Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Reconciliation of Federal Statutory Income Tax Rate

Reconciliation of the Federal statutory income tax rate of 34% to the effective rate is as follows:

	2016			2015			2014
Federal statutory income tax rate		34.00	%		34.00	%		34.00	%
State taxes, net of federal benefit		2.88			3.45			3.45
Stock compensation		(0.61	)		—			—
Permanent differences-derivative loss		—			—			(9.10	)
Permanent differences-other		(1.00	)		(4.66	)		2.24
Research and development (“R&D”) credit		0.98			0.95			2.73
Other		(0.47	)		0.64			0.61
Increase in valuation allowance		(35.78	)		(34.38	)		(33.93	)
		0.00	%		0.00	%		0.00	%

Significant Components of Deferred Tax Assets and Liabilities

The tax effects of temporary differences and net operating losses that give rise to significant components of deferred tax assets and liabilities consist of the following:

	December 31,
Deferred tax assets (liabilities)	2016			2015
Deferred revenue	$	7,377		$	7,490
Basis difference in equipment		(1,084	)		(1,013	)
Basis difference in intangibles		1,201			1,122
Accrued liabilities and other		550			1,563
R&D credit		11,589			11,138
AMT credit		79			—
Stock options		5,697			1,151
Net operating loss carry-forward		83,621			63,509
		109,030			84,960
Less: valuation allowance		(109,030	)		(84,960	)
	$	—		$	—