Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2013

Information Regarding Short-Term and Long-Term Marketable Securities

Information regarding the Company’s short-term and long-term marketable securities as of March 31, 2013 and December 31, 2012 is as follows:

	March 31, 2013
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government agency securities	$	23,714	$	8	$	(5	)	$	23,717
Corporate debt securities		23,767		29		(28	)		23,768
Commercial paper		5,493		—		(13	)		5,480
U.S. municipal securities		26,901		10		(14	)		26,897
Certificates of deposit/time deposits		4,697		8		(1	)		4,704
Total marketable securities	$	84,572	$	55	$	(61	)	$	84,566

	December 31, 2012
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government agency securities	$	23,011	$	2	$	(4	)	$	23,009
Corporate debt securities		14,675		18		(14	)		14,679
Commercial paper		1,500		—		—			1,500
U.S. municipal securities		17,971		3		(12	)		17,962
Certificates of deposit/time deposits		4,945		3		(1	)		4,947
Total marketable securities	$	62,102	$	26	$	(31	)	$	62,097

Balance of Held-To-Maturity Debt Securities by Contractual Maturity

Actual maturities may differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties.

	March 31,
(in thousands)	2013
Due in one year or less	$	35,695
Due after one year through five years		48,877
Total marketable securities	$	84,572