Revenues (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Accumulated deficit			$ (11,059,500)			$ (12,811,000)	$ (11,059,500)	$ (12,811,000)
Net earnings	$ 206,800	$ 148,900	$ 85,400	$ 1,100	$ 1,447,500	95,800	441,100	1,544,400
Cumulative effect of accounting change						$ 96,100		96,100
Accumulated deficit	(10,618,400)			(11,170,500)			(10,618,400)	(11,170,500)
Long-term receivable	$ 1,070,700			$ 1,521,700			$ 1,070,700	1,521,700	$ 1,352,200
Selling expense								$ 106,500