We classify our investment securities as available-for-sale and report them at fair value with the related unrealized gains and losses, net of tax, included in accumulated other comprehensive income, a component of stockholders’ equity.

Note 3—Investment Securities (continued)

As of June 30, 2012 and December 31, 2011, our available-for-sale investment securities were as follows:



	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
	(In thousands)
June 30, 2012
Corporate bonds	$	40,416	$	49	$	(5	)	$	40,460
Commercial paper	8,832		2		—			8,834
Negotiable certificate of deposit	3,500		—		—			3,500
U.S. treasury notes	39,661		1		(14		)	39,648
Agency securities	34,989		20		(7		)	35,002
Municipal bonds	4,804		32		—			4,836
Asset-backed securities	8,464		4		—			8,468
Total fixed income securities	$	140,666	$	108	$	(26	)	$	140,748

December 31, 2011
Corporate bonds	$	16,307	$	27	$	(1	)	$	16,333
Commercial paper	4,998		1		—			4,999
Negotiable certificate of deposit	3,500		—		—			3,500
Agency securities	3,979		12		(4		)	3,987
Municipal bonds	2,379		13		(1		)	2,391
Total fixed income securities	$	31,163	$	53	$	(6	)	$	31,210

As of June 30, 2012 and December 31, 2011, the gross unrealized losses and fair values of available-for-sale investment securities that were in unrealized loss positions were as follows:



	Less than 12 months					12 months or more				Total fair value		Total unrealized loss
	Fair value		Unrealized loss			Fair value		Unrealized loss		Total fair value		Total unrealized loss
	(In thousands)
June 30, 2012
Fixed income securities
Corporate bonds	$	16,423	$	(5	)	$	—	$	—	$	16,423	$	(5	)
U.S. treasury notes	30,582		(14		)	—		—		30,582		(14		)
Agency securities	21,039		(7		)	—		—		21,039		(7		)
Total fixed income securities	$	68,044	$	(26	)	$	—	$	—	$	68,044	$	(26	)

December 31, 2011
Fixed income securities
Corporate bonds	$	2,999	$	(1	)	$	—	$	—	$	2,999	$	(1	)
Agency securities	1,663		(4		)	—		—		1,663		(4		)
Municipal bonds	324		(1		)	—		—		324		(1		)
Total fixed income securities	$	4,986	$	(6	)	$	—	$	—	$	4,986	$	(6	)

We did not record any other-than-temporary impairment losses during the three and six-month periods ended June 30, 2012 or 2011 on our available-for-sale investment securities. We do not intend to sell these investments or it is more likely than not that we will not be required to sell these investments before recovery of their amortized cost bases, which may be at maturity.

Note 3—Investment Securities (continued)

As of June 30, 2012, the contractual maturities of our available-for-sale investment securities were as follows:



	Amortized cost		Fair value
	(In thousands)
Due in one year or less	$	73,033	$	73,063
Due after one year through five years	57,470		57,491
Due after five years through ten years	1,596		1,619
Due after ten years	103		107
Asset-backed securities	8,464		8,468
Total fixed income securities	$	140,666	$	140,748