Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Property and equipment, accumulated depreciation and amortization	$ 303,244	$ 300,258
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	12,854,376	12,854,376
Common stock, shares outstanding (in shares)	11,211,760	11,211,760
Treasury stock, shares (in shares)	1,642,616	1,642,616