Condensed Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock	Additional Paid in Capital	Retained Earnings	Treasury Stock	Total
Balances at Dec. 31, 2018	$ 7,738	$ 36,302,446	$ 72,176,719	$ (10,898,383)	$ 97,588,520
Balances (in shares) at Dec. 31, 2018	7,738,167
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon stock option exercise	$ 58	1,736,888			1,736,946
Issuance of common stock upon stock option exercise (in shares)	58,063
Stock compensation expense		260,466			260,466
Repurchases of common stock				(118,566)	(118,566)
Net income			10,843,055		10,843,055
Balances at Jun. 30, 2019	$ 7,796	38,299,800	83,019,774	(11,016,949)	110,310,421
Balances (in shares) at Jun. 30, 2019	7,796,230
Balances at Mar. 31, 2019	$ 7,740	36,502,652	76,593,314	(10,898,383)	102,205,323
Balances (in shares) at Mar. 31, 2019	7,740,167
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon stock option exercise	$ 56	1,678,470			1,678,526
Issuance of common stock upon stock option exercise (in shares)	56,063
Stock compensation expense		118,678			118,678
Repurchases of common stock				(118,566)	(118,566)
Net income			6,426,460		6,426,460
Balances at Jun. 30, 2019	$ 7,796	38,299,800	83,019,774	(11,016,949)	110,310,421
Balances (in shares) at Jun. 30, 2019	7,796,230
Balances at Dec. 31, 2019	$ 7,813	39,355,797	96,646,527	(11,519,035)	$ 124,491,102
Balances (in shares) at Dec. 31, 2019	7,813,230				7,339,578
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon vesting of restricted stock units	$ 11	(11)
Issuance of common stock upon vesting of restricted stock units (in shares)	11,450
Issuance of common stock upon stock option exercise	$ 2	61,723			$ 61,725
Issuance of common stock upon stock option exercise (in shares)	1,500
Stock compensation expense		662,770			662,770
Repurchases of common stock				(412,761)	(412,761)
Net income			4,614,602		4,614,602
Balances at Jun. 30, 2020	$ 7,826	40,080,279	101,261,129	(11,931,796)	$ 129,417,438
Balances (in shares) at Jun. 30, 2020	7,826,180				7,344,955
Balances at Mar. 31, 2020	$ 7,815	39,856,101	101,145,333	(11,740,066)	$ 129,269,183
Balances (in shares) at Mar. 31, 2020	7,815,230
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon vesting of restricted stock units	$ 9	(9)
Issuance of common stock upon vesting of restricted stock units (in shares)	9,450
Issuance of common stock upon stock option exercise	$ 2	61,723			61,725
Issuance of common stock upon stock option exercise (in shares)	1,500
Stock compensation expense		162,464			162,464
Repurchases of common stock				(191,730)	(191,730)
Net income			115,796		115,796
Balances at Jun. 30, 2020	$ 7,826	$ 40,080,279	$ 101,261,129	$ (11,931,796)	$ 129,417,438
Balances (in shares) at Jun. 30, 2020	7,826,180				7,344,955