Concentration of Sales to Major Customers) (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Total revenue	$ 639	$ 1,190	$ 2,695	$ 4,281
Customer Revenue Concentration
Total revenue	$ 539,000	$ 1,200	$ 2,600	$ 2,800
Concentration Risk, Percentage	84.00%	97.00%	96.00%	92.00%

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details