| 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 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -56.6 | -56.0 | -101.3 | -86.0 | -75.5 | 6.5 | -13.7 |
| Depreciation and amortization | 4.8 | 6.0 | 10.2 | 10.7 | 5.3 | 3.7 | 2.1 |
| Asset impairment charges | | 9.1 | | | | | |
| Stock-based compensation | 48.5 | 38.0 | 35.2 | 22.9 | 8.8 | 2.5 | 1.5 |
| Deferred taxes | 0.2 | -0.3 | 0.1 | -0.2 | -1.1 | -0.4 | -0.7 |
| Change in working capital [+] | -23.3 | 22.1 | 4.9 | 97.5 | 26.9 | -75.8 | -36.5 |
| Accounts receivable | 13.5 | -1.7 | 49.8 | 38.2 | -118.8 | -75.8 | -46.3 |
| Inventories | -7.9 | 29.3 | 2.9 | 53.6 | -48.9 | -35.6 | -22.1 |
| Other current assets | 3.4 | -3.5 | 10.4 | 11.5 | -16.6 | 0.1 | -2.5 |
| Accounts payable | -32.5 | 22.2 | -49.3 | 28.8 | 87.3 | -0.4 | 11.5 |
| Other | 0.1 | -24.2 | -8.9 | -34.7 | 123.9 | 36.0 | 23.0 |
| Other operating activities | -19.4 | -42.0 | 4.3 | -35.7 | 17.9 | 24.4 | 14.2 |
| Cash from operations | -46.0 | -23.2 | -46.5 | 9.2 | -17.7 | -39.0 | -33.1 |
| |
| Capital expenditures | -2.0 | -2.3 | -3.9 | -6.7 | -21.7 | -3.6 | -1.5 |
| Purchases of property and equipment | -2.0 | -2.3 | -3.9 | -6.7 | -21.7 | -3.6 | -1.5 |
| Acquisitions | | | | | | -0.7 | -8.8 |
| Purchases of short-term investments, net | -29.8 | 20.0 | -0.1 | 30.2 | -49.6 | | |
| Purchases of short-term investments | -69.3 | | -50.1 | -29.8 | -54.6 | | |
| Sales of short-term investments | 39.5 | 20.0 | 50.0 | 60.0 | 5.0 | | |
| Other cash from investing | | | | 52.7 | | | |
| Cash from investing | -31.8 | 17.7 | -4.0 | 76.3 | -71.3 | -4.3 | -10.3 |
| |
| Issuance of common stock, net | | | | | 173.4 | | |
| Other cash from financing | -13.9 | -5.0 | 0.0 | 0.0 | 70.9 | 43.2 | 43.6 |
| Cash from financing | -13.9 | -5.0 | 0.0 | 0.0 | 244.3 | 43.2 | 43.6 |
| |
| Free cash flow | -48.0 | -25.5 | -50.4 | 2.5 | -39.4 | -42.6 | -34.6 |
| Per share (diluted) | ($0.55) | ($0.31) | ($0.65) | $0.03 | ($0.59) | ($0.68) | ($0.56) |
| |
| Cash paid for income taxes | 0.4 | 1.0 | 5.6 | 1.0 | 0.1 | | |