Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Allowance for doubtful accounts	$ 73	$ 87
Accumulated depreciation and amortization	$ 22,428	$ 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	50,000
Common stock, shares issued (in shares)	6,354	6,349
Common stock, shares outstanding (in shares)	5,686	5,681
Treasury stock, shares (in shares)	668	668