XML 42 R75.htm IDEA: XBRL DOCUMENT

Stock Based Compensation (Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Wieghted Average Grant Date Fair Value) (Details) (USD $)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term in years	4 years 4 months 24 days	4 years 4 months 13 days	4 years 6 months 15 days
Estimated volatility	60.00%	58.00%	48.00%
Risk-free interest rate	0.61%	1.21%	2.23%
Wieghted-average fair value of grants	$ 4.70	$ 3.88	$ 1.94
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term in years	6 months	6 months	6 months
Estimated volatility	42.00%	46.00%	83.00%
Risk-free interest rate	0.11%	0.12%	0.20%
Wieghted-average fair value of grants	$ 2.66	$ 2.66	$ 3.28

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