EMPLOYEE STOCK PLANS - Stock Option Activity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
Jun. 29, 2014
Number of Shares
Outstanding at December 31, 2013 (in shares)	4,993
Granted (in shares)	611
Exercised (in shares)	(277)
Canceled or forfeited (in shares)	(252)
Outstanding at June 29, 2014 (in shares)	5,075
Vested and expected to vest at June 29, 2014 (in shares)	4,643
Exercisable at June 29, 2014 (in shares)	3,054
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)	$ 2.42
Weighted Average Exercise Price, Exercised (in usd per share)	$ 0.93
Weighted Average Exercise Price, Canceled or forfeited (in usd per share)	$ 8.31
Weighted-Average Exercise Price, Outstanding at June 29, 2014 (in usd per share)	$ 1.98
Weighted Average Exercise Price, Vested and expected to vest at June 29, 2014 (in usd per share)	$ 1.98
Weighted Average Exercise Price, Exercisable at June 29, 2014 (in usd per share)	$ 2.05
Weighted Average Remaining Term
Weighted Average Remaining Term, Outstanding at June 29, 2014	4 years 9 months 18 days
Weighted Average Remaining Term, Vested and expected to vest at June 29, 2014	4 years 8 months 12 days
Weighted Average Remaining Term, Exercisable at June 29, 2014	4 years 1 month 6 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at June 29, 2014	$ 2,614
Aggregate Intrinsic Value, Vested and expected to vest at June 29, 2014	2,454
Aggregate Intrinsic Value, Exercisable at June 29, 2014	$ 1,800

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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