Income Taxes Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Significant components deferred tax assets

Significant components of the Company’s deferred tax assets as of December 31, 2015, 2014 and 2013 are listed below (in thousands):

	December 31,
	2015			2014			2013
Deferred tax assets:
Capitalized research and development and other	$	33,894		$	31,045		$	28,283
Valuation allowance for deferred tax assets	(33,894		)	(31,045		)	(28,283		)
Net deferred taxes	$	—		$	—		$	—

Provision for income taxes

Income taxes computed by applying the U.S. federal statutory rates to income from continuing operations before income taxes are reconciled to the provision for income taxes set forth in the statement of operations as follows (in thousands):

	December 31,
	2015			2014			2013
Income tax benefit at statutory federal rate	$	(14,250	)	$	(7,256	)	$	(6,098	)
Research and development credits	1,128			991			126
Expired tax attributes	31			(60		)	—
Change in valuation allowance	12,042			6,322			5,972
Other	1,049			3			—
Provision for income taxes	$	—		$	—		$	—