Summary of Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2020
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	Term of lease
Minimum | Buildings and Improvements
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	2 years
Minimum | Plant and Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	1 year
Minimum | Production Tooling
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	2 years
Minimum | Information Technology
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	1 year
Maximum | Buildings and Improvements
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	50 years
Maximum | Plant and Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	20 years
Maximum | Production Tooling
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years
Maximum | Information Technology
Property Plant And Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years