Summary of Significant Accounting Policies - (Estimated Depreciable Lives) (Details)	12 Months Ended
	Dec. 31, 2020
Minimum | Energy Servers
Property, Plant and Equipment [Line Items]
Estimated depreciable life	15 years
Minimum | Computers, software and hardware
Property, Plant and Equipment [Line Items]
Estimated depreciable life	3 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated depreciable life	5 years
Minimum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated depreciable life	3 years
Minimum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Estimated depreciable life	1 year
Maximum | Energy Servers
Property, Plant and Equipment [Line Items]
Estimated depreciable life	21 years
Maximum | Computers, software and hardware
Property, Plant and Equipment [Line Items]
Estimated depreciable life	5 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated depreciable life	10 years
Maximum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated depreciable life	5 years
Maximum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Estimated depreciable life	10 years
Maximum | Building
Property, Plant and Equipment [Line Items]
Estimated depreciable life	35 years