Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Valuation allowance	$ 11,476,000	$ 12,067,000
Provision or benefit for income taxes	(17,000)	(242,000)
Federal net operating loss carryforwards	35,600,000
Deferred tax asset	$ 130,000	$ 242,000
Federal tax rate	21.00%	34.00%
Refundable credits	$ 260,000
Decrease in deferred tax asset	5,300,000
Accounts receivable - noncurrent	130,000	$ 242,000
Tax Period Between 2019 And 2037 [Member]
Income Taxes [Line Items]
Federal net operating loss carryforwards	34,600,000
Indefinite Tax Period [Member]
Income Taxes [Line Items]
Federal net operating loss carryforwards	$ 1,000,000
Accounting Standards Update 2016-09 [Member]
Income Taxes [Line Items]
Increase to retained earnings		$ 687,000
Minimum [Member] | Tax Period Between 2019 And 2037 [Member]
Income Taxes [Line Items]
Federal net operating loss carryforwards expiration between, years	Jan. 01, 2019
Maximum [Member] | Tax Period Between 2019 And 2037 [Member]
Income Taxes [Line Items]
Federal net operating loss carryforwards expiration between, years	Dec. 31, 2037