Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Taxes

Significant components of the Company's deferred tax assets

	December 31,
(in thousands)	2011			2010
Deferred tax assets:
Net operating loss carryforwards	$	359,000		$	311,000
Deferred revenues		56,000			63,000
Capitalized research and development expenditures		35,000			34,000
Research and development tax credit carryforwards		37,000			34,000
Other		31,000			26,000
Valuation allowance		(518,000	)		(468,000	)
Net deferred tax assets	$	—		$	—

Reconciliation of gross unrecognized tax benefits

Gross unrecognized tax benefits as of January 1, 2009	$	36,200
Gross decrease for tax positions for prior years		(100	)
Gross increase in tax positions for current year		3,500
Unrecognized tax benefits as of December 31, 2009		39,600
Gross decrease for tax positions for prior years		—
Gross increase in tax positions for current year		3,000
Unrecognized tax benefits as of December 31, 2010		42,600
Gross decrease for tax positions for prior years		—
Gross increase in tax positions for current year		4,300
Unrecognized tax benefits as of December 31, 2011	$	46,900