Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares shares in Thousands	Mar. 31, 2024	Dec. 31, 2023
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	2,500	2,500
Preferred stock, shares issued (in shares)	10	10
Preferred stock, shares outstanding (in shares)	10	10
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	50,000	50,000
Common stock, shares issued (in shares)	21,372	20,379
Common stock, shares outstanding (in shares)	21,372	20,379