Note 12 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31,
	201 8			201 7
Deferred tax assets, net:
Net operating loss carryforwards	$	103,612		$	100,631
Research and other credits		3,482			3,482
Other temporary differences		3,760			3,266
Deferred tax assets - before valuation allowance		110,854			107,379
Valuation allowance		(110,854	)		(107,379	)
Net deferred tax assets - after valuation allowance	$	–		$	–

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

	Year Ended December 31,
	201 8			201 7			201 6
Federal income tax at statutory rate		21.0	%		35.0	%		35.0	%
State income taxes, net of federal benefits		6.2	%		7.5	%		2.9	%
Research and other credits		0.0	%		0.0	%		(5.8	%)
Impact of change in statutory tax rates		(8.8	%)		(183.8	%)		0.0	%
Permanent deductions		(3.7	%)		7.5	%		(18.0	%)
Valuation allowance		(14.7	%)		133.8	%		(14.1	%)
Effective tax rate		0.0	%		0.0	%		(0.0	%)