| In millions, except per share items | Jun-30-23 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 | Mar-31-21 | Dec-31-20 |
| | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K |
| Collaboration revenue | | 75.3 | 18.9 | 19.8 | 16.1 | 38.8 | 42.6 | 44.9 |
| Collaboration revenue growth | | 94.2% | -55.6% | -56.0% | | | | |
| Operating expenses: | | | | | | | | |
| Research and development | | 96.7 | 95.6 | 87.8 | 82.9 | 77.9 | 73.3 | 73.6 |
| General and administrative | | 30.5 | 29.5 | 27.8 | 25.5 | 23.0 | 20.0 | 18.5 |
| Total operating expenses | | 127.3 | 125.1 | 115.6 | 108.4 | 100.9 | 93.3 | 92.1 |
| (Loss) income from operations | | -52.0 | -106.2 | -95.8 | -92.2 | -62.1 | -50.7 | -47.2 |
| Operating margin | | -69.0% | -561.5% | -484.0% | -571.6% | -160.2% | -119.0% | -105.0% |
| |
| Other income: | | | | | | | | |
| Interest income, net | | 0.9 | 0.4 | 0.3 | 0.2 | 0.4 | 0.8 | 1.6 |
| Other income, net | | 0.0 | 0.0 | 0.0 | | 0.0 | 0.4 | 1.3 |
| Total other income, net | | 0.9 | 0.4 | 0.3 | 0.2 | 0.4 | 0.7 | 1.6 |
| (Loss) income before provision for income taxes | | -51.1 | -105.7 | -95.5 | -92.0 | -61.8 | -50.0 | -45.6 |
| Provision for income taxes | | 0.0 | | | | | | 0.6 |
| Net (loss) income | | -51.1 | -105.7 | -95.5 | -91.9 | -61.5 | -49.5 | -45.0 |
| |
| Net (loss) income per share, basic (in dollars per share) | | ($1.42) | ($2.89) | ($2.67) | ($2.66) | ($1.79) | ($1.54) | ($1.46) |
| Net (loss) income per share, diluted (in dollars per share) | | ($1.44) | ($2.89) | ($2.67) | ($2.66) | ($1.80) | ($1.55) | ($1.47) |
| |
| Weighted average common shares outstanding, basic (in shares) | | 36.9 | 36.4 | 35.5 | 34.2 | 32.7 | 31.3 | 30.4 |
| Weighted average common shares outstanding, diluted (in shares) | | 37.3 | 36.4 | 35.5 | 34.2 | 33.2 | 31.7 | 23.3 |
| |
| Comprehensive (loss) income: | | | | | | | | |
| Net (loss) income | | -51.1 | -105.7 | -95.5 | -91.9 | -61.5 | -49.5 | -45.0 |
| |
| Other comprehensive (loss) income: | | | | | | | | |
| |
| Total other comprehensive (loss) income | | | | | | | | |
| Comprehensive (loss) income | | -53.5 | -107.5 | -96.0 | -92.0 | -61.7 | -50.2 | -45.1 |