Marketable Securities (Tables)

3 Months Ended

Mar. 31, 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 March 31, 2014
(In thousands)	Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Weighted Rate of Return
Money market funds	$	317,769	$	317,769	$	—	$	—		0.01	%
Corporate notes, bonds and commercial paper	58,347		58,355		1		(9		)	0.13	%
Total cash equivalents and marketable securities	376,116		376,124		1		(9		)
Cash	27,308		27,308		—		—
Total cash, cash equivalents and marketable securities	$	403,424	$	403,432	$	1	$	(9	)



	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
	March 31, 2014		December 31, 2013
	(In thousands)
Cash equivalents	$	319,268	$	310,131
Short term marketable securities	56,848		48,966
Total cash equivalents and marketable securities	376,116		359,097
Cash	27,308		28,565
Total cash, cash equivalents and marketable securities	$	403,424	$	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 March 31, 2014 and December 31, 2013 are as follows:



	Fair Value				Gross Unrealized Loss
	March 31, 2014		December 31, 2013		March 31, 2014			December 31, 2013
	(In thousands)
Less than one year
Corporate notes, bonds and commercial paper	$	43,151	$	53,491	$	(9	)	$	(15	)