Income Taxes (Tables)

9 Months Ended

Sep. 30, 2012

Significant Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets are as follows:

	Year Ended December 31,
(in thousands)	2009			2010			2011
Net operating losses	$	25,235		$	27,135		$	26,699
Research and other credits		1,683			2,014			2,029
Deferred revenue		—			—			1,559
Other		722			1,051			750
Total deferred tax assets		27,640			30,200			31,037
Valuation allowance		(27,640	)		(30,200	)		(31,037	)
Net deferred tax assets	$	—		$	—		$	—

Reconciliation of Statutory Tax Rates And Effective Tax Rates

A reconciliation of the statutory tax rates and the effective tax rates for the years ended December 2009, 2010, and 2011 is as follows:

	2009			2010			2011
Statutory rate		(34.0	)%		(34.0	)%		(34.0	)%
Nondeductible warrant expense		(0.4	)%		—	%		—	%
Nondeductible stock compensation		0.4	%		3.2	%		2.6	%
Therapeutic grants		1.2	%		(10.4	)%		—	%
Other		0.1	%		0.4	%		0.4	%
Valuation allowance		32.7	%		40.8	%		31.0	%
Effective tax rate		0	%		0	%		0	%

Reconciliation of Beginning And Ending Amount Of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

(in thousands)	Amount
Beginning at January 1, 2009	$	691
Additions based on tax positions related to current year		159
Balance at December 31, 2009		850
Additions based on tax positions related to current year		172
Balance at December 31, 2010		1,022
Additions based on tax positions related to current year		3
Balance at December 31, 2011	$	1,025