| 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 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 27.0 | 20.7 | 13.7 | 17.3 | 14.5 | 5.3 | 5.9 |
| Depreciation and amortization [+] | 4.0 | 3.9 | 3.7 | 2.8 | 2.1 | 0.8 | 0.9 |
| Depreciation | 2.0 | 2.0 | 1.9 | 1.2 | 0.9 | 0.8 | 0.5 |
| Amortization of intangible assets | 2.0 | 1.8 | 1.8 | 1.6 | 1.2 | | 0.4 |
| Asset impairment charges | | | | | 0.6 | | |
| Stock-based compensation | 1.0 | 1.4 | 1.5 | 1.2 | 1.2 | 0.4 | 0.3 |
| Change in working capital [+] | 1.1 | 0.2 | -4.8 | 3.4 | -0.2 | 3.8 | -1.3 |
| Accrued expenses | 3.4 | 2.8 | -3.6 | 15.4 | 0.6 | 2.8 | -1.1 |
| Other | -2.3 | -2.6 | -1.2 | -12.0 | -0.8 | 1.0 | -0.2 |
| Other operating activities | 6.5 | -15.8 | -4.1 | -17.7 | -11.9 | -0.9 | 0.5 |
| Cash from operations | 39.6 | 10.4 | 10.0 | 7.0 | 6.2 | 9.3 | 6.3 |
| |
| Capital expenditures | -0.8 | -1.3 | -3.2 | -1.4 | -1.0 | -0.4 | -0.2 |
| Purchases of property and equipment | -0.8 | -1.3 | -3.2 | -1.4 | -1.0 | -0.4 | -0.2 |
| Purchases of short-term investments, net | -17.8 | -60.0 | 10.0 | 12.6 | -4.0 | 6.5 | 9.6 |
| Purchases of short-term investments | -28.9 | -91.0 | -21.2 | -16.9 | -41.4 | -1.2 | |
| Sales of short-term investments | 11.1 | 31.0 | 31.2 | 29.5 | 37.4 | 7.7 | 9.6 |
| Other cash from investing | 72.5 | 1.0 | -80.5 | -10.3 | -6.3 | 84.3 | -42.1 |
| Cash from investing | 53.9 | -60.4 | -73.7 | 0.9 | -11.3 | 90.4 | -32.7 |
| |
| Cash dividends paid | -2.0 | | | | | | |
| Issuance of common stock, net | 46.2 | -11.6 | -18.3 | -11.0 | 66.8 | 34.8 | -0.9 |
| Option exercises | | | | | | | 0.4 |
| Other cash from financing | -340.6 | 141.8 | 85.9 | -25.1 | 12.0 | -13.4 | 48.2 |
| Cash from financing | -296.4 | 130.3 | 67.6 | -36.1 | 78.7 | 21.4 | 46.9 |
| |
| Free cash flow | 38.8 | 9.1 | 6.8 | 5.6 | 5.2 | 9.0 | 6.1 |
| Per share (diluted) | $2.95 | $0.84 | $0.57 | $0.47 | $0.54 | $1.37 | $1.12 |
| |
| Cash paid for interest | 10.2 | 9.0 | 9.2 | 7.5 | 4.9 | 4.2 | 3.1 |
| Cash paid for income taxes | 7.6 | 7.1 | 8.1 | 5.1 | 5.4 | 3.8 | |