Segment Information - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Sales to external customers	$ 31,913	$ 29,903	$ 98,198	$ 86,694
Operating income (loss)	2,140	1,991	7,735	6,693
Interest expense, net	247	149	642	420
Other expense, net	65	92	38	149
Consolidated income before income taxes	1,828	1,750	7,055	6,124
Assets	99,372		99,372		$ 81,421
United States
Sales to external customers	28,489	26,160	87,311	75,943
Operating income (loss)	1,974	1,849	7,165	6,405
Assets	90,518		90,518		73,688
Canada
Sales to external customers	1,585	1,669	5,623	5,726
Operating income (loss)	148	30	558	202
Assets	4,559		4,559		3,709
Europe
Sales to external customers	1,839	2,074	5,264	5,025
Operating income (loss)	18	$ 112	12	$ 86
Assets	$ 4,295		$ 4,295		$ 4,024