| 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 | -16.0 | -15.0 | -14.6 | -16.6 | -14.0 | -16.9 | -14.2 | 0.8 |
| |
| Adjustments to reconcile net loss to net cash used in operating activities: | | | | | | | | |
| Depreciation of property and equipment | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Amortization of debt costs | 0.1 | | | | | | | |
| Accretion of investment discount | 0.0 | -0.1 | | | | | | |
| Non-cash interest expense related to debt | 0.8 | | | | | | | |
| Share-based compensation expense | 2.5 | 2.3 | 2.4 | 2.4 | 2.1 | 2.0 | 2.0 | 1.9 |
| Changes in operating assets and liabilities: | | | | | | | | |
| Other receivables | -0.4 | 0.2 | -0.2 | 0.0 | -0.1 | 0.0 | 0.2 | 0.0 |
| Research and development tax credits receivable | -0.1 | -0.1 | 0.3 | -0.1 | -0.1 | -0.1 | 0.6 | -0.1 |
| Prepaid expenses | 0.0 | 0.6 | -1.6 | 0.6 | 0.2 | 1.7 | 1.5 | -1.2 |
| Operating lease assets and liabilities | 0.0 | 0.0 | 0.1 | 0.0 | 0.0 | | 0.0 | 0.0 |
| Accounts payable and accrued liabilities | 1.6 | -0.9 | 1.9 | -0.3 | -2.1 | 1.0 | 0.5 | -0.5 |
| Net cash used in operating activities | -10.6 | -13.9 | -11.6 | -14.1 | -13.9 | -12.4 | -9.4 | 1.0 |
| |
| Cash provided by (used in) investing activities | | | | | | | | |
| Acquisition of property and equipment | 0.0 | 0.0 | -0.1 | -0.1 | | | | |
| Acquisition of short-term investments | -55.0 | -15.0 | -39.9 | -15.0 | -8.0 | | -15.0 | |
| Redemption of short-term investments | 27.0 | 45.0 | 23.0 | | | 15.0 | 38.0 | 20.0 |
| Net cash provided by (used in) investing activities | -28.0 | 30.0 | -17.1 | -15.1 | -8.0 | 15.0 | 23.0 | 20.0 |
| |
| Cash provided by financing activities | | | | | | | | |
| Proceeds from exercise of options | -0.1 | 0.3 | 0.0 | 0.1 | 0.0 | 0.1 | 0.0 | |
| Proceeds from issuance of senior secured convertible debt | | 50.0 | | | | | | |
| Pre-funded warrant issuance costs | 0.0 | | | | | | | |
| Proceeds from employee stock purchase plan | 0.0 | 0.1 | | 0.1 | 0.0 | | | |
| Payment of debt issuance costs | -2.8 | | | | | | | |
| Cash provided by financing activities | -2.8 | 50.3 | 2.7 | 0.1 | 0.0 | 0.1 | 0.0 | 4.9 |
| Net increase (decrease) in cash and cash equivalents | -41.4 | 66.3 | | -29.0 | -21.9 | | | |