| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Operating expenses: | | | | | | | | |
| Research and development | 16.1 | 36.4 | 98.3 | 89.6 | 48.6 | 26.0 | 15.4 | 5.9 |
| General and administrative | 18.7 | 20.4 | 28.5 | 23.6 | 13.0 | 9.0 | 6.5 | 3.6 |
| Litigation settlement | 5.0 | | | | | | | |
| Total operating expenses | 39.8 | 56.9 | 126.7 | 113.2 | 61.6 | 35.0 | 21.9 | 9.5 |
| Operating loss | -39.8 | -56.0 | -122.8 | -77.1 | -56.7 | -32.6 | -20.0 | -8.9 |
| |
| Other income (expense), net: | | | | | | | | |
| Other income (expense), net | 0.0 | 11.9 | 13.3 | | | | | |
| Interest income (expense), net | -2.1 | -1.8 | -1.0 | 1.2 | 1.0 | 0.2 | 0.0 | 0.0 |
| Foreign currency exchange gain (loss), net | -0.4 | -0.4 | -0.4 | -0.2 | 0.1 | 0.0 | 0.0 | 0.0 |
| Other expense, net | -2.5 | 21.9 | 24.4 | 5.7 | 1.1 | 0.1 | 0.0 | 0.0 |
| Net loss | -42.3 | -45.6 | -111.3 | | | | | |
| |
| Earnings Per Share, Basic | ($10.15) | ($11.15) | ($1.42) | ($1.12) | ($0.98) | ($0.65) | ($0.49) | ($0.28) |
| Earnings Per Share, Diluted | ($10.15) | ($11.15) | ($1.42) | ($1.12) | ($0.98) | ($0.65) | ($0.49) | ($0.28) |
| |
| Weighted Average Number of Shares Outstanding, Basic | 4.2 | 4.1 | 78.1 | 63.9 | 57.0 | 50.2 | 41.1 | 31.4 |
| Weighted Average Number of Shares Outstanding, Diluted | 4.2 | 4.1 | 78.1 | 63.9 | 57.0 | | | |
| |
| Comprehensive loss: | | | | | | | | |
| Net loss | -42.3 | -45.6 | -111.3 | -71.5 | -55.7 | -32.4 | -20.0 | -8.9 |
| |
| Other comprehensive income (loss): | | | | | | | | |
| Change in unrealized gain (loss) on marketable debt securities | -0.1 | -0.1 | | | | | | |
| |
| Total other comprehensive income (loss) | | | | | | | | |
| Total comprehensive loss | -42.4 | -45.7 | -111.3 | | | | | |