EQUITY INCENTIVE PLANS - Option activity (Details) (Equity Incentive Plan, Stock Options, USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Equity Incentive Plan \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding	6,547,443	6,355,827	5,215,189
Granted	1,453,468	1,675,950	1,548,650
Exercised	(278,545)	(728,811)	(83,023)
Cancelled	(564,908)	(755,523)	(324,989)
Outstanding	7,157,458	6,547,443	6,355,827
Exercisable	4,428,151
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding	$ 5.34	$ 5.29	$ 6.04
Granted	$ 7.72	$ 6.69	$ 3.74
Exercised	$ 4.85	$ 5.41	$ 3.42
Cancelled	$ 7.20	$ 7.88	$ 10.37
Outstanding	$ 5.70	$ 5.34	$ 5.29
Exercisable	$ 5.17
Weighted average grant-date fair value of options granted during the year ended December 31, 2012	$ 4.67	$ 3.99	$ 2.24

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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-Name Accounting Standards Codification

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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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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.

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

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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

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