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Stockholders' Equity - Summary of Estimated Fair Value of Stock Option Award (Detail) - Stock Options [Member]
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Stock-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk free interest rate   1.87%
Expected option term   6 years
Expected volatility of common stock   71.99%
Expected dividend yield 0.00% 0.00%
Minimum [Member]    
Stock-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk free interest rate 1.25%  
Expected option term 5 years 3 months 18 days  
Expected volatility of common stock 74.44%  
Maximum [Member]    
Stock-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk free interest rate 1.575%  
Expected option term 6 years  
Expected volatility of common stock 75.91%