Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Summary of Employee and Nonemployee Stock Option Activity (Detail)

v3.21.1
Stock-Based Compensation - Summary of Employee and Nonemployee Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Options Outstanding, Number of Shares Outstanding      
Outstanding, beginning balance (shares) 64,000 100,000  
Granted (shares) 20,000 20,000  
Canceled or expired (shares) (28,000) (56,000)  
Outstanding, ending balance (shares) 56,000 64,000 100,000
Exercisable (shares) 52,000    
Options Outstanding, Weighted Average Exercise Price      
Outstanding, beginning balance (usd per share) $ 113.63 $ 173.10  
Granted (usd per share) 5.53 5.89  
Canceled or expired (usd per share) 170.67 182.37  
Outstanding, ending balance (usd per share) 45.92 $ 113.63 $ 173.10
Exercisable (usd per share) $ 47.39    
Weighted- Average Remaining Contractual Term (in years)      
Outstanding 6 years 3 months 21 days 7 years 5 months 23 days 5 years 8 months 12 days
Exercisable 6 years 2 months 12 days    
Aggregate Intrinsic Value      
Outstanding $ 0 $ 24 $ 4
Exercisable $ 0