Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	26,807,145	26,260,776
Common stock, outstanding (in shares)	25,473,453	24,974,995
Treasury stock, shares (in shares)	1,333,692	1,285,781