Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Weighted-Average Assumptions Used to Estimate Fair Value of Options Granted (Detail)

v3.21.1
Stock-Based Compensation - Weighted-Average Assumptions Used to Estimate Fair Value of Options Granted (Detail) - Employee Stock Option - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Volatility 110.43% 93.86%
Risk free interest rate 1.68% 1.95%
Dividend yield 0.00% 0.00%
Term (years) 5 years 3 months 7 days 5 years 5 months 8 days
Weighted-average fair value of options granted during the period (usd per share) $ 4.45 $ 4.32