Investments (Tables)

9 Months Ended

Sep. 30, 2013

MarketableSecuritiesTableTextBlockAbstract

Investment [Table Text Block]

Marketable securities at September 30, 2013, consisted of the following:

	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term deposits	$	106,903		$	—	$	—		$	106,903
Mutual funds	12,506			3,623		—			16,129
United States government securities	50,383			29		—			50,412
Corporate securities	69,974			8,220		(4,224		)	73,970
Corporate obligations	23,573			855		(42		)	24,386
Commercial paper	6,297			1		—			6,298
Total available-for-sale securities	269,636			12,728		(4,266		)	278,098
Amounts classified as cash equivalents	(108,603		)	—		—			(108,603		)
Amounts classified as marketable securities	$	161,033		$	12,728	$	(4,266	)	$	169,495

Marketable securities at December 31, 2012, consisted of the following:

	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term deposits	$	48,596		$	—	$	—		$	48,596
Mutual funds	10,368			1,452		—			11,820
United States government securities	99,299			178		—			99,477
Corporate securities	20,842			1,255		(1,980		)	20,117
Corporate obligations	48,708			283		(277		)	48,714
Commercial paper	22,275			16		—			22,291
Total available-for-sale securities	250,088			3,184		(2,257		)	251,015
Amounts classified as cash equivalents	(51,887		)	—		—			(51,887		)
Amounts classified as marketable securities	$	198,201		$	3,184	$	(2,257	)	$	199,128

Available-for-sale Securities [Table Text Block]

Gross realized gains and losses from sales of marketable securities, all of which are reported as a component of "Other income (expense), net" in the consolidated statements of operations for the three months and nine months ended September 30, 2013 and 2012, were as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
	(in thousands)
Gross realized gains	$	1,914		$	42		$	5,779		$	138
Gross realized losses	(51		)	(35		)	(3,945		)	(40		)
Realized gains (losses) - net	$	1,863		$	7		$	1,834		$	98

Schedule of Unrealized Loss on Investments [Table Text Block]

The fair value of the Company’s marketable securities with unrealized losses at September 30, 2013, and the duration of time that such losses had been unrealized, were as follows:

	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
	(in thousands)
Corporate securities	$	22,725	$	(3,968	)	$	176	$	(256	)	$	22,901	$	(4,224	)
Corporate obligations	940		(42		)	—		—			940		(42		)
Total	$	23,665	$	(4,010	)	$	176	$	(256	)	$	23,841	$	(4,266	)

The fair value of the Company’s marketable securities with unrealized losses at December 31, 2012, all of which had been unrealized for a period of less than twelve months, were as follows:

	Fair Value		Gross Unrealized Losses
	(in thousands)
Corporate securities	$	6,389	$	(1,980	)
Corporate obligations	14,252		(277		)
Total	$	20,641	$	(2,257	)

Investments Classified by Contractual Maturity Date [Table Text Block]

The amortized cost and estimated fair value of available-for-sale debt securities at September 30, 2013, by contractual maturity, were as follows:

	Cost		Estimated  Fair Value
	(in thousands)
Debt securities:
Mature in one year or less	$	44,134	$	44,157
Mature after one year through three years	14,285		14,435
Mature in more than three years	21,834		22,504
Total debt securities	80,253		81,096
Securities with no contractual maturities	189,383		197,002
Total	$	269,636	$	278,098