Concentration of Sales to Major Customers (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Customer Revenue Concentration
Total revenue	$ 769	$ 3,500	$ 973	$ 6,800
Concentration Risk, Percentage	53.00%	84.00%	43.00%	87.00%
Second Commercial Customer
Total revenue	$ 345	$ 486	$ 880	$ 859
Concentration Risk, Percentage	24.00%	12.00%	39.00%	11.00%
Accounts Receivable Concentration
Accounts receivable	$ 510		$ 510
Concentration Risk, Percentage			63.00%
Second Receivable
Accounts receivable	182		$ 182
Concentration Risk, Percentage			23.00%
Third Receivable
Accounts receivable	$ 92		$ 92
Concentration Risk, Percentage			11.00%