Note 11 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

	2018			2017
Deferred tax assets:
Net operating loss carryforward	$	16,681,908		$	16,273,259
Research and development tax credit carryforward		1,063,877			949,340
Stock-based compensation expense		1,808,509			1,709,867
Accrued salaries and directors’ fees		317,246			185,961
Depreciation		8,414			5,532
Total deferred tax assets		19,879,954			19,123,959
Deferred tax liabilities		-			-
Net deferred tax assets		19,879,954			19,123,959
Valuation allowance		(19,879,954	)		(19,123,959	)
Net deferred tax asset after reduction for valuation allowance	$	-0-		$	-0-

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

	2018			2017			2016
U.S. federal statutory rate applied to pretax loss	$	(537,620	)	$	(737,855	)	$	(1,112,378	)
Permanent differences		549			436			2,012
Research and development credits		(53,884	)		(57,109	)		(59,087	)
Impact of Tax Act		-			10,086,795			-
Change in valuation allowance		590,955			(9,292,267	)		1,169,453
Reported income tax expense	$	-0-		$	-0-		$	-0-