Marketable Securities, Available-for-sale (Tables)

12 Months Ended

Dec. 31, 2013

Marketable Securities, Available-for-sale

Fair value of the available-for-sale marketable securities, by type of security

	DECEMBER 31, 2013
(in thousands)		AMORTIZED COST		GROSS UNREALIZED GAINS		GROSS UNREALIZED LOSSES			ESTIMATED FAIR VALUE
Type of security:
U.S. Treasury securities	$	76,355	$	149	$	–		$	76,504
Obligations of U.S. government agencies		17,074		2		(8	)		17,068
Municipal debt securities		33,492		492		(1,008	)		32,976
Corporate debt securities		157,798		102		(21	)		157,879
Asset-backed securities		20,433		76		(20	)		20,489
Total debt securities		305,152		821		(1,057	)		304,916
Time deposits		1,606		–		–			1,606
Short-term pooled investments		6,633		–		–			6,633
Total marketable securities, available-for-sale	$	313,391	$	821	$	(1,057	)	$	313,155

	DECEMBER 31, 2012
Type of security:
U.S. Treasury securities	$	3,098	$	1	$	–		$	3,099
Obligations of U.S. government agencies		133,029		112		(31	)		133,110
Municipal debt securities		21,745		896		(458	)		22,183
Corporate debt securities		163,352		116		(75	)		163,393
Asset-backed securities		27,325		153		(164	)		27,314
Total debt securities		348,549		1,278		(728	)		349,099
Short-term pooled investments		36,533		–		(7	)		36,526
Total marketable securities, available-for-sale	$	385,082	$	1,278	$	(735	)	$	385,625

Fair value of the available-for-sale marketable securities, by contractual maturity

	DECEMBER 31,
(in thousands)		2013		2012
Contractual maturity:
Maturing in one year or less	$	129,384	$	66,546
Maturing after one year through three years		154,169		257,595
Maturing after three years		21,363		24,958
Total debt securities		304,916		349,099
Time deposits and short-term pooled investments		8,239		36,526
Total marketable securities, available-for-sale	$	313,155	$	385,625