Fair Value Measurements - Recurring Basis (Detail) - USD ($) $ in Thousands |
Sep. 26, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Financial instruments measured at fair value on a recurring basis | ||
| Warrant liabilities | $ 6,927 | |
| Convertible Preferred Stock Warrants | ||
| Financial instruments measured at fair value on a recurring basis | ||
| Warrant liabilities | $ 12,600 | |
| Recurring | Convertible Preferred Stock Warrants | ||
| Financial instruments measured at fair value on a recurring basis | ||
| Warrant liabilities | 6,927 | |
| Recurring | Level 3 | Convertible Preferred Stock Warrants | ||
| Financial instruments measured at fair value on a recurring basis | ||
| Warrant liabilities | $ 6,927 |