Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2012

Marketable Securities Classified as Available-for-Sale

Marketable securities classified as available-for-sale consisted of the following (in thousands):

	December 31, 2012
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Corporate bonds	$	49,545	$	203	$	(4	)	$	49,744
Government and agency securities		23,431		43		(27	)		23,447
Asset-backed securities		23,079		70		—			23,149
Mortgage-backed securities		12,064		40		(15	)		12,089
Commercial paper		1,200		—		—			1,200
Municipal bonds		6,273		13		—			6,286
Certificates of deposit		1,003		1		—			1,004
Floating rate notes		1,266		2		—			1,268
	$	117,861	$	372	$	(46	)	$	118,187

	December 31, 2011
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Corporate bonds	$	68,196	$	—	$	(209	)	$	67,987
Government and agency securities		60,602		—		(64	)		60,538
Asset-backed securities		37,130		—		(33	)		37,097
Commercial paper		22,266		5		—			22,271
Mortgage-backed securities		17,448		—		(24	)		17,424
Municipal bonds		7,200		14		—			7,214
Certificates of deposit		2,019		—		(3	)		2,016
Floating rate notes		327		—		(2	)		325
Collateralized mortgage obligations		72		—		—			72
	$	215,260	$	19	$	(335	)	$	214,944

Amortized Cost and Fair Value of Marketable Securities Classified by Stated Maturity

The following table summarizes the amortized cost and fair value of the Company’s marketable securities, classified by stated maturity as of December 31, 2012 and 2011 (in thousands):

	December 31, 2012				December 31, 2011
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Marketable securities
Due in 1 year or less	$	53,761	$	53,852	$	70,871	$	70,794
Due in 1-2 years		36,510		36,694		64,902		64,754
Due in 2-3 years		11,847		11,856		37,493		37,500
Due in 3-4 years		744		746		14,459		14,387
Due in 4-9 years		5,158		5,179		12,759		12,748
Due in 9-20 years		1,032		1,040		2,957		2,958
Due in 20-32 years		8,809		8,820		11,819		11,803
	$	117,861	$	118,187	$	215,260	$	214,944