Balance Sheet Components - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 62,541	$ 79,969
Less accumulated depreciation and amortization	(37,499)	(36,980)
Property and equipment, net	25,042	42,989
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	46,055	43,605
Furniture, Fixtures and Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, gross	556	2,790
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	4,284	23,645
Equipment Acquired under Capital Leases
Property Plant And Equipment [Line Items]
Total property and equipment, gross	11,568	6,125
Construction-in-Progress
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 78	$ 3,804