Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Weighted-Average Assumptions Used to Estimate Fair Value of Options Granted (Detail)

v3.7.0.1
Stock-Based Compensation - Weighted-Average Assumptions Used to Estimate Fair Value of Options Granted (Detail) - $ / shares
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Stock options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Volatility 73.57%  
Risk free interest rate 2.03%  
Dividend yield 0.00%  
Term (years) 6 years  
Weighted-average fair value of options granted during the period (usd per share) $ 1.63  
Non-Employee    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Volatility 77.41% 75.92%
Risk free interest rate 2.22% 1.56%
Dividend yield 0.00% 0.00%
Term (years) 7 years 1 month 21 days 8 years 1 month 22 days