| In millions, except per share items | Jun-30-23 | Dec-31-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 | Mar-31-21 |
| | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K |
| Operating expenses: | | | | | | | | |
| Research and development | 50.6 | 42.3 | 28.4 | 32.0 | 29.8 | 21.4 | 18.7 | 18.6 |
| Acquired in-process research and development | 12.5 | | | | | | | |
| General and administrative | 15.4 | 11.8 | 11.9 | 15.2 | 11.5 | 16.3 | 11.2 | 10.3 |
| Total operating expenses | 78.5 | 64.0 | 40.4 | 47.2 | 41.3 | 37.7 | 29.9 | 28.9 |
| Interest income | -4.1 | 2.9 | | | | | | |
| Other income | -0.5 | 1.8 | -0.4 | -1.6 | 0.1 | -0.1 | -0.6 | 0.0 |
| Loss before provision (benefit) for income taxes | -73.9 | -62.8 | -40.0 | -47.2 | -41.4 | -37.7 | -30.5 | -28.2 |
| Provision (benefit) for income taxes | 0.0 | 0.4 | 0.4 | 0.0 | | 0.0 | 0.0 | -0.1 |
| Net loss | -73.9 | -63.2 | -40.4 | -47.2 | -41.4 | -37.7 | -30.5 | -28.2 |
| |
| Net loss per common share - basic (in dollars per share) | ($0.57) | ($0.49) | ($0.35) | ($0.41) | ($0.36) | ($0.35) | ($0.31) | ($0.28) |
| Net loss per common share - diluted (in dollars per share) | ($0.57) | ($0.49) | ($0.35) | ($0.41) | ($0.36) | ($0.35) | ($0.31) | ($0.28) |
| |
| Weighted-average common shares outstanding – basic (in shares) | 130.5 | 128.6 | 116.6 | 109.7 | 115.0 | 109.1 | 98.0 | 87.8 |
| Weighted-average common shares outstanding – diluted (in shares) | 130.5 | 128.6 | 116.6 | 109.7 | 115.0 | 109.1 | 98.0 | 87.8 |