Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Allowance for doubtful accounts	$ 52	$ 87
Accumulated depreciation and amortization	$ 22,877	$ 21,964
Preferred stock, par value (in dollars per share)	$ 0.005	$ 0.005
Preferred stock, shares authorized (in shares)	873	873
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.005	$ 0.005
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	6,411,000	6,349,000
Common stock, shares outstanding (in shares)	5,743,000	5,681,000
Treasury stock, shares (in shares)	668,000	668,000