Balance Sheets (Parentheticals) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Allowance for doubtful accounts	$ 62,000	$ 61,376
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	25,000,000	25,000,000
Common stock, shares issued (in shares)	4,756,734	4,656,734
Common stock, shares outstanding (in shares)	4,621,988	4,521,988
Treasury stock, shares (in shares)	134,746	134,746