| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-05-18 | Dec-31-17 | Dec-31-16 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 8-K | 10-K | 10-K |
| Net income | -122.7 | 322.1 | -149.6 | -69.9 | -45.5 | -45.5 | -66.2 | -38.4 |
| Depreciation and amortization | 38.7 | 34.6 | 44.6 | 50.4 | 59.3 | 59.3 | 62.0 | 60.5 |
| Asset impairment charges | 6.7 | -1.2 | 67.9 | 1.7 | 2.0 | 2.0 | 15.3 | 19.7 |
| Stock-based compensation | 42.4 | 55.2 | 17.7 | 23.6 | 29.3 | 29.3 | 27.3 | 31.3 |
| Deferred taxes | -2.5 | -11.7 | -1.2 | -3.4 | -3.0 | -3.0 | -5.6 | -6.6 |
| Change in working capital [+] | -27.8 | 2.6 | -10.5 | 24.5 | -38.2 | 16.7 | -0.8 | -10.9 |
| Accounts receivable | 8.1 | -11.9 | -6.1 | 15.1 | 0.6 | 0.6 | 4.0 | 26.3 |
| Inventories | -51.1 | 7.9 | -9.9 | 18.4 | -34.0 | -34.0 | -17.7 | -20.7 |
| Other current assets | 8.2 | -8.1 | -16.2 | 9.2 | 40.9 | 40.9 | -49.8 | -3.9 |
| Accounts payable | -3.8 | 27.2 | -6.7 | -16.8 | 11.6 | 11.6 | 12.4 | -5.0 |
| Accrued expenses | 10.7 | -12.4 | 28.3 | -1.3 | -57.2 | | 50.3 | -7.7 |
| Deferred revenues | | | | | | -2.4 | | |
| Other operating activities | -4.8 | -353.4 | 11.0 | 4.6 | 0.9 | -53.9 | -5.9 | 1.9 |
| Cash from operations | -70.0 | 48.1 | -20.1 | 31.6 | 4.8 | 4.8 | 26.1 | 57.5 |
| |
| Capital expenditures [+] | -20.9 | -18.8 | -13.6 | -24.0 | -40.7 | -40.7 | -30.9 | -16.6 |
| Purchases of property and equipment | -20.9 | -18.8 | -13.6 | -24.0 | -40.7 | -40.7 | -30.9 | -16.6 |
| Sales of property and equipment | | | | | | | | 0.4 |
| Purchases of intangible assets | | | | | | | | -1.1 |
| Acquisitions | -103.7 | -139.7 | | | | | -34.3 | |
| Purchases of short-term investments, net | -184.1 | | | | | | | |
| Purchases of short-term investments | -384.4 | | | | | | | |
| Sales of short-term investments | 200.3 | | | | | | | |
| Other cash from investing | 0.3 | 419.0 | 1.9 | -0.4 | -1.1 | -1.1 | -5.5 | -4.5 |
| Cash from investing | -308.4 | 260.6 | -11.7 | -24.4 | -41.8 | -41.8 | -70.7 | -21.9 |
| |
| Issuance of common stock, net | | | 24.7 | | | | | |
| Other cash from financing | -13.8 | 405.8 | -44.2 | 16.2 | 14.3 | 14.3 | -9.2 | -3.9 |
| Cash from financing | -13.8 | 405.8 | -19.5 | 16.2 | 14.3 | 14.3 | -9.2 | -3.9 |
| |
| Free cash flow | -90.9 | 29.4 | -33.8 | 7.6 | -35.9 | -35.9 | -4.8 | 40.9 |
| Per share (diluted) | ($0.71) | $0.23 | ($0.29) | $0.07 | ($0.32) | | ($0.04) | $0.37 |
| |
| Cash paid for interest | 0.2 | 1.1 | 2.1 | 3.7 | 0.5 | | 0.5 | 0.8 |
| Cash paid for income taxes | 5.3 | 4.7 | 3.7 | 10.7 | 9.0 | | 6.3 | 11.0 |