Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2014

Available-for-sale Securities [Abstract]

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

All cash equivalents and marketable securities are classified as available-for-sale. Total cash, cash equivalents and marketable securities are summarized as follows:

	As of June 30, 2014
(In thousands)	Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Weighted Rate of Return
Money market funds	$	79,522	$	79,522	$	—	$	—		0.01	%
Corporate notes, bonds and commercial paper	146,859		146,927		—		(68		)	0.17	%
Total cash equivalents and marketable securities	226,381		226,449		—		(68		)
Cash	20,049		20,049		—		—
Total cash, cash equivalents and marketable securities	$	246,430	$	246,498	$	—	$	(68	)

	As of December 31, 2013
(In thousands)	Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Weighted Rate of Return
Money market funds	$	300,605	$	300,605	$	—	$	—		0.01	%
Corporate notes, bonds and commercial paper	58,492		58,507		—		(15		)	0.15	%
Total cash equivalents and marketable securities	359,097		359,112		—		(15		)
Cash	28,565		28,565		—		—
Total cash, cash equivalents and marketable securities	$	387,662	$	387,677	$	—	$	(15	)

Available-for-sale securities reported at fair value

Available-for-sale securities are reported at fair value on the balance sheets and classified as follows:

	As of
	June 30, 2014		December 31, 2013
	(In thousands)
Cash equivalents	$	79,522	$	310,131
Short term marketable securities	146,859		48,966
Total cash equivalents and marketable securities	226,381		359,097
Cash	20,049		28,565
Total cash, cash equivalents and marketable securities	$	246,430	$	387,662

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

The estimated fair value of cash equivalents and marketable securities classified by the length of time that the securities have been in a continuous unrealized loss position at June 30, 2014 and December 31, 2013 are as follows:

	Fair Value				Gross Unrealized Loss
	June 30, 2014		December 31, 2013		June 30, 2014			December 31, 2013
	(In thousands)
Less than one year
Corporate notes, bonds and commercial paper	$	131,101	$	53,491	$	(68	)	$	(15	)