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Research Funding Agreement - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended 12 Months Ended
Mar. 06, 2018
May 31, 2019
Mar. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Silverstein Foundation | Funding Agreement          
Research And Development Arrangement Contract To Perform For Others [Line Items]          
Upfront sum of funding amount $ 500,000        
Amounts received for qualifying expenses incurred recorded as reduction of research and development expense         $ 500,000
National Institute of Health          
Research And Development Arrangement Contract To Perform For Others [Line Items]          
Grant term   5 years      
Grant receivable   $ 1,500,000      
Qualifying expenses     $ 300,000 $ 41,000  
Amounts received for qualifying expenses incurred recorded as other current assets     0 61,000  
National Institute of Health | Funding Agreement          
Research And Development Arrangement Contract To Perform For Others [Line Items]          
Qualifying expenses     $ 300,000 $ 100,000