Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Taxes Tables

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

The effective tax rate of our provision (benefit) for income taxes differs from the Federal statutory rate as follows:

	Year Ended December 31,
	2019	2018
Statutory rate	21.0%	21.0%
Net operating loss expiration	(14.7)%	(5.8)%
Tax credits	2.8%	3.7%
Change in valuation allowance	(9.1)%	(18.9)%
Total	0.0%	0.0%

Schedule of Tax Effects of Temporary Differences that Give Rise to Significant Portions of Deferred Tax Assets and Liabilities

Deferred tax assets are summarized as follows (in thousands):

		December 31,
		2019		2018
Deferred tax assets
Reserves	$	610	$	1,152
Net operating loss carryforwards		85,282		83,608
R&D credit carryforwards		9,047		8,593
Depreciation/amortization deferred		16,978		15,884
Other		5,808		6,076
Net deferred taxes before valuation allowance		117,725		115,313
Less: Valuation allowance		(117,725)		(115,313)
Deferred tax assets	$	-	$	-