Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Allowance for doubtful accounts	$ 436	$ 575
Stockholders' equity:
Preferred Stock, par or stated value per share (in usd per share)	$ 0.01	$ 0.01
Preferred Stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred Stock, shares issued (in shares)	0	0
Common Stock, par or stated value per share (in usd per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (in shares)	30,000,000	30,000,000
Common Stock, shares issued (in shares)	11,989,229	12,011,495
Treasury stock, shares (in shares)	3,408,015	3,650,060