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Stock-Based Compensation (Details 1)	12 Months Ended
Stock-Based Compensation (Details 1)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Weighted Average Assumptions for Stock Option Awards Granted under the Incentive Plan
Expected Life	5 years 4 months 24 days	5 years 6 months	5 years 6 months
Expected Volatility	87.00%	80.00%	89.00%
Expected Dividend Yield	0.00%	0.00%	0.00%
Risk-Free Interest Rate	0.90%	2.20%	2.40%

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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