Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Allowance for doubtful accounts	$ 65	$ 94
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)	30,922,181	30,898,600
Common stock, shares outstanding (in shares)	24,628,173	25,361,409
Treasury stock, shares (in shares)	6,294,008	5,537,191