Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Disclosures [Abstract]

Schedule of Marketable Securities

The following is a summary of marketable securities and other investment-related assets held at December 31, 2012 and 2011 (in thousands):

			Gross Unrealized					Aggregate Fair Value		Classified on Balance Sheet
										Short-term Marketable Securities		Long-term Marketable Securities
As of December 31, 2012	Cost		Gains		Losses
Available-for-sale securities:
Certificates of deposit	$	3,100	$	—	$	—		$	3,100	$	3,057	$	43
Commercial paper	7,481		2		(1		)	7,482		7,482		—
Corporate debt securities	691,931		1,269		(205		)	692,995		217,548		475,447
U.S. government agency obligations	189,607		95		(28		)	189,674		7,505		182,169
	$	892,119	$	1,366	$	(234	)	$	893,251	$	235,592	$	657,659
			Gross Unrealized					Aggregate Fair Value		Classified on Balance Sheet
										Short-term Marketable Securities		Long-term Marketable Securities
As of December 31, 2011	Cost		Gains		Losses
Available-for-sale securities:
Certificates of deposit	$	42	$	—	$	—		$	42	$	—	$	42
Corporate debt securities	524,515		873		(580		)	524,808		285,012		239,796
U.S. government agency obligations	145,995		78		(165		)	145,908		5,017		140,891
	$	670,552	$	951	$	(745	)	$	670,758	$	290,029	$	380,729

Schedule of Fair Value Measurement

The following tables detail the fair value measurements within the fair value hierarchy of the Company’s financial assets and liabilities, including investments, cash equivalents and the contingent consideration obligation related to the acquisition of Verivue, at December 31, 2012 and 2011 (in thousands):

	Total Fair Value at December 31, 2012			Fair Value Measurements at Reporting Date Using
				Level 1		Level 2		Level 3
Assets
Money market funds	$	22,255		$	22,255	$	—	$	—
Certificates of deposit	7,473			7,473		—		—
Commercial paper	9,482			—		9,482		—
U.S. government agency obligations	189,674			—		189,674		—
Corporate debt securities	692,995			—		692,995		—
	$	921,879		$	29,728	$	892,151	$	—
Liabilities
Contingent consideration obligation related to Verivue acquisition	$	(1,200	)	—		—		(1,200		)
	$	(1,200	)	$	—	$	—	$	(1,200	)

	Total Fair Value at December 31, 2011		Fair Value Measurements at Reporting Date Using
			Level 1		Level 2		Level 3
Money market funds	$	302,507	$	302,507	$	—	$	—
Certificates of deposit	42		42		—		—
Commercial paper	57,498		—		57,498		—
U.S. government agency obligations	145,908		—		145,908		—
Corporate debt securities	524,808		—		524,808		—
	$	1,030,763	$	302,549	$	728,214	$	—

Schedule of Activity of Major Classes of Assets Measured at Fair Value Using Level 3 Inputs

The following tables reflect the activity for the Company’s major classes of assets and liabilities measured at fair value using Level 3 inputs for the years ended December 31, 2012 and 2011 (in thousands):

	Auction Rate Securities
Balance as of December 31, 2010	$	137,256
Redemptions and sales of securities	(137,256		)
Balance as of December 31, 2011 and 2012	$	—

	Contingent Consideration Obligation
Balance as of December 31, 2010	$	(990	)
Payments	550
Change in fair value estimate	440
Balance as of December 31, 2011	$	—
Contingent consideration obligation related to Verivue acquisition	(1,200		)
Balance as of December 31, 2012	$	(1,200	)

Schedule of Contractual Maturities of Marketable Securities and Other Investment Related Assets

Contractual maturities of the Company’s marketable securities held at December 31, 2012 and 2011 are as follows (in thousands):

	December 31,
	2012		2011
Available-for-sale securities:
Due in one year or less	$	235,592	$	290,029
Due after 1 year through 5 years	657,659		380,729
Due after 5 years	—		—
	$	893,251	$	670,758