XML 60 R46.htm IDEA: XBRL DOCUMENT v3.20.2
Stock-Based Compensation - Assumptions Used for Determining Fair Value of Stock Options Under Black-Scholes Pricing Model (Detail)
9 Months Ended
Sep. 30, 2020
$ / shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Expected dividend yield 0.00%
Expected volatility, Minimum 146.10%
Expected volatility, Maximum 171.10%
Minimum [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Stock and exercise prices $ 2.70
Discount rate-bond equivalent yield 0.38%
Expected life (in years) 5 years
Maximum [Member]  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Stock and exercise prices $ 7.10
Discount rate-bond equivalent yield 1.37%
Expected life (in years) 5 years 11 months 15 days