SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Stock Warrant Liability (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loss on stock warrant liability	$ 0	$ 0	$ 4,190
Accounting Standards Codification 815 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loss on stock warrant liability			$ 4,200