| In millions, except per share items | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 7.6 | -4.0 | -4.1 | -21.6 | -9.4 | -10.6 | -18.9 | -23.7 |
| Depreciation and amortization [+] | 41.8 | 21.7 | 15.9 | 13.6 | 12.5 | 12.6 | 10.8 | 7.9 |
| Depreciation | 13.7 | 11.5 | 12.0 | | | | | |
| Amortization | 28.1 | 10.3 | 3.9 | | | | | |
| Asset impairment charges | 0.7 | 1.0 | | | | | | |
| Stock-based compensation | 17.6 | 12.7 | 8.9 | 10.2 | 6.1 | 4.8 | 4.1 | 1.4 |
| Deferred taxes | -16.6 | -15.4 | 0.0 | 0.0 | | | | |
| Change in working capital [+] | -0.3 | 37.0 | -8.3 | 9.2 | 13.0 | 8.8 | 11.8 | 21.9 |
| Accounts receivable | -6.0 | 1.8 | -13.4 | -1.4 | 0.1 | -0.3 | -0.3 | -0.3 |
| Other current assets | -3.7 | 0.3 | -1.5 | 1.0 | -0.8 | -0.6 | -0.6 | -1.2 |
| Accounts payable | -7.4 | 5.0 | -3.3 | 2.9 | 2.0 | -1.4 | -0.6 | 1.9 |
| Accrued expenses | 5.6 | -1.0 | 8.2 | 0.6 | 1.7 | 2.4 | -1.2 | 0.8 |
| Deferred revenues | 11.3 | 6.2 | 2.4 | 7.5 | 5.6 | 8.8 | 14.4 | 20.4 |
| Other | -0.2 | 24.8 | -0.6 | -1.3 | 4.5 | -0.1 | 0.0 | 0.2 |
| Other operating activities | 2.9 | -21.9 | 0.8 | 1.8 | 0.5 | -0.9 | 1.4 | 0.0 |
| Cash from operations | 53.6 | 31.2 | 13.2 | 13.2 | 22.7 | 14.6 | 9.2 | 7.6 |
| |
| Capital expenditures [+] | -13.1 | -17.4 | -6.6 | -9.7 | -14.5 | -9.8 | -13.4 | -13.5 |
| Purchases of property and equipment | -13.1 | -17.4 | -6.6 | -9.7 | -14.5 | -9.8 | -13.4 | -13.5 |
| Sales of property and equipment | 0.9 | 1.3 | 0.0 | 0.3 | | | | |
| Purchases of intangible assets | -5.8 | -1.3 | | | | | | |
| Acquisitions | -144.6 | -69.8 | -11.6 | -1.3 | -15.8 | | -13.4 | -1.9 |
| Sales of short-term investments, net [+] | 2.6 | -4.5 | 1.9 | 18.4 | | 0.0 | -2.5 | -2.7 |
| Purchases of short-term investments | -1.4 | -5.0 | -1.5 | -0.8 | -16.5 | -10.3 | -16.2 | -12.7 |
| Sales of short-term investments | 4.0 | 0.5 | 3.4 | 19.1 | 16.5 | 10.3 | 13.7 | 10.0 |
| Other cash from investing | | | | 0.7 | -0.8 | 0.5 | -0.5 | |
| Cash from investing | -160.0 | -91.7 | -16.3 | 8.3 | -31.1 | -9.3 | -29.8 | -18.2 |
| |
| Issuance of common stock, net | 177.8 | -15.0 | -4.5 | -5.3 | | | | 55.6 |
| Option exercises | 3.8 | 6.0 | 3.6 | 2.3 | 4.2 | 4.7 | 1.1 | 1.0 |
| Other cash from financing | 2.9 | 148.6 | 6.6 | 4.2 | 8.5 | 9.5 | 2.2 | 2.0 |
| Cash from financing | 176.8 | 127.6 | -1.4 | -3.4 | 4.2 | 4.7 | 1.1 | 56.6 |
| |
| Free cash flow | 40.5 | 13.8 | 6.6 | 3.5 | 8.2 | 4.8 | -4.2 | -6.0 |
| Per share (diluted) | $1.20 | $0.50 | $0.24 | $0.13 | $0.31 | $0.18 | ($0.17) | ($0.47) |
| |
| Cash paid for interest | 4.8 | 1.8 | | | | | | |
| Cash paid for income taxes | 0.5 | 0.8 | 1.2 | 1.8 | | | | |