Balance Sheet Components (Inventories, Property and Equipment) (Details) - USD ($)
$ in Thousands
Sep. 30, 2016
Dec. 31, 2015
Inventories    
Finished goods $ 28,963 $ 16,982
Component parts 2,443 2,575
Work-in-process 308 298
Total inventories 31,714 19,855
Property and equipment, net    
Property and equipment, gross 18,247 19,024
Less: accumulated depreciation (11,892) (12,440)
Property and equipment, net 6,355 6,584
Computer equipment and software    
Property and equipment, net    
Property and equipment, gross 3,672 4,799
Manufacturing tooling and test equipment    
Property and equipment, net    
Property and equipment, gross 4,222 4,267
Lab and warehouse equipment    
Property and equipment, net    
Property and equipment, gross 3,546 3,376
Leasehold improvements    
Property and equipment, net    
Property and equipment, gross 3,120 2,949
Furniture and fixtures    
Property and equipment, net    
Property and equipment, gross 2,934 2,881
Other    
Property and equipment, net    
Property and equipment, gross $ 753 $ 752