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Research Funding Agreement - Additional Information (Details) - USD ($)
3 Months Ended
Mar. 06, 2018
Mar. 31, 2019
Mar. 31, 2018
Research And Development Arrangement Contract To Perform For Others [Line Items]      
Amounts received for qualifying expenses incurred recorded as reduction of research and development expense   $ 500,000  
Silverstein Foundation | Funding Agreement      
Research And Development Arrangement Contract To Perform For Others [Line Items]      
Upfront sum of funding amount $ 500,000    
Qualifying expenses   $ 0 $ 0