| In millions, except per share items | Jun-30-23 | Jun-30-22 | Jun-30-21 | Jun-30-20 | Jun-30-19 | Jun-30-18 | Jun-30-17 | Jun-30-16 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Revenue | 0.8 | 0.9 | 0.3 | 0.5 | 0.1 | 0.1 | 2.3 | 2.7 |
| Revenue growth | -13.7% | 160.2% | -31.6% | 284.3% | 47.7% | -96.3% | -12.8% | 420.7% |
| Cost of revenue | 0.4 | 0.7 | 0.3 | 0.4 | 0.1 | 0.0 | 1.3 | 2.3 |
| Gross profit | 0.3 | 0.2 | 0.0 | 0.0 | 0.0 | 0.1 | 1.0 | 0.3 |
| Gross margin | 40.8% | 22.1% | 10.8% | 8.0% | 29.1% | 58.1% | 44.5% | 12.7% |
| |
| Operating expenses: | | | | | | | | |
| Selling, general and administrative | 5.8 | 6.0 | 4.7 | 4.7 | 4.9 | 5.6 | 7.5 | 7.7 |
| Research and development | 5.6 | 2.8 | 2.7 | 3.4 | 3.6 | 6.1 | 5.6 | 6.5 |
| Total operating expenses | 11.4 | 8.8 | 7.9 | 8.2 | 8.5 | 13.4 | 13.1 | 14.2 |
| Loss from operations | -11.1 | -8.6 | -7.9 | -8.1 | -8.4 | -13.3 | -12.1 | -13.8 |
| Operating margin | -1474.7% | -989.1% | -2368.3% | -1662.7% | -6627.6% | -15508.1% | -518.0% | -518.1% |
| Other income and expense, net | 1.4 | 0.3 | 0.2 | -0.2 | 0.0 | 0.1 | 0.3 | 0.4 |
| Loss from operations before income taxes | -9.6 | -8.3 | -7.6 | -8.3 | -8.4 | -13.3 | -11.8 | -13.5 |
| Income tax benefit | | | | | 0.9 | | 0.0 | 0.0 |
| Net loss | -9.6 | -8.3 | -7.6 | -8.3 | -7.5 | -13.3 | -11.6 | -13.1 |
| |
| Weighted average common shares outstanding: | | | | | | | | |
| Basic and diluted (in shares) | 1.6 | 1.6 | 22.0 | 6.3 | 4.9 | 4.1 | 4.1 | 20.4 |
| |
| Basic and diluted net loss per common share: | | | | | | | | |
| Net loss per common share (in dollars per share) | ($5.95) | ($5.24) | ($0.35) | ($1.31) | ($1.53) | ($3.26) | ($2.84) | ($0.64) |
| |
| Other comprehensive loss, net of tax: | | | | | | | | |
| Net loss | -9.6 | -8.3 | -7.6 | -8.3 | -7.5 | -13.3 | -11.6 | -13.1 |
| |
| Available-for-sale securities: | | | | | | | | |
| Net unrealized loss | -0.3 | -1.2 | | | | | | |
| Total comprehensive loss | -9.9 | -9.5 | -7.6 | -8.3 | -7.5 | -13.2 | -11.5 | -13.2 |