Geographic Data - Schedule of Revenue by Geographic Areas (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue, Goods, Net	$ 110,910	$ 106,243	$ 105,686	$ 100,154	$ 101,584	$ 99,697	$ 98,693	$ 96,705	$ 422,993	$ 396,679	$ 382,310
Property, Plant and Equipment, Net	88,247				82,111				88,247	82,111
United States | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue, Goods, Net									287,092	276,033	238,796
Property, Plant and Equipment, Net	45,354				42,488				45,354	42,488
China | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue, Goods, Net									66,510	59,506	55,825
Property, Plant and Equipment, Net	32,464				33,013				32,464	33,013
CANADA | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue, Goods, Net									0	0	24,519
United Kingdom | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, Plant and Equipment, Net	590				569				590	569
Taiwan | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, Plant and Equipment, Net	3,540				2,755				3,540	2,755
Czech Republic | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue, Goods, Net									34,476	34,767	36,348
Property, Plant and Equipment, Net	5,518				2,634				5,518	2,634
Other non-U.S | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue, Goods, Net									29,319	19,705	$ 18,443
Property, Plant and Equipment, Net	$ 781				$ 652				$ 781	$ 652