XML 60 R65.htm IDEA: XBRL DOCUMENT

Equity Incentive Plans (Details) (USD $)	12 Months Ended
Equity Incentive Plans (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair value of each stock option granted weighted-average assumptions
Fair value of options granted	$ 1.26	$ 1.33	$ 2.10
Expected volatility	89.00%	78.00%	79.00%
Risk-free interest rate	1.50%	2.20%	2.80%
Expected lives	7 years	7 years	7 years
Dividend rate

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