Cash Equivalents and Investments (Tables)

12 Months Ended

Dec. 31, 2012

Company's Cash Equivalents and Investments Measured at Fair Value

The following tables summarize the Company’s cash equivalents and investments measured at fair value:

	Fair Value Measurements as of December 31, 2012
	Level 1			Level 2			Total
	(In thousands)
Cash equivalents:
Money-market funds	$	364,596	(a)	$	—		$	364,596
Government and agency securities		—			6,479	(b)		6,479
Total cash equivalents	$	364,596		$	6,479		$	371,075
Available-for-sale debt securities:
Asset-backed and mortgage-backed securities:
Agency securities	$	—		$	129,463	(b)	$	129,463
Non-agency securities		—			1,393	(b)		1,393
Government and agency securities		17,042	(a)		49,658	(b)		66,700
Corporate debt securities		—			6,001	(b)		6,001
Commercial paper		—			900	(b)		900
Total short-term investments	$	17,042		$	187,415		$	204,457
Long-term investments in equity securities:
Marketable available-for-sale equity securities	$	1,689	(c)	$	—		$	1,689

	Fair Value Measurements as of December 31, 2011
	Level 1			Level 2			Total
	(In thousands)
Cash equivalents:
Money-market funds	$	674,219	(a)	$	—		$	674,219
Available-for-sale debt securities:
Asset-backed and mortgage-backed securities:
Agency securities	$	—		$	97,408	(b)	$	97,408
Non-agency securities		—			9,989	(b)		9,989
Government and agency securities		5,403	(a)		30,572	(b)		35,975
Corporate debt securities		—			12,272	(b)		12,272
Total short-term investments	$	5,403		$	150,241		$	155,644
Long-term investments in equity securities:
Marketable available-for-sale equity securities	$	1,514	(c)	$	—		$	1,514

(a) The fair value of money-market funds is determined using unadjusted prices in active markets. The fair value of Level 1 U.S. government and agency securities is determined using quoted prices in active markets.

(b) These investments are traded less frequently than Level 1 securities and are valued using inputs that include quoted prices for similar assets in active markets and inputs other than quoted prices that are observable for the asset, such as interest rates, yield curves, prepayment speeds, collateral performance, broker/dealer quotes and indices that are observable at commonly quoted intervals.

(c) The fair value of marketable equity securities is determined using quoted prices in active markets. These amounts are included within other assets in the consolidated balance sheets.

Company's Available-for-Sale Securities

The following tables summarize the Company’s available-for-sale securities:

	December 31, 2012
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
	(In thousands)
Short-term debt securities:
Asset-backed and mortgage-backed securities	$	125,563	$	6,390	$	(1,097	)	$	130,856
Government and agency securities		65,904		802		(6	)		66,700
Corporate debt securities		5,864		137		—			6,001
Commercial paper		900		—		—			900
Total short-term debt securities	$	198,231	$	7,329	$	(1,103	)	$	204,457
Long-term marketable equity securities	$	669	$	1,020	$	—		$	1,689

	December 31, 2011
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
	(In thousands)
Short-term debt securities:
Asset-backed and mortgage-backed securities	$	99,884	$	7,891	$	(378	)	$	107,397
Government and agency securities		35,179		799		(3	)		35,975
Corporate debt securities		12,146		153		(27	)		12,272
Total short-term debt securities	$	147,209	$	8,843	$	(408	)	$	155,644
Long-term marketable equity securities	$	669	$	846	$	(1	)	$	1,514

Gross Unrealized Losses and Fair Values of Company's Short-Term Investments

As of December 31, 2012, there were 99 investments in an unrealized loss position. The following tables summarize the gross unrealized losses and fair values of the Company’s short-term investments that have been in a continuous unrealized loss position for less than and greater than 12 months, aggregated by investment category:

	December 31, 2012
	Less than 12 Months					Greater than 12 Months
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(In thousands)
Asset-backed and mortgage-backed securities	$	38,280	$	(1,018	)	$	4,141	$	(79	)
Government and agency securities		18,301		(6	)		—		—
Total	$	56,581	$	(1,024	)	$	4,141	$	(79	)

	December 31, 2011
	Less than 12 Months					Greater than 12 Months
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(In thousands)
Asset-backed and mortgage-backed securities	$	10,645	$	(286	)	$	1,301	$	(92	)
Government and agency securities		3,872		(3	)		—		—
Corporate debt securities		2,375		(27	)		505		—
Total	$	16,892	$	(316	)	$	1,806	$	(92	)

Contractual Maturities of Available-for-Sale Debt Securities

Contractual maturities of available-for-sale debt securities as of December 31, 2012 were as follows:

	Available-for-Sale Debt Securities
	(In thousands)
Due within one year	$	18,187
Due in 1-5 years		57,453
Due in 5-10 years		11,047
Due after 10 years		117,770
Total	$	204,457