Concentration of Sales to Major Customers) (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Total revenue	$ 587	$ 1,240	$ 2,056	$ 3,091
Customer Revenue Concentration
Total revenue	$ 587,000	$ 1,200	$ 2,100	$ 2,800
Concentration Risk, Percentage	100.00%	97.00%	100.00%	92.00%