Balance Sheet Components (Other assets and Accrued liabilities) (Details) - USD ($)
$ in Thousands
Mar. 31, 2017
Dec. 31, 2016
Accrued liabilities    
Sales returns and current portion of warranty accruals $ 3,082 $ 2,892
Compensation accruals 2,957 4,445
Other accrued liabilities 1,238 1,575
Total accrued liabilities $ 7,277 $ 8,912