| 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 | S-1/A |
| Net income | -132.6 | -72.4 | -41.1 | -29.8 | -18.5 | -23.4 | 0.0 |
| Depreciation and amortization | 9.6 | 3.4 | 1.5 | 1.1 | 1.3 | 1.5 | 1.1 |
| Asset impairment charges | | | 0.1 | | 1.3 | 1.0 | |
| Stock-based compensation | 22.4 | 9.7 | 1.6 | 1.3 | 1.2 | 0.4 | 0.1 |
| Deferred taxes | 1.8 | -5.8 | | | | | |
| Change in working capital [+] | -0.1 | 5.9 | -3.4 | 1.8 | 3.2 | -7.4 | -3.0 |
| Accounts receivable | -2.9 | -0.5 | 2.1 | -2.4 | -0.9 | -1.8 | -0.9 |
| Inventories | -23.7 | -15.9 | -4.2 | -3.6 | -0.4 | -0.3 | -0.7 |
| Other current assets | -3.2 | -1.3 | -1.0 | -0.2 | 0.2 | 0.8 | |
| Accounts payable | 1.9 | 6.8 | -1.8 | 1.4 | -1.0 | 1.5 | -0.6 |
| Accrued expenses | 0.4 | 4.0 | 1.5 | -0.1 | -0.2 | -0.1 | |
| Other | 27.3 | 12.9 | | 6.8 | 5.6 | -7.5 | -0.8 |
| Other operating activities | -25.9 | -12.7 | 3.1 | -4.0 | -8.5 | 7.1 | -21.8 |
| Cash from operations | -124.8 | -71.9 | -38.3 | -29.5 | -19.9 | -20.8 | -23.5 |
| |
| Capital expenditures [+] | -2.4 | -0.8 | 0.0 | -0.1 | -0.3 | -1.0 | -1.3 |
| Purchases of property and equipment | -2.4 | -0.8 | | -0.1 | -0.3 | -1.0 | -1.3 |
| Sales of property and equipment | 0.0 | | | | | | |
| Purchases of intangible assets | -0.1 | | | | | | |
| Purchases of short-term investments, net | 139.5 | -226.9 | | | | | |
| Purchases of short-term investments | -84.2 | -313.4 | | | | | |
| Sales of short-term investments | 223.7 | 86.5 | | | | | |
| Other cash from investing | -54.2 | -50.3 | -2.5 | | | | |
| Cash from investing | 82.8 | -278.1 | -2.5 | -0.1 | -0.3 | -1.0 | -1.3 |
| |
| Issuance of common stock, net | 23.1 | 342.7 | 39.9 | 19.6 | 19.4 | | |
| Option exercises | | | | | | 0.0 | |
| Other cash from financing | -0.1 | -6.6 | 22.0 | 10.8 | 16.4 | 17.6 | 25.4 |
| Cash from financing | 23.0 | 336.1 | 61.9 | 30.4 | 35.8 | 17.6 | 25.4 |
| |
| Free cash flow | -127.2 | -72.7 | -38.3 | -29.6 | -20.3 | -21.8 | -24.8 |
| Per share (diluted) | ($0.44) | ($0.26) | ($0.37) | ($1.98) | ($2.86) | ($8.08) | ($0.41) |
| |
| Cash paid for interest | 0.3 | 1.9 | 1.3 | 1.3 | 0.7 | 0.5 | |