| 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 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 6-K | 6-K |
| Revenue | | | | | | | |
| Total revenue, net | 134.0 | 45.6 | 50.1 | 0.3 | 0.5 | 0.4 | 0.2 |
| Total revenue, net growth | 193.9% | -9.0% | 15660.4% | -31.3% | 10.8% | 141.6% | |
| Operating expenses | | | | | | | |
| Cost of sales | 5.7 | 1.1 | | | | 47.3 | 25.2 |
| Selling, general and administrative | 196.4 | 173.5 | 97.3 | 22.3 | 13.7 | | |
| Research and development | 45.0 | 51.1 | 50.3 | 52.9 | 41.4 | | |
| Other (income) expense, net | -1.5 | 0.6 | 6.8 | 14.9 | -0.7 | -0.2 | 2.2 |
| Total cost of sales and operating expenses | 245.5 | 226.3 | 154.4 | 91.3 | | | |
| Loss from operations | -111.5 | -180.7 | -104.3 | -90.9 | -55.2 | | |
| Operating margin | -83.2% | -396.3% | -208.1% | -28598.4% | -11930.9% | | |
| Interest income | 5.1 | 0.5 | 1.5 | 2.7 | | | |
| Net loss before income taxes | -106.4 | -180.2 | -102.8 | -88.2 | -53.0 | | |
| Income tax (benefit) expense | 1.8 | 0.8 | -0.1 | 0.1 | 0.1 | | |
| Net loss | -108.2 | -181.0 | -102.7 | -88.4 | -53.1 | -70.8 | -23.3 |
| |
| Other comprehensive loss: | | | | | | | |
| Unrealized (loss) gain on available-for-sale securities, net of tax of nil | -0.2 | 0.0 | | | | | |
| Comprehensive loss | -108.4 | -181.0 | -102.7 | -88.4 | | | |
| |
| Basic loss per share (in usd per share) | ($0.76) | ($1.40) | ($0.87) | ($0.95) | ($0.63) | ($0.92) | ($0.66) |
| Diluted loss per share (in usd per share) | ($0.76) | ($1.40) | ($0.87) | ($0.95) | ($0.63) | ($0.92) | ($0.66) |
| |
| Weighted-average common shares outstanding used in computation of basic loss per share | 141.9 | 129.4 | 118.5 | 93.0 | 84.8 | | |
| Weighted-average common shares outstanding used in computation of diluted loss per share | 141.9 | 129.4 | 118.5 | 93.0 | 84.8 | 76.9 | 35.3 |