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Note 8 - Preferred Stock and Common Stock Warrants (Tables) | 6 Months Ended
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Jun. 30, 2022
Notes Tables |
Schedule of Allocation of Net Cash Proceeds [Table Text Block] |
|  |  |  |  |  | Allocation of Proceeds |
|  |  |  |  |  |  |  |  |  | 2022 Series C |
|  |  |  |  |  | 2022 Series C |  |  | Preferred |
|  |  |  |  |  | Warrants |  |  | Stock |
Gross proceeds |  | $ | 10,500 |  |  |  |  |  |  |  |  |
Equity issuance costs |  |  | (20 | ) |  |  |  |  |  |  |  |
Net proceeds - Initial Fair Value Allocation |  | $ | 10,480 |  |  | $ | 644 |  |  | $ | 9,836 |
Per balance sheet upon issuance |  |  |  |  |  | $ | 644 |  |  | $ | 9,836 |
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] |
|  | June 30, |  |  | December 31, |
|  | 2022 |  |  | 2021 |
Stock price |  | $ | 4.44 |  |  | $ | 2.85 |
Exercise price |  | $ | 0.01 |  |  | $ | 0.01 |
Risk-free rate |  |  | 2.9 | % |  |  | 0.1 | %
Volatility |  |  | 59.0 | % |  |  | 62.6 | %
Term (years) |  |  | 2.2 |  |  |  | 1.6 |

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