Stockholders' Equity (Schedule Of Stock Option Activity) (Details) (Stock Option [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Option [Member]
Balance as of December 31, Number of Shares	6,095	5,998	6,915
Balance as of December 31, Weighted-Average Exercise Per Share	$ 4.14	$ 4.05	$ 3.46
Options forfeited, Number of Shares	(705)	(966)	(1,536)
Options forfeited, Weighted-Average Exercise Per Share	$ 5.10	$ 5.45	$ 5.13
Options granted, Number of Shares	1,740	1,637	1,889
Options granted, Weighted-Average Exercise Per Share	$ 4.85	$ 4.76	$ 6.14
Options exercised, Number of Shares	(1,233)	(574)	(1,270)
Options exercised, Weighted-Average Exercise Per Share	$ 4.43	$ 2.82	$ 2.66
Balance as of December 31, Number of Shares	5,897	6,095	5,998	6,915
Balance as of December 31, Weighted-Average Exercise Per Share	$ 4.17	$ 4.14	$ 4.05	$ 3.46
Options outstanding weighted average remaining contractual term (years)	6 years 29 days	5 years 7 months 28 days	6 years 22 days	6 years 11 months 23 days
Balance outstanding aggregate intrinsic value	$ 27,066	$ 7,199	$ 5,575	$ 8,130
Vested and expected to vest after December 31, 2014 Number of Shares	5,445
Vested and expected to vest after December 31, 2014 Weighted-Average Exercise Per Share	$ 4.11
Vested and expected to vest after December 31, 2014 Weighted-Average Remaining Contractual Term (Years)	5 years 10 months 2 days
Vested and expected to vest after December 31, 2014 Aggregate Intrinsic Value	25,342
Exercisable as of December 31, Number of Shares	3,397
Exercisable as of December 31, Weighted-Average Exercise Per Share	$ 3.60
Exercisable as of December 31, Weighted-Average Remaining Contractual Term (Years)	4 years 1 month 2 days
Exercisable as of December 31, Aggregate Intrinsic Value	$ 17,537