| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 |
| | 8-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 30.4 | 65.8 | 46.5 | -8.6 | -5.5 | -13.5 |
| Depreciation and amortization | 1.6 | 1.3 | 1.9 | 2.1 | 1.9 | 1.6 |
| Stock-based compensation | 100.7 | 33.7 | 12.8 | 5.1 | 3.0 | 1.6 |
| Deferred taxes | -6.6 | -33.3 | -38.0 | 0.0 | -1.8 | 0.0 |
| Change in working capital [+] | -58.4 | -48.0 | 6.7 | -19.6 | 0.3 | -1.1 |
| Accounts receivable | -119.3 | -68.7 | -35.3 | -25.3 | -12.8 | -2.0 |
| Other current assets | 0.1 | 0.7 | -0.3 | -4.1 | -0.2 | -0.2 |
| Accounts payable | 47.7 | 17.8 | 25.0 | 3.5 | 10.4 | -0.9 |
| Accrued expenses | | 2.2 | 17.4 | 6.4 | 2.8 | 2.0 |
| Other | 13.1 | | | | | |
| Other operating activities | 12.7 | 6.5 | 6.2 | 19.4 | 4.5 | 2.1 |
| Cash from operations | 80.4 | 26.0 | 36.2 | -1.5 | 2.3 | -9.4 |
| |
| Capital expenditures | -3.2 | -2.1 | -1.0 | -3.0 | -0.6 | -0.6 |
| Purchases of property and equipment | -3.2 | -2.1 | -1.0 | -3.0 | -0.6 | -0.6 |
| Purchases of short-term investments, net | -40.6 | 10.9 | -39.0 | | | |
| Purchases of short-term investments | -163.3 | -111.5 | -104.0 | | | |
| Sales of short-term investments | 122.7 | 122.4 | 65.0 | | | |
| Other cash from investing | | | | 0.2 | 2.5 | |
| Cash from investing | -43.9 | 8.8 | -40.0 | -2.8 | 1.9 | -0.6 |
| |
| Issuance of common stock, net | | | | 81.0 | -1.2 | |
| Option exercises | 3.1 | 2.9 | 2.3 | 6.5 | 0.1 | 0.0 |
| Other cash from financing | -4.8 | -10.8 | -3.9 | 10.0 | -7.5 | 11.8 |
| Cash from financing | -7.9 | -13.7 | -6.2 | 84.5 | -8.7 | 11.8 |
| |
| Free cash flow | 77.2 | 23.9 | 35.2 | -4.5 | 1.7 | -10.0 |
| Per share (diluted) | $0.77 | $0.24 | $0.36 | ($0.22) | $0.31 | ($1.77) |
| |
| Cash paid for interest | | | | 0.2 | 0.5 | 0.5 |
| Cash paid for income taxes | 0.1 | 0.1 | | | | |