Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful trade receivables	$ 54	$ 119
Unamortized debt issuance costs, current	7	7
Unamortized debt issuance costs, long-term	$ 11	$ 14
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	30,237,000	30,305,000
Common stock, shares outstanding	30,237,000	30,305,000