Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Basis Of Presentation And Accounting Policies [Line Items]
Number of reportable segments | Segment	2
capitalized costs to obtain contract	$ 2,239	$ 1,946
Amortization of capitalized costs into product revenues	78	174
Cash and cash equivalents	153,891	190,606
Allowance for doubtful accounts	1,220	1,399	$ 1,161	$ 1,193
Depreciation expense	$ 33,730	29,622	$ 31,037
Investment amount		5,200
Operating lease, description	The Company has operating leases for office, manufacturing and research and development facilities, as well as land leases for certain manufacturing facilities that are accounted for as operating leases. We also have operating leases for office equipment and automobiles.
Operating lease, existence of option to extend	true
Operating lease, options to extend	Excluding land leases, our leases have remaining lease terms ranging from less than 1 year to 9 years and may include options to extend the lease.
Forciot Oy | Gentherm Automotive Segment
Basis Of Presentation And Accounting Policies [Line Items]
Investment amount		2,357
Autotech Fund III, L.P.
Basis Of Presentation And Accounting Policies [Line Items]
Investment commitment	$ 495	5,000
Capital contribution description	As a limited partner, the Company will periodically make capital contributions toward this total commitment amount over the expected ten-year life of the fund.
Production Tooling
Basis Of Presentation And Accounting Policies [Line Items]
Reimbursable tooling capitalized within prepaid expenses and other current assets	$ 15,267	$ 3,778
Concentration of Credit Risk | Accounts receivable | Lear
Basis Of Presentation And Accounting Policies [Line Items]
Concentration risk percentage	17.00%	18.00%
Concentration of Credit Risk | Accounts receivable | Adient
Basis Of Presentation And Accounting Policies [Line Items]
Concentration risk percentage	18.00%	22.00%
Foreign Jurisdictions
Basis Of Presentation And Accounting Policies [Line Items]
Cash and cash equivalents	$ 108,620	$ 161,496
Minimum
Basis Of Presentation And Accounting Policies [Line Items]
Expected period of costs to be realized to recognize assets	1 year
Operating lease, term of contract	1 year
Minimum | Production Tooling
Basis Of Presentation And Accounting Policies [Line Items]
Property plant and equipment, estimated useful life	2 years
Minimum | Ground
Basis Of Presentation And Accounting Policies [Line Items]
Operating lease, term of contract	3 years
Maximum
Basis Of Presentation And Accounting Policies [Line Items]
Original maturities of highly liquid investments	90 days
Operating lease, term of contract	9 years
Maximum | Production Tooling
Basis Of Presentation And Accounting Policies [Line Items]
Property plant and equipment, estimated useful life	10 years
Maximum | Ground
Basis Of Presentation And Accounting Policies [Line Items]
Operating lease, term of contract	40 years
Entities Ownership Interest
Basis Of Presentation And Accounting Policies [Line Items]
Ownership interest	20.00%