Investments (Tables)

6 Months Ended

Jun. 30, 2013

MarketableSecuritiesTableTextBlockAbstract

Investment [Table Text Block]

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

	Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Short-term deposits	72,186			—		—			72,186
Mutual funds	10,758			3,154		(23		)	13,889
United States government securities	49,477			83		(11		)	49,549
Corporate securities	64,292			4,956		(2,120		)	67,128
Corporate obligations	23,587			600		(89		)	24,098
Commercial paper	9,794			2		—			9,796
Total available-for-sale securities	230,094			8,795		(2,243		)	236,646
Amounts classified as cash equivalents	(76,128		)	—		—			(76,128		)
Amounts classified as marketable securities	$	153,966		$	8,795	$	(2,243	)	$	160,518

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 expense, net" in the consolidated statements of operations for the three months and six months ended June 30, 2013 and 2012, were as follows:

	Three Months Ended June 30,						Six Months Ended June 30,
	2013			2012			2013			2012
	(in thousands)
Gross realized gains	$	2,607		$	23		$	3,865		$	95
Gross realized losses	$	(3,852	)	$	(4	)	$	(3,894	)	$	(5	)
Realized gains (losses) - net	$	(1,245	)	$	19		$	(29	)	$	90

Schedule of Unrealized Loss on Investments [Table Text Block]

The fair value of the Company’s marketable securities with unrealized losses at June 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)
Mutual funds	$	13,889	$	(23	)	$	—	$	—		$	13,889	$	(23	)
United States government securities	49,549		(11		)	—		—			49,549		(11		)
Corporate securities	66,474		(1,836		)	654		(284		)	67,128		(2,120		)
Corporate obligations	24,098		(89		)	—		—			24,098		(89		)
Total	$	154,010	$	(1,959	)	$	654	$	(284	)	$	154,664	$	(2,243	)

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	$	20,117	$	(1,980	)
Corporate obligations	48,714		(277		)
Total	$	68,831	$	(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 June 30, 2013, by contractual maturity, were as follows:

	Cost		Estimated  Fair Value
	(in thousands)
Debt securities:
Mature in one year or less	$	38,062	$	38,146
Mature after one year through three years	22,958		23,095
Mature in more than three years	21,838		22,202
Total debt securities	82,858		83,443
Securities with no contractual maturities	147,236		153,203
Total	$	230,094	$	236,646