Significant Accounting Policies (Revenues) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Long-term receivable	$ 957,000	$ 1,352,200
Accrued expenses, non-current	67,000	94,700
Accumulated deficit	(11,059,500)	(12,811,000)
Net income	754,900	1,655,400
Cumulative effect of accounting change		96,100
Accumulated deficit	$ (10,304,600)	(11,059,500)
Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Long-term receivable		1,521,700
Accrued expenses, non-current		$ 106,500