Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 104,838	$ 62,317
Less: accumulated depreciation and amortization	(52,209)	(22,458)
Property and equipment, net	52,629	39,859
Test Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, gross	65,663	37,059
Computer, Equipment and Software
Property Plant And Equipment [Line Items]
Total property and equipment, gross	31,388	19,022
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, gross	2,852	2,460
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 4,935	$ 3,776