Consolidated Statements of Changes in Shareholders' Equity - USD ($)	Common stock	Treasury Shares	Additional paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Total
Balance at Dec. 31, 2017	$ 144,292,238		$ 6,171,525	$ 9,913,236	$ (96,645,954)	$ 63,731,045
Balance (in shares) at Dec. 31, 2017	27,522,852
Increase (Decrease) in Stockholders' Equity
Net income					6,662,060	6,662,060
Stock-based compensation expenses			330,232			330,232
Buyback and retirement of common shares	$ (586,797)		17,271			(569,526)
Buyback and retirement of common shares (Shares)	(137,719)
Buyback of common shares not yet retired		$ (94,418)				(94,418)
Buyback of common shares not yet retired (in shares)		26,953
Other comprehensive income				(115,306)		(115,306)
Balance at Dec. 31, 2018	$ 143,705,441	$ (94,418)	6,519,028	9,797,930	(89,983,894)	69,944,087
Balance (in shares) at Dec. 31, 2018	27,385,133	26,953
Increase (Decrease) in Stockholders' Equity
Net income					8,697,999	8,697,999
Stock-based compensation expenses			510,460			510,460
Retirement of common shares	$ (94,418)	$ 94,418
Retirement of common shares (in shares)	(26,953)	(26,953)
Exercise of stock options	$ 54,250					54,250
Exercise of stock options (in shares)	25,000
Buyback and retirement of common shares	$ (2,856,350)					(2,856,350)
Buyback and retirement of common shares (Shares)	(753,196)
Restricted stock shares vested (in shares)	161,001
Other comprehensive income				12,548		12,548
Balance at Dec. 31, 2019	$ 140,808,923		$ 7,029,488	$ 9,810,478	$ (81,285,895)	$ 76,362,994
Balance (in shares) at Dec. 31, 2019	26,790,985