Cash Equivalents and Investments (Tables)

3 Months Ended

Mar. 31, 2013

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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 March 31, 2013
	Level 1			Level 2			Total
	(In thousands)
Cash equivalents:
Money-market funds	$	325,927	(a)	$	—		$	325,927
Government and agency securities		—			8,547	(b)		8,547
Commercial paper		—			2,500	(b)		2,500
Total cash equivalents	$	325,927		$	11,047		$	336,974
Available-for-sale debt securities:
Asset-backed and mortgage-backed securities:
Agency securities	$	—		$	145,150	(b)	$	145,150
Non-agency securities		—			1,116	(b)		1,116
Government and agency securities		15,003	(a)		58,032	(b)		73,035
Corporate debt securities		—			10,006	(b)		10,006
Commercial paper		—			3,998	(b)		3,998
Total short-term investments	$	15,003		$	218,302		$	233,305
Long-term investments in equity securities:
Marketable available-for-sale equity securities	$	1,952	(c)	$	—		$	1,952

	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

(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 condensed consolidated balance sheets.

Company's Available-for-Sale Securities

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

	March 31, 2013
	Amortized Cost		Gross  Unrealized Gain		Gross  Unrealized Loss			Fair Value
	(In thousands)
Short-term debt securities:
Asset-backed and mortgage-backed securities	$	139,611	$	7,484	$	(829	)	$	146,266
Government and agency securities		72,194		843		(2	)		73,035
Corporate debt securities		9,885		124		(3	)		10,006
Commercial paper		3,998		—		—			3,998
Total short-term debt securities	$	225,688	$	8,451	$	(834	)	$	233,305
Long-term marketable equity securities	$	669	$	1,283	$	—		$	1,952

	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

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

As of March 31, 2013, there were 107 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:

	March 31, 2013
	Less than 12 Months					Greater than 12 Months
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(In thousands)
Asset-backed and mortgage-backed securities	$	47,476	$	(749	)	$	3,728	$	(80	)
Government and agency securities		4,910		(2	)		—		—
Corporate debt securities		2,956		(3	)		—		—
Total	$	55,342	$	(754	)	$	3,728	$	(80	)

	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	)

Contractual Maturities of Available-for-Sale Debt Securities

Contractual maturities of available-for-sale debt securities as of March 31, 2013 were as follows:

	Available-For-Sale Debt Securities
	(In thousands)
Due within one year	$	29,424
Due in 1-5 years		59,264
Due in 5-10 years		10,497
Due after 10 years		134,120
Total	$	233,305