Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Allowance for doubtful accounts	$ 75	$ 75
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	110,000,000	110,000,000
Common stock, shares issued (in shares)	31,078,202	31,002,919
Common stock, shares outstanding (in shares)	23,877,315	24,219,887
Treasury Stock, Shares (in shares)	7,200,887	6,783,032