Income Taxes (Tables)

12 Months Ended

Dec. 31, 2013

Income Taxes [Abstract]

Total provision for income taxes

The total (benefit) provision for income taxes consists of the following (in thousands):

	Year ended December 31,
	2013			2012			2011
Federal income tax (benefit) provision	$	(14	)	$	(74	)	$	15
Total	$	(14	)	$	(74	)	$	15

Components of net deferred tax assets

The significant components of net deferred tax assets as of December 31, 2013 and 2012 were as follows (in millions):

	December 31,
	2013			2012
Capitalized research and development expenses	$	49.4		$	51.5
Net operating loss carryforwards		78.4			150.8
Research and development and other credit carryforwards		8.8			8.5
Other		23.5			23.3
Total deferred tax assets		160.1			234.1
Valuation allowance		(160.1	)		(234.1	)
Net deferred tax assets	$	-		$	-

Schedule of unrecognized tax benefits

The following table summarizes the Company's activity related to its unrecognized tax benefits (in thousands):

	December 31, 2013
Balance at January 1, 2013	$	4,104
Increase related to current year tax position		164
Increase related to prior year tax position		6
Balance at December 31, 2013	$	4,274