| In millions, except per share items | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -74.8 | -36.3 | -31.3 | -26.8 | -61.1 | -36.2 | -2.9 | -5.4 |
| Depreciation and amortization [+] | 0.2 | 0.1 | 0.1 | 0.2 | 0.4 | 0.2 | 0.3 | 0.3 |
| Depreciation | 0.2 | 0.1 | 0.1 | 0.2 | 0.4 | 0.2 | 0.3 | 0.3 |
| Asset impairment charges | | | | | 1.7 | | | |
| Stock-based compensation | 5.0 | 3.3 | 2.7 | 3.5 | 3.3 | 3.3 | 0.8 | 0.7 |
| Deferred taxes | 0.0 | 0.0 | 0.0 | -0.9 | 0.0 | 0.0 | 0.0 | -0.1 |
| Change in working capital [+] | -5.1 | 17.0 | 4.8 | -0.8 | 4.7 | -1.0 | -10.1 | 8.5 |
| Accounts receivable | -0.5 | | | | | | | |
| Inventories | -10.9 | | | | | | | |
| Other current assets | -2.4 | -1.4 | 0.5 | 0.8 | 0.7 | -1.7 | 0.1 | 0.2 |
| Accounts payable | | | | | | | | 1.0 |
| Accrued expenses | | | | | | | | 4.4 |
| Deferred revenues | | | | | | | -2.9 | 2.9 |
| Other | 8.7 | 18.4 | 4.3 | -1.6 | 4.0 | 0.7 | -7.3 | 0.1 |
| Other operating activities | -0.7 | -19.0 | -0.4 | 0.4 | -1.0 | 0.5 | 5.5 | 42.0 |
| Cash from operations | -75.3 | -35.0 | -24.1 | -24.4 | -52.0 | -33.3 | -6.4 | 46.2 |
| |
| Capital expenditures [+] | -0.4 | -0.3 | 0.0 | 0.0 | -3.0 | -0.3 | 0.0 | 0.0 |
| Purchases of property and equipment | -0.4 | -0.3 | 0.0 | 0.0 | -3.0 | -0.3 | | 0.0 |
| Sales of property and equipment | | | | | 0.1 | 0.0 | 0.1 | 0.0 |
| Purchases of short-term investments, net | -55.5 | -35.4 | 24.2 | 3.7 | 51.9 | -107.7 | | |
| Purchases of short-term investments | -145.3 | -99.7 | -38.0 | -89.2 | -117.1 | -108.2 | | |
| Sales of short-term investments | 89.9 | 64.4 | 62.2 | 92.9 | 169.0 | 0.5 | | |
| Other cash from investing | | | | | | -1.1 | 0.0 | 0.0 |
| Cash from investing | -55.8 | -35.7 | 24.2 | 3.7 | 49.0 | -109.1 | 0.1 | 0.0 |
| |
| Issuance of common stock, net | | | | | | 106.5 | | |
| Option exercises | 0.3 | 0.1 | 0.0 | 0.0 | 0.6 | 0.7 | 0.0 | 0.0 |
| Other cash from financing | 139.6 | 85.5 | -1.6 | -1.7 | -0.5 | 37.5 | 33.6 | -51.8 |
| Cash from financing | 139.3 | 85.5 | -1.7 | -1.7 | -1.1 | 143.3 | 33.6 | -51.8 |
| |
| Free cash flow | -75.7 | -35.3 | -24.1 | -24.4 | -54.9 | -33.6 | -6.4 | 46.2 |
| Per share (diluted) | ($1.45) | ($1.03) | ($0.99) | ($1.00) | ($2.26) | ($3.01) | ($145.42) | $1,079.77 |
| |
| Cash paid for interest | | | | | | | | 0.9 |
| Cash paid for income taxes | 0.2 | 0.4 | 0.3 | 0.1 | 0.1 | | | |