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Commitments and Contingencies - Additional Information (Details) - USD ($)		12 Months Ended
	Oct. 18, 2016	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017	Mar. 31, 2018
Loss Contingencies [Line Items]
Rent expense recognized under operating leases		$ 25,600,000	$ 19,400,000	$ 16,600,000
Non-cancelable purchase obligation related to software services		21,400,000	26,800,000
Outstanding letters of credit		10,800,000	$ 9,600,000
Loss contingency		0
Mountain View, California \| Letter of Credit
Loss Contingencies [Line Items]
Principal amount					$ 1,500,000.0
Convertible Senior Notes
Loss Contingencies [Line Items]
Principal		$ 575,000,000
Dell
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value	$ 30,000,000