GEOGRAPHIC AND CUSTOMER CONCENTRATION INFORMATION - Summary of Geographic Information Relating to Property and Equipment (Details) (USD $) In Thousands, unless otherwise specified	Mar. 29, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 9,248	$ 7,534
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,582	4,140
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,456	3,185
Others
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 210	$ 209