Note 13 - Capital Stock (Details Textual) - USD ($) | | | | 1 Months Ended | 3 Months Ended | 6 Months Ended | | |
Mar. 03, 2023 | Apr. 14, 2022 | Dec. 30, 2020 | Jun. 30, 2023 | Oct. 31, 2022 | Jun. 30, 2023 | Mar. 31, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022 | Dec. 31, 2022 | May 31, 2021 |
Common Stock, Shares Authorized (in shares) | | | | 300,000,000 | | 300,000,000 | | | 300,000,000 | | 150,000,000 | |
Common Stock, Par or Stated Value Per Share (in dollars per share) | | | $ 0.0001 | $ 0.0001 | | $ 0.0001 | | | $ 0.0001 | | $ 0.0001 | |
Preferred Stock, Shares Authorized (in shares) | | | | 1,000,000 | | 1,000,000 | | | 1,000,000 | | | |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | | | | $ 0.0001 | | $ 0.0001 | | | $ 0.0001 | | | |
Common Stock, Shares, Issued (in shares) | | | | 128,401,112 | | 128,401,112 | | | 128,401,112 | | 74,759,591 | |
Preferred Stock, Shares Issued (in shares) | | | | 0 | | 0 | | | 0 | | 0 | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | 105,432,083 | | 105,432,083 | | | 105,432,083 | | 4,477,045 | |
Proceeds from Issuance of Common Stock | | | | | | $ 37,400,000 | | | | | | |
Payments of Stock Issuance Costs | | | | | | | | | $ 0 | $ 100,000 | | |
Gain (Loss) on Issuance of Equity | | | | | | $ (14,840,000) | | $ 0 | $ (14,840,000) | $ 0 | | |
Common Stock, Shares, Outstanding (in shares) | | | | 128,401,112 | | 128,401,112 | | | 128,401,112 | | 74,759,591 | |
Preferred Stock, Shares Outstanding (in shares) | | | | 0 | | 0 | | | 0 | | 0 | |
Lincoln Park Capital Fund, LLC [Member] | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | 332,668 | | | | | | | | | | | |
Purchase Agreement, Commencing Period (Month) | 36 months | | | | | | | | | | | |
Purchase Agreement, Regular Purchase (in shares) | 75,000 | | | | | | | | | | | |
Purchase Agreement, Regular Purchase, Shares, Closing Price One (in shares) | 100,000 | | | | | | | | | | | |
Purchase Agreement, Closing Price One (in dollars per share) | $ 1 | | | | | | | | | | | |
Purchase Agreement, Regular Purchase, Shares, Closing Price Two (in shares) | 150,000 | | | | | | | | | | | |
Purchase Agreement, Closing Price Two (in dollars per share) | $ 2 | | | | | | | | | | | |
Purchase Agreement, Regular Purchase, Shares, Closing Price Three (in shares) | 200,000 | | | | | | | | | | | |
Purchase Agreement, Closing Price Three (in dollars per share) | $ 4 | | | | | | | | | | | |
Purchase Agreement, Accelerated Purchase, Maximum Percentage of Regular Purchase | 300% | | | | | | | | | | | |
Purchase Agreement, Accelerated Purchase, Maximum Percentage Of Prior Day Volume | 30% | | | | | | | | | | | |
Purchase Agreement, Additional Accelerated Purchase, Maximum Percentage of Regular Purchase | 300% | | | | | | | | | | | |
Purchase Agreement, Additional Accelerated Purchase, Maximum Percentage of Prior Day Volume | 30% | | | | | | | | | | | |
Purchase Agreement, Price Discount of Additional Purchases | 97% | | | | | | | | | | | |
Purchase Agreement, Additional Commitment Shares (in shares) | 166,334 | | | | | | | | | | | |
Purchase Agreement, Shares Sell Limitation (in shares) | 15,310,115 | | | | | | | | | | | |
Purchase Agreement, Shares Sell Limitation, Percentage Of Outstanding Shares | 19.99% | | | | | | | | | | | |
Percentage of Common Stock Beneficial Ownership | 4.99% | | | | | | | | | | | |
Derivative, Notional Amount | | | | $ 0 | | $ 0 | | | $ 0 | | | |
Lincoln Park Capital Fund, LLC [Member] | Maximum [Member] | | | | | | | | | | | | |
Purchase Agreement, Amount Of Shares Commit To Purchase | $ 25,000,000 | | | | | | | | | | | |
Percentage of Common Stock Beneficial Ownership | 9.99% | | | | | | | | | | | |
Lincoln Park Capital Fund, LLC [Member] | Minimum [Member] | | | | | | | | | | | | |
Purchase Agreement, Minimum Average Price Per Share To Avoid Sell Limitation (in dollars per share) | $ 1.2404 | | | | | | | | | | | |
Lincoln Park [Member] | Purchase Agreement [Member] | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | 400,000 | | | 400,000 | | | |
Proceeds from Issuance or Sale of Equity | | | | | | $ 400,000 | | | $ 400,000 | | | |
Offering Agreement [Member] | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | 10,723,926 | | | | | | | |
Shares Issued, Price Per Share (in dollars per share) | | | | | $ 1.01 | | | | | | | |
Proceeds from Issuance of Common Stock | | | | | $ 10,800,000 | | | | | | | |
Payments of Stock Issuance Costs | | | | | $ 25,000 | | | | | | | |
Underwriting Agreement [Member] | Canaccord [Member] | | | | | | | | | | | | |
Payments of Stock Issuance Costs | | | | $ 200,000 | | | | | | | | |
Unit Issued During Period, Units, New Issues (in shares) | | | | 50,000,000 | | | | | | | | |
Unit Issued, Price Per Unit (in dollars per share) | | | | $ 0.80 | | $ 0.80 | | | $ 0.80 | | | |
Each Unit, Number of Common Stock (in shares) | | | | 1 | | 1 | | | 1 | | | |
Proceeds from Issuance or Sale of Equity | | | | $ 40,000,000 | | | | | | | | |
Payment for Underwriting Fees and Commissions | | | | 2,400,000 | | | | | | | | |
Gain (Loss) on Issuance of Equity | | | | $ (14,800,000) | | | | | | | | |
ATM Facility [Member] | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | 0 | | | 2,895,090 | | | |
Proceeds from Issuance of Common Stock | | | | | | $ 0 | | | $ 4,500,000 | | | |
Aggregate Offering Price | | $ 50,000,000 | | | | | | | | | | |
Fixed Commission Rate Percentage | | 3% | | | | | | | | | | |
Payments for Commissions | | | | | | $ 0 | | | $ 100,000 | | | |
Commitment Shares [Member] | Lincoln Park [Member] | Purchase Agreement [Member] | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | 2,893 | | | 2,893 | | | |
Warrants with Tranche 2 of 2021 Avenue Loan [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | | | | | | | 115,851 |
Warrants Originally Issued by Tottenham Acquisition I Limited [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | 2,407,500 | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | | 0.5 | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | $ 0.01 | | | | | | | | | |
Class of Warrant or Right, Redemption, Threshold Stock Price Trigger (in dollars per share) | | | $ 16.50 | | | | | | | | | |
Class of Warrant or Right, Redemption, Threshold Consecutive Trading Days (Day) | | | 20 days | | | | | | | | | |
Class of Warrant or Right, Redemption, Threshold Trading Days (Day) | | | 30 days | | | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | 0 | | | | | |
Chardan Unit Purchase Option [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | 24,583 | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | | 0.5 | | | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | 0 | | | | | |
Warrants Originally Issued by Clene Nanomedicine [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | 1,929,111 | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | | 1 | | | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | 0 | | | | | |
Warrants with Tranche 2 of 2021 Avenue Loan [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | | | 0 | | | |
New Avenue Warrant [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | 3,000,000 | | 3,000,000 | | | 3,000,000 | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | | | 0 | | | |
Tranche A Warrant [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | 50,000,000 | | 50,000,000 | | | 50,000,000 | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | | | 1 | | 1 | | | 1 | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | | | 0 | | | |
Tranche A Warrant [Member] | Canaccord [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | | | 1 | | 1 | | | 1 | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | | $ 1.10 | | $ 1.10 | | | $ 1.10 | | | |
Each Unit, Number of Warrant (in shares) | | | | 1 | | 1 | | | 1 | | | |
Tranche B Warrant [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | 50,000,000 | | 50,000,000 | | | 50,000,000 | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | | | 1 | | 1 | | | 1 | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | | | 0 | | | |
Tranche B Warrant [Member] | Canaccord [Member] | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | | | 1 | | 1 | | | 1 | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | | $ 1.50 | | $ 1.50 | | | $ 1.50 | | | |
Each Unit, Number of Warrant (in shares) | | | | 1 | | 1 | | | 1 | | | |