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Shareholders' Equity (Schedule Of Weighted Average Assumptions) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	4 years 2 months 12 days	4 years 6 months
Expected volatility	71.00%	70.00%
Dividend yield	0.00%	0.00%
Risk-free interest rate	0.58%	1.60%
Stock Purchase Plan Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	1 year	1 year
Expected volatility	46.00%	30.00%
Dividend yield	0.00%	0.00%
Risk-free interest rate	0.12%	0.30%

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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