Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value Disclosures [Abstract]

Cash Cash Equivalents and Marketable Securities

Cash and cash equivalents consisted of the following (in thousands):

	March 31, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Cash and Cash Equivalents		Marketable Securities
Cash	$	422,742	$	—	$	—	$	422,742	$	422,742	$	—
Money market funds	27,769		—		—		27,769		27,769		—
Totals	$	450,511	$	—	$	—	$	450,511	$	450,511	$	—
	December 31, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Cash and Cash Equivalents		Marketable Securities
Cash	$	343,548	$	—	$	—	$	343,548	$	343,548	$	—
Money market funds	43,648		—		—		43,648		43,648		—
Totals	$	387,196	$	—	$	—	$	387,196	$	387,196	$	—

Available-for-Sale Securities and Other Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table summarizes, by major security type, our available-for-sale securities and liabilities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands):

	March 31, 2013						December 31, 2012
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Unobservable Inputs (Level 3)		Total Estimated Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Unobservable Inputs (Level 3)		Total Estimated Fair Value
Assets:
Available-for-sale securities:
Money market funds	$	27,769	$	—	$	27,769	$	43,648	$	—	$	43,648
Liabilities:
Contingent consideration	$	—	$	39,300	$	39,300	$	—	$	34,800	$	34,800

Roll forward of contingent consideration

The change in fair value of the contingent consideration payable was estimated as follows (in thousands):

	Level 3
Balance at December 31, 2012	$	34,800
Fair value adjustment recorded within selling, general and administrative expenses	4,500
Balance at March 31, 2013	$	39,300