Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

United States and Foreign Components of Consolidated Loss Before Income Taxes

U.S and foreign components of consolidated loss before income taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands):

	2016			2015			2014
Loss before income taxes:
U.S.	$	(63,246	)	$	(59,897	)	$	(38,928	)
Foreign		515			358			368
Loss before income taxes	$	(62,731	)	$	(59,539	)	$	(38,560	)

Provision Benefit for Income Taxes

The provision for income taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands):

	2016		2015			2014
Provision for income taxes:
Current:
Foreign	$	147	$	147		$	168
Federal		—		—			—
State		—		—			1
Total current		147		147			169
Deferred:
Foreign		—		—			—
Federal		28		(3,750	)		22
State		—		(68	)		4
Total deferred		28		(3,818	)		26
Provision (benefit)  for income taxes	$	175	$	(3,671	)	$	195

Difference Between Provision for Income Taxes and Amounts Computed by Applying Federal Statutory Income Tax Rate to Loss before Taxes

The difference between the provision for income taxes and the amount computed by applying the federal statutory income tax rate to loss before taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands):

	2016			2015			2014
Federal statutory tax	$	(21,329	)	$	(20,243	)	$	(13,110	)
Warrants		—			(3,565	)		(3,367	)
Expiration of federal loss carryovers		—			3,337			—
Change in valuation allowance		13,589			11,754			16,576
Change in state apportionment		—			4,085			—
Revision to prior year items		7,551			—			—
Other		364			961			96
Provision (benefit) for income taxes	$	175		$	(3,671	)	$	195

Significant Components of Deferred Tax Assets and Liabilities

The significant components of the Company’s deferred tax assets and liabilities at December 31, 2016 and 2015, were as follows (in thousands):

	December 31,
	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	176,490		$	165,813
Research and development credit carryforwards		31,777			35,131
Capitalized research and development		22,575			17,916
Deferred compensation		8,242			5,908
Other		3,184			3,911
Total deferred tax assets		242,268			228,679
Valuation allowance		(238,443	)		(224,854	)
Net deferred tax assets	$	3,825		$	3,825
Deferred tax liabilities:
Unrealized gain on investments	$	3,825		$	3,825
Amortization of goodwill		150			122
Total deferred tax liabilities	$	3,975		$	3,947

Reconciliation of Unrecognized Tax Benefits

The following is a tabular reconciliation of the total amounts of unrecognized tax benefits (in thousands):

	December 31,
	2016
Unrecognized tax benefits at beginning of period	$	—
Increases related to prior year tax positions		10,691
Increases related to current year tax positions		145
Unrecognized tax benefits at beginning of period	$	10,836