EMPLOYEE STOCK PLANS - Stock Option Activity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 30, 2014
Number of Shares
Outstanding at December 31, 2013 (in shares)	4,993
Granted (in shares)	451
Exercised (in shares)	(94)
Canceled or forfeited (in shares)	(154)
Outstanding at March 30, 2014 (in shares)	5,196
Vested and expected to vest at March 30, 2014 (in shares)	4,741
Exercisable at March 30, 2014 (in shares)	3,061
Weighted-Average Exercise Price
Weighted-Average Exercise Price, Outstanding at December 31, 2013 (in usd per share)	$ 2.18
Weighted Average Exercise Price, Granted (in usd per share)	$ 2.51
Weighted Average Exercise Price, Exercised (in usd per share)	$ 0.98
Weighted Average Exercise Price, Canceled or forfeited (in usd per share)	$ 8.27
Weighted-Average Exercise Price, Outstanding at March 30, 2014 (in usd per share)	$ 2.05
Weighted Average Exercise Price, Vested and expected to vest at March 30, 2014 (in usd per share)	$ 2.07
Weighted Average Exercise Price, Exercisable at March 30, 2014 (in usd per share)	$ 2.20
Weighted Average Remaining Term
Weighted Average Remaining Term, Outstanding at March 30, 2014	4 years 11 months 2 days
Weighted Average Remaining Term, Vested and expected to vest at March 30, 2014	4 years 9 months 18 days
Weighted Average Remaining Term, Exercisable at March 30, 2014	4 years 2 months 24 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at March 30, 2014	$ 3,526
Aggregate Intrinsic Value, Vested and expected to vest at March 30, 2014	3,276
Aggregate Intrinsic Value, Exercisable at March 30, 2014	$ 2,324