Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings per share [Abstract]
Net income	$ (992)	$ 746
Shares [Abstract]
Basic: Weighted average common shares outstanding (in shares)	7,507	7,461
Add: Dilutive effect of outstanding options and restricted stock units as determined by the treasury stock method (in shares)	0	158
Diluted: Weighted average common and common equivalent shares outstanding (in shares)	7,507	7,619
Net income per common share [Abstract]
Basic (in dollars per share)	$ (0.13)	$ 0.10
Diluted (in dollars per share)	$ (0.13)	$ 0.10
Stock Awards [Member]
Earnings per share [Abstract]
Anti-dilutive securities excluded from computation of earnings per dilutive share (in shares)	708	540