Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Allowance for doubtful accounts	$ 347,087	$ 375,919
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	8,000,000	8,000,000
Common stock, shares issued (in shares)	5,085,348	4,919,548
Common stock, shares outstanding (in shares)	4,941,428	4,881,548
Treasury shares (in shares)	40,920	40,920