XML 23 R17.htm IDEA: XBRL DOCUMENT

Weighted-average assumptions used in determining the fair value of share based awards at the grant date by using the Black-Scholes option-pricing model (Detail)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Dividend Yield		0.00%
Risk free interest rate		2.50%
Expected volatility		56.00%
Expected lives	0 years
Minimum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expected lives		2 years
Maximum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expected lives		5 years

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