| 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 | 10.0 | 8.4 | 8.2 | 8.1 | 7.8 | 6.7 | 5.6 | 5.7 |
| Total revenues growth | 29.4% | 25.6% | 46.7% | 42.0% | 27.7% | 53.7% | 24.2% | 6.3% |
| Cost and expenses: | | | | | | | | |
| Cost of sales (excluding amortization of intangible asset) | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 | 1.0 | 1.0 | 1.0 |
| Selling, general and administrative | 16.0 | 10.9 | 11.6 | 9.2 | 9.6 | 10.4 | 12.0 | 12.8 |
| Research and development | 5.4 | 5.8 | 5.3 | 6.8 | 6.2 | 7.6 | 8.0 | 7.6 |
| Amortization of intangible asset | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 |
| Total cost and expenses | 23.1 | 18.5 | 18.6 | 17.7 | 17.4 | 20.2 | 22.2 | 22.6 |
| Operating loss | -13.1 | -10.1 | -10.4 | -9.6 | -9.7 | -13.5 | -16.6 | -16.9 |
| Operating margin | -130.1% | -120.1% | -126.4% | -118.7% | -124.7% | -202.4% | -296.7% | -297.9% |
| |
| Other expense, net: | | | | | | | | |
| Interest expense | -0.8 | -0.8 | -0.6 | -0.5 | -0.3 | | | |
| Unrealized gain (loss) on fair value of warrants | 0.7 | -0.8 | -1.0 | 6.9 | -7.4 | 0.6 | 1.3 | 3.2 |
| Other (expense) income, net | 0.0 | -0.2 | 0.0 | 0.0 | 0.0 | 0.2 | 0.2 | 0.6 |
| Total other expense, net | -0.2 | -1.7 | -1.6 | 6.4 | -7.6 | 0.8 | 7.7 | 3.8 |
| Loss before income taxes | -13.2 | -11.8 | -12.0 | -3.2 | -17.3 | -12.7 | -9.0 | -13.1 |
| Income tax expense | 0.0 | | 0.0 | | | | | -0.7 |
| Net loss | -13.2 | -11.8 | -11.9 | -3.2 | -17.3 | -12.7 | -9.0 | -13.8 |
| |
| Other comprehensive loss: | | | | | | | | |
| Unrealized loss on marketable securities | | | | | 0.0 | | | |
| Comprehensive loss | -13.2 | -11.8 | -11.9 | -3.2 | -17.3 | -12.7 | -9.0 | -13.8 |
| |
| Net loss attributable to ordinary shareholders: | | | | | | | | |
| Basic | -13.2 | -11.8 | -11.9 | -3.2 | -17.3 | -12.7 | -20.4 | -13.8 |
| Diluted | -13.2 | -11.8 | -11.9 | -3.2 | -17.3 | -12.7 | -20.4 | -13.8 |
| |
| Net loss per share attributable to ordinary shareholders: | | | | | | | | |
| Basic (in dollars per share) | ($0.20) | ($0.18) | ($0.18) | ($0.06) | ($0.32) | ($0.23) | ($0.16) | ($0.25) |
| Diluted (in dollars per share) | ($0.21) | ($0.18) | ($0.18) | ($0.18) | ($0.32) | ($0.24) | ($0.19) | ($0.31) |
| |
| Weighted-average shares used in computing net loss per share attributable to ordinary shareholders: | | | | | | | | |
| Basic (in shares) | 67.7 | 67.4 | 58.0 | 56.1 | 54.3 | 54.2 | 54.2 | 54.2 |
| Diluted (in shares) | 67.9 | 67.4 | 58.0 | 57.4 | 54.3 | 54.4 | 55.4 | 54.5 |