| In millions, except per share items | Jun-05-23 | Mar-05-23 | Dec-31-22 | Dec-05-22 | Sep-30-22 | Sep-05-22 | Jun-30-22 | Jun-05-22 |
| | 8-K | 8-K | 10-K | 8-K | 10-Q | 8-K | 10-Q | 8-K |
| Revenue | 0.7 | 1.1 | 0.2 | 0.2 | 1.4 | 1.4 | 1.5 | 1.5 |
| Revenue growth | -50.2% | 1.0% | -93.5% | -93.5% | -60.6% | -60.6% | -42.6% | |
| Cost of revenue | 2.7 | 2.5 | 3.3 | 3.3 | 2.8 | 2.8 | 1.0 | 1.0 |
| Gross profit (loss) | -1.9 | -1.4 | -3.1 | -3.1 | -1.4 | -1.4 | 0.5 | 0.5 |
| Gross margin | -258.1% | -120.3% | -1663.8% | -1663.8% | -101.2% | -101.2% | 33.6% | 33.6% |
| Research and development expenses | 32.3 | 29.9 | 32.2 | 36.3 | 26.1 | 30.3 | 25.9 | 30.6 |
| General and administrative expenses | 8.9 | 9.0 | 7.4 | 8.6 | 8.1 | 9.4 | 8.7 | 10.0 |
| Selling and marketing expenses | 1.5 | 2.6 | 1.6 | 1.6 | 2.2 | 2.2 | 1.6 | 1.6 |
| Total operating expenses | 79.0 | 41.4 | 41.3 | 87.8 | 36.4 | 78.3 | 36.2 | 78.3 |
| Operating loss | -38.2 | -37.3 | -44.4 | -44.4 | -37.8 | -37.8 | -35.7 | -35.7 |
| Operating margin | -5138.8% | -3246.2% | -23614.4% | -23614.4% | -2751.2% | -2751.2% | -2390.2% | -2390.2% |
| Interest income | 2.2 | | 1.7 | 1.7 | 1.2 | | 0.6 | 0.6 |
| Other income (expense), net | 0.0 | | 0.0 | 0.0 | 0.1 | | 0.1 | 0.1 |
| Net loss before income taxes | | | -42.7 | | -36.5 | | -35.0 | |
| Net loss | -36.0 | | -42.7 | -42.7 | -36.5 | -36.5 | -35.0 | -35.0 |
| Unrealized loss on available-for-sale securities | | | 1.1 | | -0.8 | | -1.0 | |
| Total comprehensive loss | | | -41.6 | | -37.3 | | -35.9 | |
| |
| Net loss per share, basic | ($0.16) | ($0.16) | ($0.20) | ($0.20) | ($0.17) | ($0.17) | ($0.16) | ($0.16) |
| Net loss per share, diluted | ($0.16) | ($0.16) | ($0.20) | ($0.20) | ($0.17) | ($0.17) | ($0.16) | ($0.16) |
| |
| Weighted-average shares used in computing net loss per share, basic | 220.5 | 219.6 | 217.3 | 218.4 | 217.9 | 217.9 | 216.9 | 216.9 |
| Weighted-average shares used in computing net loss per share, diluted | 220.5 | 219.6 | 217.3 | 218.4 | 217.9 | 217.9 | 216.9 | 216.9 |