Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	175,000,000	175,000,000
Common stock, shares issued (in shares)	154,607,052	151,465,598
Common stock, shares outstanding (in shares)	154,565,743	151,424,289
Treasury Stock, Common, Shares (in shares)	41,309	41,309