Note 2 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2022 |
Dec. 31, 2021 |
|
| Antidilutive securities (in shares) | 35,065,139 | 4,044,004 |
| Warrant [Member] | ||
| Antidilutive securities (in shares) | 33,208,944 | 2,431,168 |
| Restricted Stock [Member] | ||
| Antidilutive securities (in shares) | 621,668 | 1,567,368 |
| Share-Based Payment Arrangement, Option [Member] | ||
| Antidilutive securities (in shares) | 1,234,527 | 45,468 |