Income Taxes (Tables)

12 Months Ended

Dec. 31, 2013

Income Tax Disclosure [Abstract]

Income (Loss) Before Provision for Income Taxes

Income (loss) before provision for income taxes includes the following components (in thousands):

	Year Ended December 31,
	2013			2012			2011
Domestic	$	(161,068	)	$	(174,258	)	$	(135,880	)
Foreign		1,300			2,809			2,920
Loss before provision for income taxes	$	(159,768	)	$	(171,449	)	$	(132,960	)

Provision for Income Taxes

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

	Year Ended December 31,
	2013			2012			2011
Current:
Federal	$	—		$	(137	)	$	—
State		1			1			1
Foreign		1,838			1,029			921
Total Current		1,839			893			922
Deferred:
Federal		422			(422	)		—
State		49			(49	)		—
Foreign		(65	)		(16	)		96
Total Deferred		406			(487	)		96
Provision for income taxes	$	2,245		$	406		$	1,018

Income Tax Provision Related to Continuing Operations

Income tax provision related to continuing operations differs from the amount computed by applying the statutory income tax rate of 35% to pretax loss as follows (in thousands):

	Year Ended December 31,
	2013			2012			2011
U.S. federal provision (benefit)
At statutory rate	$	(55,919	)	$	(60,007	)	$	(46,536	)
State taxes		50			(48	)		1
Change in valuation allowance		55,042			47,349			48,959
Foreign tax inclusion		—			6,510			—
Non-cash interest expense on liability related to sale of future royalties		7,808			6,320			—
Foreign tax differential		(20	)		(227	)		(129	)
Research credits		(6,273	)		(591	)		(893	)
Other		1,557			1,100			(384	)
Provision for income taxes	$	2,245		$	406		$	1,018

Significant Components of Deferred Tax Assets and Liabilities

Significant components of our deferred tax assets for federal and state income taxes are as follows (in thousands):

	December 31,
	2013			2012
Deferred tax assets:
Net operating loss carryforwards	$	391,385		$	351,354
Research and other credits		61,707			52,769
Deferred revenue		35,588			39,521
Sale of future royalties		28,057			39,750
Stock-based compensation		25,962			23,746
Capitalized research expenses		17,687			7,192
Reserves and accruals		14,685			8,776
Property and equipment		8,580			8,482
Other		2,539			2,773
Deferred tax assets before valuation allowance		586,190			534,363
Valuation allowance for deferred tax assets		(586,040	)		(534,268	)
Total deferred tax assets		150			95
Total deferred tax liabilities		—			—
Net deferred tax assets	$	150		$	95

Unrecognized Tax Benefits

We have the following activity relating to unrecognized tax benefits (in thousands):

	December 31,
	2013		2012			2011
Beginning balance	$	14,067	$	13,576		$	13,058
Tax positions related to current year
Additions:
Federal		477		289			297
State		381		302			221
Reductions		—		—			—
Tax positions related to prior year
Additions:
Federal		636		37			—
State		—		—			—
Foreign		802		—			—
Reductions		—		—			—
Settlements		—		—			—
Lapses in statute of limitations		—		(137	)		—
Ending balance	$	16,363	$	14,067		$	13,576