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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, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Expected stock price volatility, minimum 77.00% 74.00%
Expected stock price volatility, maximum 107.00% 87.00%
Risk-free interest rate, minimum 0.00% 1.00%
Risk-free interest rate, maximum 1.00% 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) 4 years  
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Expected life of option (in years) 6 years