Note 19 - Subsequent Events (Details Textual) - USD ($)	Mar. 29, 2021	Feb. 17, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 24, 2018
Common Stock, Shares, Issued, Total (in shares)			16,297,381	6,825,183	592,592
Subsequent Event [Member] | Purchase Agreement with Lincoln Park [Member]
Proceeds from Issuance of Common Stock	$ 2,000,000
Common Stock, Shares, Issued, Total (in shares)	373,832
Shares Issued, Price Per Share (in dollars per share)	$ 5.35
Sale of Stock, Aggregate Value, Maximum	$ 20,000,000
Stock Issuable, Shares, Commitment Fess (in shares)	75,000
Stock Issuable, Additional Shares as a Further Commitment Fee (in shares)	50,000
Stock Issued During the Period, Shares, Commission Fees (in shares)	80,000
Stock Issued During the Period, Shares on a pro Rata Basis in Respect of the Initial Purchase Included in Total Stock Issued as Commitment Shares (in shares)	5,000
Subsequent Event [Member] | Helix Biotherapeutic Delivery System [Member]
Proceeds From Agreement		$ 500,000