XML 116 R95.htm IDEA: XBRL DOCUMENT v3.22.4
Stock Award Plans - Fair Value of Employee Stock Options Assumptions (Detail)
12 Months Ended
Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Risk free interest rate, minimum 2.63%
Risk free interest rate, maximum 3.11%
Volatility, minimum 92.68%
Volatility, maximum 93.62%
Minimum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected lives 5 years 10 months 24 days
Maximum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected lives 7 years 2 months 8 days