| In millions, except per share items | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -36.5 | -43.1 | -23.7 | -22.3 | -6.3 | 6.3 | 7.2 | -1.4 |
| Depreciation and amortization [+] | 8.1 | 8.4 | 9.9 | 11.6 | 11.4 | 9.2 | 7.5 | 7.4 |
| Depreciation | 6.8 | 7.6 | 9.9 | 11.4 | 11.2 | 8.9 | 7.1 | 6.8 |
| Amortization of intangible assets | 1.2 | 0.8 | | 0.2 | 0.2 | 0.3 | 0.4 | 0.6 |
| Asset impairment charges | 1.8 | 2.6 | 3.3 | 1.6 | | | | |
| Stock-based compensation | 9.0 | 8.2 | 5.4 | 3.9 | 4.0 | 4.0 | 3.1 | 2.6 |
| Deferred taxes | -5.9 | -0.1 | 2.0 | 2.0 | 2.3 | 1.0 | 0.6 | -1.1 |
| Change in working capital [+] | -14.6 | -8.4 | 7.8 | 11.3 | -11.9 | -2.5 | -26.4 | -10.0 |
| Accounts receivable | 2.8 | -9.4 | 20.1 | 0.3 | -15.1 | 3.7 | -4.9 | -0.8 |
| Inventories | -12.3 | 5.6 | -5.0 | 5.3 | -1.5 | -4.6 | -7.0 | -14.7 |
| Other current assets | 0.2 | 0.4 | -0.4 | 0.0 | -0.1 | 0.1 | 0.3 | 0.1 |
| Deferred revenues | | | | | | -5.4 | 5.4 | |
| Other | -5.3 | -5.0 | -6.9 | 5.8 | 4.8 | 3.6 | -20.2 | 5.4 |
| Other operating activities | -12.7 | 9.6 | -19.0 | 1.3 | | | | |
| Cash from operations | -50.8 | -22.8 | -14.4 | 9.4 | -6.2 | 19.9 | -1.1 | -5.1 |
| |
| Capital expenditures [+] | -10.3 | -3.4 | -6.0 | -4.1 | -7.0 | -16.9 | -15.2 | -14.5 |
| Purchases of property and equipment | -10.3 | -3.4 | -6.0 | -4.1 | -7.0 | -16.9 | -15.2 | -14.5 |
| Sales of property and equipment | 0.0 | | 0.1 | | | | | |
| Acquisitions | | -0.1 | | | | | | |
| Other cash from investing | 49.0 | -0.9 | 20.5 | | | | | |
| Cash from investing | 38.8 | -4.4 | 14.7 | -4.1 | -7.0 | -16.9 | -15.2 | -14.5 |
| |
| Issuance of common stock, net | 23.0 | | | 9.6 | | | | |
| Option exercises | 0.4 | 0.3 | 0.8 | 0.9 | 1.4 | 0.4 | 1.8 | 2.8 |
| Other cash from financing | 0.4 | 43.6 | 1.6 | -14.1 | 11.0 | -0.9 | 17.3 | 13.3 |
| Cash from financing | 22.9 | 43.3 | 0.8 | -5.4 | 9.6 | -1.4 | 15.6 | 10.4 |
| |
| Free cash flow | -61.1 | -26.2 | -20.3 | 5.2 | -13.1 | 3.0 | -16.3 | -19.6 |
| Per share (diluted) | ($1.49) | ($0.74) | ($0.64) | $0.17 | ($0.45) | $0.11 | ($0.57) | ($0.71) |
| |
| Cash paid for interest | 2.8 | 0.1 | 0.1 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 |
| Cash paid for income taxes | 0.0 | 0.0 | 2.6 | 3.5 | 3.3 | 2.0 | 1.6 | 3.3 |