XML 54 R38.htm IDEA: XBRL DOCUMENT v3.20.4
Stock-Based Compensation Plan - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 19, 2019
Stock Based Compensation Plans [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value $ 4.34 $ 16.26  
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options $ 0.9    
Stock-based compensation expense $ 0.6 $ 0.7  
Share-based Compensation Arrangement By Share-based Payment Award, Options Outstanding And Unvested, Weighted Average Remaining Contractual Term 2 years 7 months 6 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
Common stock shares reserved for future issuance 402,724    
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 $ 0.1 0.1  
General and Administrative Expense [Member]      
Stock Based Compensation Plans [Line Items]      
Stock-based compensation expense $ 0.5 $ 0.6