Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

The components of the Company's deferred tax assets and liabilities, all of which are long-term, are as follows (in thousands):

	December 31,
	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	126,244		$	105,661
Tax credit carryforwards		29,970			27,671
Equipment, furnishings and other		9,297			10,547
Total deferred tax assets		165,511			143,879
Deferred tax liabilities		(301	)		(270	)
Net deferred tax assets		165,210			143,609
Valuation allowance		(165,210	)		(143,609	)
	$	—		$	—

Effective Income Tax Rate Reconciliation

The provision for income taxes differs from the provision computed by applying the Federal statutory rate to net loss before income taxes as follows (in thousands):

	Years ended December 31,
	2016			2015			2014
Federal benefit at statutory rate	$	(17,262	)	$	(19,919	)	$	(10,240	)
State income taxes, net of Federal taxes		(3,086	)		(3,556	)		(2,773	)
State credits		(1,031	)		(1,324	)		(990	)
Warrant liabilities		(1,301	)		(1,509	)		(6,477	)
Other permanent differences		40			16			37
Provision related to change in valuation allowance		21,601			20,142			23,440
Current year tax credit		(1,119	)		(2,050	)		(1,300	)
Return to provision		2,156			8,198			(1,504	)
Other, net		3			3			(192	)
	$	1		$	1		$	1