| In millions, except per share items | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Aug-31-12 | Dec-31-11 | Aug-31-11 | Aug-31-10 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Product revenue | 94.2 | 69.5 | 16.9 | | | | 14.8 | |
| Product revenue growth | 35.6% | 311.9% | | | | | | -100.0% |
| Cost of sales | 12.6 | 9.4 | 1.7 | | | | 14.8 | -19.3 |
| Gross profit | 81.6 | 60.1 | 15.2 | | | | | |
| Gross margin | 86.6% | 86.5% | 90.2% | | | | | |
| |
| Operating expenses: | | | | | | | | |
| Research and development | 58.6 | 43.5 | 29.2 | 9.0 | | 21.4 | | 9.3 |
| Selling, general and administrative | 71.4 | 56.7 | 37.9 | | | | | 3.7 |
| Total operating expenses | 262.1 | 201.7 | 134.9 | 17.9 | | 36.2 | 21.0 | 32.3 |
| Loss from operations | -48.5 | -40.1 | -51.9 | -17.9 | | -36.2 | -21.0 | -13.1 |
| Operating margin | -51.4% | -57.6% | -307.6% | | | | | |
| Interest income | 0.3 | 0.1 | 0.2 | 0.2 | | 0.3 | 0.0 | 0.0 |
| Interest expense | -15.8 | -14.0 | -6.8 | -0.1 | | 0.0 | 0.0 | 0.0 |
| Foreign currency transaction gain (loss) | -0.3 | 0.3 | 0.0 | 0.1 | | 0.1 | | |
| Adjustment to fair value of common stock warrants | -0.5 | -1.1 | -10.7 | | | | | |
| Loss before provision for income taxes | -64.8 | -52.5 | -69.4 | | | | | |
| Provision for income taxes | 0.4 | 0.1 | | | | | | |
| Net Loss | -65.2 | -52.5 | -69.4 | -19.3 | | -38.6 | -37.2 | -18.9 |
| |
| Other comprehensive income (loss): | | | | | | | | |
| Foreign currency translation gain (loss), net of tax | -1.3 | 0.3 | -0.3 | | | | | 0.0 |
| Comprehensive Loss | -66.5 | -52.2 | -69.7 | -19.4 | | -38.7 | -37.2 | -18.9 |
| |
| Net loss per share: | | | | | | | | |
| Basic and diluted | ($0.83) | ($0.83) | ($1.20) | ($0.37) | | ($0.80) | ($1.15) | ($0.85) |
| |
| Weighted-average shares outstanding: | | | | | | | | |
| Basic and diluted | 78.9 | 63.2 | 57.9 | 51.7 | | 48.1 | 32.3 | 22.2 |