| In millions, except per share items | Jun-30-23 | Mar-31-23 | Dec-31-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 |
| | 10-Q | 8-K | 8-K | 10-Q | 10-Q | 8-K | 10-Q | 10-Q |
| Revenue: | | | | | | | | |
| Total revenue | 2.8 | 0.4 | 0.0 | 0.7 | | 10.6 | | |
| Total revenue growth | 312.1% | | -99.8% | | | 164.4% | -100.0% | |
| Operating expenses: | | | | | | | | |
| Research and development | 19.5 | | | 16.2 | 12.9 | | | 6.2 |
| Sales and marketing | 1.7 | 1.9 | 1.7 | 1.9 | 1.5 | 1.2 | | 0.7 |
| General and administrative | 5.8 | 5.3 | 6.9 | 6.8 | 7.8 | 19.6 | 1.7 | 3.2 |
| Total operating expenses | 27.0 | 7.1 | 31.4 | 24.9 | 22.2 | 31.4 | 1.7 | 10.2 |
| Loss from operations | -24.2 | -24.5 | -31.4 | -24.2 | -22.2 | -31.4 | -1.7 | -10.2 |
| Operating margin | -856.3% | -6585.8% | -196225.0% | -3524.2% | | -297.6% | | |
| |
| Other income (expenses), net: | | | | | | | | |
| Interest income, net | 1.3 | 1.3 | 1.2 | 0.2 | 0.0 | -0.2 | | -0.1 |
| Gain (loss) on revaluation of common stock warrant liabilities | -0.1 | | | 8.6 | 15.7 | | -2.2 | -6.4 |
| Other income (expense), net | 0.1 | 0.7 | -0.1 | -0.3 | 0.0 | | -2.2 | 0.0 |
| Total other income (expenses), net | 1.3 | 0.7 | -0.1 | 8.6 | 16.5 | | -2.2 | -80.3 |
| Net loss to common stockholders | -22.9 | | | -15.6 | -5.7 | | -3.9 | -90.4 |
| Comprehensive loss to common stockholders | -22.9 | | | -15.6 | | | | |
| |
| Net loss per share - basic (in USD per share) | ($0.15) | ($0.14) | ($0.16) | ($0.10) | ($0.04) | ($1.33) | | ($1.35) |
| Net loss per share - diluted (in USD per share) | ($0.15) | ($0.14) | ($0.16) | ($0.10) | ($0.04) | ($1.33) | | ($1.35) |
| |
| Weighted average shares used in per share calculation, basic (in shares) | 154.9 | | | 152.7 | 151.7 | | 62.5 | 67.1 |
| Weighted average shares used in per share calculation, diluted (in shares) | 154.9 | | | 152.7 | 151.7 | | | 67.1 |