Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Taxes [Abstract]

Deferred Tax Assets and Liabilities

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

	December 31,
	2017			2016
Deferred tax assets:
Net operating loss carryforwards	$	66,251		$	126,244
Tax credit carryforwards		33,899			29,970
Equipment, furnishings and other		4,909			9,297
Total deferred tax assets		105,059			165,511
Deferred tax liabilities		—			(301	)
Net deferred tax assets		105,059			165,210
Valuation allowance		(105,059	)		(165,210	)
	$	—		$	—

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,
	2017			2016			2015
Federal benefit at statutory rate	$	(11,895	)	$	(17,262	)	$	(19,919	)
State income taxes, net of Federal taxes		(2,073	)		(3,086	)		(3,556	)
State credits		(506	)		(1,031	)		(1,324	)
Warrant liabilities		(465	)		(1,301	)		(1,509	)
Other permanent differences		11			40			16
Provision related to change in valuation allowance		(60,358	)		21,601			20,142
Federal rate adjustment		27,314			—			—
NQ Options		47			—			—
Current year tax credit		(665	)		(1,119	)		(2,050	)
NOL Adjustments		45,521			—			—
Termination/Cancellation of Equity Compensation Awards		2,983			2,274			5,960
Return to provision		84			(118	)		2,238
Other, net		3			3			3
	$	1		$	1		$	1