Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2014

Marketable Securities

Summary of marketable securities

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
June 30, 2014
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	46,138	$	59	$	—		$	46,197
Maturing after one year through three years	39,447		89		(11		)	39,525
Total U.S. government and municipal obligations	$	85,585	$	148	$	(11	)	$	85,722
Corporate debt securities
Maturing in one year or less	$	96,350	$	39	$	(11	)	$	96,378
Maturing after one year through three years	29,474		11		(13		)	29,472
Total corporate debt securities	$	125,824	$	50	$	(24	)	$	125,850
Total marketable securities	$	211,409	$	198	$	(35	)	$	211,572
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