| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -303.1 | -247.6 | -266.8 | -174.2 | -117.0 | -82.5 | -46.4 | -23.8 |
| Depreciation and amortization | 5.9 | 8.3 | 8.6 | 4.6 | 1.7 | 1.2 | 0.9 | 0.7 |
| Stock-based compensation | 78.7 | 71.5 | 45.7 | 30.1 | 13.7 | 9.2 | 3.2 | 0.4 |
| Change in working capital [+] | 39.8 | 44.0 | 26.2 | 4.7 | 8.0 | 4.3 | 23.5 | 8.3 |
| Accounts receivable | -11.3 | -14.9 | -2.6 | | | | | |
| Inventories | -16.1 | -36.8 | -1.3 | | | | | |
| Other current assets | -17.7 | -0.7 | -5.2 | -1.3 | -0.2 | -0.5 | 0.0 | -0.3 |
| Accounts payable | -3.7 | 8.4 | 4.5 | -1.3 | 2.8 | 1.1 | 2.7 | -0.3 |
| Other | 88.7 | 88.0 | 30.8 | 7.3 | 5.3 | 3.7 | 20.8 | 8.9 |
| Other operating activities | -78.1 | -88.1 | -8.1 | -0.6 | 0.7 | 0.1 | -12.2 | -5.6 |
| Cash from operations | -256.8 | -211.9 | -194.4 | -135.4 | -93.0 | -67.7 | -30.9 | -20.1 |
| |
| Capital expenditures [+] | -3.2 | -8.8 | -3.5 | -4.8 | -3.3 | -1.4 | -1.0 | -0.3 |
| Purchases of property and equipment | -3.2 | -8.8 | -3.5 | -4.8 | -3.1 | -1.4 | -1.0 | -0.3 |
| Capitalized product costs | | | | | -0.2 | | | |
| Sales of property and equipment | | | 0.0 | 0.1 | | | | |
| Purchases of short-term investments, net | 15.3 | 326.1 | -73.4 | -179.4 | -31.7 | -105.5 | | |
| Purchases of short-term investments | -50.4 | -57.9 | -434.9 | -361.4 | -127.7 | -105.5 | | |
| Sales of short-term investments | 65.7 | 384.0 | 361.5 | 182.0 | 96.0 | | | |
| Other cash from investing | | | | | | | | -0.1 |
| Cash from investing | 12.1 | 317.3 | -76.9 | -184.2 | -35.0 | -106.9 | -1.0 | -0.4 |
| |
| Issuance of common stock, net | 46.1 | | 219.4 | 396.5 | 232.0 | 117.0 | 126.2 | |
| Option exercises | | | | | | | 2.1 | 0.5 |
| Other cash from financing | 388.2 | 87.1 | 78.7 | 1.4 | 3.2 | 1.1 | 4.2 | 69.8 |
| Cash from financing | 434.3 | 87.1 | 298.2 | 397.9 | 235.2 | 118.1 | 128.3 | 69.3 |
| |
| Free cash flow | -260.0 | -220.6 | -197.9 | -140.2 | -96.1 | -69.1 | -31.9 | -20.4 |
| Per share (diluted) | ($4.13) | ($3.60) | ($3.39) | ($2.74) | ($2.27) | ($2.08) | ($2.49) | ($12.21) |
| |
| Cash paid for interest | 13.9 | 6.3 | | | | | | |