Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Preferred stock, par value (in dollars per share)	$ 0.01
Preferred stock, shares authorized (in shares)	3,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	47,000,000	47,000,000
Common stock, shares issued (in shares)	21,845,414	21,320,312
Treasury stock, shares (in shares)	54,329	54,329
Series A Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	2,445,598	2,445,598
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Series B Convertible Preferred Stock [Member]
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)	1,650,000	0
Preferred stock, shares outstanding (in shares)	1,650,000	0