| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Sales, net | 188.4 | 81.9 | 41.8 | 33.3 | 34.5 | 29.8 | 29.6 | 34.5 |
| Sales, net growth | 130.1% | 95.9% | 25.6% | -3.5% | 15.6% | 0.9% | -14.4% | 12.1% |
| Cost of sales: | | | | | | | | |
| Total cost of sales | 93.0 | 44.9 | 27.7 | 23.1 | 24.5 | 19.5 | 16.5 | 19.8 |
| Gross profit | 95.4 | 37.0 | 14.1 | 10.2 | 10.0 | 10.3 | 10.6 | 12.0 |
| Gross margin | 50.6% | 45.2% | 33.8% | 30.7% | 28.9% | 34.7% | 35.8% | 34.8% |
| |
| Operating expenses: | | | | | | | | |
| Sales and marketing | 4.5 | 4.1 | 4.2 | 4.4 | 4.7 | 4.0 | 3.8 | 4.0 |
| Research and development | 0.9 | 0.6 | 0.5 | 0.6 | 0.7 | 0.6 | 0.6 | 0.6 |
| General and administrative | 17.4 | 8.3 | 6.4 | 6.8 | 8.4 | 8.8 | 9.3 | 9.6 |
| Total operating expenses | 22.8 | 12.9 | 11.2 | 11.8 | 13.8 | 13.8 | 35.3 | 14.2 |
| Income (loss) from operations | 72.6 | 24.1 | 3.0 | -1.3 | -3.8 | -3.5 | -3.2 | -2.2 |
| Operating margin | 38.5% | 29.4% | 7.1% | -4.0% | -11.0% | -11.8% | -10.9% | -6.3% |
| Other income - TIA | 0.4 | | | | | | | |
| Interest and other income | 0.8 | 2.3 | 0.4 | 0.2 | 0.1 | 0.0 | 0.0 | 0.0 |
| Interest expense | -0.2 | -0.3 | -0.2 | -0.2 | -0.2 | -0.2 | -0.2 | -0.2 |
| Income (loss) before income taxes | 75.0 | 26.1 | 3.2 | | | | | |
| Provision (benefit) for income taxes | 18.9 | 1.9 | 0.0 | 0.0 | -0.2 | 0.0 | 0.0 | 0.0 |
| Net income (loss) | 56.1 | 24.2 | 3.1 | -1.3 | -3.7 | -3.7 | 4.3 | -2.4 |
| Preferred Stock dividend requirements | -0.2 | -0.6 | -0.7 | -0.7 | -0.7 | -0.7 | -0.7 | -0.9 |
| Net income (loss) applicable to common shareholders | 55.8 | 26.6 | 2.4 | -2.0 | -4.4 | -4.4 | 5.9 | -3.3 |
| |
| Basic earnings (loss) per share | $1.65 | $0.80 | $0.07 | ($0.06) | ($0.14) | ($0.15) | $0.21 | ($0.12) |
| Diluted earnings (loss) per share | $1.63 | $0.80 | $0.07 | ($0.06) | ($0.14) | ($0.15) | $0.20 | ($0.12) |
| |
| Weighted average common shares outstanding: | | | | | | | | |
| Basic (in shares) | 33.9 | 33.2 | 32.7 | 32.7 | 32.0 | 29.4 | 27.8 | 27.4 |
| Diluted (in shares) | 34.2 | 33.3 | 32.7 | 32.7 | 32.0 | 29.4 | 29.5 | 27.4 |