Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

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-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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No definition available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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- Definition

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

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No definition available.

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- Definition

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

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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

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No definition available.

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STOCKHOLDERS' EQUITY (Details 5) (USD $)	3 Months Ended		6 Months Ended
STOCKHOLDERS' EQUITY (Details 5) (USD $)	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted			487,408
Stock-based compensation expense	$ 5,999,000	$ 2,035,000	$ 10,956,000	$ 3,600,000
Options outstanding (in shares)	6,926,466		6,926,466		7,410,588
Assumptions used to calculate stock-based compensation for each stock purchase right granted under the Employee Stock Purchase Plan (ESPP)
Volatility (as a percent)		61.70%
Dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%
2008 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price expressed as a percentage of fair market value of common stock on the first or the last trading day of the offering period			100.00%
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price expressed as a percentage of fair market value of common stock on the first or the last trading day of the offering period			100.00%
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of deduction from eligible compensation authorized by employee to purchase common stock at discount	15.00%		15.00%
Purchase price expressed as a percentage of fair market value of common stock on the first or the last trading day of the offering period			85.00%
Total compensation costs related to rights to purchase common shares but not yet vested which will be recognized over the offering period	1,700,000		1,700,000
Assumptions used to calculate stock-based compensation for each stock purchase right granted under the Employee Stock Purchase Plan (ESPP)
Dividend yield (as a percent)	0.00%		0.00%
Options to Nonemployees \| 2008 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted		2,000		7,000
Stock-based compensation expense				100,000
Options outstanding (in shares)	5,900		5,900		8,900
Options to Nonemployees \| 2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted	2,000		2,000
Stock-based compensation expense	100,000		100,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards issued (in shares)			0	0
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,500,000
Number of awards issued (in shares)			520,358
Number of awards released (in shares)			26,606
Number of awards cancelled (in shares)			31,145
Unrecognized compensation expense	$ 27,200,000		$ 27,200,000