Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings per share [Abstract]
Net (loss) income	$ (1,853)	$ 186	$ (2,845)	$ 932
Shares [Abstract]
Basic: Weighted average common shares outstanding (in shares)	7,543	7,462	7,525	7,461
Add: Dilutive effect of outstanding options and restricted stock units as determined by the treasury stock method (in shares)	0	135	0	146
Diluted: Weighted average common and common equivalent shares outstanding (in shares)	7,543	7,597	7,525	7,607
Net (loss) income per common share [Abstract]
Basic (in dollars per share)	$ (0.25)	$ 0.02	$ (0.38)	$ 0.12
Diluted (in dollars per share)	$ (0.25)	$ 0.02	$ (0.38)	$ 0.12
Stock Awards [Member]
Earnings per share [Abstract]
Anti-dilutive securities excluded from computation of earnings per dilutive share (in shares)	1,400	500	1,300	500