Available-for-Sale Securities (Tables)

3 Months Ended

Mar. 31, 2014

Available-for-Sale Securities

Schedule of available-for-sale securities

(In thousands)	March 31, 2014		December 31, 2013
Cash and cash equivalents	$	119,160	$	125,009
Short-term investments	245,648		321,615
Marketable securities	59,831		55,374
Restricted cash	833		833
Total	$	425,472	$	502,831

Schedule of amortized cost and estimated fair values for available-for-sale securities

	March 31, 2014
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government securities	$	37,042	$	74	$	—		$	37,116
U.S. government agencies	110,171		59		—			110,230
U.S. corporate notes	88,607		48		(10		)	88,645
U.S. commercial paper	74,487		—		—			74,487
Money market funds	114,994		—		—			114,994
Total	$	425,301	$	181	$	(10	)	$	425,472

	December 31, 2013
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government securities	$	42,104	$	55	$	(1	)	$	42,158
U.S. government agencies	141,278		61		(8		)	141,331
U.S. corporate notes	94,923		54		—			94,977
U.S. commercial paper	102,021		2		(1		)	102,022
Money market funds	122,343		—		—			122,343
Total	$	502,669	$	172	$	(10	)	$	502,831