| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 8-K | 10-K/A | 10-K/A | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net sales | 24.2 | 25.8 | 20.3 | 21.6 | 29.2 | 34.1 | 23.4 | 22.0 |
| Net sales growth | -6.3% | 27.1% | -5.7% | -26.2% | -14.2% | 45.4% | 6.3% | 0.4% |
| Cost of goods sold | | 11.1 | 9.5 | 9.0 | 11.9 | 14.0 | 10.5 | |
| Gross margin | 13.2 | 14.7 | 10.8 | 12.6 | 17.4 | 20.1 | 12.9 | 11.5 |
| Gross margin | 54.5% | 57.0% | 53.2% | 58.2% | 59.4% | 58.9% | 55.0% | 52.4% |
| |
| Operating expenses: | | | | | | | | |
| Research and development | 6.1 | | | | | | | 4.7 |
| Selling, general and administrative | 7.9 | | | | | | | 5.9 |
| Total operating expenses | 14.0 | 15.0 | 13.9 | 13.8 | 15.6 | 15.0 | 11.4 | 10.6 |
| Operating income (loss) | -0.7 | -0.6 | -4.1 | -1.1 | 1.9 | 5.5 | 1.8 | 1.0 |
| Operating margin | -3.1% | -2.4% | -20.1% | -5.1% | 6.6% | 16.2% | 7.8% | 4.5% |
| |
| Non-operating income (loss): | | | | | | | | |
| Interest income | 0.0 | | | | | | | |
| Gain on sale of assets | | | | | | | | |
| Foreign currency transaction gain (loss) | 0.2 | | | | | | | -0.2 |
| Total non-operating income (loss) | -0.3 | -0.2 | -0.5 | 0.1 | 0.2 | -0.3 | 0.3 | -0.1 |
| Income (loss) before income taxes | | -0.4 | -3.6 | -1.2 | 1.9 | 5.2 | 1.7 | |
| Income tax (expense) benefit | -0.7 | -0.1 | -0.4 | 0.0 | -0.3 | 0.3 | 0.0 | 0.0 |
| Net income (loss) | | -0.6 | -4.0 | -1.2 | 1.6 | 5.4 | 1.7 | 0.9 |
| |
| Basic earnings (loss) per share | | ($0.06) | ($0.48) | ($0.14) | $0.19 | $0.67 | $0.21 | $0.12 |
| Diluted earnings (loss) per share | | ($0.06) | ($0.48) | ($0.14) | $0.19 | $0.65 | $0.20 | $0.12 |
| |
| Weighted-average basic shares | 8.7 | 8.5 | 8.3 | 8.2 | 0.0 | 8.1 | 8.0 | 7.9 |
| Weighted-average diluted shares | 8.7 | 8.5 | 8.3 | 8.2 | 8.4 | 8.4 | 8.1 | 8.1 |