Note 8 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

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

	2019			2018
Deferred income tax assets:
Tax loss carryforwards	$	42,107,372		$	30,239,898
Deferred revenue		—			1,856,507
Research and development credits		3,016,889			2,382,047
Stock-based compensation		973,905			489,694
Lease liability		1,508,645			—
Compensation		564,572			431,649
Fixed assets		—			160,784
Patent amortization		86,985			97,942
Other		55,972			669,151
Valuation allowance		(47,505,967	)		(36,327,672	)
Total deferred income tax assets		808,373			—
Deferred income tax liabilities:
Fixed assets		158,787			—
Operating leases		649,586			—
Total deferred income tax liabilities		808,373			—
Total net deferred tax	$	—		$	—

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

	2019						2018
				% of Pretax						% of Pretax
	Amount			Earnings			Amount			Earnings
Income tax benefit at statutory rate	$	(10,019,974	)		21.0	%	$	(11,158,530	)		21.0	%
State income taxes, net of federal tax benefit		(957,616	)		2.0			(1,062,492	)		2.0
Non-deductible expenses		94,903			(0.2	)		6,810			—
Stock-based compensation		258,338			(0.5	)		10,925			—
Non-deductible interest expense		—			—			4,074,501			(7.7	)
Derivative and warrant fair value adjustments		—			—			(63,873	)		0.1
Credits		(634,842	)		1.3			—			—
Change in state rate		3,887			—			(2,842	)		—
Other		77,009			(0.1	)		(139,660	)		0.3
Change in valuation allowance		11,178,295			(23.5	)		8,335,161			(15.7	)
Provision for income taxes	$	—			0.0	%	$	—			0.0	%

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

Balance at December 31, 2017	$	—
Increases related to 2018		—
Increases related to prior periods		—
Balance at December 31, 2018		—
Increases related to 2019		158,710
Increases related to prior periods		—
Balance at December 31, 2019	$	158,710