Annual report pursuant to Section 13 and 15(d)

Concentrations (Details)

v3.19.1
Concentrations (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Concentration Risk [Line Items]      
Cash and cash equivalents $ 39,154 $ 48,260  
Foreign      
Concentration Risk [Line Items]      
Cash and cash equivalents $ 17,700    
Customer Concentration Risk | Sales Revenue      
Concentration Risk [Line Items]      
Concentration risk 18.00% 19.00% 22.00%
Customer Concentration Risk | Sales Revenue | Connectivity      
Concentration Risk [Line Items]      
Concentration risk 35.00% 36.00% 54.00%
Customer Concentration Risk | Accounts Receivable | Connectivity      
Concentration Risk [Line Items]      
Concentration risk 16.00% 10.00% 12.00%