| In millions, except per share items | Dec-31-16 | Dec-26-15 | Dec-27-14 | Dec-28-13 | Dec-31-12 | Dec-31-11 | Dec-31-10 | Dec-31-09 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | S-1/A | S-1 |
| Revenue: | | | | | | | | |
| Product | 215.2 | 152.7 | 105.6 | 101.7 | 69.5 | 51.3 | 35.6 | |
| Service | 95.6 | 69.2 | 51.5 | 38.6 | 27.2 | 16.8 | 10.9 | |
| Total revenue | 310.9 | 222.0 | 157.1 | 140.3 | 96.7 | 68.1 | 46.5 | 31.4 |
| Total revenue growth | 40.0% | 41.3% | 12.0% | 45.1% | 42.0% | 46.5% | 48.1% | |
| Cost of revenue: | | | | | | | | |
| Product | 46.0 | 38.9 | 31.0 | 26.1 | 18.0 | 12.5 | 6.1 | |
| Service | 8.8 | 6.9 | 6.4 | 4.7 | 2.2 | 1.9 | 2.2 | |
| Total cost of revenue | 54.8 | 45.8 | 37.4 | 30.8 | 20.3 | 14.4 | 8.4 | |
| Gross profit | 256.1 | 176.2 | 119.7 | 109.5 | 76.4 | 53.7 | 38.1 | |
| Gross margin | 82.4% | 79.4% | 76.2% | 78.0% | 79.0% | 78.8% | 82.0% | |
| |
| Operating expenses: | | | | | | | | |
| Research and development | 68.1 | 49.6 | 42.8 | 42.1 | 17.7 | 12.5 | 12.3 | |
| Sales and marketing | 122.7 | 87.5 | 76.1 | 72.0 | 39.4 | 19.4 | 12.5 | |
| General and administrative | 34.9 | 27.5 | 20.7 | 25.6 | 11.7 | 4.8 | 6.6 | |
| Total operating expenses | 225.6 | 164.6 | 139.6 | 139.7 | 68.8 | 36.7 | 31.4 | |
| Income (loss) from operations | 30.4 | 11.6 | -19.9 | -30.2 | 7.7 | 17.0 | 6.7 | |
| Operating margin | 9.8% | 5.2% | -12.6% | -21.5% | 7.9% | 25.0% | 14.4% | |
| Interest income | 0.9 | 0.4 | 0.3 | 0.1 | 0.1 | 0.0 | 0.0 | |
| Other expense, net | -0.7 | -0.2 | -0.1 | -0.1 | -0.1 | 0.0 | 0.0 | |
| Income (loss) before income tax benefit | 30.6 | 11.9 | -19.7 | -30.2 | 7.7 | 17.0 | | |
| Income tax benefit (provision) | 18.8 | -5.7 | -21.1 | 20.7 | -0.1 | -0.1 | -0.1 | |
| Net income (loss) | 49.4 | 6.2 | -40.8 | -9.5 | 7.5 | 16.9 | 6.6 | |
| |
| Net income (loss) per share: | | | | | | | | |
| Basic (in dollars per share) | $1.40 | $0.18 | ($1.27) | ($0.39) | $0.21 | $0.58 | $0.19 | |
| Diluted (in dollars per share) | $1.31 | $0.17 | ($1.27) | ($0.39) | $0.21 | $0.58 | $0.19 | |
| |
| Weighted average shares used in computing net income (loss) per share: | | | | | | | | |
| Basic (in shares) | 35.4 | 33.6 | 32.2 | 24.7 | 17.3 | 17.3 | 17.9 | |
| Diluted (in shares) | 37.6 | 35.9 | 32.2 | 24.7 | 17.3 | 17.3 | 17.9 | |