| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | S-1/A |
| Net income | -29.2 | -33.9 | -32.8 | -26.8 | -25.6 | -12.9 |
| Depreciation and amortization [+] | | | 0.0 | 0.0 | 0.0 | 0.0 |
| Depreciation | | | 0.0 | 0.0 | 0.0 | 0.0 |
| Stock-based compensation | | | 2.4 | 1.1 | 0.5 | 0.2 |
| Change in working capital [+] | | | 1.1 | 1.6 | -0.6 | 0.8 |
| Accounts receivable | | | | -0.4 | -0.1 | 0.0 |
| Other current assets | | | 0.7 | | | |
| Accounts payable | | | 0.4 | 0.8 | 0.1 | 0.1 |
| Accrued expenses | | | -0.1 | 1.4 | 0.8 | |
| Other | | | | -0.2 | -1.3 | 0.7 |
| Other operating activities | 1.0 | 5.0 | 0.2 | 0.9 | 7.4 | 3.9 |
| Cash from operations | -28.2 | -28.9 | -29.0 | -23.1 | -18.3 | -8.0 |
| |
| Capital expenditures | 0.2 | 0.0 | 0.0 | 0.0 | -0.2 | 0.0 |
| Purchases of property and equipment | 0.2 | | 0.0 | 0.0 | -0.2 | 0.0 |
| Purchases of short-term investments | 126.2 | | | | | |
| Purchases of short-term investments | 126.2 | | | | | |
| Other cash from investing | -233.7 | | | | | |
| Cash from investing | -107.4 | 0.0 | 0.0 | 0.0 | -0.2 | 0.0 |
| |
| Issuance of common stock, net | | | | 65.1 | | |
| Option exercises | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Financing costs | | | -0.1 | | | |
| Other cash from financing | 111.4 | 20.8 | 16.7 | 8.2 | 3.6 | 21.7 |
| Cash from financing | 111.3 | 20.8 | 16.7 | 73.2 | 3.6 | 21.7 |
| |
| Free cash flow | -28.0 | -28.9 | -29.0 | -23.1 | -18.4 | -8.0 |
| Per share (diluted) | ($0.43) | ($1.27) | ($1.61) | ($1.97) | ($42.15) | ($18.51) |
| |
| Cash paid for interest | 0.6 | 0.6 | 0.2 | | 0.2 | |