Other Current Liabilities (Schedule of Other Current Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other Current Liabilities [Abstract]
Operating lease liability, current	$ 345	$ 652
Operating lease liability, current statement of financial position	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Due to affiliate	$ 98	$ 5
Accrued professional fees	1,287	1,419
Pension and other post-retirement liabilities	82	77
Income taxes payable	0	673
Accrued liabilities	190	57
Other current liabilities, total	$ 2,002	$ 2,883