GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION - Property and Equipment by Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 9,047	$ 9,216
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,819	4,949
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,984	4,129
Others
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 244	$ 138