Revenues (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Long-term receivable	$ 1,423,800		$ 1,423,800
Accrued expenses, non-current	99,600		99,600
Accumulated deficit			(12,811,000)
Net earnings	1,100	$ 109,800	1,544,400	$ 224,200
Cumulative effect of accounting change			96,100
Accumulated deficit	(11,170,500)		(11,170,500)
Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Long-term receivable	1,521,700		1,521,700
Accrued expenses, non-current	$ 106,500		$ 106,500