| 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 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -82.7 | -37.1 | -21.8 | -14.6 | -34.4 | -19.3 | -12.0 | -6.4 |
| Depreciation and amortization [+] | | | | 10.2 | 10.8 | 10.8 | 9.9 | 9.9 |
| Depreciation | | | | 10.2 | 10.8 | 10.8 | 9.9 | 9.9 |
| Asset impairment charges | | | | | 7.4 | | | |
| Stock-based compensation | | | | 3.8 | 4.3 | 5.1 | 5.3 | 5.4 |
| Change in working capital [+] | 32.0 | 4.3 | 0.3 | -3.7 | -0.1 | -5.4 | -2.6 | -3.4 |
| Accounts receivable | | | | -6.7 | -1.7 | -9.2 | 3.1 | -2.6 |
| Inventories | | | | -1.5 | 1.6 | 4.0 | -6.3 | -1.6 |
| Other current assets | | | | -0.1 | 0.3 | 0.4 | 0.0 | -0.9 |
| Accounts payable | | | | 0.1 | 1.6 | 1.3 | 0.1 | 1.5 |
| Accrued expenses | 32.0 | 4.7 | -0.1 | 4.4 | -1.9 | -1.9 | -0.1 | -5.6 |
| Deferred revenues | | | | | | | | 0.3 |
| Other | | -0.4 | 0.4 | -0.1 | 0.1 | 0.0 | 0.6 | 5.5 |
| Other operating activities | -43.6 | 14.2 | 11.5 | 3.3 | 3.4 | 4.3 | -1.1 | -0.1 |
| Cash from operations | -94.4 | -18.6 | -9.9 | -1.1 | -8.7 | -4.6 | -0.6 | 5.4 |
| |
| Capital expenditures | 178.0 | 13.8 | 3.4 | -2.1 | -3.6 | -6.1 | -13.2 | -22.0 |
| Purchases of property and equipment | 178.0 | 13.8 | 3.4 | -2.1 | -3.6 | -6.1 | -13.2 | -22.0 |
| Purchases of short-term investments | | | | | | | | -2.5 |
| Sales of short-term investments | | | | | | | | 2.5 |
| Other cash from investing | -355.9 | -27.6 | -6.8 | | | | | |
| Cash from investing | -178.0 | -13.8 | -3.4 | -2.1 | -3.6 | -6.1 | -13.2 | -22.0 |
| |
| Option exercises | 0.6 | 2.3 | 2.7 | | | | | |
| Financing costs | | | 0.0 | | | | | |
| Other cash from financing | 478.9 | 94.8 | 28.9 | 3.5 | 4.9 | 3.3 | -0.9 | -0.3 |
| Cash from financing | 478.4 | 92.5 | 26.2 | 3.5 | 4.9 | 3.3 | -0.9 | -0.3 |
| |
| Free cash flow | 83.6 | -4.9 | -6.5 | -3.2 | -12.2 | -10.7 | -13.8 | -16.6 |
| Per share (diluted) | $2.12 | ($0.16) | ($0.25) | ($0.13) | ($0.52) | ($0.46) | ($0.60) | ($0.72) |
| |
| Cash paid for interest | 0.2 | 0.2 | 0.2 | 0.4 | 0.3 | 0.2 | 0.2 | 0.2 |