| 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 |
| Revenues | 699.0 | 502.0 | 383.9 | 304.0 | 242.7 | 188.2 | 147.0 | 115.9 |
| Revenues growth | 39.2% | 30.8% | 26.3% | 25.3% | 28.9% | 28.1% | 26.8% | 38.3% |
| Cost of Revenue | 594.6 | 420.1 | 319.0 | 252.6 | 199.6 | 21.4 | 18.4 | 96.0 |
| Technology and Development Expense | 16.9 | 9.9 | 7.0 | 5.8 | 9.8 | 9.5 | 11.2 | 9.9 |
| General and Administrative Expense | 31.9 | 21.8 | 18.4 | 17.1 | 16.8 | 15.2 | 15.6 | 14.3 |
| Selling and Marketing Expense | 78.6 | 47.8 | 35.5 | 25.0 | 19.1 | 15.2 | 15.2 | 11.6 |
| Depreciation, Depletion and Amortization | 12.0 | 7.1 | 5.6 | 4.5 | | | | |
| Operating Expenses | 139.4 | 86.7 | 66.5 | 52.4 | 45.7 | 40.0 | 42.0 | 35.8 |
| Income (Loss) from Equity Method Investments | -0.2 | -0.1 | -0.4 | | | | | |
| Operating Income (Loss), Total | -35.2 | -4.9 | -1.9 | -1.0 | -2.6 | -6.7 | -16.8 | -15.9 |
| Operating margin | -5.0% | -1.0% | -0.5% | -0.3% | -1.1% | -3.6% | -11.4% | -13.8% |
| Interest Expense | 0.0 | -1.4 | -1.3 | -1.2 | -0.5 | -0.2 | -0.3 | -6.7 |
| Other Nonoperating Income (Expense) | 0.0 | -0.6 | -1.6 | -1.3 | -1.2 | -0.1 | 0.0 | -1.5 |
| Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest | -35.2 | -5.7 | -1.6 | -0.9 | -1.9 | -6.9 | -17.1 | -21.2 |
| Income Tax Expense (Benefit) | 0.3 | 0.1 | 0.2 | 0.0 | -0.4 | 0.0 | 0.1 | 0.0 |
| Net Income (Loss) Available to Common Stockholders, Basic, Total | -35.5 | -5.8 | -1.8 | -0.9 | -1.5 | -6.9 | -17.2 | -21.2 |
| |
| Earnings Per Share, Basic and Diluted [Abstract] | | | | | | | | |
| Earnings Per Share, Basic | ($0.89) | ($0.16) | ($0.05) | ($0.03) | ($0.05) | ($0.24) | ($0.62) | ($1.64) |
| Earnings Per Share, Diluted | ($0.89) | ($0.16) | ($0.05) | ($0.03) | ($0.05) | ($0.24) | ($0.62) | ($1.64) |
| |
| Weighted Average Number of Shares Outstanding, Basic | 40.1 | 35.9 | 34.6 | 32.0 | 29.6 | 28.5 | 27.6 | 12.9 |
| Weighted Average Number of Shares Outstanding, Diluted | 40.1 | 35.9 | 34.6 | 32.0 | 29.6 | 28.5 | 27.6 | 12.9 |