Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2015

Marketable Securities

Summary of marketable securities

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
September 30, 2015
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	43,379	$	21	$	(2	)	$	43,398
Maturing after one year through three years	22,921		54		(45		)	22,930
Total U.S. government and municipal obligations	$	66,300	$	75	$	(47	)	$	66,328
Corporate debt securities
Maturing in one year or less	$	135,613	$	24	$	(89	)	$	135,548
Maturing after one year through three years	35,942		21		(20		)	35,943
Total corporate debt securities	$	171,555	$	45	$	(109	)	$	171,491
Total marketable securities	$	237,855	$	120	$	(156	)	$	237,819
December 31, 2014
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	44,580	$	30	$	(6	)	$	44,604
Maturing after one year through three years	16,108		49		(1		)	16,156
Total U.S. government and municipal obligations	$	60,688	$	79	$	(7	)	$	60,760
Corporate debt securities
Maturing in one year or less	$	89,636	$	6	$	(37	)	$	89,605
Maturing after one year through three years	22,690		3		(35		)	22,658
Total corporate debt securities	$	112,326	$	9	$	(72	)	$	112,263
Total marketable securities	$	173,014	$	88	$	(79	)	$	173,023