Financial Instruments

Cash, Cash Equivalents and Marketable Securities

The following tables summarize our cash and available-for-sale securities by significant investment category.



	December 31, 2013
(In thousands)	Cost		Unrealized Gains		Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities		Long-Term Marketable Securities

Cash	$	71,880	$	—	$	—		$	71,880	$	71,880	$	—	$	—

Available for sale:
Level 1:
Money market funds	2,763,094		—		—			2,763,094		2,763,094		—		—
U.S. treasury securities	1,604,450		15		(28,298		)	1,576,167		34,184		39,262		1,502,721
Subtotal	4,367,544		15		(28,298		)	4,339,261		2,797,278		39,262		1,502,721

Level 2:
U.S. agency securities	53,755		33		(18		)	53,770		—		26,999		26,771
Non-U.S. government securities	18,352		5		—			18,357		—		9,306		9,051
Municipal bond	2,603		—		(7		)	2,596		—		603		1,993
Corporate debt securities	219,491		425		(69		)	219,847		—		65,317		154,530
Subtotal	294,201		463		(94		)	294,570		—		102,225		192,345
Total	$	4,733,625	$	478	$	(28,392	)	$	4,705,711	$	2,869,158	$	141,487	$	1,695,066



	December 31, 2012
(In thousands)	Cost		Unrealized Gains		Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities			Long-Term Marketable Securities

Cash	$	89,194	$	—	$	—		$	89,194	$	89,194	$	—		$	—

Available for sale:
Level 1:
Money market funds	2,739,904		—		—			2,739,904		2,739,904		—			—
U.S. treasury securities	564,713		5,231		(3		)	569,941		33,519		22,493			513,929
Subtotal	3,304,617		5,231		(3		)	3,309,845		2,773,423		22,493		—	513,929

Level 2:
U.S. agency securities	116,802		58		(1		)	116,859		11,799		53,438			51,622
Non-U.S. government securities	11,644		10		(2		)	11,652		—		2,730			8,922
Municipal bond	1,372		1		—			1,373		—		752			621
Corporate debt securities	193,048		436		(64		)	193,420		2,211		61,545			129,664
Subtotal	322,866		505		(67		)	323,304		14,010		118,465			190,829
Total	$	3,716,677	$	5,736	$	(70	)	$	3,722,343	$	2,876,627	$	140,958		$	704,758

We have made certain cost method investments of approximately $12.4 million. These investments are included within Other assets, net in our consolidated balance sheets. The investments are in privately held companies in which we have less than a 20% interest and no significant influence over the investee's operations. We report our cost method investments at cost, except when investments are found to be more than temporarily impaired after an impairment review. Factors considered during an impairment review include the investee’s revenue and earnings trends relative to predefined milestones and overall business prospects, the investee's ability to stay in business such as the investee's liquidity and debt ratios, and overall general market conditions in the investee's industry. Investments are considered impaired when the fair value is below the investment’s adjusted cost basis, and the impairment will be charged to the consolidated statements of comprehensive income. We performed such a review as of December 31, 2013 and determined that no impairment existed.

The adjusted cost and estimated fair value of marketable debt securities (corporate debt securities, municipal bonds, U.S. and foreign government securities, and U.S. treasury securities) as of December 31, 2013, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations without call or prepayment penalties.



	December 31, 2013
(In thousands)	Adjusted Cost		Estimated Fair Value
Due in one year or less	$	175,584	$	175,671
Due after one year through five years	1,723,067		1,695,066
	$	1,898,651	$	1,870,737

As of December 31, 2013, we had 137 or $1.6 billion out of our total available-for-sale securities investment portfolio that were in a continuous unrealized loss position for less than 12 months with a gross unrealized loss of $28.4 million. As of December 31, 2012, we had 91 or $118.7 million out of our total available-for-sale securities portfolio that were in a continuous unrealized loss position for less than 12 months with a gross unrealized loss of $0.1 million.

We concluded that the declines in market value of our available-for-sale securities investment portfolio were temporary in nature and did not consider any of our investments to be other-than-temporarily impaired. In accordance with our investment policy, we place investments in highly-rated securities with high credit quality issuers, and limit the amount of credit exposure to any one issuer. We evaluate securities for other-than-temporary impairment on a quarterly basis. Impairment is evaluated considering numerous factors, and their relative significance varies depending on the situation. Factors considered include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the issuer, and our intent and ability to hold the investment in order to allow for an anticipated recovery in fair value. Furthermore, the aggregate of individual unrealized losses that had been outstanding for twelve months or less was not significant as of December 31, 2013 and December 31, 2012. We neither intend to sell these investments nor conclude that it is more-likely-than-not that we will have to sell them until recovery of their carrying values. We also believe that we will be able to collect both principal and interest amounts due to us at maturity, given the high credit quality of these investments.