Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation - Summary of Fair Values of Purchase Options Granted (Detail)

v3.21.1
Stock Based Compensation - Summary of Fair Values of Purchase Options Granted (Detail) - Employee Stock Purchase Plan [Member] - Employee Stock Option [Member] - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Dividend yield 0.00% 0.00%
Expected life 6 months 6 months
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock price range $ 1.77 $ 4.27
Expected volatility range 61.00% 83.00%
Risk-free interest rate range 0.17% 2.10%
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock price range $ 2.96 $ 5.79
Expected volatility range 182.00% 96.00%
Risk-free interest rate range 1.57% 2.53%