| 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 | -280.3 | 127.8 | -111.3 | -94.7 | 99.9 | -73.2 | -63.0 | -23.8 |
| Depreciation and amortization | 12.9 | 9.6 | 8.4 | 7.2 | 4.0 | 2.7 | 0.5 | 0.1 |
| Stock-based compensation | | | | 26.9 | 16.6 | 10.6 | 7.0 | 2.9 |
| Change in working capital [+] | 103.0 | -2.6 | 66.2 | 43.2 | -18.8 | 26.4 | 33.5 | 10.4 |
| Accounts receivable | | | | -8.6 | -16.8 | 0.6 | 1.1 | -0.3 |
| Other current assets | | | | -0.5 | -2.1 | -0.4 | -0.2 | -0.9 |
| Accounts payable | 18.8 | -2.3 | 3.9 | 1.5 | -0.2 | 2.6 | 0.2 | 0.6 |
| Accrued expenses | -25.6 | 29.9 | 17.4 | 6.9 | 7.6 | 1.9 | 3.9 | 2.2 |
| Deferred revenues | -1.2 | -0.9 | | -0.6 | 3.9 | | | |
| Other | 111.0 | -29.3 | 45.0 | 44.5 | -11.2 | 21.7 | 28.5 | 8.7 |
| Other operating activities | -43.1 | 84.1 | -17.4 | -90.1 | 2.9 | -24.5 | -26.7 | -12.1 |
| Cash from operations | -207.5 | 218.9 | -54.1 | -107.7 | 104.6 | -58.0 | -48.6 | -22.5 |
| |
| Capital expenditures | 30.7 | 84.2 | 26.9 | -11.7 | -13.3 | -7.2 | -8.1 | -0.5 |
| Purchases of property and equipment | 30.7 | 84.2 | 26.9 | -11.7 | -13.3 | -7.2 | -8.1 | -0.5 |
| Purchases of short-term investments, net | 185.4 | 503.7 | 160.0 | 99.3 | 625.6 | 1.6 | 27.5 | -163.3 |
| Purchases of short-term investments | 184.9 | 498.1 | 123.0 | -190.7 | 445.8 | -68.6 | -45.1 | -163.3 |
| Sales of short-term investments | 0.5 | 5.6 | 36.9 | 290.0 | 179.7 | 70.2 | 72.6 | |
| Other cash from investing | -228.1 | -994.6 | -64.1 | 6.0 | -891.7 | 0.8 | 0.0 | |
| Cash from investing | -11.9 | -406.6 | 122.8 | 93.6 | -279.4 | -4.8 | 19.4 | -163.8 |
| |
| Issuance of common stock, net | | | | | | | | 145.2 |
| Option exercises | 2.8 | 4.3 | 5.6 | 7.1 | 14.5 | 2.5 | 0.2 | 0.1 |
| Other cash from financing | -26.0 | 199.5 | 205.8 | 15.4 | 218.9 | 87.1 | 0.3 | 94.2 |
| Cash from financing | -28.8 | 195.3 | 200.2 | 8.4 | 204.4 | 84.6 | 0.1 | 239.3 |
| |
| Free cash flow | -176.8 | 303.1 | -27.2 | -119.4 | 91.4 | -65.2 | -56.7 | -23.0 |
| Per share (diluted) | ($4.10) | $6.90 | ($0.73) | ($3.25) | $2.49 | ($2.18) | ($2.15) | ($2.51) |
| |
| Cash paid for interest | | | | | | | | 0.0 |
| Cash paid for income taxes | 11.8 | 6.0 | -0.2 | 0.9 | 3.4 | | | |