| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 20-F | 20-F |
| Net income | -66.8 | -85.5 | -55.2 | -28.3 | 0.0 | 0.0 |
| Depreciation and amortization [+] | 1.2 | 1.2 | 0.9 | 0.6 | | |
| Amortization of intangible assets | 0.2 | 0.3 | 0.2 | 0.1 | | |
| Stock-based compensation | 17.1 | 9.4 | 7.8 | 9.8 | | |
| Deferred taxes | 0.0 | -0.1 | -0.1 | -0.2 | | |
| Change in working capital [+] | 6.8 | 5.2 | 2.9 | -4.6 | | |
| Accounts receivable | -5.0 | 1.1 | 0.6 | -1.6 | | |
| Other current assets | -1.1 | -2.9 | -1.0 | -2.8 | | |
| Accounts payable | 10.7 | -0.1 | 0.0 | -0.1 | | |
| Accrued expenses | 2.1 | 7.0 | 3.3 | 0.0 | | |
| Other operating activities | -17.9 | -10.0 | -19.5 | -23.4 | | |
| Cash from operations | -59.6 | -79.9 | -63.0 | -46.1 | | |
| |
| Capital expenditures | -0.9 | -1.3 | -2.2 | -1.8 | | |
| Purchases of property and equipment | -0.9 | -1.3 | -2.2 | -1.8 | | |
| Purchases of intangible assets | | | -0.4 | -2.5 | | |
| Purchases of short-term investments, net | -145.8 | -0.2 | 26.8 | -20.8 | | |
| Purchases of short-term investments | -215.8 | -66.8 | -60.4 | -89.7 | | |
| Sales of short-term investments | 70.1 | 66.6 | 87.2 | 68.9 | | |
| Cash from investing | -146.6 | -1.5 | 24.2 | -25.2 | | |
| |
| Issuance of common stock, net | 248.3 | 38.1 | 74.2 | 62.0 | | |
| Option exercises | 17.4 | 1.4 | 0.0 | 1.0 | | |
| Other cash from financing | 51.0 | 2.9 | 0.1 | 2.1 | | |
| Cash from financing | 282.0 | 39.5 | 74.2 | 63.0 | | |
| |
| Free cash flow | -60.5 | -81.2 | -65.3 | -47.9 | | |
| Per share (diluted) | ($1.57) | ($2.78) | ($2.70) | ($2.15) | | |
| |
| Cash paid for income taxes | -0.6 | -0.3 | -0.3 | | | |