Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2014

Marketable Securities

Summary of marketable securities

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
September 30, 2014
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	40,198	$	43	$	(5	)	$	40,236
Maturing after one year through three years	30,293		67		(9		)	30,351
Total U.S. government and municipal obligations	$	70,491	$	110	$	(14	)	$	70,587
Corporate debt securities
Maturing in one year or less	$	92,510	$	20	$	(34	)	$	92,496
Maturing after one year through three years	28,510		2		(42		)	28,470
Total corporate debt securities	$	121,020	$	22	$	(76	)	$	120,966
Total marketable securities	$	191,511	$	132	$	(90	)	$	191,553
December 31, 2013
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	55,531	$	27	$	(4	)	$	55,554
Maturing after one year through three years	18,234		56		(4		)	18,286
Total U.S. government and municipal obligations	$	73,765	$	83	$	(8	)	$	73,840
Corporate debt securities
Maturing in one year or less	$	38,973	$	9	$	(9	)	$	38,973
Maturing after one year through three years	20,761		12		(5		)	20,768
Total corporate debt securities	$	59,734	$	21	$	(14	)	$	59,741
Total marketable securities	$	133,499	$	104	$	(22	)	$	133,581