Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings per share [Abstract]
Net (loss) income	$ (867)	$ 384	$ (3,712)	$ 1,316
Shares [Abstract]
Basic: Weighted average common shares outstanding (in shares)	7,548	7,470	7,533	7,464
Add: Dilutive effect of outstanding options and restricted stock units as determined by the treasury stock method (in shares)	0	283	0	194
Diluted: Weighted average common and common equivalent shares outstanding (in shares)	7,548	7,753	7,533	7,658
Net (loss) income per common share [Abstract]
Basic (in dollars per share)	$ (0.11)	$ 0.05	$ (0.49)	$ 0.18
Diluted (in dollars per share)	$ (0.11)	$ 0.05	$ (0.49)	$ 0.17
Stock Awards [Member]
Earnings per share [Abstract]
Anti-dilutive securities excluded from computation of earnings per dilutive share (in shares)	1,400	300	1,400	500