Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2015

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 September 30, 2015
(In thousands)	Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Weighted Rate of Return
Money market funds	$	186,481	$	186,481	$	—	$	—		0.01	%
Corporate notes, bonds and commercial paper	146,325		146,398		6		(79		)	0.44	%
Total cash equivalents and marketable securities	332,806		332,879		6		(79		)
Cash	30,072		30,072		—		—
Total cash, cash equivalents and marketable securities	$	362,878	$	362,951	$	6	$	(79	)

	As of December 31, 2014
(In thousands)	Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Weighted Rate of Return
Money market funds	$	124,938	$	124,938	$	—	$	—		0.01	%
Corporate notes, bonds and commercial paper	145,983		146,096		1		(114		)	0.25	%
Total cash equivalents and marketable securities	270,921		271,034		1		(114		)
Cash	29,188		29,188		—		—
Total cash, cash equivalents and marketable securities	$	300,109	$	300,222	$	1	$	(114	)

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
	September 30, 2015		December 31, 2014
	(In thousands)
Cash equivalents	$	186,481	$	124,938
Short term marketable securities	146,325		145,983
Total cash equivalents and marketable securities	332,806		270,921
Cash	30,072		29,188
Total cash, cash equivalents and marketable securities	$	362,878	$	300,109

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 September 30, 2015 and December 31, 2014 are as follows:

	Fair Value				Gross Unrealized Loss
	September 30, 2015		December 31, 2014		September 30, 2015			December 31, 2014
	(In thousands)
Less than one year
Corporate notes, bonds and commercial paper	$	110,870	$	139,989	$	(79	)	$	(114	)