Stockholders' Equity (Schedule Of Valuation Assumptions Used For Stock Options And ESPP Plans) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Dividend yield	0.00%	0.00%	0.00%
Stock Option [Member]
Risk-free interest rate	1.61%	1.02%	0.92%
Volatility factor of the market price of common stock	57.96%	64.12%	63.79%
Weighted-average expected life (years)	5 years	5 years 1 month 6 days	5 years 2 months 16 days
Performance-Based Stock Options [Member]
Risk-free interest rate		1.22%	0.96%
Volatility factor of the market price of common stock		63.20%	63.66%
Weighted-average expected life (years)		5 years 15 days	5 years 2 months 19 days
ESPP [Member]
Risk-free interest rate	0.04%	0.06%	0.09%
Volatility factor of the market price of common stock	42.50%	37.36%	56.79%
Weighted-average expected life (years)	3 months	3 months	3 months