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Summary of Significant Accounting Policies (Stock Option Valuation Assumptions) (Details) (USD $)
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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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| Accounting Policies [Abstract] | |||
| Expected stock price volatility | 77.11% | 79.70% | 72.90% |
| Annual dividend rate | 0.00% | 0.00% | 0.00% |
| Risk-free interest rate | 0.55% | 0.40% | 0.90% |
| Expected option life (in years) | 4 years 3 months 18 days | 3 years | 4 years 3 months 18 days |
| Estimated fair value per share | $ 3.04 | $ 3.44 | $ 4.67 |
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- Details
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- Definition
Period the instrument, asset or liability is expected to be outstanding, 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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- Definition
Risk-free interest rate assumption used in valuing an instrument. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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