Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 320,586	$ 279,181
Less: accumulated depreciation	(187,212)	(155,204)
Total property and equipment, net	133,374	123,977
Servers
Property Plant And Equipment [Line Items]
Total property and equipment, gross	195,594	170,422
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	76,789	72,599
Computer hardware and software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	19,711	14,558
Furniture and fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, gross	13,625	14,254
Construction in progress
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 14,867	$ 7,348