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Basis of Presentation and Summary of Significant Accounting Policies - Certain Risks and Concentrations (Details)
3 Months Ended 12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Customer concentration risk      
Concentration Risk [Line Items]      
Concentration risk 10.00%    
Customer concentration risk | Distributor To The U.S. Navy | Revenue      
Concentration Risk [Line Items]      
Concentration risk 50.00% 38.00%  
Customer concentration risk | Distributor To The U.S. Navy | Accounts receivable      
Concentration Risk [Line Items]      
Concentration risk 45.00%   28.00%
Customer concentration risk | Distributor for the U.S. Navy and a Regional Commercial Lighting Retrofit Company | Revenue      
Concentration Risk [Line Items]      
Concentration risk 11.00% 15.00%  
Customer concentration risk | Distributor for the U.S. Navy and a Regional Commercial Lighting Retrofit Company | Accounts receivable      
Concentration Risk [Line Items]      
Concentration risk 16.00%    
Customer concentration risk | Distributor To The U.S. Navy Combined With Sales To Shipbuilders | Revenue      
Concentration Risk [Line Items]      
Concentration risk 57.00% 46.00%  
Customer concentration risk | Shipbuilder For U.S. Navy | Accounts receivable      
Concentration Risk [Line Items]      
Concentration risk     21.00%
Supplier concentration risk | Offshore Supplier      
Concentration Risk [Line Items]      
Concentration risk 26.00% 22.00%  
Supplier concentration risk | Offshore Supplier | Accounts Payable      
Concentration Risk [Line Items]      
Concentration risk 39.00%   44.00%
Supplier concentration risk | Domestic Supplier | Accounts Payable      
Concentration Risk [Line Items]      
Concentration risk 10.00%    
Geographic concentration risk | Revenue | Countries outside of the United States      
Concentration Risk [Line Items]      
Concentration risk 1.00% 1.00%