| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Sep-30-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Revenue: | | | | | | | | |
| Revenue | 40.6 | 8.3 | 9.6 | 12.7 | 0.0 | 11.4 | | 5.1 |
| Revenue growth | 388.4% | -13.8% | -24.4% | 1273900.0% | -100.0% | 122.9% | | |
| Cost and operating expenses: | | | | | | | | |
| Cost of product revenue | 1.4 | | | | | | | |
| Research and development | 82.5 | 76.8 | 45.6 | 31.7 | 13.0 | 8.1 | 3.7 | 5.6 |
| Selling, general and administrative | 69.6 | 42.4 | | | | | | |
| Other operating expense, net | 10.6 | -14.6 | 2.2 | 0.8 | -3.7 | -0.2 | | -0.3 |
| Operating loss | -123.5 | -96.3 | -61.1 | -37.9 | -24.6 | -12.3 | 14.0 | -4.7 |
| Operating margin | -304.3% | -1158.8% | -634.2% | -297.4% | -2457700.0% | -108.2% | | -92.7% |
| |
| Other (loss) income: | | | | | | | | |
| Gain from sale of priority review voucher, net of transaction costs | 103.4 | | | | | | | |
| Interest expense, net | -13.9 | -11.4 | -5.3 | -4.8 | 0.0 | -1.3 | -0.3 | -1.7 |
| Net (loss) income before income taxes | -34.0 | -107.6 | -62.7 | -46.1 | -24.2 | -16.3 | 13.7 | -6.8 |
| Provision for income taxes | | | | 0.0 | -0.2 | -0.1 | -0.1 | |
| Net (loss) income | -34.0 | -107.6 | -62.7 | -46.1 | -24.4 | -16.4 | -13.8 | -6.8 |
| |
| Net (loss) income per share attributable to holders of common stock: | | | | | | | | |
| Basic (in dollars per share) | ($1.77) | ($6.73) | ($5.04) | ($3.94) | ($3.12) | ($13.19) | ($6.45) | ($25.49) |
| Diluted (in dollars per share) | ($1.77) | ($6.73) | ($5.04) | ($3.94) | ($3.12) | ($13.19) | ($6.45) | ($25.49) |
| |
| Weighted-average common shares outstanding: | | | | | | | | |
| Basic (in shares) | 19.2 | 16.0 | 12.4 | 11.7 | 7.8 | 1.2 | 2.1 | 0.3 |
| Diluted (in shares) | 19.2 | 16.0 | 12.4 | 11.7 | 7.8 | 1.2 | 2.1 | 0.3 |