| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 |
| | 8-K | 10-K | 10-K | 10-K | S-1/A |
| Revenues: | | | | | |
| Total revenues | | | | | |
| Operating expenses: | | | | | |
| Research and development | | 41.7 | 18.8 | 3.2 | |
| General and administrative | 44.9 | 25.4 | 8.2 | 1.1 | 0.4 |
| Total operating expenses | 177.1 | | | | |
| Loss from operations before other income (expense) and income taxes | -63.5 | -12.2 | -27.0 | -4.3 | |
| |
| Other income (expense): | | | | | |
| Interest income | 3.5 | | | | |
| Interest expense | -2.2 | | | | |
| Other (expense) income, net | 0.1 | -0.1 | | | |
| Change in fair value of equity warrants issued by licensee | -0.5 | | | | |
| Total other income (expense), net | 0.1 | -1.6 | 0.2 | -0.4 | |
| Provision for income taxes | 0.0 | 0.1 | 0.0 | 0.0 | 0.0 |
| Net (loss) income | -62.1 | -13.8 | -26.8 | -4.7 | |
| |
| Other comprehensive loss: | | | | | |
| Comprehensive loss | -62.2 | -13.8 | -26.8 | -4.7 | |
| |
| Earnings Per Share [Abstract] | | | | | |
| Net loss per share, basic (usd per share) | ($2.52) | ($0.67) | ($4.32) | ($1.98) | ($0.75) |
| Net loss per share, diluted (usd per share) | ($2.52) | ($0.67) | ($4.32) | ($1.98) | ($0.75) |
| |
| Weighted Average Number of Shares Outstanding, Diluted [Abstract] | | | | | |
| Weighted-average shares outstanding, basic (shares) | 24.6 | 20.6 | 6.2 | 2.4 | 1,759.5 |
| Weighted-average shares outstanding, diluted (shares) | 24.6 | 20.6 | 6.2 | | |