Shareholders' Equity - Changes in Shareholders’ Equity (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 35,864,471	$ 42,451,169
Stock-based compensation	426,939	309,563
Exercise of stock options	175,000
Net loss	(2,214,139)	(2,175,258)
Ending balance	34,252,271	40,585,474
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	39,613	38,967
Exercise of stock options	100
Ending balance	39,713	38,967
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(18,929,915)	(18,929,915)
Ending balance	(18,929,915)	(18,929,915)
Additional paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	96,105,851	94,385,230
Stock-based compensation	426,939	309,563
Exercise of stock options	174,900
Ending balance	96,707,690	94,694,793
Accumulated deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(41,351,078)	(33,043,113)
Net loss	(2,214,139)	(2,175,258)
Ending balance	$ (43,565,217)	$ (35,218,371)