Note 11 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

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

	201 7			201 6
Deferred tax assets:
Net operating loss carryforward	$	16,273,259		$	24,689,298
Research and development tax credit carryforward		949,340			892,231
Stock-based compensation expense		1,709,867			2,748,899
Accrued salaries and directors ’ fees		185,961			-
Depreciation		5,532			1,331
Total deferred tax assets		19,123,959			28,331,759
Deferred tax liabilities		-			-
Net deferred tax assets		19,123,959			28,331,759
Valuation allowance		(19,123,959	)		(28,331,759	)
Net deferred tax asset after reduction for valuation allowance	$	-0-		$	-0-

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

	201 7			201 6			20 15
U.S. federal statutory rate applied to pretax loss	$	(737,855	)	$	(1,112,378	)	$	(936,936	)
Permanent differences		436			2,012			2,914
Research and development credits		57,109			59,087			67,901
Impact of Tax Act		10,086,795			-			-
Change in valuation allowance		(9,406,485	)		1,051,279			866,121
Reported income tax expense	$	-0-		$	-0-		$	-0-