XML 87 R91.htm IDEA: XBRL DOCUMENT

Stock-Based Compensation and Other Plans (Details 4) (Stock options)	12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2011 CEO	Dec. 31, 2011 CEO
Significant assumptions used to estimate the fair value of share based compensation awards
Expected term	3 years 3 months 7 days	3 years 11 months 8 days	3 years 8 months 12 days
Expected volatility (as a percent)	73.60%	87.10%	89.90%
Risk-free interest rate (as a percent)	0.50%	1.20%	1.00%
Options granted (in shares)	666,668	4,373,686	2,722,092	1,000,000	1,000,000

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.

+ References+ Details