Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	325,000,000	325,000,000
Common stock, shares issued (in shares)	4,658,274	3,947,101
Common stock, shares outstanding (in shares)	4,649,447	3,938,274
Treasury stock, shares (in shares)	8,827	8,827