Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Oct. 31, 2017	Jan. 31, 2017
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 262,877	$ 237,677
Less: accumulated depreciation	(144,599)	(120,501)
Total property and equipment, net	118,278	117,176
Servers
Property Plant And Equipment [Line Items]
Total property and equipment, gross	160,067	143,219
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	64,507	64,379
Computer hardware and software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	11,996	11,373
Furniture and fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, gross	13,073	12,824
Construction in progress
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 13,234	$ 5,882