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Stock-Based Compensation Plan - Additional Information (Details) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 19, 2019
Stock Based Compensation Plans [Line Items]      
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options $ 1,900,000    
Stock-based compensation expense 100,000 $ 200,000  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value $ 400,000    
Share-based Compensation Arrangement By Share-based Payment Award, Options Outstanding And Unvested, Weighted Average Remaining Contractual Term 3 years 3 months 18 days    
Stock Incentive Plan 2007 [Member]      
Stock Based Compensation Plans [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant     600,000
Stock Incentive Plan 2007 [Member] | Maximum [Member]      
Stock Based Compensation Plans [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant     660,000
Research and Development Expense [Member]      
Stock Based Compensation Plans [Line Items]      
Stock-based compensation expense $ 29,000 21,000  
General and Administrative Expense [Member]      
Stock Based Compensation Plans [Line Items]      
Stock-based compensation expense $ 100,000 $ 100,000