Note 13 - Stock Based Compensation - Stock-based Compensation Expense (Details) - USD ($)		3 Months Ended		6 Months Ended
	Jan. 13, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock compensation expense		$ 1,036,484	$ 5,318,796	$ 1,724,236	$ 5,594,629
General and Administrative Expense [Member]
Stock compensation expense		702,561	3,401,653	1,185,561	3,626,329
Research and Development Expense [Member]
Stock compensation expense		$ 333,923	$ 1,917,143	$ 538,675	1,968,300
Liability Options [Member]
Stock compensation expense	$ 1,741,919				1,741,919
Liability Options [Member] | General and Administrative Expense [Member]
Stock compensation expense					1,074,183
Liability Options [Member] | Research and Development Expense [Member]
Stock compensation expense					$ 667,736