Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Increase (decrease) in valuation allowance	$ (7,000)	$ 41,000
Income tax expense (benefit)	0	0	$ 0
Unrecognized tax benefits	0	0	0
Income tax penalties and interest accrued	0	0	0
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	$ 0	$ 0	$ 0