| 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 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 20-F |
| Net income | -150.7 | -144.6 | -152.0 | -163.4 | -230.5 | -39.7 | -19.1 |
| Depreciation and amortization [+] | 2.7 | 2.3 | 2.0 | 1.7 | 1.2 | 0.3 | 0.0 |
| Depreciation | 2.7 | 2.3 | 2.0 | 1.7 | 1.2 | 0.3 | 0.0 |
| Asset impairment charges | | | 5.7 | | | | |
| Stock-based compensation | | | 28.0 | 19.4 | 6.8 | 1.0 | 0.2 |
| Deferred taxes | | | -2.3 | -2.9 | | | |
| Change in working capital [+] | 34.3 | 59.7 | 27.4 | 18.6 | 90.2 | 10.8 | 6.0 |
| Accounts receivable | | | 0.6 | 0.7 | -0.9 | | |
| Other current assets | | | -5.1 | -2.2 | -5.9 | -3.8 | |
| Accounts payable | | | | -6.4 | 14.8 | 1.9 | 0.7 |
| Accrued expenses | | | | 11.4 | 31.7 | 4.7 | 1.5 |
| Other | 34.3 | 59.7 | 31.9 | 15.1 | 50.4 | 7.9 | 3.9 |
| Other operating activities | 37.6 | -42.5 | -35.0 | -39.5 | 34.8 | -4.9 | -1.7 |
| Cash from operations | -76.0 | -125.1 | -126.3 | -166.1 | -97.5 | -32.5 | -14.6 |
| |
| Capital expenditures | 6.5 | 2.3 | -2.7 | -4.4 | -4.0 | -1.6 | -0.2 |
| Purchases of property and equipment | 6.5 | 2.3 | -2.7 | -4.4 | -4.0 | -1.6 | -0.2 |
| Purchases of short-term investments, net | 112.3 | 263.9 | 158.2 | -305.0 | | | |
| Purchases of short-term investments | 112.3 | 263.9 | -123.3 | -414.0 | | | |
| Sales of short-term investments | | | 281.4 | 109.0 | | | |
| Other cash from investing | -28.2 | -298.4 | 1.9 | | | | |
| Cash from investing | 90.6 | -32.2 | 157.4 | -309.4 | -4.0 | -1.6 | -0.2 |
| |
| Issuance of common stock, net | | | | 130.3 | 209.7 | | |
| Option exercises | 0.2 | 3.3 | 3.9 | 5.3 | 0.0 | | |
| Other cash from financing | -0.5 | 161.4 | 7.8 | 32.5 | 145.2 | 115.7 | 18.0 |
| Cash from financing | -0.7 | 158.1 | 3.9 | 157.5 | 354.9 | 115.7 | 18.0 |
| |
| Free cash flow | -69.5 | -122.7 | -128.9 | -170.5 | -101.6 | -34.0 | -14.8 |
| Per share (diluted) | ($0.54) | ($0.99) | ($1.30) | ($1.83) | ($4.50) | ($3.84) | ($2.08) |
| |
| Cash paid for interest | 2.6 | 2.1 | 1.8 | 1.2 | | | |
| Cash paid for income taxes | 0.2 | 1.7 | 1.0 | 1.5 | | | |