FAIR VALUE MEASUREMENT - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 27, 2015	Dec. 31, 2014
Assets measured at fair value:
Restricted cash	$ 1,811	$ 1,993
Fair Value, Measurements, Recurring | Fair Value Disclosure, Total
Assets measured at fair value:
Total assets measured at fair value	16,821	8,813
Fair Value, Measurements, Recurring | Money Market Funds | Fair Value Disclosure, Total
Assets measured at fair value:
Cash and cash equivalents	15,010	7,007
Restricted cash	1,811	1,806
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets measured at fair value:
Total assets measured at fair value	16,821	8,813
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Money Market Funds
Assets measured at fair value:
Cash and cash equivalents	15,010	7,007
Restricted cash	$ 1,811	$ 1,806