| 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-K | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K |
| Revenue | 0.4 | 0.0 | 0.0 | 0.0 | 0.1 | 0.6 | 0.2 | 0.0 |
| Revenue growth | 1625.0% | -63.9% | -79.7% | 140.0% | 79.6% | 331.5% | 33.6% | -93.9% |
| Cost of revenue | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.4 | 0.2 | 0.0 |
| Gross profit | 0.2 | 0.0 | 0.0 | 0.0 | 0.1 | 0.1 | 0.0 | 0.0 |
| Gross margin | 43.7% | 31.4% | 15.8% | 37.5% | 52.6% | 21.4% | 6.4% | -10.0% |
| |
| Operating expenses: | | | | | | | | |
| Selling, general and administrative | 1.2 | 1.4 | 1.6 | 1.4 | 1.5 | 1.7 | 1.4 | 1.3 |
| Research and development | 1.7 | 1.4 | 1.1 | 0.8 | 0.7 | 0.7 | 0.6 | 0.7 |
| Total operating expenses | 2.9 | 2.8 | 2.8 | 2.1 | 2.2 | 2.4 | 2.1 | 2.0 |
| Loss from operations | -2.7 | -2.8 | -2.8 | -2.1 | -2.1 | -2.3 | -2.1 | -2.0 |
| Operating margin | -659.9% | -7857.1% | -7276.3% | -8895.8% | -2213.4% | -402.9% | -1097.9% | -19590.0% |
| Other income and expense, net | 0.4 | 0.4 | -0.2 | 0.1 | 0.0 | 0.1 | 0.0 | 0.4 |
| Loss from operations before income taxes | -2.3 | -2.4 | -2.5 | -2.0 | -2.1 | -2.2 | -2.0 | -1.5 |
| Income tax benefit | | | | | | | | |
| Net loss | -2.3 | -2.4 | -2.5 | -2.0 | -2.1 | -2.2 | -2.0 | -1.5 |
| |
| Weighted average common shares outstanding: | | | | | | | | |
| Basic and diluted (in shares) | 1.6 | 1.6 | 48.4 | 1.6 | 1.6 | 47.5 | 47.4 | 22.0 |
| |
| Basic and diluted net loss per common share: | | | | | | | | |
| Net loss per common share (in dollars per share) | ($1.41) | ($1.47) | ($0.05) | ($1.26) | ($1.32) | ($0.05) | ($0.04) | $0.07 |
| |
| Other comprehensive loss, net of tax: | | | | | | | | |
| Net loss | -2.3 | -2.4 | -2.5 | -2.0 | -2.1 | -2.2 | -2.0 | -1.5 |
| |
| Available-for-sale securities: | | | | | | | | |
| Net unrealized loss | -0.3 | | | -1.2 | | | | |
| Total comprehensive loss | -2.4 | -2.2 | -2.9 | -2.4 | -2.6 | -2.4 | -2.1 | -1.5 |