Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Deferred Tax Assets

The components of the Company’s deferred tax assets are as follows (in thousands):

	December 31,
	2016			2015
Net operating loss carryforwards	$	85,148		$	83,558
Stock based compensation		435			333
Research and development credits		2,925			2,628
Fixed assets		2,617			1
Accruals		391			239
Total Deferred tax assets		91,516			86,759
Valuation allowance		(91,516	)		(86,759	)
Net deferred tax asset	$	—		$	—

Reconciliation of the Federal Statutory Rate to the Company's Effective Tax Rate

A reconciliation of the federal statutory rate to the Company’s effective tax rate is as follows:

	Years ended December 31,
	2016			2015
Federal statutory rate		34.00	%		34.00	%
State income taxes		0.42			(0.49	)
Federal NOL adjustment		—			(0.43	)
State NOL expired or adjusted		—			(0.07	)
Permanent items		(0.97	)		(3.26	)
Stock compensation		(0.37	)		(0.11	)
Federal research credits		1.75			1.86
State rate change		—			—
Miscellaneous		—			—
(Increase)/ Decrease in Valuation Allowance		(34.83	)		(31.50	)
Provision for income taxes		0.00	%		0.00	%

Changes in Unrecognized Tax Benefits

The change in unrecognized tax benefits from December 31, 2014 is as follows (in thousands):

Unrecognized tax benefits as of December 31, 2014	$	1,093
Increase in prior year unrecognized tax benefits		195
Increase in current year unrecognized tax benefits		122
Unrecognized tax benefits as of December 31, 2015		1,410
Decrease in prior year unrecognized tax benefits		(447	)
Increase in current year unrecognized tax benefits		109
Unrecognized tax benefits as of December 31, 2016	$	1,072