Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Trade, allowance	$ 4,319	$ 3,482
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
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	40,000,000	40,000,000
Common stock, issued (in shares)	23,394,046	23,391,438
Common stock, outstanding (in shares)	11,167,261	11,455,790
Treasury stock (in shares)	12,226,785	11,935,648