Consolidated Balance Sheets (Parentheticals) - $ / shares |
Dec. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Preferred stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
| Common stock, par value (in dollars per share) | $ 0.001 | $ 0.001 |
| Common stock, authorized (in shares) | 600,000,000 | 600,000,000 |
| Common stock, issued (in shares) | 6,381,541 | 3,834,095 |
| Common stock, outstanding (in shares) | 6,381,541 | 3,834,095 |
| Series B Convertible Preferred Stock [Member] | ||
| Preferred stock, par value (in dollars per share) | $ 1,000 | $ 1,000 |
| Preferred stock, shares authorized (in shares) | 10,000,000 | 10,000,000 |
| Preferred stock, shares issued (in shares) | 0 | 100 |
| Preferred stock, shares outstanding (in shares) | 0 | 100 |