Commitment and Contingencies (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Aug. 31, 2020	Jul. 31, 2020	Jan. 31, 2020
Other Commitments [Line Items]
Sublease income	$ 3,200,000	$ 2,300,000	$ 9,600,000	$ 2,800,000
Cost of matching contributions	0	$ 0	0	$ 0
Letters of credit outstanding	$ 15,000,000.0		$ 15,000,000.0
Third-Party Cloud Infrastructure Agreements And Subscription Arrangements One
Other Commitments [Line Items]
Other contractual commitments					$ 550,000,000.0		$ 50,700,000
Third-Party Cloud Infrastructure Agreements And Subscription Arrangements Two
Other Commitments [Line Items]
Other contractual commitments						$ 1,200,000,000	118,800,000
Other contractual commitments, year one						115,000,000.0	1,800,000
Other contractual commitments, year two						185,000,000.0	58,500,000
Other contractual commitments, year three						250,000,000.0	$ 58,500,000
Other contractual commitments, year four						300,000,000.0
Other contractual commitments, year five						$ 350,000,000.0