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%