| In millions, except per share items | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Sales | 27.7 | 37.2 | 30.5 | 32.9 | 35.3 | 26.5 | 29.6 | 24.9 |
| Sales growth | -25.5% | 21.9% | -7.4% | -6.7% | 33.4% | -10.5% | 18.8% | -12.1% |
| Cost of sales | -18.4 | -23.7 | -19.6 | | | | | |
| Gross profit | 9.4 | 13.4 | 11.0 | 12.1 | 12.3 | 9.5 | 11.4 | 8.9 |
| Gross margin | 33.8% | 36.1% | 35.9% | 36.6% | 35.0% | 35.8% | 38.4% | 35.8% |
| |
| Operating expenses: | | | | | | | | |
| Selling, general and administrative | 7.5 | 6.7 | 6.0 | 7.1 | 6.6 | 6.9 | 6.0 | 5.8 |
| Research and development | 3.2 | 2.9 | 2.9 | 2.3 | | | | |
| |
| Pension | | | | | | | | |
| Total operating expenses | 10.8 | 9.8 | 9.2 | 9.7 | 13.0 | 10.2 | 9.4 | 10.5 |
| Operating income (loss) | -1.5 | 3.7 | 1.8 | 2.4 | -1.5 | -1.2 | 1.3 | -2.4 |
| Operating margin | -5.3% | 9.8% | 5.8% | 7.1% | -4.1% | -4.6% | 4.3% | -9.7% |
| Other income, net | -0.3 | -0.3 | 0.1 | 0.0 | -0.2 | 0.1 | 0.0 | -0.1 |
| Income (loss) before income tax provision | -1.7 | 3.3 | 1.4 | 1.8 | -1.3 | -1.3 | 1.3 | -2.3 |
| Income tax benefit (provision) | 0.1 | 0.0 | 0.1 | -0.1 | | | | |
| Tax rate | 7.9% | 0.6% | | 5.1% | 0.0% | 0.0% | 0.0% | 0.0% |
| Net income (loss) | -1.6 | 3.3 | 1.5 | 1.7 | | | | |
| |
| Net income (loss) per common share - basic | ($0.14) | $0.29 | $0.13 | $0.16 | ($0.11) | ($0.12) | $0.11 | ($0.21) |
| Net income (loss) per common share - diluted | ($0.14) | $0.28 | $0.12 | $0.15 | ($0.11) | ($0.12) | $0.11 | ($0.21) |
| |
| Weighted average common shares outstanding - basic | 11.5 | 11.4 | 11.4 | 11.2 | 11.2 | 11.1 | 11.1 | 11.1 |
| Weighted average common shares outstanding - diluted | 11.5 | 12.0 | 12.0 | 11.8 | 11.2 | 11.1 | 11.1 | 11.1 |
| |
| Comprehensive income (loss), net of tax: | | | | | | | | |
| Net income (loss) | -1.6 | 3.3 | 1.5 | 1.7 | | | | |
| |
| Decrease (increase) in minimum pension liability | | | | | | | | |
| Total comprehensive income (loss) | | | | | | | | |