Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

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:

	2014			2013			2012
Federal statutory income tax rate		34.00	%		34.00	%		34.00	%
State taxes, net of federal benefit		3.45			3.45			3.45
Permanent differences-derivative loss (gain)		(9.10	)		0.11			110.51
Permanent differences-other		2.24			(1.07	)		44.12
Research and development (“R&D”) credit		2.73			4.91			(129.12	)
Other		0.61			0.64			(30.89	)
Decrease in valuation allowance		(33.93	)		(42.04	)		(24.82	)
		0.00	%		0.00	%		7.25	%

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)	2014			2013
Deferred revenue	$	315		$	1,576
Basis difference in equipment		(975	)		(890	)
Basis difference in intangibles		1,102			(502	)
Accrued liabilities and other		360			418
R&D credit		11,316			10,366
Stock options		462			2,200
Net operating loss carry-forward		59,481			40,495
		72,061			53,663
Less: valuation allowance		(72,061	)		(53,663	)
	$	—		$	—