Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2019	39,612,659	(12,253,502)
Balance at Dec. 31, 2019	$ 39,613	$ (18,929,915)	$ 96,105,851	$ (41,351,078)	$ 35,864,471
Stock-based compensation expenses	$ 0	$ 0	1,651,893	0	$ 1,651,893
Issuance of common stock upon exercise of stock options (in shares)	135,000	0			135,000
Issuance of common stock upon exercise of stock options	$ 135	$ 0	255,335	0	$ 255,470
Net loss	$ 0	$ 0	0	(9,325,273)	(9,325,273)
Balance (in shares) at Dec. 31, 2020	39,747,659	(12,253,502)
Balance at Dec. 31, 2020	$ 39,748	$ (18,929,915)	98,013,079	(50,676,351)	28,446,561
Stock-based compensation expenses	$ 0	$ 0	1,784,102	0	$ 1,784,102
Issuance of common stock upon exercise of stock options (in shares)	735,000	0			735,000	[1]
Issuance of common stock upon exercise of stock options	$ 735	$ 0	1,229,315	0	$ 1,230,050
Net loss	$ 0	$ 0	0	(13,070,251)	(13,070,251)
Balance (in shares) at Dec. 31, 2021	40,482,659	(12,253,502)
Balance at Dec. 31, 2021	$ 40,483	$ (18,929,915)	$ 101,026,496	$ (63,746,602)	$ 18,390,462

[1] Represents the following stock options exercised: • 500,000 stock options exercised at $1.67, 150,000 stock options exercised at $1.63, 60,000 stock options exercised at $1.93, and 25,000 stock options exercised at $1.39.