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Stock-Based Compensation and Employee Benefit Plans Fair Value of Employee Stock Purchase Rights (Details) (Employee Stock Purchase Rights [Member], USD $)
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9 Months Ended | |
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Sep. 30, 2013
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Sep. 30, 2012
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Employee Stock Purchase Rights [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Weighted-average grant date fair value per share (usd per share) | $ 1.85 | $ 1.28 |
| Risk-free interest rate | 0.09% | 0.15% |
| Dividend yield | 0.00% | 0.00% |
| Expected life (years) | 6 months | 6 months |
| Volatility | 41.58% | 46.60% |
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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
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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- 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 risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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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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