CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
CONDENSED CONSOLIDATED BALANCE SHEETS
Trade receivables, allowance for doubtful accounts (in dollars)	$ 487	$ 341
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, authorized shares	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, authorized shares	50,000	50,000
Common stock, shares issued	9,475	9,427
Common stock, shares outstanding	9,475	9,427