Stock-Based Compensation - Summary of Weighted-Average Assumptions Used in the Black-Scholes Option Pricing Model to Determine the Fair Value of the Employee Stock Option Grants (Detail) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] | ||
| Risk-free interest rate | 1.68% | 1.83% |
| Expected volatility | 62.60% | 104.50% |
| Expected term (in years) | 6 years 15 days | 6 years 29 days |
| Expected dividend yield | 0.00% | 0.00% |