Balance Sheet Components (PPE) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Property and equipment, net      
Property and equipment, gross $ 2,245 $ 1,176  
Less accumulated depreciation (841) (621)  
Property and equipment, net 1,404 555  
Depreciation expense 256 182 $ 148
Leasehold improvements      
Property and equipment, net      
Property and equipment, gross 86 69  
Laboratory equipment and toolings      
Property and equipment, net      
Property and equipment, gross 366    
Computer equipment      
Property and equipment, net      
Property and equipment, gross 277 138  
Software      
Property and equipment, net      
Property and equipment, gross 655 166  
Office equipment      
Property and equipment, net      
Property and equipment, gross 137 167  
Furniture and fixtures      
Property and equipment, net      
Property and equipment, gross $ 724 $ 636