| In millions, except per share items | Dec-31-22 | Dec-05-22 | Dec-31-21 | Dec-05-21 | Dec-31-20 | Dec-31-19 |
| | 10-K | 8-K | 10-K | 8-K | 10-K | 10-K |
| Net income | -147.3 | -147.3 | -101.9 | -101.9 | -25.6 | -19.6 |
| Depreciation and amortization [+] | 3.3 | 3.3 | 1.1 | 1.1 | 0.8 | 0.6 |
| Depreciation | 3.3 | 3.3 | 1.1 | 1.1 | 0.8 | 0.6 |
| Asset impairment charges | | | 0.1 | 0.1 | | |
| Stock-based compensation | 24.2 | 24.2 | 22.2 | 22.2 | 3.8 | 2.2 |
| Change in working capital [+] | 8.8 | 6.2 | -2.5 | -4.0 | -0.3 | 0.4 |
| Accounts receivable | -0.5 | -0.5 | -2.2 | -2.2 | 0.2 | -0.4 |
| Inventories | -2.6 | -2.6 | -0.8 | -0.8 | -0.9 | 0.6 |
| Other current assets | 3.6 | 3.6 | -7.3 | -7.3 | -3.5 | -0.6 |
| Accounts payable | 1.3 | 1.3 | 2.7 | 2.7 | 1.4 | 0.2 |
| Accrued expenses | 5.0 | 5.0 | 3.2 | 3.2 | 2.3 | 0.2 |
| Other | 2.0 | -0.5 | 1.9 | 0.5 | 0.3 | 0.4 |
| Other operating activities | 1.1 | 3.6 | -1.1 | 0.3 | 0.0 | 0.0 |
| Cash from operations | -109.9 | -109.9 | -82.1 | -82.1 | -21.2 | -16.4 |
| |
| Capital expenditures | -7.4 | -7.4 | -3.9 | -3.9 | -0.9 | -0.4 |
| Purchases of property and equipment | -7.4 | -7.4 | -3.9 | -3.9 | -0.9 | -0.4 |
| Purchases of short-term investments, net | 118.3 | 118.3 | -380.2 | -380.2 | | |
| Purchases of short-term investments | -210.2 | -210.2 | -571.9 | -571.9 | | |
| Sales of short-term investments | 328.5 | 328.5 | 191.7 | 191.7 | | |
| Other cash from investing | | | -4.5 | -4.5 | | |
| Cash from investing | 110.9 | 110.9 | -388.6 | -388.6 | -0.9 | -0.4 |
| |
| Option exercises | 0.4 | 0.4 | 0.9 | 0.9 | 0.1 | 0.0 |
| Financing costs | | | | | | -0.1 |
| Other cash from financing | 0.0 | 0.0 | 513.8 | 513.8 | 0.1 | 36.0 |
| Cash from financing | -0.4 | -0.4 | 512.9 | 512.9 | 0.1 | 36.0 |
| |
| Free cash flow | -117.4 | -117.4 | -86.0 | -86.0 | -22.1 | -16.8 |
| Per share (diluted) | ($0.54) | ($0.54) | ($0.43) | ($0.43) | ($0.16) | ($0.15) |
| |