Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	21,127,130	19,859,650
Treasury stock, common shares (in shares)	273,937	273,937