| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 |
| | 10-K | 10-K | 10-K | 10-K | 10-K |
| Assets | | | | | |
| Current assets: | | | | | |
| Cash and cash equivalents | 28.4 | 45.7 | 8.1 | 0.0 | |
| Prepaid expenses and other current assets | 7.6 | 0.3 | 0.0 | 0.0 | |
| Total current assets | 36.0 | 46.0 | 8.1 | 0.7 | |
| Total assets | 36.0 | 46.0 | 8.1 | 1.1 | |
| |
| Liabilities and Stockholders' Equity | | | | | |
| Current liabilities: | | | | | |
| Accounts payable | 4.0 | 0.7 | 0.3 | 1.2 | |
| Accrued expenses | 3.7 | 0.8 | 0.2 | 0.8 | |
| Total current liabilities | 7.7 | 1.5 | 0.6 | 2.0 | |
| Total liabilities | 7.7 | 1.5 | 0.6 | 2.6 | |
| |
| Commitments and contingencies (Note 7) | | | | | |
| Stockholders' equity: | | | | | |
| Preferred stock - $0.0001 par value, 2,000,000 shares authorized and 0 shares issued and outstanding | | | | | |
| Common stock | 0.0 | 0.0 | 0.0 | 0.0 | |
| Additional paid-in capital | 82.4 | 73.2 | 21.8 | 0.2 | |
| Accumulated deficit | -54.1 | -28.7 | -14.2 | -8.8 | |
| Total stockholders' equity | 28.3 | 44.5 | 7.5 | -8.6 | |
| Total liabilities and stockholders' equity | 36.0 | 46.0 | 8.1 | 1.1 | |