Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Loss from Continuing Operations Before Provision for Income Tax

Loss from continuing operations before provision for income tax for the Company’s domestic and international operations was as follows (in thousands):

	December 31,
	2017			2016			2015
US	$	(113,679	)	$	129,361		$	(358,047	)
Foreign		(3,603	)		(3,697	)		(10,398	)
Loss before provision for income taxes	$	(117,282	)	$	125,664		$	(368,445	)

Provision for Income Taxes

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

	Year Ended December 31,
	2017			2016			2015
Current
U.S. federal	$	51		$	—		$	—
U.S. state		—			—			—
Non-U.S.		—			—			—
Total current		51			—			—
Deferred
U.S. federal		244,801			(43,814	)		109,512
U.S. state		15,398			(4,311	)		(29,394	)
Non-U.S.		—			—			—
Total deferred		260,199			(48,125	)		80,118
Valuation allowance		(260,199	)		48,125			(80,118	)
Total	$	51		$	—		$	—

Components of Net Deferred Tax Assets

Components of the net deferred tax assets as of December 31, 2017 and 2016, are as follows (in thousands):

	December 31,
	2017			2016
Deferred tax assets:
Net operating loss carryforwards	$	507,235		$	712,124
Research and development credits		83,461			77,998
Capitalized research		1,016			5,117
Milestone Rights		1,908			3,242
Accrued expenses		211			440
Loss on purchase commitment		23,654			36,775
Non-qualified stock option expense		7,004			17,331
Capitalized patent costs		5,194			8,781
Other		795			7,380
Depreciation		23,820			45,310
Total net deferred tax assets		654,298			914,498
Valuation allowance		(654,298	)		(914,498	)
Net deferred tax assets	$	—		$	—

Effective Income Tax Rate

The Company’s effective income tax rate differs from the statutory federal income tax rate as follows for the years ended December 31, 2017, 2016 and 2015:

	December 31,
	2017			2016			2015
Federal tax benefit rate		35.0	%		35.0	%		35.0	%
Permanent items		6.2			(1.9	)		—
Intercompany transfer of intellectual property		—			0.9			(1.0	)
2017 tax law changes		(265.0	)		—			—
Stock based compensation		(5.0	)		—			—
Tax attribute expirations		(2.8	)		—			—
Valuation allowance		231.6			(34.0	)		(34.0	)
Effective income tax rate		—	%		—	%		—	%