Balance Sheet Components - Components of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities And Other Liabilities [Abstract]
Accrued salary and payroll related expenses	$ 3,894	$ 4,829
Accrued accounts payable	1,915	3,417
Customer advances	1,582	1,463
Income tax payable		236
Sales and use tax payable	210	434
Deferred rent and other	761	806
Accrued expenses and other current liabilities	$ 8,362	$ 11,185