Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Accounts receivable, allowance	$ 19,250	$ 19,250
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	4,910,408	4,888,975
Common stock, shares outstanding (in shares)	4,910,408	4,888,975