Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Reconciliation of Federal Statutory Income Tax Rate

Reconciliation of the Federal statutory income tax rate of 21% to the effective rate is as follows:

	2019		2018		2017
Federal statutory income (benefit) tax rate	21.00	%	21.00	%	(34.00)	%
2017 Tax Act, net deferred tax remeasurement	—		—		(626.73)
State taxes, net of federal benefit	(0.18)		(0.11)		(2.01)
Stock compensation	(5.39)		(4.74)		(5.18)
Permanent differences-other	(7.67)		(1.33)		(13.39)
North Carolina tax rate change	—		—		(32.75)
Research and development (“R&D”) credit	—		—		5.54
Valuation release for bargain purchase gain	—		—		(302.23)
Other	1.71		(2.07)		(1.36)
Decrease (increase) in valuation allowance	(9.44)		(12.65)		709.88
	0.03	%	0.10	%	(302.23)	%

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)	2019		2018
Basis difference in equipment	$(438)		$(459)
Basis difference in intangibles	(5,356)		(6,045)
Accrued liabilities and other	3,942		2,246
R&D credit	10,980		10,980
Stock options	4,416		4,360
Net operating loss carry-forward	62,535		64,376
	76,079		75,458
Less: valuation allowance	(76,079)		(75,458)
	$	—	$	—