| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-05-18 | Dec-31-17 | Dec-31-16 |
| | 8-K | 10-K | 10-K | 10-K | 8-K | 10-K | 10-K |
| Net income | -176.6 | -264.8 | -176.9 | -102.8 | -102.8 | -41.3 | -28.7 |
| Depreciation and amortization [+] | | 0.9 | 0.8 | 0.6 | | 0.3 | 0.4 |
| Depreciation | | 0.9 | 0.8 | 0.6 | | 0.3 | 0.4 |
| Stock-based compensation | | 28.3 | 25.2 | 5.2 | | 0.9 | 0.3 |
| Change in working capital [+] | | -4.6 | 21.8 | 2.1 | | 5.4 | 3.2 |
| Other current assets | | 0.2 | -1.5 | -1.3 | | -1.2 | -0.1 |
| Accounts payable | | -2.4 | -2.6 | 4.6 | | 1.8 | 1.6 |
| Accrued expenses | | -2.4 | 26.0 | -1.1 | | 4.8 | 1.7 |
| Other operating activities | | 9.0 | -0.5 | 0.0 | | -5.7 | 1.6 |
| Cash from operations | | -231.2 | -129.6 | -94.9 | | -40.4 | -23.1 |
| |
| Capital expenditures | | -1.6 | -1.4 | -0.9 | | -1.0 | -0.2 |
| Purchases of property and equipment | | -1.6 | -1.4 | -0.9 | | -1.0 | -0.2 |
| Purchases of short-term investments, net | | 141.9 | -126.1 | -147.5 | | -36.9 | -20.0 |
| Purchases of short-term investments | | -329.4 | -497.5 | -233.9 | | -76.8 | -39.1 |
| Sales of short-term investments | | 471.3 | 371.4 | 86.4 | | 39.9 | 19.0 |
| Cash from investing | | 140.3 | -127.5 | -148.4 | | -37.9 | -20.3 |
| |
| Issuance of common stock, net | | | 217.9 | 237.8 | | | |
| Option exercises | | 2.0 | 3.0 | 0.6 | | 0.0 | 0.0 |
| Other cash from financing | | 212.2 | 23.6 | 33.5 | | 82.5 | 43.0 |
| Cash from financing | | 210.2 | 238.5 | 270.6 | | 82.4 | 43.0 |
| |
| Free cash flow | | -232.8 | -131.0 | -95.7 | | -41.4 | -23.4 |
| Per share (diluted) | | ($4.65) | ($2.76) | ($4.32) | | ($19.37) | ($12.79) |
| |
| Cash paid for interest | | 9.1 | 3.3 | 1.6 | | | |