Cash, Cash Equivalents And Marketable Securities (Schedule Of Gross Unrealized Losses And Fair Values Of Investments) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Cash, Cash Equivalents And Marketable Securities [Line Items]
Fair Value, Less than 12 months	$ 24,585
Gross Unrealized Losses, Less than 12 months	(8)
Fair Value, Total	24,585
Gross Unrealized Losses, Total	(8)
Number of securities in an unrealized loss position	18
Corporate Debt Securities [Member]
Cash, Cash Equivalents And Marketable Securities [Line Items]
Fair Value, Less than 12 months	16,215
Gross Unrealized Losses, Less than 12 months	(5)
Fair Value, Total	16,215
Gross Unrealized Losses, Total	(5)
U.S. Treasury Securities [Member]
Cash, Cash Equivalents And Marketable Securities [Line Items]
Fair Value, Less than 12 months	8,370
Gross Unrealized Losses, Less than 12 months	(3)
Fair Value, Total	8,370
Gross Unrealized Losses, Total	$ (3)