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Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2012

Available-for-sale Securities [Abstract]

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

	As of December 31, 2012
(Dollars in thousands)	Fair Value				Amortized Cost				Gross Unrealized Gains				Gross Unrealized Losses				Weighted Rate of Return
Money market funds	$	126,570			$	126,570			$	—			$	—			0.01	%
Corporate notes, bonds and commercial paper	57,345				57,356				4				(15)				0.17	%
Total cash equivalents and marketable securities	183,915				183,926				4				(15)
Cash	19,415				19,415				—				—
Total cash, cash equivalents and marketable securities	$	203,330			$	203,341			$	4			$	(15	)

	As of December 31, 2011
(Dollars in thousands)	Fair Value				Amortized Cost				Gross Unrealized Gains				Gross Unrealized Losses				Weighted Rate of Return
Money market funds	$	127,559			$	127,559			$	—			$	—			0.01	%
Corporate notes, bonds and commercial paper	137,108				137,208				—				(100		)		0.29	%
Total cash equivalents and marketable securities	264,667				264,767				—				(100		)
Cash	24,789				24,789				—				—
Total cash, cash equivalents and marketable securities	$	289,456			$	289,556			$	—			$	(100	)

Available-for-sale securities reported at fair value

	As of
	December 31, 2012				December 31, 2011
	(Dollars in thousands)
Cash equivalents	$	129,569			$	137,455
Short term marketable securities	54,346				127,212
Total cash equivalents and marketable securities	183,915				264,667
Cash	19,415				24,789
Total cash, cash equivalents and marketable securities	$	203,330			$	289,456

Estimated fair value of cash equivalents and marketable securities classified by date of contractual maturity and the length of time that the securities have been in a continuous unrealized loss position

	Fair Value								Gross Unrealized Loss
	December 31, 2012				December 31, 2011				December 31, 2012				December 31, 2011
	(In thousands)
Less than one year
Corporate notes, bonds and commercial paper	$	51,819			$	137,108			$	(15	)		$	(100	)

X

- Definition

Tabular disclosure of cash and the reconciliation of available-for-sale securities from cost basis to fair value.

+ References

No definition available.

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- Definition

Tabular disclosure of the components of cash, cash equivalents, and short-term investments. Short-term investments may include current marketable securities.

+ References

No definition available.

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- Definition

For all investments in an unrealized loss position, including those for which other-than-temporary impairments have not been recognized in earnings (including investments for which a portion of an other-than-temporary impairment has been recognized in other comprehensive income), a tabular disclosure of the aggregate related fair value of investments with unrealized losses and the aggregate amount of unrealized losses (that is, the amount by which amortized cost basis exceeds fair value).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27290-111563

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