BALANCE SHEET COMPONENTS - SCHEDULE OF PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property and equipment – gross	$ 56,666	$ 52,626
Less: accumulated depreciation and amortization	(23,205)	(19,522)
Property and equipment – net	33,461	33,104
Computer equipment
Property Plant And Equipment [Line Items]
Property and equipment – gross	19,293	17,262
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment – gross	11,760	11,123
Capitalized software development costs
Property Plant And Equipment [Line Items]
Property and equipment – gross	2,114	1,877
Office equipment
Property Plant And Equipment [Line Items]
Property and equipment – gross	2,887	2,668
Software licenses
Property Plant And Equipment [Line Items]
Property and equipment – gross	4,174	3,258
Building leased
Property Plant And Equipment [Line Items]
Property and equipment – gross	$ 16,438	$ 16,438