Major Customers (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Major Customer [Line Items]
Sales Revenue, Goods, Net	$ 59,712,000	$ 36,336,000
Contracts Revenue	3,334,000	410,000
Total net sales	63,046,000	36,746,000
Navistar [Member]
Revenue, Major Customer [Line Items]
Sales Revenue, Goods, Net	10,951,000	9,257,000
Contracts Revenue	0	18,000
Total net sales	10,951,000	9,275,000
Volvo [Member]
Revenue, Major Customer [Line Items]
Sales Revenue, Goods, Net	10,197,000	5,235,000
Contracts Revenue	0	31,000
Total net sales	10,197,000	5,266,000
Paccar [Member]
Revenue, Major Customer [Line Items]
Sales Revenue, Goods, Net	6,763,000	5,462,000
Contracts Revenue	3,203,000	190,000
Total net sales	9,966,000	5,652,000
Other Customers [Member]
Revenue, Major Customer [Line Items]
Sales Revenue, Goods, Net	31,801,000	16,382,000
Contracts Revenue	131,000	171,000
Total net sales	$ 31,932,000	$ 16,553,000