$ 2.9