Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	69,805,700	69,772,367
Common stock, shares outstanding (in shares)	69,306,497	69,273,164
Treasury Stock, Common, Shares	33,333	33,333