| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-05-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 |
| | 10-K | 10-K | 8-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -67.7 | -116.7 | -116.7 | -49.9 | -55.6 | -27.4 | -16.8 | -11.4 |
| Depreciation and amortization | 2.4 | 2.2 | | 2.1 | 1.6 | 0.6 | 0.4 | 0.2 |
| Stock-based compensation | | | | | | 0.7 | 0.4 | 0.1 |
| Change in working capital [+] | 10.5 | 18.8 | | 12.5 | 16.1 | 9.7 | 1.4 | 0.0 |
| Other current assets | | | | | | -0.5 | 0.3 | -0.3 |
| Accounts payable | | | | | | 2.6 | 0.8 | 0.6 |
| Accrued expenses | | | | | | 1.0 | 0.3 | -0.3 |
| Other | 10.5 | 18.8 | | 12.5 | 16.1 | 6.6 | 0.0 | 0.0 |
| Other operating activities | -34.3 | -26.4 | | 26.7 | 35.0 | -10.7 | 16.4 | 0.3 |
| Cash from operations | -89.2 | -122.2 | | -8.6 | -2.9 | -27.1 | 1.7 | -10.8 |
| |
| Capital expenditures | 0.3 | 0.1 | | 0.7 | 3.5 | -0.7 | -2.3 | -0.6 |
| Purchases of property and equipment | 0.3 | 0.1 | | 0.7 | 3.5 | -0.7 | -2.3 | -0.6 |
| Purchases of short-term investments | 24.4 | 152.0 | | 202.2 | 141.8 | | | |
| Purchases of short-term investments | 24.4 | 152.0 | | 202.2 | 141.8 | | | |
| Other cash from investing | 65.0 | -117.7 | | -266.5 | -214.6 | | 6.8 | |
| Cash from investing | 89.7 | 34.4 | | -63.6 | -69.3 | -0.7 | 4.5 | -0.6 |
| |
| Issuance of common stock, net | | 107.6 | | 3.0 | 70.6 | | 0.0 | |
| Other cash from financing | 6.4 | 3.9 | | 1.6 | 0.8 | 88.3 | 22.2 | 10.0 |
| Cash from financing | 6.4 | 111.5 | | 4.7 | 71.4 | 88.3 | 22.2 | 10.0 |
| |
| Free cash flow | -88.8 | -122.1 | | -7.9 | 0.6 | -27.8 | -0.6 | -11.3 |
| Per share (diluted) | ($2.68) | ($3.78) | | ($0.32) | $0.03 | ($26.05) | ($0.63) | ($21.49) |