Annual report pursuant to Section 13 and 15(d)

Information Concerning Industry Segments and Major Customers (Narrative) (Details)

v3.20.1
Information Concerning Industry Segments and Major Customers (Narrative) (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2019
USD ($)
customer
Dec. 31, 2018
USD ($)
customer
Sales [Member] | Suttle [Member]    
Segment Reporting Information [Line Items]    
Number of customers   2
Sales [Member] | Transition Networks [Member]    
Segment Reporting Information [Line Items]    
Number of customers 2 2
Accounts Receivable [Member] | JDL Technologies [Member]    
Segment Reporting Information [Line Items]    
Concentration risk percentage   21.00%
Number of customers   1
Accounts Receivable [Member] | Transition Networks [Member]    
Segment Reporting Information [Line Items]    
Number of customers 2 2
Foreign Countries [Member] | Suttle [Member]    
Segment Reporting Information [Line Items]    
Long-lived assets | $ $ 112 $ 159
United States [Member] | Sales [Member]    
Segment Reporting Information [Line Items]    
Concentration risk percentage 74.00% 77.00%
Customer 1 [Member] | Sales [Member] | Transition Networks [Member]    
Segment Reporting Information [Line Items]    
Concentration risk percentage 21.20% 17.60%
Customer 1 [Member] | Accounts Receivable [Member] | Transition Networks [Member]    
Segment Reporting Information [Line Items]    
Concentration risk percentage 45.00% 23.00%
Customer 2 [Member] | Sales [Member] | Transition Networks [Member]    
Segment Reporting Information [Line Items]    
Concentration risk percentage 16.20% 15.40%
Customer 2 [Member] | Accounts Receivable [Member] | Transition Networks [Member]    
Segment Reporting Information [Line Items]    
Concentration risk percentage 17.00% 19.00%