Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Payables And Accruals [Abstract]
Accrued payroll and related benefits	$ 1,779	$ 1,652
Accrued accounts payable	478	946
Sales tax and medical device excise tax payable	33	499
Accrued legal and accounting	410	901
Accrued interest		142
Accrued debt facility fee	1,500
Other	814	296
Total accrued liabilities	$ 5,014	$ 4,436