Statements of Changes in Stockholders' Equity - USD ($)	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2018		$ 783	$ 14,272,834	$ (37,308)	$ (3,638,978)	$ 10,597,331
Balance, shares at Dec. 31, 2018		7,827,651
Stock options exercised		$ 2	11,424			11,426
Stock options exercised, shares		10,775
Stock options repurchased			(34,076)			(34,076)
Purchase of treasury stock				(318,204)		(318,204)
Treasury stock cancelled		$ (10)	(355,502)	355,512
Treasury stock cancelled, shares		(93,396)
Net income					(75,277)	(75,277)
Balance at Dec. 31, 2019		$ 775	13,894,680		(3,714,255)	10,181,200
Balance, shares at Dec. 31, 2019		7,745,030
Stock options exercised		$ 3	30,163			30,166
Stock options exercised, shares		30,000
Stock options repurchased			(31,183)			(31,183)
Net income					1,478,403	1,478,403
Balance at Dec. 31, 2020		$ 778	$ 13,893,660		$ (2,235,852)	$ 11,658,586
Balance, shares at Dec. 31, 2020		7,775,030