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Stock-Based Awards and Per Share Information (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012 Rate	Jun. 30, 2011 Rate	Jun. 30, 2012 Rate	Jun. 30, 2011 Rate
Assumptions used in estimating the fair value of stock options granted
Expected term (years)	3 years 8 months 12 days	3 years 10 months 24 days	3 years 9 months 18 days	3 years 11 months 23 days
Volatility	103.00%	107.00%	103.00%	106.00%
Annual dividend per share	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Risk-free interest rate	0.87%	1.81%	0.88%	1.91%

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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