Property, Plant and Equipment (Details) - Property, Plant and Equipment (USD $) In Thousands, unless otherwise specified	Jun. 29, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 46,539	$ 43,977
Less accumulated depreciation	25,022	24,107
Property, plant and equipment, net	21,517	19,870
Land and Building [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	13,896	13,896
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	28,406	28,406
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	1,153	1,153
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 3,084	$ 522