| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Royalty revenue | 2.8 | 5.4 | 2.3 | 2.2 | 8.0 | 17.4 | 19.3 | 5.2 |
| Royalty revenue growth | -48.0% | 136.6% | 6.4% | -73.1% | -53.9% | -9.9% | 269.2% | -82.3% |
| Operating costs and expenses: | | | | | | | | |
| Research and development | 4.1 | 4.0 | 4.7 | 13.1 | 19.4 | 21.4 | 22.5 | 24.5 |
| Selling, general and administrative | 30.9 | 36.3 | 45.0 | 20.8 | 16.6 | | | |
| Total operating costs and expenses | 38.8 | 46.4 | 56.5 | 37.9 | 46.7 | 61.6 | 41.0 | 42.9 |
| |
| Loss from operations | | | | | | | | |
| Other income (expense): | | | | | | | | |
| Interest expense | -2.3 | -3.3 | -2.5 | -2.2 | -3.3 | -2.8 | -3.0 | -2.6 |
| Interest income and other (expense) income, net | -0.1 | -0.6 | -2.2 | -1.1 | -0.5 | -0.9 | -1.7 | -6.9 |
| Total other income (expense) | 0.9 | 0.6 | 1.0 | -11.4 | -13.5 | -11.2 | -3.7 | 4.3 |
| |
| Net income (loss) before income taxes | | | | | | | | |
| Provision for income taxes | 0.0 | 0.0 | 0.0 | 0.0 | -0.7 | 0.0 | 0.8 | |
| Net income (loss) | -35.1 | -40.4 | -53.2 | -47.1 | -51.5 | -43.2 | -24.4 | -33.4 |
| |
| Net income (loss) attributable to Common Shareholders, basic | ($0.29) | ($0.47) | ($0.67) | ($0.81) | ($1.10) | ($0.95) | ($0.60) | ($0.91) |
| |
| Basic earnings (loss) per share | | | | | | | | |
| Net income (loss) per share (in dollars per share) | ($0.29) | ($0.47) | ($0.67) | ($0.81) | ($1.10) | ($0.95) | ($0.55) | ($0.77) |
| |
| Diluted earnings (loss) per share | | | | | | | | |
| Net income (loss) per share (in dollars per share) | ($0.29) | ($0.47) | ($0.67) | ($0.81) | ($1.10) | ($0.95) | ($0.60) | ($0.91) |
| |
| Shares used in computing net income | 119.9 | 85.3 | 79.2 | 58.4 | 46.9 | 45.3 | 44.3 | 43.4 |
| Shares used in computing net income | 119.9 | 85.3 | 79.2 | 58.4 | 46.9 | 45.3 | 44.5 | 44.3 |