| 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 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -93.0 | -97.9 | -52.5 | -40.0 | -29.4 | -45.0 | -52.0 | -122.6 |
| Depreciation and amortization | 2.0 | 0.5 | 0.5 | 0.5 | 0.6 | 0.7 | 0.8 | 1.0 |
| Asset impairment charges | | | | | | | 1.2 | 1.3 |
| Stock-based compensation | 10.0 | 4.7 | 4.3 | 5.2 | 6.4 | 5.7 | 13.3 | 14.8 |
| Change in working capital [+] | -7.9 | 7.9 | -2.4 | -5.9 | 0.8 | -12.8 | 0.5 | 6.6 |
| Accounts receivable | -15.4 | | | | | 0.4 | -0.2 | 1.6 |
| Inventories | -0.7 | | | | | 1.1 | 0.6 | -0.4 |
| Other current assets | 0.5 | 2.3 | 2.3 | 1.1 | -0.2 | 0.3 | 1.6 | -0.4 |
| Accounts payable | | | | | | -4.7 | -3.0 | 4.4 |
| Accrued expenses | | | | | | -11.1 | 2.6 | 2.4 |
| Deferred revenues | | | | | | | -1.1 | -0.9 |
| Other | 7.7 | 5.6 | -4.7 | -7.0 | 0.9 | 1.2 | 0.0 | 0.0 |
| Other operating activities | 7.7 | -0.1 | 7.8 | 12.4 | -18.1 | 12.1 | -40.6 | 3.6 |
| Cash from operations | -81.2 | -84.9 | -42.2 | -27.8 | -39.8 | -39.3 | -76.7 | -95.2 |
| |
| Capital expenditures | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | -0.1 | -0.1 |
| Purchases of property and equipment | | | 0.0 | | 0.0 | 0.0 | -0.1 | -0.1 |
| Purchases of intangible assets | -25.0 | | | | | | | |
| Purchases of short-term investments, net | -48.9 | 12.0 | -9.6 | 28.1 | -30.5 | 0.0 | | |
| Purchases of short-term investments | -88.9 | | -12.1 | -11.0 | -42.1 | | | |
| Sales of short-term investments | 40.0 | 12.0 | 2.5 | 39.2 | 11.6 | 0.0 | | |
| Cash from investing | -73.9 | 12.0 | -9.6 | 28.1 | -30.5 | 0.0 | -0.1 | -0.1 |
| |
| Issuance of common stock, net | | | | | 64.2 | 0.0 | | 15.1 |
| Option exercises | 4.9 | 0.4 | 0.1 | 0.0 | 0.1 | 0.0 | | |
| Other cash from financing | 125.0 | 98.3 | 61.2 | -5.6 | -0.6 | 39.0 | -7.4 | 136.9 |
| Cash from financing | 120.0 | 97.9 | 61.1 | -5.6 | 63.5 | 39.0 | -7.4 | 152.0 |
| |
| Free cash flow | -81.2 | -84.9 | -42.2 | -27.8 | -39.9 | -39.3 | -76.8 | -95.3 |
| Per share (diluted) | ($0.71) | ($0.94) | ($0.59) | ($0.48) | ($0.71) | ($1.08) | ($2.75) | ($5.06) |
| |
| Cash paid for interest | 6.1 | 2.0 | 0.5 | 1.0 | 1.2 | 2.0 | 4.4 | 2.1 |