Property and Equipment - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Property, Plant and Equipment [Line Items] | ||
| Total property and equipment | $ 13,202 | $ 11,253 |
| less: accumulated depreciation | (7,989) | (6,375) |
| Property and equipment, net | 5,213 | 4,878 |
| Office Equipment [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property and equipment | 539 | 467 |
| Laboratory Equipment [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property and equipment | 4,337 | 2,978 |
| Leasehold Improvements [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property and equipment | 7,683 | 7,503 |
| Construction in Progress [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property and equipment | 547 | 270 |
| Software [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property and equipment | $ 96 | $ 35 |