Segment Information - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Sales to external customers	$ 40,997	$ 33,954	$ 66,285	$ 56,791
Operating income (loss)	4,640	3,875	5,595	4,701
Interest expense, net	211	141	395	271
Other expense (income), net	11	(20)	(27)	56
Consolidated income before income taxes	4,418	3,754	5,227	4,374
Assets	104,728		104,728		$ 81,421
United States
Sales to external customers	36,296	29,649	58,822	49,782
Operating income (loss)	4,246	3,552	5,190	4,522
Assets	95,643		95,643		73,688
Canada
Sales to external customers	2,646	2,813	4,039	4,054
Operating income (loss)	377	282	410	175
Assets	5,130		5,130		3,709
Europe
Sales to external customers	2,055	1,492	3,425	2,955
Operating income (loss)	17	$ 41	(6)	$ 4
Assets	$ 3,955		$ 3,955		$ 4,024