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Stock-Based Compensation (Details 7)	3 Months Ended		6 Months Ended
Stock-Based Compensation (Details 7)	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Stock Options [Member]
Schedule of Employee Stock Purchase Plan, Valuation Assumptions
Expected life (in years)	4 years 6 months	5 years 2 months 12 days	4 years 6 months	5 years 2 months 12 days
Volatility	70.00%	68.00%	70.00%	68.00%
Interest rate	0.70%	2.00%	0.70%	2.00%
Dividend yield
Employee Stock [Member]
Schedule of Employee Stock Purchase Plan, Valuation Assumptions
Expected life (in years)			6 months	6 months
Volatility			72.00%	50.00%
Interest rate			0.10%	0.20%
Dividend yield

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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