SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Jan. 02, 2013	Dec. 31, 2012
Liabilities
Warrant liability	$ 33,407	$ 16,200	$ 0
Recurring basis | Total
Assets
Cash and cash equivalents	14,235		18,403
Short-term investments	47,835		18,580
Assets	62,070		36,983
Liabilities
Warrant liability	33,407		0
Liabilities	33,407		0
Recurring basis | Level 1
Assets
Cash and cash equivalents	12,431		2,825
Short-term investments	0		0
Assets	12,431		2,825
Liabilities
Warrant liability	0		0
Liabilities	0		0
Recurring basis | Level 2
Assets
Cash and cash equivalents	1,804		15,578
Short-term investments	47,835		18,580
Assets	49,639		34,158
Liabilities
Warrant liability	0		0
Liabilities	0		0
Recurring basis | Level 3
Assets
Cash and cash equivalents	0		0
Short-term investments	0		0
Assets	0		0
Liabilities
Warrant liability	33,407		0
Liabilities	$ 33,407		$ 0