| In millions, except per share items | Jun-30-21 | Mar-31-21 | Dec-31-20 | Sep-30-20 | Jun-30-20 | Mar-31-20 | Dec-31-19 | Sep-30-19 |
| | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q |
| Revenues: | | | | | | | | |
| Total revenues | 34.7 | 32.4 | 30.7 | 28.1 | 25.7 | 24.0 | 21.7 | 20.6 |
| Total revenues growth | 35.0% | 34.9% | 41.5% | 36.3% | 26.8% | 30.0% | 20.4% | 25.0% |
| Cost and expenses: | | | | | | | | |
| Cost of sales (excluding amortization of intangible asset) | 1.7 | 1.7 | 2.2 | 2.8 | 3.3 | 4.0 | 3.8 | 2.8 |
| Selling, general and administrative | 47.8 | 41.4 | 40.9 | 41.2 | 44.8 | 47.4 | 49.1 | 53.3 |
| Research and development | 23.3 | 24.1 | 25.8 | 28.5 | 29.3 | 31.9 | 30.9 | 30.8 |
| Amortization of intangible asset | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.4 |
| Total cost and expenses | 77.8 | 72.2 | 73.9 | 77.5 | 82.5 | 88.2 | 88.8 | 93.5 |
| Operating loss | -43.1 | -39.7 | -43.2 | -49.4 | -56.7 | -64.2 | -67.1 | -72.8 |
| Operating margin | -124.2% | -122.5% | -140.5% | -175.7% | -220.6% | -267.0% | -309.0% | -353.3% |
| |
| Other expense, net: | | | | | | | | |
| Interest expense | -2.7 | -2.1 | -1.3 | -0.8 | -0.3 | | | |
| Unrealized gain (loss) on fair value of warrants | 5.9 | -2.2 | -0.8 | 1.5 | -2.3 | 13.8 | 11.4 | 10.0 |
| Other (expense) income, net | -0.3 | -0.2 | 0.2 | 0.4 | 1.0 | 1.6 | 2.1 | 2.2 |
| Total other expense, net | 2.9 | -4.5 | -1.9 | 7.3 | 4.7 | 21.6 | 19.4 | 118.7 |
| Loss before income taxes | -40.2 | -44.2 | -45.1 | -42.1 | -52.0 | -42.6 | -47.7 | 45.9 |
| Income tax expense | 0.0 | | 0.0 | | | | | -2.3 |
| Net loss | -40.2 | -44.2 | -45.1 | -42.1 | -52.7 | -43.7 | -49.5 | 43.6 |
| |
| Other comprehensive loss: | | | | | | | | |
| Comprehensive loss | -40.2 | -44.2 | -45.1 | -42.1 | -52.7 | -43.7 | -49.4 | -40.5 |
| |
| Net loss attributable to ordinary shareholders: | | | | | | | | |
| Basic | -40.2 | -44.2 | -45.1 | -53.5 | -64.1 | -55.1 | -60.8 | 27.2 |
| Diluted | -40.2 | -44.2 | -45.1 | -53.5 | -64.1 | -55.1 | -60.8 | 27.2 |
| |
| Net loss per share attributable to ordinary shareholders: | | | | | | | | |
| Basic (in dollars per share) | ($0.62) | ($0.74) | ($0.79) | ($0.77) | ($0.96) | ($0.79) | ($0.90) | $1.09 |
| Diluted (in dollars per share) | ($0.75) | ($0.86) | ($0.92) | ($0.93) | ($1.06) | ($1.04) | ($1.14) | $0.73 |
| |
| Weighted-average shares used in computing net loss per share attributable to ordinary shareholders: | | | | | | | | |
| Basic (in shares) | 62.3 | 58.9 | 55.7 | 54.7 | 54.2 | 47.6 | 47.6 | 45.6 |
| Diluted (in shares) | 62.7 | 59.3 | 56.0 | 55.4 | 54.7 | 54.6 | 54.6 | 53.1 |