| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -53.3 | -35.6 | 9.4 | -5.3 | -65.0 | -26.9 | -15.0 | -52.7 |
| Depreciation and amortization | 0.1 | 0.0 | | | | 0.0 | 9.6 | 6.2 |
| Asset impairment charges | | | | | | | 0.4 | |
| Stock-based compensation | 5.1 | 2.4 | 2.4 | 2.5 | 1.1 | 1.0 | 1.1 | 2.8 |
| Change in working capital [+] | -7.8 | 2.7 | -3.1 | 14.5 | -12.5 | 3.3 | -10.4 | -28.3 |
| Restricted cash | | | | | | | 3.0 | 0.6 |
| Accounts receivable | -9.8 | | | -2.6 | 0.6 | 3.6 | -2.3 | -1.4 |
| Inventories | -1.7 | | | | | | | |
| Other current assets | -1.6 | -1.3 | -0.7 | 0.8 | 0.7 | -0.3 | -0.1 | 1.5 |
| Accounts payable | -0.7 | 1.9 | -2.0 | 1.1 | 0.3 | 0.8 | -1.8 | -1.0 |
| Accrued expenses | 4.0 | 0.3 | -0.6 | 0.2 | 0.9 | -0.6 | -1.6 | -0.9 |
| Deferred revenues | | | | | | | 2.9 | -17.6 |
| Other | 1.9 | 1.8 | 0.2 | 15.0 | -15.0 | -0.1 | -10.5 | -9.5 |
| Other operating activities | -1.3 | -7.5 | -11.5 | -36.7 | 57.3 | -8.6 | -3.9 | 17.8 |
| Cash from operations | -57.3 | -38.0 | -2.9 | -25.0 | -19.2 | -31.1 | -18.2 | -54.2 |
| |
| Capital expenditures [+] | 0.0 | -0.4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | -12.9 |
| Purchases of property and equipment | | -0.4 | | | | 0.0 | 0.0 | -12.9 |
| Sales of property and equipment | | | | | | | 1.2 | 0.2 |
| Sales of short-term investments, net [+] | -16.9 | 18.1 | -17.9 | 18.6 | -10.4 | -0.8 | -7.5 | 67.5 |
| Purchases of short-term investments | -28.2 | -36.1 | -17.9 | -6.7 | -34.9 | -29.4 | -19.1 | -42.3 |
| Sales of short-term investments | 11.3 | 54.2 | | 25.3 | 24.5 | 28.7 | 11.6 | 109.8 |
| Cash from investing | -16.9 | 17.7 | -17.9 | 18.6 | -10.4 | -0.8 | -6.3 | 54.7 |
| |
| Issuance of common stock, net | 55.1 | 53.6 | 30.3 | | | | | |
| Option exercises | 0.6 | 0.0 | 0.0 | 0.5 | 0.0 | 0.0 | 0.3 | 0.2 |
| Financing costs | -0.1 | -0.3 | | | -0.1 | -0.1 | | -1.4 |
| Other cash from financing | 28.3 | -1.6 | -4.0 | 16.4 | 29.3 | 20.2 | -0.9 | -0.2 |
| Cash from financing | 82.9 | 52.3 | 26.2 | 15.9 | 29.4 | 20.3 | -1.1 | 1.0 |
| |
| Free cash flow | -57.3 | -38.3 | -2.9 | -25.0 | -19.2 | -31.1 | -18.3 | -67.2 |
| Per share (diluted) | ($1.75) | ($1.79) | ($0.06) | ($1.91) | ($1.81) | ($0.45) | ($0.33) | ($1.28) |
| |
| Cash paid for interest | 2.9 | 1.3 | 2.0 | 2.0 | 2.1 | 1.5 | 2.0 | 2.0 |