| In millions, except per share items | Mar-31-19 | Sep-30-18 | Jun-30-18 | Mar-31-18 | Dec-31-17 | Sep-30-17 | Jun-30-17 | Mar-31-17 |
| | 10-Q | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q |
| Revenue | 15.4 | 33.7 | 29.5 | 23.0 | 30.8 | 35.8 | 37.1 | 26.7 |
| Revenue growth | -32.9% | -5.8% | -20.6% | -13.8% | 16.5% | 40.4% | 8.7% | -24.2% |
| Cost of revenue | 17.0 | 27.4 | 24.0 | 19.7 | 23.2 | 28.5 | 29.4 | 20.6 |
| Gross profit (loss) | -1.5 | 6.4 | 5.4 | 3.3 | 7.6 | 7.3 | 7.8 | 6.1 |
| Gross margin | -9.9% | 18.9% | 18.4% | 14.4% | 24.7% | 20.4% | 20.9% | 22.9% |
| |
| Operating expenses: | | | | | | | | |
| Selling, general and administrative | 9.7 | 9.1 | 9.8 | 7.8 | 9.5 | 14.6 | 12.1 | 9.6 |
| Research and development | 5.2 | 5.6 | 5.5 | 4.9 | 4.3 | 4.9 | 4.4 | 4.7 |
| Restructuring and exit costs | | 0.0 | 0.1 | -0.1 | 0.0 | 1.3 | | 1.0 |
| Total operating expenses | 14.9 | 14.6 | 15.4 | 12.6 | 14.1 | 20.7 | 16.6 | 15.3 |
| Loss from operations | -16.4 | -8.2 | -10.0 | -9.3 | -6.5 | -13.4 | -8.8 | -9.2 |
| Operating margin | -106.2% | -24.4% | -33.9% | -40.5% | -21.1% | -37.4% | -23.8% | -34.4% |
| Interest expense | 1.1 | -1.3 | -1.0 | 1.1 | -1.0 | -0.2 | -0.1 | -0.1 |
| Other components of defined benefit plans, net | 0.0 | -0.2 | -0.2 | 0.0 | 0.4 | -0.1 | -0.1 | -0.2 |
| Other income | -0.1 | 0.0 | 0.0 | -0.1 | -0.2 | 0.0 | -0.1 | 0.0 |
| Foreign currency exchange loss, net | 0.2 | 0.1 | 0.2 | 0.1 | 0.3 | -0.1 | 0.0 | 0.1 |
| Loss from continuing operations before income taxes | -17.6 | -9.4 | -11.0 | -10.4 | -8.2 | -13.3 | -8.7 | -9.2 |
| Income tax provision | 0.0 | 0.4 | 0.3 | 0.1 | 0.5 | 0.5 | 1.4 | 1.2 |
| Tax rate | | | | | | | | |
| Loss from continuing operations | -17.6 | | | -10.5 | | | | |
| Income from discontinued operations, net of income taxes | | | | 1.3 | | | | |
| Net loss | -17.6 | -9.7 | -11.3 | -9.2 | -8.8 | -13.9 | -10.1 | -10.4 |
| |
| Net income (loss) per share - basic and diluted: | | | | | | | | |
| Continuing operations | 0.0 | | | 0.0 | | | | |
| Discontinued operations | | | | 0.0 | | | | |
| |
| Basic and diluted (in dollars per share) | ($0.38) | ($0.23) | ($0.30) | ($0.25) | ($0.24) | ($0.37) | ($0.28) | ($0.32) |
| |
| Weighted average common shares outstanding: | | | | | | | | |
| Weighted average common shares outstanding, basic and diluted | 46.2 | 42.5 | 38.1 | 37.5 | 35.5 | 37.0 | 35.5 | 32.2 |