Note 16 - Warrant Liabilities - Fair Value of Warrants (Details) $ in Thousands | Sep. 30, 2022 USD ($) yr | Jun. 30, 2022 USD ($) yr | Dec. 31, 2021 USD ($) yr | Sep. 30, 2021 USD ($) yr | Jul. 02, 2021 USD ($) | Jun. 30, 2021 USD ($) yr | Feb. 18, 2021 USD ($) | Dec. 31, 2020 USD ($) yr |
Warrant liabilities as of the closing date | | $ 1,280 | $ 257 | $ 2,039 | $ 3,686 | | $ 58 | $ 6,597 | | $ 11,921 | | $ 1,505 | |
Investor Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Warrant liabilities as of the closing date | | 782 | 167 | 964 | 1,824 | | | 3,257 | [1] | 10,476 | | | |
Placement Agent Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Warrant liabilities as of the closing date | | 106 | 22 | 132 | 237 | [1] | | 431 | [1] | $ 1,445 | [1] | | |
Investor Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Warrant liabilities as of the closing date | | 328 | 57 | 795 | 1,383 | | | 2,420 | | | | 1,279 | |
Placement Agent Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Warrant liabilities as of the closing date | | $ 64 | $ 11 | $ 148 | 242 | | | 423 | | | | 224 | |
Investor Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Warrant liabilities as of the closing date | [2] | | | | | | 58 | | | | | | |
Placement Agent Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Warrant liabilities as of the closing date | | | | | $ 0 | | $ 58 | $ 66 | [2] | | | $ 2 | [2] |
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.92 | 0.34 | 1 | 1.26 | | | 2 | [1] | 4.48 | | | |
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.92 | 0.34 | 1 | 1.26 | [1] | | 2 | [1] | 4.48 | [1] | | |
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.92 | 0.34 | 1 | 1.26 | | | 2 | | | | 1.35 | |
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.92 | 0.34 | 1 | 1.26 | | | 2 | | | | 1.35 | |
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | 1.94 | | | | | | |
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | | 2 | | | | 1.35 | |
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.88 | 2.13 | 2.63 | 2.88 | | | 3.14 | [1] | 3.50 | | | |
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.88 | 2.13 | 2.63 | 2.88 | [1] | | 3.14 | [1] | 3.50 | [1] | | |
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.20 | 1.45 | 1.95 | 2.20 | | | 2.45 | | | | 2.95 | |
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.20 | 1.45 | 1.95 | 2.20 | | | 2.45 | | | | 2.95 | |
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | 0.04 | | | | | | |
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | | 0.05 | | | | 0.05 | |
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.0416 | 0.0297 | 0.0087 | 0.0050 | | | 0.0048 | [1] | 0.0026 | | | |
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.0416 | 0.0297 | 0.0087 | 0.0050 | [1] | | 0.0048 | [1] | 0.0026 | [1] | | |
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.0390 | 0.0279 | 0.0072 | 0.0034 | | | 0.0034 | | | | 0.0017 | |
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.0390 | 0.0279 | 0.0072 | 0.0034 | | | 0.0034 | | | | 0.0017 | |
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | 0.0005 | | | | | | |
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | | 0.0004 | | | | 0.0008 | |
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.27 | 1.24 | 1.15 | 1.15 | | | 1.14 | [1] | 1.68 | | | |
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.27 | 1.24 | 1.15 | 1.15 | [1] | | 1.14 | [1] | 1.68 | [1] | | |
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.03 | 1.07 | 1.28 | 1.22 | | | 1.20 | | | | 1.02 | |
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 1.03 | 1.07 | 1.28 | 1.22 | | | 1.20 | | | | 1.02 | |
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | 0.75 | | | | | | |
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | | 0.74 | | | | 0.59 | |
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 3.59 | 3.59 | 3.59 | 3.59 | | | 3.59 | [1] | 3.59 | | | |
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 4.4875 | 4.4875 | 4.4875 | 4.4875 | [1] | | 4.4875 | [1] | 4.4875 | [1] | | |
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 2.03 | 2.03 | 2.03 | 2.03 | | | 2.03 | | | | 2.03 | |
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 2.03 | 2.03 | 2.03 | 2.03 | | | 2.03 | | | | 2.03 | |
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | 1.4927 | | | | | | |
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | | 1.4927 | | | | 1.4927 | |
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.297 | 0.064 | 0.37 | 0.70 | | | 1.25 | [1] | 4.02 | | | |
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.287 | 0.061 | 0.36 | 0.65 | [1] | | 1.18 | [1] | 3.96 | [1] | | |
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.195 | 0.033 | 0.46 | 0.80 | | | 1.40 | | | | 0.74 | |
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | | 0.211 | 0.036 | 0.49 | 0.80 | | | 1.40 | | | | 0.74 | |
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | 0.45 | | | | | | |
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member] | | | | | | | | | | | | | |
Fair value of the warrants | [2] | | | | | | | 0.51 | | | | 0.02 | |
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[1]Closing date of the 2021 Financing.[2]The investor warrants issued in the 2018 Financing expired in July 2020. The placement agent warrants issued in the 2018 Financing were cashless exercised in July 2021. | |