Note 8 - Income Taxes - Components of Deferred Assets and Liabilities (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
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
Fixed assets	158,787
Operating leases	649,586
Total deferred income tax liabilities	808,373
Total net deferred tax