NET LOSS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jul. 01, 2012	Apr. 01, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Earnings Per Share [Line Items]
Net loss	$ 2,512	$ (412)	$ (3,567)	$ (9,508)	$ (8,820)	$ (6,034)	$ (3,346)	$ (1,119)	$ (10,975)	$ (19,319)	$ (17,950)
Weighted Average Number of Shares Outstanding Reconciliation
Weighted-average shares outstanding - basic	59,127,000	59,024,000	58,891,000	58,728,000					58,944,000	58,538,000	55,299,000
Weighted-average shares outstanding - diluted	60,830,000	59,024,000	58,891,000	58,728,000					58,944,000	58,538,000	55,299,000
Basic and diluted (in usd per share)					$ (0.15)	$ (0.10)	$ (0.06)	$ (0.02)	$ (0.19)	$ (0.33)	$ (0.32)
Stock Options and Restricted Stock Units
Weighted Average Number of Shares Outstanding Reconciliation
Total number of options to purchase common stock and restricted stock units, outstanding (in shares)	5,500,000				7,600,000				5,500,000	7,600,000	6,700,000
Antidilutive securities included in computation of earnings per share, amount (in shares)									0	0	0
Stock Options and Restricted Stock Units
Weighted Average Number of Shares Outstanding Reconciliation
Effect of dilutive potential common shares from stock options and restricted stock units									0	0	0