| 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 | 46.9 | 94.9 | 17.8 | -17.8 | -27.6 | -10.8 | -22.4 | -41.9 |
| Depreciation and amortization | 7.4 | 8.9 | 11.3 | 10.0 | 7.9 | 8.5 | 8.3 | 8.7 |
| Asset impairment charges | 0.7 | 0.1 | 1.1 | 1.2 | 1.2 | 2.9 | 2.4 | 2.8 |
| Stock-based compensation | 13.3 | 14.4 | 12.3 | 16.5 | 17.0 | 17.2 | 16.9 | 16.9 |
| Change in working capital [+] | -7.6 | -81.1 | 2.0 | -7.3 | -1.1 | -25.6 | 3.9 | 29.7 |
| Accounts receivable | -10.1 | -10.4 | 2.3 | 0.6 | -6.1 | 12.4 | -8.7 | -3.0 |
| Inventories | 2.0 | -1.8 | 0.5 | -5.6 | -1.5 | -4.7 | 0.5 | -0.8 |
| Other current assets | 1.6 | -2.1 | 1.1 | -0.5 | -2.4 | -2.4 | -0.2 | -0.4 |
| Accounts payable | 0.1 | 2.0 | -2.7 | -0.6 | -0.6 | -0.9 | -0.3 | 1.1 |
| Accrued expenses | -1.3 | -5.6 | 3.9 | -5.9 | 3.1 | -8.9 | 3.1 | 5.4 |
| Deferred revenues | | | | | | | | 14.8 |
| Other | | -63.2 | -3.3 | 4.7 | 6.4 | -21.0 | 9.5 | 12.6 |
| Other operating activities | 5.4 | 12.9 | 10.8 | -3.0 | 0.0 | 22.0 | 9.7 | -12.8 |
| Cash from operations | 66.1 | 50.1 | 55.3 | -0.4 | -2.7 | 14.3 | 18.8 | 3.4 |
| |
| Capital expenditures | -10.8 | -5.2 | -3.6 | -4.3 | -2.8 | -5.7 | -4.9 | -3.5 |
| Purchases of property and equipment | -10.8 | -5.2 | -3.6 | -4.3 | -2.8 | -5.7 | -4.9 | -3.5 |
| Purchases of intangible assets | | | | | | | -1.5 | |
| Acquisitions | | | | | | | -4.4 | |
| Purchases of short-term investments, net | 21.9 | -32.9 | 8.8 | 4.1 | -3.1 | 0.6 | -85.6 | |
| Purchases of short-term investments | -55.4 | -128.6 | -58.0 | -71.6 | -86.8 | -87.4 | -126.2 | |
| Sales of short-term investments | 77.3 | 95.7 | 66.8 | 75.7 | 83.7 | 88.0 | 40.6 | |
| Other cash from investing | | | | | -1.0 | | | |
| Cash from investing | 11.1 | -38.1 | 5.2 | -0.3 | -6.9 | -5.1 | -96.4 | -3.5 |
| |
| Cash dividends paid | -15.9 | -3.9 | | | | | | |
| Repurchase of common stock, net | -79.3 | -18.3 | -32.5 | | | -3.1 | -1.8 | 6.0 |
| Option exercises | 7.0 | 5.8 | 9.6 | 5.8 | 3.7 | 12.2 | 10.3 | |
| Other cash from financing | 14.1 | 11.5 | 19.2 | 11.6 | 7.3 | 23.7 | 20.6 | 0.3 |
| Cash from financing | -88.1 | -16.4 | -22.9 | 5.8 | 3.6 | 8.4 | 8.4 | 6.3 |
| |
| Free cash flow | 55.3 | 44.9 | 51.7 | -4.8 | -5.5 | 8.6 | 13.9 | -0.1 |
| Per share (diluted) | $0.71 | $0.56 | $0.65 | ($0.06) | ($0.08) | $0.12 | $0.21 | $0.00 |
| |
| Cash paid for interest | | 0.0 | 0.0 | 0.3 | 0.1 | 0.1 | 0.2 | 0.2 |
| Cash paid for income taxes | 1.7 | 0.2 | 1.0 | 0.9 | 0.5 | 1.1 | 0.6 | 1.0 |