| 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 | -32.7 | -30.9 | -34.1 | -32.1 | -25.9 | -19.8 | -14.4 | -21.3 |
| Depreciation and amortization | 0.7 | 0.8 | 0.8 | 0.7 | 0.5 | 0.8 | 0.8 | 1.0 |
| Stock-based compensation | 0.9 | 0.5 | 5.0 | 4.4 | 7.2 | 10.3 | 8.9 | 10.1 |
| Change in working capital [+] | 3.9 | 6.8 | 9.2 | 6.0 | -22.3 | -0.7 | -3.4 | 20.0 |
| Accounts receivable | -1.7 | 0.0 | 2.8 | -0.6 | -1.0 | -1.2 | -0.6 | 0.1 |
| Inventories | -0.7 | -1.3 | 0.3 | -0.8 | 0.3 | -6.1 | -4.0 | -1.1 |
| Accounts payable | -0.4 | 1.1 | -1.5 | 0.3 | -1.6 | 1.9 | -1.3 | -3.4 |
| Deferred revenues | | | | | | -2.1 | -2.1 | 19.5 |
| Other | 6.7 | 6.9 | 7.6 | 7.2 | -20.0 | 6.8 | 4.5 | 4.9 |
| Other operating activities | -6.4 | -6.8 | -8.1 | 0.7 | 19.4 | -3.1 | -5.2 | -5.5 |
| Cash from operations | -33.5 | -29.6 | -27.3 | -20.4 | -21.1 | -12.5 | -13.3 | 4.3 |
| |
| Capital expenditures [+] | -0.5 | -1.0 | -0.6 | -0.7 | -1.7 | -0.4 | -0.8 | -0.7 |
| Purchases of property and equipment | -0.5 | -1.0 | -0.6 | -0.7 | -1.7 | -0.4 | -0.8 | -0.7 |
| Sales of property and equipment | | | | 0.0 | 0.0 | 0.0 | 0.0 | |
| Sales of short-term investments, net [+] | 0.8 | 4.3 | -3.4 | 33.9 | 51.9 | 50.3 | 23.3 | -8.1 |
| Purchases of short-term investments | -26.1 | -29.3 | -41.7 | | | 25.8 | 21.8 | -13.1 |
| Sales of short-term investments | 26.9 | 33.6 | 38.3 | 33.9 | 51.9 | 24.5 | 1.5 | 5.0 |
| Other cash from investing | | | -0.8 | -20.4 | -35.7 | -51.6 | -43.6 | |
| Cash from investing | 0.3 | 3.2 | -4.8 | 12.7 | 14.5 | -1.6 | -21.1 | -8.8 |
| |
| Issuance of common stock, net | | | | | 0.1 | | | |
| Option exercises | 0.1 | | 0.1 | 0.1 | | | | |
| Financing costs | | -1.3 | | | | | | |
| Other cash from financing | -2.1 | 62.0 | 21.2 | 22.1 | -2.3 | 0.1 | -0.1 | 58.5 |
| Cash from financing | -2.2 | 63.3 | 21.1 | 22.0 | -2.2 | 0.1 | -0.1 | 58.5 |
| |
| Free cash flow | -34.1 | -30.7 | -27.8 | -21.2 | -22.8 | -12.8 | -14.1 | 3.6 |
| Per share (diluted) | ($0.36) | ($0.41) | ($0.46) | ($0.40) | ($0.45) | ($0.25) | ($0.28) | $0.09 |
| |
| Cash paid for interest | 1.8 | 1.6 | | | | | | 3.5 |
| Cash paid for income taxes | | | | | | 0.4 | | |