NET INCOME (LOSS) PER SHARE - Schedule of Computation of Net Income (Loss) per Share of Common Stock (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 31, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net income (loss)	$ 4,963	$ 537	$ 1,916	$ 2,465	$ 2,512	$ (412)	$ (3,567)	$ (9,508)	$ 9,881	$ (10,975)	$ (19,319)
Denominator:
Weighted-average shares outstanding - basic (in shares)	73,861,000	73,731,000	73,532,000	66,275,000	59,127,000	59,024,000	58,891,000	58,728,000	71,897,000	58,944,000	58,538,000
Effect of dilutive stock options and restricted stock units (in shares)									1,506,000	0	0
Weighted-average shares outstanding - diluted (in shares)	75,486,000.00	75,023,000.00	74,679,000.00	67,971,000.00	60,830,000.00	59,024,000.00	58,891,000.00	58,728,000.00	73,403,000.00	58,944,000.00	58,538,000.00
Net income (loss) per share of common stock:
Basic (in usd per share)	$ 0.07	$ 0.01	$ 0.03	$ 0.04	$ 0.04	$ (0.01)	$ (0.06)	$ (0.16)	$ 0.14	$ (0.19)	$ (0.33)
Diluted (in usd per share)	$ 0.07	$ 0.01	$ 0.03	$ 0.04	$ 0.04	$ (0.01)	$ (0.06)	$ (0.16)	$ 0.13	$ (0.19)	$ (0.33)