Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2011

Fair Value of Financial Instruments

Financial assets and liabilities subject to fair value measurements (excluding restricted cash and cash equivalents (Alios))

			Fair Value Measurements as of September 30, 2011
					Fair Value Hierarchy
			Total		Level 1		Level 2		Level 3
			(in thousands)
Financial assets carried at fair value:
	Cash equivalents:
		Money market funds	$	193,694	$	193,694	$	—	$	—
		U.S. Treasury securities		7,788		7,788
		Government-sponsored enterprise securities		186,558		186,558		—		—
	Marketable securities:
		Government-sponsored enterprise securities		116,140		116,140		—		—
	Restricted cash			34,119		34,119		—		—
		Total	$	538,299	$	538,299	$	—	$	—
Financial liabilities carried at fair value:
	Embedded derivative related to 2012 Notes		$	6,057	$	—	$	—	$	6,057
	Liability related to sale of future milestone payments			94,162		—		—		94,162
		Total	$	100,219	$	—	$	—	$	100,219

Reconciliation of financial liabilities measured at fair value using significant unobservable inputs

		Nine Months Ended September 30, 2011
		(in thousands)
Balance, December 31, 2010		$	89,888
	Change in fair value of derivative instruments		15,933
	Redemption of a portion of the 2012 Notes		(5,602	)
Balance, September 30, 2011		$	100,219