Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Basis Of Presentation And Accounting Policies [Line Items]
Number of reportable segments | Segment		2
capitalized costs to obtain contract		$ 7,305	$ 2,239
Amortization of capitalized costs into product revenues		179	78
Cash and cash equivalents		149,673	153,891
Allowance for doubtful accounts		1,171	1,220	$ 1,399	$ 1,161
Depreciation expense		42,186	33,730	29,622
Investment amount		5,700		5,200
Additional investment made	$ 500
Non-cash impairment charges		$ 2,900
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 8 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		$ 810		$ 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		$ 16,877	$ 15,267
Concentration of Credit Risk | Accounts receivable | Lear
Basis Of Presentation And Accounting Policies [Line Items]
Concentration risk percentage		17.00%	17.00%
Concentration of Credit Risk | Accounts receivable | Adient
Basis Of Presentation And Accounting Policies [Line Items]
Concentration risk percentage		19.00%	18.00%
Foreign Jurisdictions
Basis Of Presentation And Accounting Policies [Line Items]
Cash and cash equivalents		$ 125,251	$ 108,620
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		2 years
Maximum
Basis Of Presentation And Accounting Policies [Line Items]
Original maturities of highly liquid investments		90 days
Operating lease, term of contract		8 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		39 years
Entities Ownership Interest
Basis Of Presentation And Accounting Policies [Line Items]
Ownership interest		20.00%