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Stock-Based Compensation - Schedule of Assumptions Used in Black-Scholes Option Pricing Model to Determine the Fair Value of Stock Options Granted (Detail)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Expected stock price volatility, minimum 74.00% 63.00%
Expected stock price volatility, maximum 77.00% 86.00%
Risk-free interest rate, minimum 1.00% 2.00%
Risk-free interest rate, maximum 3.00% 3.00%
Expected life of option (in years) 6 years  
Estimated dividend yield 0.00% 0.00%
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Expected life of option (in years)   5 years
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Expected life of option (in years)   7 years