Note N - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

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

	Year ended December 31,
	2019			2018
Federal statutory rate		21.00			21.00
Effect of:
Change in valuation allowance		(28.52	)		(30.44	)
Return to provision and deferred true-up		-			0.38
Change in rate		(0.33	)		0.03
State tax benefit (net of federal)		3.39			4.35
Warrant liability		1.71			2.02
State research and development credit		0.09			0.22
Federal research and development credit		1.44			3.30
Amortization		(0.29	)		-
Stock-based compensation		(1.10	)		(0.63	)
Other		2.70			(0.01	)
Federal income tax provision effective rate		0.09			0.22

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

	December 31,
	2019			2018
Deferred tax assets relating to:
Net operating loss carryforwards	$	56,827		$	51,269
Research and development tax carryforward		6,411			5,657
Other deferred tax assets		4,488			3,437
Total gross deferred tax assets		67,726			60,363
Deferred tax liabilities relating to:
Property and equipment		-			161
Other deferred tax liabilities		540			10
Total gross deferred tax liabilities		540			171
Deferred tax assets less liabilities		67,186			60,192
Valuation allowance		(67,186	)		(60,192	)
Net deferred tax asset (liability)	$	-		$	-

Summary of Operating Loss Carryforwards [Table Text Block]

	Net Operating		Research
Year Incurred	Loss CF		Activities Cr.		Expiration
2007	$	454	$	30		2027
2008		1,178		65		2028
2009		3,060		176		2029
2010		3,423		149		2030
2011		9,929		176		2031
2012		-		170		2032
2013		4,353		133		2033
2014		15,897		894		2034
2015		23,496		598		2035
2016		41,580		745		2036
2017		34,776		652		2037
2018		56,155		2,272	Indefinite
2019		22,784		352	Indefinite
	$	217,085	$	6,412