CONDENSED BALANCE SHEETS (Parenthetical) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
CONDENSED BALANCE SHEETS
Trade receivables, allowance	$ 52,000	$ 54,000
INTANGIBLE ASSETS, accumulated amortization	$ 162,032	$ 149,072
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized	250,000	250,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized	4,750,000	4,750,000
Common stock, shares issued	2,017,053	2,018,753
Common stock, shares outstanding	2,017,053	2,018,753