Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Financial assets:
Cash and cash equivalents	$ 3,062		$ 4,035
Investment in equity securities	42	$ 52	308	$ 406	$ 898
Warrants, fair value	145	$ 144	142	161	$ 157
Financial liabilities:
Options - short position	0		1	16		$ 50
Non-recourse debt	1,214		1,673
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	3,062		4,035
Investment in equity securities	42		308
Warrants, fair value	145		142
Financial liabilities:
Options - short position			1
Non-recourse debt	1,247		1,633
Fair Value, Inputs, Level 1 [Member]
Financial assets:
Cash and cash equivalents	3,062		4,035
Investment in equity securities	42		308	406		1,448
Warrants, fair value	0		0
Financial liabilities:
Options - short position			1
Non-recourse debt	0		0
Fair Value, Inputs, Level 2 [Member]
Financial assets:
Cash and cash equivalents	0		0
Investment in equity securities	0		0
Warrants, fair value	0		0
Financial liabilities:
Options - short position			0
Non-recourse debt	0		0
Fair Value, Inputs, Level 3 [Member]
Financial assets:
Cash and cash equivalents	0		0
Investment in equity securities	0		0
Warrants, fair value	145		142	$ 161		$ 187
Financial liabilities:
Options - short position			0
Non-recourse debt	$ 1,214		$ 1,673