EMPLOYEE STOCK PLANS - Stock Option Activity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Number of Shares
Outstanding at December 31, 2012 (in shares)	7,614
Granted (in shares)	1,579	3,100	1,600
Exercised (in shares)	(405)
Canceled or forfeited (in shares)	(3,795)
Outstanding at December 31, 2013 (in shares)	4,993	7,614
Vested and expected to vest at December 31, 2013 (in shares)	4,626
Exercisable at December 31, 2013 (in shares)	1,778
Weighted-Average Exercise Price
Weighted-Average Exercise Price, Outstanding at December 31, 2012 (in usd per share)	$ 3.34
Weighted Average Exercise Price, Granted (in usd per share)	$ 1.40
Weighted Average Exercise Price, Exercised (in usd per share)	$ 1.10
Weighted Average Exercise Price, Canceled or forfeited (in usd per share)	$ 4.29
Weighted-Average Exercise Price, Outstanding at December 31, 2013 (in usd per share)	$ 2.18	$ 3.34
Weighted Average Exercise Price, Vested and expected to vest at December 31, 2013 (in usd per share)	$ 2.23
Weighted Average Exercise Price, Exercisable at December 31, 2013 (in usd per share)	$ 3.63
Weighted Average Remaining Term
Weighted Average Remaining Term, Outstanding at December 31, 2013	4 years 10 months 24 days
Weighted Average Remaining Term, Vested and expected to vest at December 31, 2013	4 years 9 months 18 days
Weighted Average Remaining Term, Exercisable at December 31, 2013	3 years 1 month 6 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at December 31, 2013	$ 5,281
Aggregate Intrinsic Value, Vested and expected to vest at December 31, 2013	4,851
Aggregate Intrinsic Value, Exercisable at December 31, 2013	$ 884