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Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2011

Marketable Securities

Cash equivalents and marketable securities classified as available-for-sale

		September 30, 2011
(Dollars in thousands)		Fair Value			Amortized Cost			Gross Unrealized Gains			Gross Unrealized Losses			Weighted Rate of Return
Money market funds		$	132,721		$	132,721		$	—		$	—		0.01	%
U.S. government sponsored obligations		35,668			35,668			3			(3		)	0.25	%
Corporate notes, bonds and commercial paper		96,241			96,359			—			(118		)	0.43	%
Total cash equivalents and marketable securities		264,630			264,748			3			(121		)
Cash		28,123			28,123			—			—
Total cash, cash equivalents and marketable securities		$	292,753		$	292,871		$	3		$	(121	)

		December 31, 2010
(Dollars in thousands)		Fair Value			Amortized Cost			Gross Unrealized Gains			Gross Unrealized Losses			Weighted Rate of Return
Money market funds		$	132,364		$	132,364		$	—		$	—		0.04	%
U.S. government sponsored obligations		266,817			266,840			29			(52		)	0.26	%
Corporate notes, bonds and commercial paper		95,724			95,773			8			(57		)	0.39	%
Total cash equivalents and marketable securities		494,905			494,977			37			(109		)
Cash		17,104			17,104			—			—
Total cash, cash equivalents and marketable securities		$	512,009		$	512,081		$	37		$	(109	)

Available-for-sale securities reported at fair value

(Dollars in thousands)		September 30, 2011			December 31, 2010
Cash equivalents		$	132,721		$	198,158
Short term marketable securities		131,909			296,747
Total cash equivalents and marketable securities		264,630			494,905
Cash		28,123			17,104
Total cash, cash equivalents and marketable securities		$	292,753		$	512,009

Estimated fair value of cash equivalents and marketable securities classified by date of contractual maturity and the associated unrealized gain, net

		As of						Unrealized Loss, net
(Dollars in thousands)		September 30, 2011			December 31, 2010			September 30, 2011			December 31, 2010
Contractual maturity:
Due within one year		$	264,630		$	494,905		$	(118	)	$	(72	)

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