| In millions, except per share items | Jun-30-23 | Dec-31-22 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 |
| | 10-Q | 8-K | 10-Q | 10-Q | 10-Q | 10-K/A | 10-Q | 10-Q |
| Net sales | 7.4 | 7.3 | 7.2 | 4.8 | 5.0 | 6.4 | 6.7 | 6.7 |
| Net sales growth | 55.1% | 14.4% | 7.2% | -29.2% | -17.5% | 28.7% | 13.2% | 44.6% |
| Cost of goods sold | 3.0 | | 3.1 | 2.0 | 2.7 | 2.9 | 2.6 | 2.9 |
| Gross margin | 4.4 | 4.0 | 4.1 | 2.8 | 2.3 | 3.5 | 4.1 | 3.8 |
| Gross margin | 59.1% | 55.5% | 57.0% | 57.8% | 46.4% | 54.4% | 60.7% | 57.0% |
| |
| Operating expenses: | | | | | | | | |
| Research and development | 1.7 | 1.5 | 1.4 | 1.6 | 1.6 | | 1.7 | 1.7 |
| Selling, general and administrative | 2.5 | 1.9 | 2.0 | 1.9 | 2.0 | | 2.2 | 2.1 |
| Total operating expenses | 4.2 | 3.4 | 3.4 | 3.5 | 3.7 | 3.7 | 3.9 | 3.7 |
| Operating income (loss) | 0.2 | 0.6 | 0.7 | -0.7 | -1.4 | -0.5 | 0.1 | 0.1 |
| Operating margin | 2.2% | 8.6% | 9.9% | -15.2% | -27.4% | -8.4% | 2.1% | 1.6% |
| |
| Non-operating income (loss): | | | | | | | | |
| Interest income | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | | 0.0 | |
| Gain on sale of assets | | | | | 0.1 | | | |
| Foreign currency transaction gain (loss) | 0.2 | -0.2 | 0.3 | 0.1 | -0.1 | 0.1 | 0.0 | -0.1 |
| Total non-operating income (loss) | 0.2 | 0.0 | 0.3 | 0.1 | -0.1 | -0.1 | 0.0 | -0.1 |
| Income (loss) before income taxes | 0.4 | | | -0.6 | -1.4 | -0.3 | | |
| Income tax (expense) benefit | -0.1 | 0.0 | -0.2 | -0.1 | -0.5 | 0.1 | -0.1 | 0.1 |
| Net income (loss) | 0.3 | 0.5 | 0.8 | -0.7 | -1.8 | -0.2 | 0.0 | 0.0 |
| |
| Basic earnings (loss) per share | $0.03 | $0.06 | $0.10 | ($0.08) | ($0.21) | ($0.02) | | |
| Diluted earnings (loss) per share | $0.03 | $0.06 | $0.10 | ($0.08) | ($0.21) | ($0.02) | | |
| |
| Weighted-average basic shares | 8.9 | 8.8 | 8.8 | 0.0 | 8.6 | 8.5 | 8.6 | 8.5 |
| Weighted-average diluted shares | 9.1 | 8.9 | 8.9 | 0.0 | 8.6 | 8.5 | 8.8 | 8.5 |