Stockholders' Equity (Schedule Of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Options exercised, Number of Shares	(1,270,000)	(2,288,000)	(730,000)
Stock Option [Member]
Balance at December 31, Number of Shares	6,915,000	7,461,000	7,939,000
Balance at December 31, Weighted-Average Exercise Per Share	$ 3.46	$ 2.74	$ 2.93
Options forfeited, Number of Shares	(1,536,000)	(762,000)	(1,223,000)
Options forfeited, Weighted-Average Exercise Per Share	$ 5.13	$ 3.84	$ 5.35
Options granted, Number of Shares	1,889,000	2,504,000	1,475,000
Options granted, Weighted-Average Exercise Per Share	$ 6.14	$ 5.06	$ 3.46
Options exercised, Number of Shares	(1,270,000)	(2,288,000)	(730,000)
Options exercised, Weighted-Average Exercise Per Share	$ 2.66	$ 2.71	$ 1.87
Balance at December 31, Number of Shares	5,998,000	6,915,000	7,461,000	7,939,000
Balance at December 31, Weighted-Average Exercise Per Share	$ 4.05	$ 3.46	$ 2.74	$ 2.93
Options outstanding weighted average remaining contractual term (years)	6 years 22 days	6 years 11 months 23 days	6 years 2 months 19 days	6 years 4 months 2 days
Balance outstanding aggregate intrinsic value	$ 5,575	$ 8,130	$ 12,034	$ 3,181
Vested and expected to vest after December 31, 2012, Number of Shares	5,673,000
Vested and expected to vest after December 31, 2012, Weighted-Average Exercise Per Share	$ 3.96
Vested and expected to vest after December 31, 2012, Weighted-Average Remaining Contractual Term (Years)	5 years 11 months 1 day
Vested and expected to vest after December 31, 2012, Aggregate Intrinsic Value	5,552
Exercisable at December 31, 2012, Number of Shares	3,648,000
Exercisable at December 31, 2012, Weighted-Average Exercise Per Share	$ 3.25
Exercisable at December 31, 2012, Weighted-Average Remaining Contractual Term (Years)	4 years 7 months 28 days
Exercisable at December 31, 2012, Aggregate Intrinsic Value	$ 5,055