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Income Taxes - Additional Information (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Operating Loss Carryforwards [Line Items]    
Net loss $ (22,127,000) $ (16,306,000)
Income Tax Expense (Benefit) 0 0
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit 0  
Valuation allowance 41,451,000 35,150,000
Increase in valuation allowance 6,300,000 5,100,000
Unrecognized tax benefits income tax penalties accrued 0 0
U.S. federal jurisdiction    
Operating Loss Carryforwards [Line Items]    
Operating loss carryforwards $ 91,400,000  
Operating loss carryforwards limitations on use offset future income tax liabilities and expire at various dates through 2037  
Deferred Tax Assets, Tax Credit Carryforwards, Research $ 3,600,000 3,200,000
U.S. federal jurisdiction | Minimum [Member]    
Operating Loss Carryforwards [Line Items]    
Operating loss carryforwards 44,000,000  
State jurisdiction    
Operating Loss Carryforwards [Line Items]    
Operating loss carryforwards $ 116,000,000  
Operating loss carryforwards limitations on use offset future income tax liabilities and expire at various dates through 2040  
Deferred Tax Assets, Tax Credit Carryforwards, Research $ 2,000,000 $ 1,800,000