EARNINGS PER SHARE (Calculation of Basic and Diluted Net Income Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net income	$ 8,190us-gaap_NetIncomeLoss	$ 1,789us-gaap_NetIncomeLoss	$ 31,704us-gaap_NetIncomeLoss
Undistributed Earnings, Diluted			(22,668)us-gaap_UndistributedEarningsDiluted
Net Income (Loss) Available to Common Stockholders, Basic and Diluted	$ 8,190	$ 1,789	$ 9,036
Denominator:
Basic (in shares)	82,908	76,744	24,847
Weighted-average effect of potentially dilutive shares:
Employee stock options	10,538	16,442	12,788
RSUs and ESPP	222	175	140
Diluted (in shares)	93,668	93,361	37,775
Net income per share of common stock:
Basic (USD per share)	$ 0.10us-gaap_EarningsPerShareBasic	$ 0.02us-gaap_EarningsPerShareBasic	$ 0.36us-gaap_EarningsPerShareBasic
Diluted (USD per share)	$ 0.09us-gaap_EarningsPerShareDiluted	$ 0.02us-gaap_EarningsPerShareDiluted	$ 0.24us-gaap_EarningsPerShareDiluted

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Net Income (Loss) Available to Common Stockholders, Basic and Diluted

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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The earnings that is allocated to common stock and participating securities to the extent that each security may share in earnings as if all of the earnings for the period had been distributed. Includes the adjustments resulting from the assumption that dilutive securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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