| 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 |
| | 8-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 0.0 | -164.4 | -157.6 | -306.9 | -273.5 | -276.4 | -279.7 |
| Depreciation and amortization [+] | | 53.5 | 52.3 | 78.6 | 53.9 | 54.4 | 43.1 |
| Depreciation | | 53.5 | 52.3 | 78.6 | 53.9 | 54.4 | 43.1 |
| Asset impairment charges | | | | | | | 2.1 |
| Stock-based compensation | | 73.3 | 73.9 | 196.3 | 168.5 | 29.1 | 28.2 |
| Change in working capital [+] | | 63.4 | -34.2 | 119.6 | -2.4 | -136.4 | -156.0 |
| Accounts receivable | | 8.6 | -61.7 | 52.0 | -55.0 | 3.2 | -0.7 |
| Inventories | | -0.9 | -33.0 | 18.4 | -37.0 | -10.6 | -0.2 |
| Other current assets | | 1.5 | -3.1 | 8.6 | -8.0 | -1.0 | -8.4 |
| Accounts payable | | 13.1 | -0.6 | -11.3 | 18.3 | 7.1 | 4.8 |
| Other | | 41.0 | 64.2 | 51.9 | 79.4 | -135.1 | -151.5 |
| Other operating activities | | -86.3 | -33.2 | 76.1 | -38.4 | 237.3 | 79.5 |
| Cash from operations | | -60.7 | -98.8 | 163.8 | -91.9 | -92.0 | -282.8 |
| |
| Capital expenditures | | -49.8 | -37.9 | -51.1 | -45.2 | -61.5 | -9.0 |
| Purchases of property and equipment | | -49.8 | -37.9 | -51.1 | -45.2 | -61.5 | -9.0 |
| Purchases of intangible assets | | | | | -3.3 | | |
| Sales of short-term investments, net [+] | | | | 104.5 | -76.9 | -26.8 | |
| Purchases of short-term investments | | | | | -103.9 | -29.0 | |
| Sales of short-term investments | | | | 104.5 | 27.0 | 2.3 | |
| Other cash from investing | | 3.1 | | | | | |
| Cash from investing | | -46.7 | -37.9 | 53.4 | -125.4 | -88.2 | -9.0 |
| |
| Issuance of common stock, net | | 89.8 | 23.5 | 12.7 | 1.5 | 2.4 | 3.1 |
| Financing costs | | -2.0 | -13.2 | | | -6.1 | -0.2 |
| Other cash from financing | | 214.6 | 139.3 | -133.0 | 315.7 | 134.4 | 280.1 |
| Cash from financing | | 306.4 | 176.0 | -120.3 | 317.2 | 142.9 | 283.4 |
| |
| Free cash flow | | -110.5 | -136.7 | 112.7 | -137.2 | -153.4 | -291.8 |
| Per share (diluted) | | ($0.64) | ($0.99) | $0.98 | ($2.57) | ($14.97) | ($29.05) |
| |
| Cash paid for interest | | 68.7 | 71.7 | 69.9 | 59.5 | 37.6 | 20.5 |