Income Taxes Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Reconciliations of the differences between the benefit for income taxes and income taxes at the statutory U.S. federal income tax rate is as follows:



	Years Ended December 31,
	2016					2015					2014
	Amount			Percent of Pretax Income		Amount			Percent of Pretax Income		Amount			Percent of Pretax Income
Income taxes from continuing operations at statutory rate	$	(10,196	)	34.0	%	$	(9,635	)	34.0	%	$	(2,301	)	34.0	%
State income taxes	(1,287		)	4.3	%	(196		)	0.7	%	(471		)	7.0	%
Stock warrant derivative liability	—			—		—			—		(3,427		)	50.6	%
Stock-based compensation	215			(0.8	)%	15			(0.1	)%	268			(4.0	)%
R&D tax credits	(955		)	3.2	%	(1,152		)	4.1	%	(320		)	4.7	%
Loss on sale of discontinued operations, net of reduction in related valuation allowances	—			—		(1,458		)	5.1	%	—			—
Warrants issuance	730			(2.4	)%	—			—		—			—
Other	719			(2.4	)%	(127		)	0.5	%	(190		)	2.8	%
Increase in valuation allowance	10,774			(35.9	)%	12,553			(44.3	)%	5,275			(77.9	)%
Total income tax benefit	$	—		—	%	$	—		—	%	$	(1,166	)	17.2	%

The components of deferred tax assets and liabilities as of December 31, 2016 and 2015 are as follows:



	December 31,
	2016			2015
Current deferred tax assets:
Accrued expenses	$	215		$	783
Stock-based compensation	1,664			1,507
Other	39			19
	1,918			2,309
Noncurrent deferred tax assets (liabilities);
Net operating loss carryforwards	53,173			42,358
Research and development credits	4,185			3,836
	57,358			46,194
Total deferred tax assets	59,276			48,503
Valuation allowances	(59,276		)	(48,503		)
Net deferred tax assets	$	—		$	—

The following is a tabular reconciliation of the total amounts of unrecognized tax benefits as of December 31, 2016 and 2015:



	December 31,
	2016		2015
Unrecognized tax benefit—January 1	$	623	$	623
Additions for tax positions of current period	—		—
Additions for tax positions of prior periods	—		—
Other	—		—
Unrecognized tax benefit—December 31	$	623	$	623