The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

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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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)-(4)

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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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No definition available.

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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 price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Paragraph 2

-Subparagraph (e)(1)

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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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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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Employee And Non-Employee Benefit And Compensation Plans (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May 01, 2008
Prior Plans
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, Beginning Balance	875,000,000
Options outstanding, Ending Balance	845,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, beginning balance, weighted average exercise price	$ 7.06
Options outstanding, ending balance, weighted average exercise price	$ 7.04
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, weighted average remaining contractual term	2 months 1 day
Prior Plans \| Service period-based options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options canceled	(30,000,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options canceled, weighted average exercise price	$ 7.63
Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, Beginning Balance	3,656,675
Options outstanding, Ending Balance	3,306,665
Options exercisable, end of period	2,343,122
Shares available for grant at end of period	6,327,129,000			10,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, beginning balance, weighted average exercise price	$ 4.38
Options outstanding, ending balance, weighted average exercise price	$ 3.74
Options exercisable, end of period, weighted average exercise price	$ 3.43
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, weighted average remaining contractual term	6 years 5 months 19 days
Exercisable, weighted average remaining contractual term	5 years 5 months 23 days
Outstanding, intrinsic value	$ 3,531,899
Exercisable, intrinsic value	$ 2,837,529
Stock Plan \| Service period-based options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options granted	25,070	1,190,000	505,000
Options exercised	(300,952)
Options canceled	(159,128)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options granted, weighted average exercise price	$ 5.12
Options exercised, weighted average exercise price	$ 3.27
Options canceled, weighted average exercise price	$ 4.58
Stock Plan \| Price-based options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options granted	185,000
Options canceled	(100,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options granted, weighted average exercise price	$ 8.38
Options canceled, weighted average exercise price	$ 9.00