Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Income Tax Disclosure [Abstract]

Summary of Deferred Tax Assets

Amounts for the years ended December 31 were as follows (in thousands):

Deferred Tax Assets	2014			2013
Net operating losses	$	85,510		$	82,753
Credit carryovers		19,903			19,903
Depreciation and amortization		14,922			12,915
Accruals and reserves		808			322
Capital loss carryover		100			100
Other		3,660			3,808
Total deferred tax assets		124,903			119,801
Less valuation allowance		(124,903	)		(119,801	)
Net deferred tax assets	$	—		$	—

Reconciliation Between Provision for Income Taxes and Income Taxes

The reconciliation between the provision for income taxes and income taxes computed using the U.S. federal statutory corporate tax rate were as follows for the years ended December 31 (in thousands):

	2014			2013			2012
Computed “expected” tax benefit	$	(5,607	)	$	(10,621	)	$	(7,712	)
State income taxes, net of federal benefit		(444	)		(1,947	)		451
Tax effect of:
Change in valuation allowance		5,102			13,074			(37,179	)
Expiration of prior year credits and net operating losses		675			(237	)		45,382
Research and development and other tax credits carryovers		—			(672	)		(1,097	)
Stock compensation		274			337			358
Other		—			66			(203	)
Provision for income taxes	$	—		$	—		$	—