| 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 From Operating Activities: | | | | | | | | |
| Net loss | | | -63.3 | -56.5 | -44.4 | -13.8 | -10.4 | -4.9 |
| Adjustments to reconcile net loss to net cash used in operating activities: | | | | | | | | |
| Depreciation and amortization | | | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 |
| Accretion of term loan-related costs | | | 0.2 | 0.1 | 0.1 | | | |
| Stock-based compensation | | | 12.0 | 10.5 | 9.8 | 8.5 | 6.7 | 4.8 |
| Non-cash lease expense | | | 0.5 | 0.4 | 0.4 | 0.3 | 0.2 | 0.2 |
| Net amortization/accretion on marketable securities | | | -0.1 | | | | | |
| Change in fair value of equity warrants issued by licensee | | | 0.5 | 0.8 | 1.5 | | 1.2 | 0.9 |
| Unrealized gain from transactions denominated in a foreign currency | | | | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Changes in operating assets and liabilities: | | | | | | | | |
| Accounts receivable | | | | | 25.0 | | 0.0 | -20.0 |
| Other receivables | | | -3.9 | -0.4 | -0.1 | -0.1 | -0.1 | -0.2 |
| Prepaid expenses | | | 0.3 | -0.9 | 0.3 | | -0.7 | |
| Other non-current assets | | | | 0.0 | -1.0 | -2.3 | -2.8 | -2.4 |
| Accounts payable and other accrued liabilities | | | 1.5 | -0.9 | 0.8 | 3.9 | 3.7 | 5.9 |
| Accrued payroll and benefits | | | 1.8 | 1.3 | 1.1 | 1.8 | 1.7 | 1.2 |
| Other long-term liabilities | | | -0.1 | -0.1 | -0.1 | 0.1 | 0.2 | 0.1 |
| Net cash used in operating activities | | | -50.3 | -24.6 | 0.3 | 3.7 | 5.9 | -7.8 |
| |
| Cash Flows From Investing Activities: | | | | | | | | |
| Purchases of marketable securities | | | -57.0 | | | | | |
| Purchases of property and equipment | | | -0.7 | -0.7 | -0.6 | -0.6 | -0.3 | -0.3 |
| Net cash provided by (used in) investing activities | | | -57.7 | -0.7 | -0.6 | -0.6 | -0.3 | -0.3 |
| |
| Cash Flows From Financing Activities: | | | | | | | | |
| Proceeds from issuance of common stock upon follow-on public offering, net of paid issuance costs | | | 74.4 | 74.6 | | | | |
| Proceeds from sale of common stock under employee stock purchase plan | | | | 0.2 | | | | |
| Proceeds from exercise of equity awards | | | | 0.5 | | 0.2 | | |
| Proceeds from term loan | | | | | 20.0 | | | |
| Payment of term loan issuance costs | | | | -0.9 | -0.8 | | | |
| Payment of deferred offering costs | | | | -0.4 | -0.4 | -0.3 | | |
| Net cash provided by financing activities | | | 93.6 | 93.9 | 19.1 | 0.0 | 91.9 | 131.7 |
| |
| Supplemental Disclosures Noncash Investing and Financing Activities: | | | | | | | | |
| Interest expense paid in cash | | | 1.1 | | 0.1 | | | |
| Additions of property and equipment included within accounts payable and other accrued liabilities | | | 0.0 | 0.1 | 0.0 | | | |