Equity Incentive Plans (Details) Black-Scholes Assumptions
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12 Months Ended | ||
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2010
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Share-based Compensation | |||
Average expected term | 5 years 7 months 6 days | 5 years 9 months 18 days | 5 years 8 months 12 days |
Risk free interest rate, minimum | 0.80% | 1.14% | 1.39% |
Risk free interest rate, maximum | 1.15% | 2.55% | 2.80% |
Expected dividend rate | 0.00% | 0.00% | 0.00% |
Minimum [Member]
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Share-based Compensation | |||
Expected volatility rate | 64.00% | 64.00% | 65.80% |
Maximum [Member]
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Share-based Compensation | |||
Expected volatility rate | 69.20% | 65.10% | 70.80% |
X | ||||||||||
- 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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- 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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
The maximum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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- Definition
The minimum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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- Details
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