| In millions, except per share items | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 |
| | 10-K/A | 10-K/A | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Total revenue | 53.1 | 54.8 | 63.5 | 67.7 | 61.1 | 54.5 | 50.7 | 57.8 |
| Total revenue growth | -3.1% | -13.7% | -6.1% | 10.8% | 12.1% | 7.4% | -12.2% | 1.0% |
| Operating expense: | | | | | | | | |
| Cost of services | 22.8 | 25.3 | 32.4 | 33.6 | 31.7 | 27.4 | 24.9 | 26.5 |
| Sales and marketing | 14.2 | 12.2 | 15.7 | 16.2 | 15.6 | 14.5 | 13.4 | 16.7 |
| General and administrative | 15.9 | 14.8 | 16.2 | 15.0 | 13.9 | 12.2 | 13.6 | 15.8 |
| Depreciation and amortization | 4.6 | 4.4 | 5.7 | 4.3 | 3.2 | 3.8 | 5.5 | 5.8 |
| Transaction costs | 3.4 | | | | | | | |
| Restructuring and other charges | | 0.4 | 1.0 | -1.2 | | 0.4 | 6.6 | 1.8 |
| Total operating expense | 82.4 | 57.2 | 163.2 | 67.9 | 64.5 | 58.4 | 63.8 | 66.6 |
| Operating loss | -29.3 | -2.4 | -17.2 | -0.2 | -3.4 | -4.0 | -13.1 | -8.8 |
| Operating margin | -55.3% | -4.3% | -27.1% | -0.4% | -5.6% | -7.3% | -25.8% | -15.3% |
| Net interest income | 0.2 | 0.0 | 0.0 | -0.1 | 0.1 | 0.2 | 0.4 | 0.7 |
| Loss before income taxes from continuing operations | -6.8 | 0.3 | | | | | | |
| (Loss) income from discontinued operations | 1.4 | 3.2 | | | | | | |
| Gain on sale of business, net of tax | 23.6 | | | | | | | |
| (Loss) income before income taxes | -29.2 | -2.3 | -17.2 | -0.4 | -3.3 | -3.8 | -12.7 | |
| Benefit for income taxes | -22.4 | -2.6 | 0.3 | 1.2 | 0.5 | | | |
| Net (loss) income attributable to common stockholders | 18.2 | 3.6 | -17.5 | -1.5 | -3.8 | -3.8 | -12.7 | -8.2 |
| |
| Net income (loss) per share: | | | | | | | | |
| Basic net (loss) income attributable to common stockholders: | | | | | | | | |
| Continuing operations (in dollars per share) | 0.0 | 0.0 | | | | | | 0.0 |
| Discontinued operations (in dollars per share) | 0.0 | 0.0 | | | | | | |
| |
| Basic net (loss) income per share (in dollars per share) | $0.37 | $0.69 | ($0.50) | ($0.06) | ($0.12) | ($0.11) | ($0.39) | ($0.26) |
| |
| Diluted net (loss) income attributable to common stockholders: | | | | | | | | |
| Continuing operations (in dollars per share) | 0.0 | 0.0 | | | | | | 0.0 |
| Discontinued operations (in dollars per share) | 0.0 | 0.0 | | | | | | |
| Diluted net (loss) income per share (in dollars per share) | $0.36 | $0.68 | ($0.50) | ($0.06) | ($0.12) | ($0.11) | ($0.39) | ($0.26) |
| |
| Weighted average basic shares outstanding (in shares) | 49.4 | 37.6 | 35.2 | 34.8 | 34.4 | 33.7 | 32.7 | 32.0 |
| Weighted average diluted shares outstanding (in shares) | 51.0 | 37.8 | 35.2 | 34.8 | 34.4 | 33.7 | 32.7 | 32.0 |