Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2012

Marketable Securities

Schedule of marketable securities

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
September 30, 2012
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	12,338	$	28	$	2	$	12,364
Maturing after one year through three years	17,297		114		1		17,410
Total U.S. government and municipal obligations	$	29,635	$	142	$	3	$	29,774
Corporate debt securities
Maturing in one year or less	$	17,817	$	39	$	3	$	17,853
Maturing after one year through three years	6,790		13		2		6,801
Total corporate debt securities	$	24,607	$	52	$	5	$	24,654
Total marketable securities	$	54,242	$	194	$	8	$	54,428
December 31, 2011
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	19,993	$	20	$	—	$	20,013
Maturing after one year through three years	10,808		122		6		10,924
Total U.S. government and municipal obligations	$	30,801	$	142	$	6	$	30,937
Corporate debt securities
Maturing in one year or less	$	5,817	$	3	$	4	$	5,816
Maturing after one year through three years	4,730		2		72		4,660
Total corporate debt securities	$	10,547	$	5	$	76	$	10,476
Total marketable securities	$	41,348	$	147	$	82	$	41,413