Cash Equivalents And Investments (Schedule Of Estimated Fair Value Of Available-For-Sale Securities) (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 14,965,000	$ 17,216,000
Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Due within one year, Amortized Cost	2,685,000
Due after one year through five years, Amortized Cost	10,057,000
Amortized Cost	12,742,000
Due within one year, Fair Value	2,686,000
Due after one year through five years, Fair Value	10,057,000
Fair Value	$ 12,743,000	$ 16,143,000