| In millions, except per share items | 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 |
| Net income | -148.9 | -72.4 | -35.9 | -20.7 | 0.0 |
| Depreciation and amortization [+] | 0.2 | 0.6 | 0.4 | 0.0 | |
| Depreciation | 0.1 | 0.1 | 0.0 | 0.0 | |
| Amortization of intangible assets | 0.1 | 0.5 | 0.4 | 0.0 | |
| Stock-based compensation | 19.4 | 8.0 | 6.2 | 3.0 | |
| Change in working capital [+] | 237.0 | 12.5 | -0.9 | -0.1 | |
| Accounts payable | 2.9 | 0.8 | 0.0 | 0.0 | |
| Deferred revenues | 228.7 | | | | |
| Other | 5.4 | 11.7 | -0.9 | -0.1 | |
| Other operating activities | | | | 0.0 | |
| Cash from operations | 107.8 | -51.3 | -30.2 | -17.7 | 0.0 |
| |
| Capital expenditures | -0.8 | -0.2 | -0.1 | 0.0 | 0.0 |
| Purchases of property and equipment | -0.8 | -0.2 | -0.1 | 0.0 | |
| Purchases of short-term investments, net | -373.4 | -26.3 | -17.1 | -69.1 | |
| Purchases of short-term investments | -574.5 | -163.3 | -133.7 | -74.6 | |
| Sales of short-term investments | 201.1 | 137.0 | 116.6 | 5.5 | |
| Cash from investing | -374.2 | -26.5 | -17.2 | -69.1 | 0.0 |
| |
| Issuance of common stock, net | 375.3 | 38.7 | 71.3 | 74.2 | |
| Option exercises | 2.7 | 1.3 | 0.3 | 0.2 | |
| Financing costs | | | | -1.8 | |
| Other cash from financing | 5.5 | 2.5 | 0.6 | 39.9 | |
| Cash from financing | 378.0 | 40.0 | 71.6 | 115.7 | 0.0 |
| |
| Free cash flow | 107.0 | -51.6 | -30.3 | -17.7 | 0.0 |
| Per share (diluted) | $3.82 | ($2.47) | ($1.79) | ($2.61) | |