| In millions, except per share items | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 |
| | 10-K | 10-K | 10-K | 10-K | 10-K |
| Revenue | 187.7 | 142.2 | 111.1 | 83.5 | |
| Cost of revenue | 59.7 | 42.1 | 31.9 | 20.6 | |
| Gross profit | 128.0 | 100.2 | 79.2 | 62.9 | |
| |
| Operating expenses: | | | | | |
| Sales and marketing | 77.9 | 61.8 | 48.4 | 35.9 | |
| Research and development | 22.0 | 14.0 | 11.2 | 7.6 | |
| General and administrative | 34.7 | 23.1 | 19.4 | 11.5 | |
| Foreign Currency Transaction Gain (Loss), before Tax | 2.4 | 1.1 | 1.8 | | |
| Total operating expenses | 144.5 | 203.8 | 163.0 | 112.1 | |
| Loss from operations | -16.5 | -0.2 | -1.9 | 7.9 | |
| Interest income | 2.5 | 1.6 | 1.0 | 0.8 | |
| Other income (loss) | -0.4 | -0.4 | | | |
| Income (loss) from operations before income taxes | -14.5 | 0.9 | -0.9 | 8.7 | |
| Provision for (benefit from) income taxes | 4.4 | -0.9 | 2.3 | 4.4 | |
| Net loss | -18.8 | 1.8 | -3.2 | 4.3 | |
| |
| Net loss per common share: | | | | | |
| Basic (USD per share) | ($0.45) | $0.04 | ($0.13) | $0.13 | |
| Diluted (USD per share) | ($0.45) | $0.04 | ($0.13) | $0.12 | |
| |
| Weighted average common shares outstanding-basic (shares) | 41.6 | 41.0 | 25.3 | 33.2 | |
| Weighted average common shares outstanding-diluted (shares) | 41.6 | 43.2 | 25.3 | 34.8 | |
| |
| Other comprehensive income (loss): | | | | | |
| Foreign currency translation gain | -0.1 | -0.2 | | | |
| Comprehensive income (loss) | -18.9 | 1.6 | -3.2 | 4.3 | |