| In millions, except per share items | Jun-30-23 | Mar-31-23 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 |
| | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q |
| Cash flows used in operating activities | | | | | | | | |
| Net loss | | | -62.1 | -61.8 | -44.3 | -42.9 | -75.9 | -73.7 |
| |
| Adjustments to reconcile net loss to net cash used in operating activities: | | | | | | | | |
| Depreciation of property and equipment | | | 0.1 | 0.1 | 0.1 | 0.1 | 0.2 | 0.2 |
| Share-based compensation expense | | | 8.9 | 8.5 | 8.0 | 7.3 | 10.2 | 9.6 |
| Changes in operating assets and liabilities: | | | | | | | | |
| Other receivables | | | -0.3 | 0.0 | 0.0 | 0.1 | | |
| Research and development tax credits receivable | | | 0.1 | 0.4 | 0.4 | 0.4 | | |
| Prepaid expenses | | | 0.9 | 4.0 | 2.2 | 1.1 | -4.1 | -3.0 |
| Accounts payable and accrued liabilities | | | 0.4 | -1.0 | -1.2 | 0.6 | -2.4 | -2.1 |
| Net cash used in operating activities | | | -52.0 | -49.8 | -34.7 | -33.2 | -71.6 | -69.5 |
| |
| Cash provided by (used in) investing activities | | | | | | | | |
| Acquisition of property and equipment | | | -0.2 | -0.1 | | | | |
| Acquisition of short-term investments | | | -62.9 | -38.0 | -23.0 | | | |
| Redemption of short-term investments | | | 38.0 | | | 85.0 | 90.0 | 56.0 |
| Net cash provided by (used in) investing activities | | | -25.1 | 14.9 | 50.0 | 70.0 | -15.0 | -62.0 |
| |
| Cash provided by financing activities | | | | | | | | |
| Proceeds from exercise of options | | | 0.3 | 0.3 | 0.2 | 0.1 | 0.3 | |
| Proceeds from employee stock purchase plan | | | | 0.2 | 0.0 | | | |
| Cash provided by financing activities | | | 3.0 | 0.3 | 5.1 | 5.1 | 78.2 | 103.0 |