GCT Semiconductor Holding (GCTS) 10-Q 14 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 11, 2024
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-41013
Entity Registrant Name	GCT Semiconductor Holding, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	86-2171699
Entity Address, Address Line One	2290 North 1st Street, Suite 201
Entity Address, City or Town	San Jose
Entity Address State Or Province	CA
Entity Address, Postal Zip Code	95131
City Area Code	408
Local Phone Number	434‑6040
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		47,736,824
Entity Central Index Key	0001851961
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false
Common Stock
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	GCTS
Security Exchange Name	NYSE
Warrants, each whole warrant exercisable for one share of Common Stock for $11.50 per share
Title of 12(b) Security	Warrants, each whole warrant exercisable for one share of Common Stock for $11.50 per share
Trading Symbol	GCTSW
Security Exchange Name	NYSE

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands		Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents		$ 1,812	$ 258
Accounts receivable, net		6,441	4,920
Inventory		3,110	1,486
Contract assets		5,098	3,439
Prepaid expenses and other current assets		3,545	2,906
Total current assets		20,006	13,009
Property and equipment, net		641	772
Operating lease right-of-use assets		1,065	1,521
Intangibles, net		99	245
Other assets		810	881
Total assets		22,621	16,428
Current liabilities:
Accounts payable		1,070	17,814
Contract liabilities		511	48
Accrued and other current liabilities		22,365	23,956
Common stock forward liability		451
Borrowings		32,819	44,509
Convertible promissory notes, current		4,008	27,794
Operating lease liabilities, current		724	680
Total current liabilities		61,948	114,801
Convertible promissory notes, net of current		4,830	6,239
Net defined benefit liabilities		8,052	7,689
Long-term operating lease liabilities		358	850
Income taxes payable		2,245	2,178
Warrant liabilities		3,197
Other liabilities		242	108
Total liabilities		80,872	131,865
Commitments and contingencies (Note 8)
Stockholders' deficit:
Preferred stock, par value $0.0001 per share; 40,000 and 82,352 shares authorized as of September 30, 2024 and December 31, 2023, respectively; no shares issued and outstanding as of September 30, 2024 and December 31, 2023
Common stock, par value $0.0001 per share; 400,000 and 200,000 shares authorized as of September 30, 2024 and December 31, 2023, respectively; 47,611 and 24,166 shares issued and outstanding as of September 30, 2024 and December 31, 2023, respectively	[1]	5	3
Additional paid-in capital	[1]	499,751	435,752
Accumulated other comprehensive loss		(946)	(1,538)
Accumulated deficit		(557,061)	(549,654)
Total stockholders' deficit		(58,251)	(115,437)	[2]
Total liabilities and stockholders' deficit		$ 22,621	$ 16,428
[1] Amounts as of December 31, 2023 differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (as defined in the Notes to the Unaudited Condensed Consolidated Financial Statements.) Amounts as of December 31, 2023 and before that date differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (as defined in the Notes to the Unaudited Condensed Consolidated Financial Statements).

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Condensed Consolidated Balance Sheets
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized	40,000,000	82,352,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	400,000,000	200,000,000
Common stock, shares issued	47,611,000	24,166,000
Common stock, shares outstanding	47,611,000	24,166,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net revenues:
Total net revenues		$ 2,610	$ 4,476	$ 7,343	$ 11,839
Cost of net revenues:
Total cost of net revenues		984	3,949	2,843	6,960
Gross profit		1,626	527	4,500	4,879
Operating expenses:
Research and development		4,210	2,367	13,895	7,254
Sales and marketing		949	744	2,921	2,337
General and administrative		2,379	1,433	8,075	5,537
Gain on extinguishment of liability				(14,636)
Total operating expenses		7,538	4,544	10,255	15,128
Loss from operations		(5,912)	(4,017)	(5,755)	(10,249)
Interest expense		(667)	(1,220)	(3,509)	(4,878)
Other income (expenses), net		(481)	929	2,044	2,946
Loss before provision for income taxes		(7,060)	(4,308)	(7,220)	(12,181)
Provision for income taxes		61	38	187	125
Net loss		$ (7,121)	$ (4,346)	$ (7,407)	$ (12,306)
Net loss per common share - basic	[1]	$ (0.16)	$ (0.18)	$ (0.19)	$ (0.51)
Net loss per common share - diluted	[1]	$ (0.16)	$ (0.18)	$ (0.19)	$ (0.51)
Weighted average number of common shares used in computing net loss per common share - basic	[1]	45,645	24,055	38,418	23,934
Weighted average number of common shares used in computing net loss per common share - diluted	[1]	45,645	24,055	38,418	23,934
Product
Net revenues:
Total net revenues		$ 1,715	$ 4,026	$ 4,111	$ 8,667
Cost of net revenues:
Total cost of net revenues		710	3,985	1,522	5,954
Service
Net revenues:
Total net revenues		895	450	3,232	3,172
Cost of net revenues:
Total cost of net revenues		$ 274	$ (36)	$ 1,321	$ 1,006
[1] Amounts for the three and nine months ended September 30, 2023 and before that date differ from those in prior year condensed consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (as defined in the Notes to the Unaudited Condensed Consolidated Financial Statements).

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Comprehensive loss, net of taxes:
Net loss	$ (7,121)	$ (4,346)	$ (7,407)	$ (12,306)
Foreign currency translation adjustment	(1,180)	537	592	1,386
Comprehensive loss	$ (8,301)	$ (3,809)	$ (6,815)	$ (10,920)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Deficit - USD ($) $ in Thousands		Total		Previously reported	Common Stock		Common Stock Previously reported	Common Stock Revision of prior period, adjustment	Additional Paid-in Capital		Additional Paid-in Capital Previously reported	Additional Paid-in Capital Revision of prior period, adjustment	Accumulated Other Comprehensive Income (Loss)		Accumulated Other Comprehensive Income (Loss) Previously reported	Accumulated Deficit		Accumulated Deficit Previously reported
Balance as at beginning at Dec. 31, 2022		$ (94,929)	[1]	$ (94,929)	$ 2	[1]	$ 128	$ (126)	$ 434,116	[1]	$ 433,990	$ 126	$ (1,862)	[1]	$ (1,862)	$ (527,185)	[1]	$ (527,185)
Balance as at beginning (in shares) at Dec. 31, 2022					23,861,000	[1]	127,761,000	(103,900,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from option exercises	[1]	1							1
Issuance of common stock from option exercises (in shares)	[1]				5,000
Stock-based compensation		2							2
Foreign currency translation adjustment		674											674
Net loss		(1,393)														(1,393)
Balance as at end at Mar. 31, 2023	[1]	(95,645)			$ 2				434,119				(1,188)			(528,578)
Balance as at end (in shares) at Mar. 31, 2023	[1]				23,866,000
Balance as at beginning at Dec. 31, 2022		(94,929)	[1]	(94,929)	$ 2	[1]	$ 128	$ (126)	434,116	[1]	433,990	126	(1,862)	[1]	(1,862)	(527,185)	[1]	(527,185)
Balance as at beginning (in shares) at Dec. 31, 2022					23,861,000	[1]	127,761,000	(103,900,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment		1,386
Net loss		(12,306)
Balance as at end at Sep. 30, 2023	[1]	(105,746)			$ 3				434,218				(476)			(539,491)
Balance as at end (in shares) at Sep. 30, 2023	[1]				24,075,000
Balance as at beginning at Mar. 31, 2023	[1]	(95,645)			$ 2				434,119				(1,188)			(528,578)
Balance as at beginning (in shares) at Mar. 31, 2023	[1]				23,866,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from option exercises	[1]	4							4
Issuance of common stock from warrant exercise (in shares)	[1]				33,000
Issuance of common stock from conversion of convertible promissory notes and accrued interest	[1]	72							72
Issuance of common stock from conversion of convertible promissory notes and accrued interest (in shares)	[1]				4,000
Stock-based compensation		3							3
Foreign currency translation adjustment		175											175
Net loss		(6,567)														(6,567)
Balance as at end at Jun. 30, 2023	[1]	(101,958)			$ 2				434,198				(1,013)			(535,145)
Balance as at end (in shares) at Jun. 30, 2023	[1]				23,903,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from option exercises	[1]	18			$ 1				17
Issuance of common stock from option exercises (in shares)	[1]				171,000
Issuance of common stock from conversion of convertible promissory notes and accrued interest (in shares)	[1]				1,000
Stock-based compensation		3							3
Foreign currency translation adjustment		537											537
Net loss		(4,346)														(4,346)
Balance as at end at Sep. 30, 2023	[1]	(105,746)			$ 3				434,218				(476)			(539,491)
Balance as at end (in shares) at Sep. 30, 2023	[1]				24,075,000
Balance as at beginning at Dec. 31, 2023		$ (115,437)	[2]	(115,437)	$ 3	[2]	$ 129	$ (126)	435,752	[2]	435,626	126	(1,538)	[2]	(1,538)	(549,654)	[2]	(549,654)
Balance as at beginning (in shares) at Dec. 31, 2023		24,166,000			24,166,000	[2]	129,396,000	(105,230,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reverse recapitalization transaction, net of transaction costs and acquired liabilities		$ 50,033			$ 2				50,031
Reverse recapitalization transaction, net of transaction costs and acquired liabilities (in shares)					21,667,000
Stock-based compensation		1,223							1,223
Foreign currency translation adjustment		1,064											1,064
Net loss		757														757
Balance as at end at Mar. 31, 2024		(62,360)			$ 5				487,006				(474)			(548,897)
Balance as at end (in shares) at Mar. 31, 2024					45,833,000
Balance as at beginning at Dec. 31, 2023		$ (115,437)	[2]	$ (115,437)	$ 3	[2]	$ 129	$ (126)	435,752	[2]	$ 435,626	$ 126	(1,538)	[2]	$ (1,538)	(549,654)	[2]	$ (549,654)
Balance as at beginning (in shares) at Dec. 31, 2023		24,166,000			24,166,000	[2]	129,396,000	(105,230,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from option exercises (in shares)		117,670
Issuance of commitment shares in connection with common stock purchase agreement (in shares)		56,818
Foreign currency translation adjustment		$ 592
Net loss		(7,407)
Balance as at end at Sep. 30, 2024		$ (58,251)			$ 5				499,751				(946)			(557,061)
Balance as at end (in shares) at Sep. 30, 2024		47,611,000			47,611,000
Balance as at beginning at Mar. 31, 2024		$ (62,360)			$ 5				487,006				(474)			(548,897)
Balance as at beginning (in shares) at Mar. 31, 2024					45,833,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under common stock purchase agreement		$ 3,388							3,388
Issuance of common stock under common stock purchase agreement (in shares)		678,462			679,000
Issuance of commitment shares in connection with common stock purchase agreement (in shares)					57,000
Issuance of common stock to underwriter		$ 667							667
Issuance of common stock to underwriter (in shares)					110,000
Stock-based compensation		323							323
Foreign currency translation adjustment		708											708
Net loss		(1,043)														(1,043)
Balance as at end at Jun. 30, 2024		(58,317)			$ 5				491,384				234			(549,940)
Balance as at end (in shares) at Jun. 30, 2024					46,679,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from option exercises		13							13
Issuance of common stock from option exercises (in shares)					118,000
Issuance of common stock under common stock purchase agreement		$ 5,541							5,541
Issuance of common stock under common stock purchase agreement (in shares)		1,421,715			1,422,000
Issuance of common stock and common stock warrants in a private placement		$ 2,240							2,240
Issuance of common stock and common stock warrants in a private placement (in shares)					742,000
Forfeiture of unvested sponsor earnout shares (in shares)					(1,350,000)
Stock-based compensation		573							573
Foreign currency translation adjustment		(1,180)											(1,180)
Net loss		(7,121)														(7,121)
Balance as at end at Sep. 30, 2024		$ (58,251)			$ 5				$ 499,751				$ (946)			$ (557,061)
Balance as at end (in shares) at Sep. 30, 2024		47,611,000			47,611,000
[1] Amounts as of December 31, 2023 and before that date differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (as defined in the Notes to the Unaudited Condensed Consolidated Financial Statements). Amounts as of December 31, 2023 and before that date differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (as defined in the Notes to the Unaudited Condensed Consolidated Financial Statements).

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities:
Net loss	$ (7,407)	$ (12,306)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	528	654
Operating lease right-of-use amortization	463	581
Stock-based compensation	2,119	8
Issuance of common stock to underwriter	667
Change in credit loss allowance	(547)	793
Change in fair value of convertible promissory notes	1,354	(1,116)
Change in fair value of warrant liabilities	(2,761)
Loss from initial recognition of common stock forward liability	586
Gain on extinguishment of liability	(14,636)
Changes in operating assets and liabilities:
Accounts receivable	(895)	(3,290)
Inventory	(1,624)	1,816
Contract assets	(1,659)	(1,984)
Prepaid expenses and other current assets	(21)	785
Other assets	70	87
Accounts payable	(2,328)	(744)
Contract liabilities	463	16
Accrued and other current liabilities	(3,040)	7,387
Net defined benefit liabilities	674	328
Income tax payable	35	(135)
Lease liabilities	(455)	(797)
Other liabilities	(275)	(3)
Net cash used in operating activities	(28,689)	(7,920)
Investing activities:
Purchases of property and equipment	(185)	(284)
Net cash used in investing activities	(185)	(284)
Financing activities:
Proceeds from reverse recapitalization and PIPE Financing, net of transaction costs	17,238
Proceeds from issuance of convertible promissory notes	16,290
Proceeds from issuance of common stock under common stock purchase agreement	7,814
Proceeds from issuance of common stock and common stock warrants in a private placement	2,240
Proceeds from borrowings	3,696	7,604
Proceeds from exercise of stock options	13	23
Repayments of borrowings	(14,065)	(23)
Repayments of convertible promissory notes	(1,630)
Payments of financial lease liabilities		(13)
Net cash provided by financing activities	31,596	7,591
Effect of exchange rate changes on cash and cash equivalents	(1,168)	(665)
Net increase (decrease) in cash and cash equivalents	1,554	(1,278)
Cash and cash equivalents at beginning of period	258	1,398
Cash and cash equivalents at end of period	1,812	120
Supplemental disclosure of cash flow information:
Cash paid for interest	3,059	1,515
Cash paid for income taxes	212	47
Cash paid for operating leases	562	797
Non-cash financing activities:
Issuance of common stock from conversion of convertible promissory notes	41,209	72
Settlement of common stock forward liability in equity	135
Proceeds from issuance of common stock withheld for outstanding payables	975
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	$ 54	$ 1,473

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (7,121)	$ (1,043)	$ 757	$ (4,346)	$ (6,567)	$ (1,393)	$ (7,407)	$ (12,306)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Organization and Liquidity

Organization and Liquidity	9 Months Ended
	Sep. 30, 2024
Organization and Liquidity
Organization and Liquidity	1. Organization and Liquidity Description of Business GCT Semiconductor Holding, Inc. (formerly known as Concord Acquisition Corp III) and its wholly owned subsidiaries (collectively “GCT” or the “Company”) is headquartered in San Jose, California with international offices in South Korea, China, Taiwan, and Japan. The Company is a fabless semiconductor company that specializes in the design, manufacturing, and sale of communication semiconductors, including high-speed wireless communication technologies such as 5G/4.75G/4.5G/4G transceivers and modems, which are essential for a wide variety of industrial, B2B and consumer applications. On March 26, 2024 (the “Closing Date” or “Closing”), Concord Acquisition Corp III (“Concord III”), a Delaware corporation, consummated a series of transactions that resulted in the combination of Gibraltar Merger Sub Inc., a Delaware corporation and a wholly-owned subsidiary of Concord III (“Merger Sub”), and GCT Semiconductor, Inc. ( “Legacy GCT”), pursuant to a Business Combination Agreement, dated November 2, 2023 (as amended, the “Business Combination Agreement”), by and among Concord III, Merger Sub and Legacy GCT. Pursuant to the terms of the Business Combination Agreement, Merger Sub merged with and into Legacy GCT, with Legacy GCT surviving the merger as a wholly-owned subsidiary of Concord III (the “Business Combination”). On the Closing Date, Concord III changed its name from Concord III to “GCT Semiconductor Holding, Inc.” The Business Combination was accounted for as a reverse recapitalization with Legacy GCT being the accounting acquirer and Concord III identified as the acquired company for accounting purposes. Accordingly, all historical financial information presented in the unaudited condensed consolidated financial statements represent the accounts of Legacy GCT. Subsequent to the Business Combination, the shares and net loss per common share information prior to the Closing have been retroactively restated as shares reflecting the exchange ratio established in the Closing of approximately 0.1868 . Prior to the Business Combination, Concord III’s public shares and public redeemable warrants were listed on the New York Stock Exchange (“NYSE”) under the symbols “CNDB.U,” “CNDB,” and “CNDB.WS,” respectively. On March 27, 2024, the Company’s common stock and public warrants began trading on the NYSE under the symbols “GCTS” and “GCTSW,” respectively. In connection with the Closing, Concord III’s Class A common stock and Class B common stock were recapitalized into a single class of common stock. See Note 3 for additional information. Liquidity The accompanying unaudited condensed consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and liabilities and commitments in the normal course of business. Through September 30, 2024, the Company has incurred operating losses and negative cash flows from operating activities and had an accumulated deficit of $ 557.1 million as of September 30, 2024. The Company’s existing sources of liquidity as of September 30, 2024 include cash and cash equivalents of $ 1.8 million . The Company has historically funded operations primarily with issuances of capital stock and the incurrence of debt. In March 2024, the Company received $ 17.2 million in cash proceeds from the reverse recapitalization and PIPE Financing (as defined in Note 3), net of transaction costs. In April 2024, the Company executed a common stock purchase agreement (“Purchase Agreement”) with B. Riley Principal Capital II, LLC (“B. Riley”). Pursuant to the Purchase Agreement, the Company has the right, but not the obligation, to sell, from time to time, B. Riley up to $ 50.0 million worth of shares of the Company’s common stock at its request, at any time prior to June 2026, subject to compliance with the required conditions and limitations. Through September 30, 2024, the Company received $ 7.8 million in net proceeds under the Purchase Agreement. Management believes that the available financing under the Purchase Agreement and other capital resources available to the Company , including future sales of products and services, will be sufficient to fund the Company’s operations for at least 12 months after the filing date of this Quarterly Report on Form 10‑Q. To fund its operations over the longer term, the Company will need to start generating positive cash flows, renegotiate its existing debt obligations and raise additional capital through debt or equity financing. There can be no assurance that such additional debt or equity financing will be available on terms acceptable to the Company or at all.

Summary of Significant Accounti

Summary of Significant Accounting Policies and Basis of Presentation	9 Months Ended
	Sep. 30, 2024
Summary of Significant Accounting Policies and Basis of Presentation
Summary of Significant Accounting Policies and Basis of Presentation	2. Summary of Significant Accounting Policies and Basis of Presentation Principles of Consolidation and Basis of Presentation The unaudited condensed consolidated financial statements and accompanying notes include the accounts of the Company and its wholly owned subsidiaries, after elimination of intercompany balances and transactions. The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and the requirements of the Securities and Exchange Commission (“SEC”) for interim financial information. Certain information and disclosures normally included in unaudited consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. Accordingly, these interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto for the year ended December 31, 2023, which are included in the Company’s Form 8‑K filed with the SEC on April 1, 2024. The information as of December 31, 2023 included in the condensed consolidated balance sheets was derived from the audited consolidated financial statements. Certain amounts reported in the audited consolidated financial statements for the year ended December 31, 2023 have been reclassified to conform to the current year’s presentation. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial information. The unaudited condensed consolidated results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other future annual or interim period. Use of Estimates The preparation of the accompanying unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make judgments, estimates, and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. These judgments, estimates, and assumptions are used for but not limited to revenue recognition, provision for credit losses, deferred income taxes and related valuation allowances, inventory obsolescence, recoverability of long-lived assets, certain accrued expenses, stock-based compensation, determination of the fair value of the Company’s financial instruments, including convertible promissory notes, common stock of Legacy GCT prior to the reverse recapitalization, warrant liabilities, stock options, and common stock forward liability. The Company bases its estimates and judgments on historical experience and on various other assumptions that it believes are reasonable under the circumstances. Actual results could differ from these estimates, and these differences may be material. Fair Value of Financial Instruments The carrying amount of certain financial instruments held by the Company, such as cash equivalents, accounts receivable, contract assets and liabilities, accounts payable, and accrued and other current liabilities, approximate fair value due to their short maturities. The carrying amount of the liabilities for the convertible promissory notes and the historical convertible promissory notes (see Note 5) represents their fair value. The carrying amounts of the Company’s bank borrowings and lease liabilities approximate their fair values due to the market interest rates that these obligations bear and interest rates available to the Company. Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows: Level 1 Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 Inputs other than quoted prices included within Level 1 that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity for the related assets or liabilities. A financial instrument's categorization within the valuation hierarchy is based on the lowest level of input that is significant to the fair value measurement. The Company’s Level 3 financial instruments consist of a common stock forward liability, convertible promissory notes, and warrant liabilities. Risk and Uncertainties The Company is subject to certain risks and uncertainties and believes changes in any of the following areas could have a material adverse effect on the Company’s future financial position or results of operations or cash flows: 5G and other new product development, including market receptivity, the ability to satisfy obligations under development agreements with major partners, litigation or claims against the Company based on intellectual property, patent, product regulation or other factors, competition from other products, general economic conditions, the ability to attract and retain qualified employees and ultimately to sustain profitable operations. The semiconductor industry is characterized by rapid technological change, competition, competitive pricing pressures, and cyclical market patterns. The Company’s financial results are affected by a wide variety of factors, such as general economic conditions specific to the semiconductor industry and the Company’s particular market, the timely implementation of new 5G and other new products, new manufacturing process technologies, and the ability to safeguard patents and intellectual property in a rapidly evolving market. In addition, the semiconductor market has historically been cyclical and subject to significant economic downturns. As a result, the Company may experience significant period-to-period fluctuations in unaudited condensed consolidated operating results due to the abovementioned factors. The Company’s revenue may be impacted by its ability to obtain adequate wafer supplies from foundries and back-end production capacity from the Company’s test and assembly subcontractors. The foundries with which the Company currently has arrangements may not be willing or able to satisfy all of the Company’s manufacturing requirements on a timely basis or at favorable prices. The Company is also subject to the risks of service disruptions, raw material shortages and price increases by its foundries. Such disruptions, shortages and price increases could harm the Company’s consolidated operating results. Provision for Credit Losses The provision for credit losses is based on the Company’s assessment of the collectibility of its customer accounts. The Company reviews the provision for credit losses by considering certain factors such as historical experience, industry data, credit quality, age of balances, and current economic conditions that may affect a customer’s ability to pay. Uncollectible receivables are written off when all efforts to collect have been exhausted and recoveries are recognized when they are recovered. The Company determined that provisions for credit losses of approximately $ 1.1 million and $ 1.6 million were necessary as of September 30, 2024 and December 31, 2023 , respectively. Concentration of Credit Risk The Company’s financial instruments subject to credit risk concentration consist of cash and cash equivalents and accounts receivable. The Company maintains its cash and cash equivalents primarily with one financial institution located in the United States and another located in South Korea, where amounts deposited may exceed Federal Deposit Insurance Corporation or Korea Deposit Insurance Corporation limits. The Company’s accounts receivable balances are primarily derived from revenues recognized from customers located in the United States, China, South Korea, Japan, and Taiwan. The Company performs ongoing credit evaluations of the financial condition of its customers and distributors and generally does not require collateral. The Company’s net revenues and accounts receivable are concentrated among a few significant customers, which could expose the Company to financial risk in the event of adverse developments. The following represents the concentration of the Company’s gross accounts receivable among key customers to the extent their share exceeds 10%: Customer September 30, 2024 December 31, 2023 Customer A 27 % — % Customer H 20 % 19 % Customer I 12 % 14 % Customer J 12 % 27 % Customer K — % 10 % The following table includes customers that individually accounted for more than 10% of the Company’s net revenues in the periods indicated: Three Months Ended Nine Months Ended Customer 2024 2023 2024 2023 Customer A — % — % 27 % — % Customer B 24 % — % 25 % — % Customer C — % — % 12 % — % Customer D — % — % — % 25 % Customer F — % 13 % — % 13 % Customer H 57 % — % 20 % — % Customer I — % 24 % — % — % Customer J — % 47 % — % 20 % Management closely monitors the creditworthiness and performance of these key customers and has established credit limits and terms to mitigate potential credit risks. The Company also continues diversifying its customer base and exploring opportunities to reduce its reliance on a few major customers. Foreign Currency Financial statements of foreign subsidiaries that use the local currency as their functional currency are translated into U.S. dollars at the end-of-period exchange rates or at historical exchange rates for purposes of consolidation. Revenues and expenses are translated using average exchange rates during the reporting period. Translation adjustments are included in accumulated other comprehensive loss within stockholders’ deficit. Gains and losses resulting from transactions denominated in a currency other than the functional currency are included in other income (expenses), net in the unaudited condensed consolidated statements of operations. The Company recognized foreign currency exchange losses of $ 1.1 million and gains of $ 0.8 million for the three and nine months ended September 30, 2024, respectively. The Company recognized $ 0.9 million and $ 1.8 million of foreign currency exchange gains for the three and nine months ended September 30, 2023 , respectively. Convertible Promissory Notes The Company has elected the fair value option to account for its outstanding convertible promissory notes. Changes in the estimated fair value of the outstanding convertible promissory notes are recognized in other income (expenses), net in the condensed consolidated statements of operations. Common Stock Warrants Common stock warrants are classified as liabilities if they do not meet equity classification requirements based on their settlement mechanism upon a change of control and similar transactions. The corresponding liability is remeasured at fair value while the common stock warrants remain outstanding, with changes in fair value recognized in other income (expenses), net in the unaudited condensed consolidated statements of operations. Common stock warrants that meet equity classification requirements are credited to stockholders’ deficit on their issuance dates and are not subsequently remeasured. Certain Equity Contracts The Company’s promises to potentially issue additional shares in the future based on certain market conditions, including the Legacy GCT Earnout Shares and the Sponsor Earnout Shares, are discussed in Note 3. These financial instruments were determined to be equity classified and credited to the stockholders’ deficit upon consummation of the Business Combination. Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS” Act). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards using private company timelines. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these unaudited condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recent Accounting Pronouncements Adopted In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2020‑06, Debt—Debt with Conversion and Other Options (Subtopic 470‑20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815‑40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020‑06 reduces the number of accounting models for convertible instruments and allows more contracts to qualify for equity classification. The Company adopted this guidance effective January 1, 2024 and noted no material impact on the Company’s unaudited condensed consolidated financial statements. In October 2021, the FASB issued ASU 2021‑08, Business Combinations (Topic 805) : Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (“ASU 2021-08”), which provides an exception to fair value measurement for contract assets and contract liabilities related to revenue contracts acquired in a business combination. ASU 2021-08 requires an acquirer to recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with Topic 606. At the acquisition date, an acquirer should account for the related revenue contracts in accordance with Topic 606 as if it had originated the contracts. The Company adopted this guidance effective January 1, 2024 and noted no material impact on the Company’s unaudited condensed consolidated financial statements. In June 2022, the FASB issued ASU 2022‑03, Fair Value Measurement (Topic 820) : Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions (“ASU 2022-03”). ASU 2022-03 clarifies that a contractual restriction on the sale of an equity security should not be considered in measuring the fair value of the equity security and cannot be recognized as a separate unit of account. ASU 2022-03 also requires the investor to disclose the fair value of equity securities subject to contractual sale restrictions, the nature and remaining duration of the restrictions, and the circumstances that could cause a lapse in the restrictions. ASU 2022-03 is effective for annual and interim periods beginning after December 15, 2024, with early adoption permitted. The Company retrospectively adopted this guidance effective July 1, 2024 and noted no material impact on the Company’s unaudited condensed consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280) : Improvements to Reportable Segment Disclosures (“ASU 2023-07”), which expands annual and interim disclosure requirements for reportable segments, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for annual periods beginning after December 15, 2023 and for interim periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the effect of the adoption of ASU 2023-07 on its unaudited condensed consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740) : Improvements to Income Tax Disclosures (“ASU 2023-09”), which requires companies to disclose, on an annual basis, specific categories in the effective tax rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. In addition, companies are required to disclose additional information about income taxes paid. ASU 2023 -09 is effective for annual periods beginning after December 15, 2024, with early adoption permitted. The standard is required to be adopted on a prospective basis; however, retrospective application is permitted. The Company is currently evaluating the effect of the adoption of ASU 2023-09 on its unaudited condensed consolidated financial statements.

Reverse Recapitalization

Reverse Recapitalization	9 Months Ended
	Sep. 30, 2024
Reverse Recapitalization
Reverse Recapitalization	3. Reverse Recapitalization In connection with the Business Combination described in Note 1, Concord III completed the acquisition of Legacy GCT and acquired 100 % of Legacy GCT’s common stock. Legacy GCT received net proceeds of $ 17.1 million from the PIPE Financing (as defined below). Concord III incurred total direct transaction costs of $ 13.1 million , which were expensed by Concord III, and of which $ 0.9 million related to the PIPE Financing. Legacy GCT incurred transaction costs of $ 8.9 million , consisting of legal, accounting, and other professional fees, which were recorded as additional paid-in capital. Each share of Legacy GCT capital stock received a deemed value of $ 10.00 per share after giving effect to the applicable exchange ratio of 0.1868 . Upon Closing of the Business Combination, the following occurred: • Each share of Legacy GCT common stock issued and outstanding prior to the Closing was cancelled and converted into the right to receive a number of shares of the Company common stock at the exchange ratio of 0.1868 . • Each outstanding instrument of Legacy GCT stock options, restricted stock units (“RSUs”), and warrant shares were converted into equivalent Company stock options, RSUs, and warrant shares with the same terms and conditions and at the exchange ratio of 0.1868 . • Certain GCT convertible promissory notes, including the CVT Financing (see Note 7), were automatically converted into the right to receive a number of shares of the Company common stock at the conversion price of $ 6.67 per share (see Note 7). Immediately after the Closing, the Company’s outstanding common stock included the following components (in thousands): Shares Common stock of Concord III outstanding prior to the Business Combination 3,941 Less: redemption of Concord III’s common stock ( 3,766 ) Sponsor earnout common stock outstanding prior to the Business Combination 8,625 Common stock of Concord III issued and outstanding 8,800 Common stock issued in PIPE Financing 4,530 Legacy GCT common stock 32,503 Total common stock issued and outstanding 45,833 The Business Combination was accounted for as a reverse recapitalization under U.S. GAAP because Legacy GCT was determined to be the accounting acquirer, and Concord III was identified as the accounting acquiree for financial reporting purposes. Accordingly, the consolidated financial statements of the Company represent a continuation of the consolidated financial statements of Legacy GCT, with the Business Combination treated as the equivalent of Legacy GCT issuing its common stock for the net assets of Concord III, accompanied by a recapitalization, and the net assets of Concord III were recorded at historical cost, with no goodwill or other intangible assets recorded. The results of operations prior to the Business Combination are those of Legacy GCT. Legacy GCT was determined to be the accounting acquirer based the following facts and circumstances: • Legacy GCT stockholders comprised a relative majority of the voting power of GCT; • Legacy GCT stockholders had the ability to nominate a majority of the members of the board of directors of GCT; • Legacy GCT’s operations prior to the Business Combination comprised the only ongoing operations of GCT; • Legacy GCT’s senior management comprised the senior management of GCT; • GCT substantially assumed the Legacy GCT name; • Legacy GCT’s headquarters became GCT’s headquarters; and • Concord III did not meet the definition of a business. PIPE Financing Concurrent with the execution of the Business Combination Agreement, certain investors entered into agreements and committed to purchase in a private placement an aggregate of 4,529,967 shares of the Company’s common stock (the “PIPE Shares”) at a purchase price of $ 6.67 per share for an aggregate purchase price of $ 30.2 million (the “PIPE Financing”) upon the Business Combination Closing. The PIPE Financing was consummated immediately prior to the Closing and resulted in net proceeds of $ 17.1 million to the Company. Private Placement Warrants and Public Warrants In November 2021, Concord III issued warrants to purchase shares of Concord III’s common stock that were assumed by the Company at the Closing of the Business Combination on the same terms and conditions: (i) 9,400,000 warrant shares that were issued in a private placement and held by the sponsor and another company (the “Private Placement Warrants”) and (ii) 17,250,000 warrant shares that were issued in connection with the initial public offering of Concord III (the “Public Warrants”). The Private Placement Warrants were reallocated at the Closing of the Business Combination as follows: (i) 4,492,650 warrants were vested and retained by the sponsor parties, (ii) 2,087,350 warrants were reallocated from the sponsor parties to certain recipients at Legacy GCT’s discretion to incentivize investment, and (iii) 2,820,000 were forfeited by the sponsor parties. Subsequent to the Closing, the outstanding Private Placement Warrants and Public Warrants remained liability-classified as the applicable provisions precluding classification in equity did not change as a result of the Business Combination. Legacy GCT Earnout Shares At the Closing of the Business Combination, former Legacy GCT stockholders and other investors of Legacy GCT have the right to receive up to 20,000,000 shares of Company common stock (“Legacy GCT Earnout Shares”). The Legacy GCT Earnout Shares may vest between May 2024 and March 2029 if the volume-weighted average price (“VWAP”) of the Company’s common stock for any 20 trading days within 30 consecutive trading day periods exceeds the following amounts per share (“VWAP Threshold”): (i) one -third of the shares based on the $ 12.50 per share VWAP Threshold, (ii) one -third of the shares based on the $ 15.00 per share VWAP Threshold, and (iii) one -third of the shares based on the $ 17.50 per share VWAP Threshold. In the event of a future transaction that results in a change in control in which shares of the Company common stock are converted into the right to receive cash or other consideration having a value equal to or in excess of a triggering event, then the Legacy GCT Earnout Shares subject to the applicable triggering event that have not been previously issued will be issued to the Legacy GCT stockholders effective as of immediately prior to the consummation of such transaction. In the event of a transaction that results in a change in control in which shares of Company common stock are converted into the right to receive cash or other consideration having a value less than a triggering event, then the Legacy GCT Earnout Shares subject to the applicable triggering event that have not been previously issued will be forfeited. The Legacy GCT Earnout Shares were recognized at a fair value of approximately $ 108.8 million upon the Closing and classified within the stockholders’ deficit as they are indexed solely to the Company’s common stock and are otherwise not precluded from equity classification based on their settlement provisions. Under the reverse recapitalization method of accounting, the fair value of the Legacy GCT Earnout Shares was treated as a deemed dividend and, in the absence of retained earnings, credited to additional paid-in capital without any impact on the stockholders’ deficit balances. Sponsor Earnout Shares Concurrently with entering into the Business Combination Agreement, the sponsor parties and the Company entered into that certain sponsor support agreement, as amended, modified, or supplemented (the “Sponsor Support Agreement”). Pursuant to the terms of the Sponsor Support Agreement, the sponsor parties have the right to receive up to 1,920,375 shares of the Company's common stock (“Sponsor Earnout Shares”). The Sponsor Earnout Shares are legally outstanding and remain unvested through September 30, 2024 . The Sponsor Earnout Shares may vest between September 2024 and March 2029 if the VWAP of the Company’s common stock for any 20 trading days within 30 consecutive trading day periods exceeds the following VWAP Thresholds: (i) one -third of the shares based on the $ 12.50 per share VWAP Threshold, (ii) one -third of the shares based on the $ 15.00 per share VWAP Threshold, and (iii) one -third of the shares based on the $ 17.50 per share VWAP Threshold. The Sponsor Earnout Shares were recognized at a fair value of approximately $ 10.4 million upon the Closing and classified within the stockholders’ deficit as they are indexed solely to the Company’s common stock and are otherwise not precluded from equity classification based on their settlement provisions. Under the reverse recapitalization method of accounting, the fair value of the Sponsor Earnout Shares was treated as a deemed dividend and, in the absence of retained earnings, credited to additional paid-in capital without any impact on the stockholders’ deficit balances. In July 2024, the number of Sponsor Earnout Shares subject to the market-based vesting condition was reduced to 570,796 shares of the Company’s common stock, as the sponsor parties did not meet the required performance condition for the entire grant. The remaining 1,349,579 shares previously included in the outstanding common stock were forfeited. No adjustments to the stockholders' deficit are required upon the forfeiture of the share-based awards that contain market conditions.

Disaggregation of Revenue

Disaggregation of Revenue	9 Months Ended
	Sep. 30, 2024
Disaggregation of Revenue
Disaggregation of Revenue	4. Disaggregation of Revenue All product revenue presented in the condensed consolidated statement of operations is recognized at a point in time, and all service revenue is recognized over time. Net revenues are categorized by customer location as follows (in thousands): Three Months Ended Nine Months Ended 2024 2023 2024 2023 South Korea $ 1,500 $ 4 $ 3,500 $ 3,010 United States 837 572 2,565 2,888 Germany 46 353 916 353 China 32 3,567 167 5,133 Other 195 ( 20 ) 195 455 Total $ 2,610 $ 4,476 $ 7,343 $ 11,839 Contract Assets and Liabilities Net revenues recognized during the nine months ended September 30, 2024 and 2023 for the amounts included in the contract liabilities balance at the beginning of the respective annual periods are less than $ 0.1 million and $ 0.7 million , respectively. As of September 30, 2024 and December 31, 2023, the contract assets were $ 5.1 million and $ 3.4 million , respectively. The balances of contract liabilities related to contract fulfillment were $ 0.5 million and immaterial as of September 30, 2024 and December 31, 2023 .

Fair Value of Measurements

Fair Value of Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value of Measurements
Fair Value of Measurements	5. Fair Value of Measurements Recurring Fair Value Measurements The following financial instruments are measured at fair value on a recurring basis (in thousands): September 30, 2024 Level 1 Level 2 Level 3 Total Liabilities: Convertible promissory notes $ — $ — $ 8,838 8,838 Warrant liabilities — — 3,197 3,197 Common stock forward liability — — 451 451 December 31, 2023 Level 1 Level 2 Level 3 Total Liabilities: Convertible promissory notes $ — $ — $ 34,033 $ 34,033 Valuation techniques and the inputs The table below presents valuation techniques and inputs used in the fair value measurement categorized within Level 3 of the fair value hierarchy (in thousands): Valuation techniques Inputs September 30, 2024 December 31, 2023 Convertible promissory notes, current Discounted Cash Flow Model (“DCF”) Discount rate, risk-free rate, credit spread, contractual cash flows $ 4,008 $ — PWERM Scenario of initial public offering (“IPO”) and merger and acquisition (“M&A”) — 27,794 Common stock forward liability DCF Various utilization scenarios, risk-free rate, remaining term 451 — Convertible promissory notes, net of current Binomial Lattice Model (“BLM”) Stock price, volatility, remaining term, risk-free rate, credit spread 4,830 — PWERM Scenario of initial public offering (“IPO”) and merger and acquisition (“M&A”) — 6,239 Warrant liabilities Black Scholes Merton Exercise price, term to expiration, volatility, risk-free rate 3,197 — As of September 30, 2024 , the key inputs for the convertible promissory notes valuation using the DCF model were as follows: remaining term ranging from 0.08 to 0.25 years and a discount rate of 10.07 %. As of September 30, 2024 , the key inputs for the convertible promissory notes, net of current, using the BLM were as follows: stock price of $ 3.35 , volatility of 35.5 %, remaining term of 1.4 years, risk-free rate of 3.85 %, and credit spread of 5.6 %. As of September 30, 2024 , the key inputs for the common stock forward valuation using the DCF model were as follows: a remaining term of 1.6 years and future risk-free rate estimates ranging from 3.78 to 4.93 % for this period. As of September 30, 2024 , the key inputs for the private placement warrants using the BSM were as follows: exercise price of $ 11.50 per share, term to expiratio n of 4.5 years, volatility of 35.5 %, and a risk-free rate of 3.55 %. As of September 30, 2024 , the key inputs for the public warrants using the BLM were as follows: exercise price of $ 11.50 per share and term to expiration of 4.5 years. As of September 30, 2024, th e key inputs for the other warrant liabilities using the BSM were as follows: an exercise price of $ 10.00 per share, or $ 18.75 per share, term to expiration ranging from 1.41 years to 2.1 years, volatility ranging from 38.1 % to 39.0 %, and a risk-free rate ranging from 3.62 % to 3.81 %. As of December 31, 2023, the PWERM was used as Legacy GCT was a private company. After the Closing, and as of September 30, 2024, the valuation techniques used reflect that the Business Combination was consummated. The following table sets forth a summary of the changes in the fair value of the convertible promissory notes (in thousands): As of December 31, 2023 $ 34,033 Conversion ( 41,209 ) Borrowing 16,290 Change in fair value 1,203 As of March 31, 2024 10,317 Repayment ( 630 ) Change in fair value ( 14 ) As of June 30, 2024 9,673 Repayment ( 1,000 ) Change in fair value 165 As of September 30, 2024 $ 8,838 The following table sets forth a summary of the changes in the fair value of the warrant liabilities (in thousands): As of December 31, 2023 $ — Fair value of warrants assumed at Closing 5,958 Change in fair value 4,626 As of March 31, 2024 10,584 Change in fair value ( 6,628 ) As of June 30, 2024 3,956 Change in fair value ( 759 ) As of September 30, 2024 $ 3,197 The following table sets forth a summary of the changes in the fair value of the common stock forward liability (in thousands): As of March 31, 2024 $ — Loss from initial recognition 586 Settlement in equity ( 51 ) As of June 30, 2024 535 Settlement in equity ( 84 ) As of September 30, 2024 $ 451

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2024
Balance Sheet Components [Abstract]
Balance Sheet Components	6. Balance Sheet Components Inventory Inventories consist of the following (in thousands): September 30, December 31, 2024 2023 Raw materials $ 1,247 $ 448 Work-in-process 504 601 Finished goods 1,359 437 Total inventory $ 3,110 $ 1,486 There were no inventory write-downs during the nine months ended September 30, 2024 and 2023. Prepaid expenses and other assets Prepaid expenses and other assets consist of the following (in thousands): September 30, December 31, 2024 2023 Prepaid expenses $ 1,372 $ 433 Prepaid insurance 566 — Prepaid research and development 565 — Prepaid inventory 524 279 Lease deposit 422 434 Other receivables and current assets 96 117 Deferred transaction costs — 1,643 Total prepaid expenses and other current assets $ 3,545 $ 2,906 Accrued and other current liabilities Accrued and other current liabilities consist of the following (in thousands): September 30, December 31, 2024 2023 Payroll and related expenses $ 9,126 $ 9,880 Accrued payables 6,764 6,319 Other taxes payable 3,191 158 Current portion of interest payable 2,560 6,915 Professional fees 548 499 Product warranty liabilities 37 55 Royalty and license fee 43 58 Other 96 72 Total accrued and other current liabilities $ 22,365 $ 23,956

Debt

Debt	9 Months Ended
	Sep. 30, 2024
Debt
Debt	7. Debt The Company’s outstanding debt was as follows (in thousands): September 30, 2024 December 31, 2023 Outstanding Fair Value Outstanding Fair Value Convertible promissory notes: Historical convertible promissory notes $ 4,000 $ 4,008 $ 35,347 $ 34,033 2024 convertible promissory note 5,000 4,830 — — Total convertible promissory notes 9,000 8,838 35,347 34,033 Borrowings: KEB Hana Bank 6,820 6,820 6,980 6,980 IBK Industrial Bank 6,972 6,972 7,135 7,135 Note payable (one individual investor) — — 1,000 1,000 Mujin Electronics Co., Ltd. 3,789 3,789 — — M-Venture Investment, Inc. — — 7,756 7,756 Anapass, Inc., related party 9,851 9,851 10,082 10,082 i Best Investment Co., Ltd 4,546 4,546 10,082 10,082 Kyeongho Lee, related party 841 841 1,474 1,474 Total debt $ 41,819 41,657 $ 79,856 78,542 Less: current portion ( 36,827 ) ( 72,303 ) Debt, net of current portion $ 4,830 $ 6,239 Expected future minimum principal payments under the Company’s total debt is as follows as of September 30, 2024 (in thousands): Years Convertible Borrowings Total 2024, remainder $ 4,000 $ 7,813 $ 11,813 2025 — 25,006 25,006 2026 5,000 — 5,000 Total debt $ 9,000 $ 32,819 $ 41,819 Convertible Promissory Notes Historical Convertible Promissory Notes Between 2017 and 2022, the Company issued convertible promissory notes to various investors with maturity dates ranging from October 2020 to April 2025. The annual interest rates varied between 4.0 % and 7.0 % . In November 2023, the Company entered into an amendment with certain convertible promissory noteholders to modify the conversion terms such that these notes were automatically convertible upon a special purpose acquisition company (“SPAC”) transaction. In March 2024, upon the Closing of the Business Combination, an aggregate principal and interest amount of $ 32.1 million converted into 4,258,223 shares of common stock at a conversion price of $ 10.00 . In April 2024, the Company repaid one of the convertible promissory notes that was issued in 2021 with a principal amount of $ 0.6 million . In August and September 2024, the Company repaid one of the convertible promissory notes that was issued in 2017 with a principal amount of $ 1.0 million. As of September 30, 2024 , the remaining principal and interest amount of $ 5.9 million was outstanding and related to one noteholder where conversion is at the noteholder’s discretion and at a conversion price of $ 3.50 per share. 2023 and 2024 Convertible Promissory Notes In November 2023, February 2024 and March 2024, the Company issued convertible promissory notes to certain investors (the “CVT Investors”), pursuant to which the CVT Investors agreed to lend to the Company an aggregate principal amount of $ 13.3 million . These notes had maturity dates ranging from November 2026 to March 2027, bore an interest rate of 5.0 % , and were automatically convertible upon IPO or SPAC transaction. In March 2024, upon the Closing of the Business Combination, an aggregate principal and interest amount of $ 13.4 million converted into 2,004,535 shares of common stock at a conversion price of $ 6.67 . As of September 30, 2024 , none of the notes issued to CVT Investors remain outstanding. In February 2024, the Company issued a convertible promissory note to a strategic investor for a principal amount of $ 5.0 million , which matures in February 2026 and bears an interest rate of 5.0 % per annum. On or after the earlier of (i) six months from the issuance date of the convertible promissory note and (ii) the Closing of the Business Combination, the noteholder may demand that the Company convert all principal and interest due under the convertible promissory note into shares of Company’s common stock, at a conversion price of $ 10.00 per share. This note includes customary representations, warranties, and events of default, as well as a covenant relating to the performance of obligations by the Company related to the Company’s 5G activity. As of September 30, 2024 , the remaining principal and interest amount of $ 5.1 million was outstanding. Borrowings Pursuant to Term Loan and Security Agreements The amounts in Korean Won (“KRW”) presented below were converted into US dollars based on the applicable historical exchange rates. KEB Hana Bank In July 2016, the Company entered into an unsecured term loan agreement with KEB Hana Bank, pursuant to which it borrowed 9.0 billion in KRW ($ 6.7 million), bearing a variable interest rate (initial annual interest rate of 2.6 % and interest ranging between 3.5 - 5.2 % as of June 30, 2024), paid monthly, and maturing in July 2017. The terms of such unsecured term loan agreement have been extended annually for additional one-year terms since 2017, and the maturity date was July 2024. In April 2024, the Company executed an amendment to extend the maturity date to April 2025 for the principal amount of KRW 1.0 billion ($ 0.7 million) with an interest rate of 3.5 %. In July 2024, the Company executed an amendment to extend the maturity date to July 2025 for the principal amount of KRW 8.0 billion ($ 6.0 million) with an interest rate of 4.9 %. Anapass, Inc., a related party, provided certificates of deposit as collateral to KEB Hana Bank to secure the Company’s obligations under this loan (see Note 8). IBK Industrial Bank In January 2017, the Company entered into a term loan agreement with IBK Industrial Bank, pursuant to which the Company borrowed KRW 9.2 billion ($ 6.8 million). The term loan has a maturity date in November 2024 and bears an annual interest rate of 4.9 %. Note Payable (One Individual Investor) In June 2021, the Company entered into a note payable agreement with an individual investor, pursuant to which the Company borrowed $ 1.0 million. The note had a maturity date of June 2024 and bears an annual interest rate of 4.0 %. In April 2022, the Company entered into an amendment with this one individual investor to remove the conversion right from the note payable. In June 2024, the Company executed an amendment with the individual investor to extend the maturity date from June 2024 to August 2024. In August 2024, the Company repaid this note. M-Venture Investment, Inc. In October 2021, the Company entered into a term loan and security agreement with M-Venture Investment, Inc. pursuant to which the Company borrowed KRW 5.0 billion ($ 3.7 million) and repaid KRW 0.6 billion ($ 0.4 million) and KRW 0.4 billion ($ 0.3 million) in 2021 and 2022, respectively, such that KRW 4.0 billion ($ 3.0 million) remained outstanding. The term loan bears an annual interest rate of 6.5 %. In April 2024, the Company executed an amendment with M-Venture Investment, Inc., pursuant to which the Company repaid KRW 2.0 billion ($ 1.5 million) in April 2024. In May 2024, the Company repaid the term loan in full. In April 2022, the Company entered into a term loan and security agreement with M-Venture Investment, Inc., pursuant to which the Company borrowed amounts in two draws of KRW 1.0 billion ($ 0.7 million) and KRW 5.0 billion ($ 3.7 million), respectively. The term loan had a maturity date in April 2024, and each respective draw bears an annual interest rate of 6.5 % and 8.7 %. In April 2024, the Company executed an amendment with M-Venture Investment, Inc., pursuant to which the maturity date for both draws were amended. The maturity date for the principal amount of KRW 1.0 billion ($ 0.7 million) was extended from April 2024 to June 2024. The maturity date for the principal amount of KRW 5.0 billion ($ 3.7 million) was extended from April 2024 to July 2024. In July 2024, the Company partially repaid the loan of KRW 1.0 billion ($ 0.7 million) and transferred the remaining balance (“M-Venture Loan”) as further discussed below. Mujin Electronics Co., Ltd. In July 2024, the Company executed agreement with M-Venture Investment, Inc. and Mujin Electronics Co., Ltd., in which Mujin Electronics Co., Ltd. fully assumed the remaining M-Venture Loan with the same principal amount of KRW 5.0 billion ($ 3.7 million). The maturity date of assumed loan is January 2025, with an interest rate of 6.8 %. Anapass, Inc., Related Party In July 2016, the Company entered into a loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 6.0 billion ($ 4.5 million) in a term loan. Interest only payments are due monthly at 5.5 % per annum and the principal amount of the term loan is due on the maturity date of July 2024. In July 2024, the Company and Anapass, Inc. amended the loan agreement to extend the maturity date from July 2024 to July 2025. The loan is collateralized by the Company’s assets as described under the Assets Pledged as Collateral (see Note 8). In May and September 2022, the Company entered into two term loan agreements with Anapass, Inc. pursuant to which the Company borrowed KRW 3.0 billion ($ 2.2 million) and KRW 4.0 billion ($ 3.0 million). The term loans had respective maturity dates in May 2024 and September 2024 and both bear an annual interest rate of 5.5 %. In May 2024, the Company executed an amendment with Anapass, Inc., to extend the maturity date from May 2024 to May 2025 for the term loan entered in May 2022. In September 2024, the Company executed an amendment with Anapass, Inc., to extend the maturity date from September 2024 to September 2025 for the term loan entered in September 2022. i Best Investment Co., Ltd Between 2022 and 2023 , the Company entered into multiple term loans and security agreements with i Best Investment Co., Ltd pursuant to which it borrowed principal amounts in six draws with an aggregate principal balance of KRW 14.0 billion ($ 10.3 million). All of the term loans had a maturity date in June 2024 and bear an annual interest rate of 6.5 %. In June 2024, the Company executed an amendment with the I Best Investment Co., Ltd to extend the maturity date from June 2024 to August 2024 for its first draw, fifth draw and sixth draw. In December 2023, the Company made a $ 0.8 million repayment of the outstanding principal and interest on its second draw. In March 2024, the Company repaid $ 2.3 million of the outstanding principal and interest amount of its fourth draw. In June 2024, the Company repaid in full of the term loans with a principal amount of $ 1.4 million outstanding on its third draw. In July 2024, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from August 2024 to February 2025 for its first draw, fifth draw and sixth draw. Kyeongho Lee, Related Party Between 2017 and 2021, the Company entered into multiple promissory note and term loan agreements with Kyeongho Lee pursuant to which the Company borrowed (a) KRW 500.0 million ($ 0.4 million), and KRW 500.0 million ($ 0.4 million) in promissory notes, and (b) KRW 1.0 billion ($ 0.7 million) and KRW 110.0 million ($ 0.1 million) in term loans. The promissory notes have a maturity date in November 2024 and bear an annual interest rate varying from 7.5 % and 9.0 %. In March 2024, the Company repaid to Kyeongho Lee the term loan of KRW 1.0 billion ($ 0.7 million). The outstanding term loan had a maturity date in May 2024 and bears no interest. In May 2024, the Company executed an amendment with Kyeongho Lee to extend the maturity date from May 2024 to November 2024 for its term loan.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies
Commitments and Contingencies	8. Commitments and Contingencies Litigations The Company is subject to various claims arising in the ordinary course of business. Although no assurance can be given, the Company believes that it is not a party to any litigation of which the outcome, if determined adversely, would individually, or in the aggregate, be reasonably expected to have a material adverse effect on the business, consolidated operating results, cash flows or financial position of the Company as of September 30, 2024. Third parties have from time to time claimed, and others may claim in the future, that the Company has infringed their past, current or future intellectual property rights. These claims, whether meritorious or not, could be time-consuming, result in costly litigation, require expensive changes in the Company’s methods of doing business or could require the Company to enter into costly royalty or licensing agreements, if available. As a result, these claims could harm the Company’s business, consolidated operating results, cash flows, and financial position. Purchase Commitments The Company has certain commitments for outstanding purchase orders related to the manufacture of certain wafers utilized by the Company and other services that, once the wafers are placed into production, are noncancelable. Otherwise, these production agreements are cancellable at any time with the Company required to pay all costs incurred through the cancellation date. However, the Company does not have a history of cancelling these agreements once production has started. As of September 30, 2024 , the Company had outstanding noncancelable purchase commitments for these production agreements of $ 0.2 million. Samsung Agreement Liability Release In July 2020, the Company entered into a research and development agreement with Samsung Electronics Co., Ltd (“Samsung”). According to the agreement, the Company would design 5G chip products and Samsung would provide development and intellectual property support, mass production set up support including mask sets for manufacturing and engineering sample chip supply to the Company for a specific product. The total fee amount for the research and development (“R&D”) services pursuant to the agreement was $ 21.1 million . The Company bore the risk of R&D failure and was obligated to pay the $ 21.1 million total fee based on milestones defined in the agreement, of which $ 11.7 million was due based on development milestones and $ 9.4 million of additional NRE (“non-recurring engineering”) was to be paid within a maximum of 4 years after the planned product first shipment date. The Company recognized R&D expenses based on an estimate of the percentage completion of services provided by Samsung during the respective financial reporting period. In the first quarter of 2024, Samsung agreed to unconditionally release the Company from payment for work Samsung had completed to date because it had not met certain of the development milestones and due to a change in Samsung’s business strategy. As a result, the Company recognized a gain of $ 14.6 million upon such unconditional release of its liability to Samsung. During the period ended March 31, 2024, the parties mutually agreed that the agreement had expired and there were no remaining obligations of either party under the agreement. Alpha Foundry Product Development Agreement In February 2024, the Company and Alpha Holdings Co., Ltd. (“Alpha”) entered into a foundry product development agreement related to 5G chip development for a total fee of $ 7.6 million . The Company bears the risk of R&D failure and is obligated to pay the fee based on milestones defined in the agreement. The Company recognizes R&D expenses based on an estimate of the percentage completion of services provided by Alpha during the respective financial reporting period. For the three and nine months ended September 30, 2024 , the Company recorded $ 1.2 million and $ 6.0 million in R&D expenses related to services provided by Alpha. The aggregate unpaid amount related to this agreement was $ 4.9 million as of September 30, 2024. Assets Pledged as Collateral The Company has provided collateral to Anapass, Inc., a related party (see Note 14), for borrowings from KEB Hana Bank, IBK Industrial Bank and Anapass, Inc. in the amount of $ 6.8 million, $ 7.0 million and $ 9.9 million, respectively, as of September 30, 2024, and $ 7.0 million , $ 7.1 million and $ 10.1 million , respectively, as of December 31, 2023 (see Note 7). The following table includes a summary of the carrying amounts related to collateral provided to Anapass, Inc. (in thousands): September 30, December 31, 2024 2023 Cash and cash equivalents $ 1,732 $ 254 Accounts receivable 6,447 4,920 Inventory 3,110 1,486 Property and equipment 206 352 Intangible assets and others 884 199

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2024
Common Stock
Common Stock	9. Common Stock B. Riley Purchase Agreement Pursuant to the Purchase Agreement, the Company has the right, but not the obligation, to sell to B. Riley, from time to time, up to $ 50.0 million worth of shares of its common stock (“Commitment Amount”), subject to certain limitations and conditions at the Company’s sole discretion. The price per share payable by B. Riley on each trading day represents an amount equal to 98 % of the VWAP of the Company’s common stock for the applicable pricing period. The Purchase Agreement requires settlement in registered shares. In May 2024, the Company filed a registration statement on Form S-1 with the SEC, which became effective on June 6, 2024 (“Registration Statement”). The Company may sell shares of its common stock to B. Riley through June 2026 up to the Commitment Amount so long that it remains in compliance with the Purchase Agreement. The Purchase Agreement was determined to be an equity-linked contract that contains a purchased put option on the Company’s common stock and variable share forward. These freestanding instruments are precluded from equity classification since the Purchase Agreement requires shareholder approval for the issuance of shares in excess of the applicable ownership limitation caps, which is not an input in a fixed-for-fixed option or forward on equity shares. As of April 2024, the Company determined that the fair value of the put option was nominal due to the short settlement period of one day or less, and the Company recognized a liability of $ 0.6 million related to the freestanding common stock forward contract. The fair value of the common stock forward liability represents the probability-adjusted present value of the discount to be granted to B. Riley with respect to the sales of its common stock under the Purchase Agreement compared to the VWAP of the company’s common stock for the applicable pricing period. In connection with the Purchase Agreement, the Company issued 56,818 shares of its common stock (“Commitment Shares”), which included a make-whole provision requiring the Company to reimburse B. Riley in cash if the fair value of these shares is less than $ 0.25 million . The Company recognized this amount as a liability which remained outstanding as of September 30, 2024 since the Commitment Shares remained unsold by B. Riley. During the three months ended June 30, 2024, the Company sold an aggregate of 678,462 shares of common stock for $ 3.3 million , of which $ 0.5 million was withheld by B. Riley against the outstanding amounts payable, and $ 2.8 million was received by the Company in cash. During the three months ended September 30, 2024, the Company sold an aggregate of 1,421,715 shares of common stock for $ 5.5 million. B. Riley withheld an additional $ 0.5 million from the aggregate proceeds against the outstanding amounts payable, and $ 5.0 million was received by the Company in cash. Issuance of Common Stock to Underwriter In April 2024, the Company authorized the issuance of 110,000 shares of its common stock to an underwriter previously involved in activities leading to the Business Combination, contingent on the Registration Statement’s effectiveness. The Company determined that its obligation to issue the underwriter shares met the criteria for equity classifications, and the underlying shares of common stock were issued in June 2024. Based on the timing of approval, the Company recognized $ 0.7 million in charges to equity and included this amount in general and administrative expenses for the three months ended June 30, 2024. Private Placement In September 2024, the Company executed a securities purchase agreement with Anapass, Inc, and issued 741,603 shares of common stock (“Anapass Shares”) and 148,320 equity-classified common stock warrants (“Anapass Warrants”) in exchange for $ 2.2 million in cash (“Private Placement”). The Company allocated the proceeds based on the relative fair value of the securities issued, including $ 2.0 million to the Anapass Shares and $ 0.2 million to the Anapass Warrants. The Anapass Warrants are immediately exercisable at $ 3.02 per share and will expire five years following the issuance date. Anapass, Inc. remains subject to a lock-up and market stand-off agreement for any shares and share-based instruments issued to it by the Company through March 2025. Common Stock Reserved for Issuance Upon the Closing of the Business Combination in March 2024, the Company increased its total number of authorized shares to 440,000,000 shares, consisting of 400,000,000 shares of common stock and 40,000,000 shares of preferred stock. The Company has reserved shares of common stock for issuance as follows (in thousands): September 30, December 31, 2024 2023 Common stock warrants 26,273 2,894 Legacy GCT Earnout Shares 20,000 — Shares available for future grant from 2024 plan 3,762 — Convertible promissory notes 713 1,835 Options issued and outstanding 550 668 Shares available for future grant from 2024 ESPP 600 — RSUs outstanding 611 392 Shares available for future grant from 2011 plan — 113 Total 52,509 5,902

Warrants

Warrants	9 Months Ended
	Sep. 30, 2024
Warrants
Warrants	10. Warrants The following table represents a summary of warrants to purchase shares of the Company’s common stock that are outstanding (in thousands, except for exercise price): Issue Date September 30, 2024 Exercise Price Expiration February 2023 - June 2023 2,115 $ 10.00 - $ 18.75 February 2026 – June 2026 July 2023 80 $ 10.00 July 2026 October 2023 100 $ 10.00 October 2026 Private and public warrants 23,830 $ 11.50 March 2029 September 2024 148 $ 3.02 September 2029 Total 26,273

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2024
Stock-Based Compensation
Stock-Based Compensation	11. Stock-Based Compensation 2011 Incentive Compensation Plan Legacy GCT’s 2011 Incentive Compensation Plan (the “2011 Plan”) permitted the grant of options, stock awards, and RSUs. In connection with the Closing of the Business Combination, the 2011 Plan was terminated, the remaining unallocated shares reserved under the 2011 Plan were cancelled. In March 2024, each award of Legacy GCT stock options and RSUs were converted into equivalent Company stock options and RSUs with the same terms and conditions under the plan described below. 2024 Incentive Compensation Plan In March 2024, the Company adopted the 2024 Omnibus Incentive Compensation Plan (the “2024 Plan”), under which 3,983,334 shares of common stock were initially reserved for issuance. The 2024 Plan permits the grant of stock options, stock appreciation rights, stock awards, RSUs, dividend equivalent rights, cash awards, and other awards to employees and non-employees, including members of the board of directors, consultants, or advisors. Stock options outstanding under the 2024 Plan were as follows (in thousands, except per share amounts and years): Number of Weighted Weighted Aggregate Balance as of December 31, 2023 3,579 $ 0.02 5.5 $ 4,045 Reverse recapitalization ( 2,911 ) 0.09 — — Balance as of December 31, 2023 (1) 668 0.11 5.5 4,045 Exercised ( 118 ) 0.11 Balance as of September 30, 2024 550 $ 0.11 4.6 $ 1,785 Vested and expected to vest as of September 30, 2024 550 $ 0.11 4.6 $ 1,785 Exercisable as of September 30, 2024 533 $ 0.11 4.5 $ 1,729 (1) Amounts as of December 31, 2023 differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (see Note 3). No options were granted during the nine months ended September 30, 2024. As of September 30, 2024 , unrecognized compensation cost related to stock options was nominal. The aggregate intrinsic value of 117,670 options exercised during the three months ended September 30, 2024 was $ 0.3 million. Founder Awards to Board of Directors In 2021, an aggregate of 90,000 shares of common stock were transferred to three members of Concord III’s board of directors (“Founder Shares”). The Founder Shares contained double-trigger vesting, which required continuous service and a liquidity event for any shares to vest. As the required conditions were met upon the Closing, the Company recognized $ 0.9 million of stock-based compensation upon the Closing in March 2024. Restricted Stock Units In December 2023, various employees and directors of Legacy GCT were granted 392,000 RSUs that contain both a performance condition based upon a liquidity event and a service vesting condition such that (subject to the liquidity event condition being satisfied) the RSUs vest in four equal annual installments from the grant date (“2023 RSUs”). The liquidity condition was met upon the Closing. In June 2024, the Company granted to the members of its board of directors certain share-based awards with a fixed monetary amount of $ 0.7 million equally allocated among six grantees (“2024 RSUs”). The number of shares issuable to each grantee under the 2024 RSUs is calculated by dividing one-fourth of the allocated fixed monetary amount by the closing price of the Company’s common stock at the end of each fiscal quarter between April 1, 2024 and March 31, 2025. The RSUs will vest on March 31, 2025, subject to the grantees’ continuous service to the Company and will be settled in common stock on various dates in 2026 and 2027. The 2024 RSUs are initially classified as a liability and reclassified to equity up to the monetary amount for which the number of shares to be issued becomes determinable. Through September 30, 2024, this determination was made for 80,916 shares based on the closing price of the Company’s common stock as of each fiscal quarter-end after the grant date. In August 2024, the Company granted various employees 140,000 RSUs that vest in four equal annual installments subject to continuous service. RSUs outstanding under the 2024 Plan were as follows (in thousands, except per share amounts): Number of RSUs Weighted Balance as of December 31, 2023 2,100 $ 1.15 Reverse recapitalization ( 1,708 ) 5.01 Balances as of December 31, 2023 (1) 392 $ 6.16 Granted 221 3.69 Cancelled ( 2 ) 6.16 Balance as of September 30, 2024 611 $ 5.26 (1) Amounts as of December 31, 2023 differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (see Note 3). The Company recognized $ 0.6 million and $ 1.2 million of stock-based compensation during the three and nine months ended September 30, 2024, respectively, related to the outstanding RSUs. As of September 30, 2024 , there was $ 2.3 million of unrecognized compensation cost related to RSUs, which is expected to be recognized on a straight-line basis over a weighted average period of 3.0 years. Any unvested RSUs are forfeited upon separation from the Company. Forfeitures are accounted for as they occur. Stock-Based Compensation The following table summarizes stock-based compensation included in the Company’s condensed consolidated statements of operations: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Cost of revenues 33 — 33 — Research and development 135 1 389 3 Sales and marketing 36 1 108 3 General and administrative 369 1 1,589 2 Total $ 573 $ 3 $ 2,119 $ 8

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Taxes
Income Taxes	12. Income Taxes For financial reporting purposes, the Company’s effective tax rate used for the interim periods is based on the estimated full-year income tax rate. For the three and nine months ended September 30, 2024, the Company’s effective tax rate differs from the statutory rate primarily due to the valuation allowance recorded against the net deferred tax asset balance. For the nine months ended September 30, 2024 and 2023 , the Company recorded income tax of $ 0.2 million and $ 0.1 million, respectively. The effective tax rate is ( 2.6 )% and ( 1.0 )% for nine months ended September 30, 2024 and 2023, respectively. Through September 30, 2024, the Company was not under examination by any taxing authority. As of September 30, 2024 the Company had unrecognized tax benefits of $ 3.1 million of which $ 1.7 million would currently affect the Company’s effective tax rate if recognized due to the Company’s deferred tax assets being fully offset by a valuation allowance. The Company does not anticipate that the amount of unrecognized tax benefits relating to tax positions existing as of September 30, 2024 will significantly increase or decrease within the next twelve months. There was no interest expense or penalties related to unrecognized tax benefits recorded as of September 30, 2024. A number of years may elapse before an uncertain tax position is audited and finally resolved. While it is often difficult to predict the final outcome or the timing of resolution of any particular uncertain tax position, the Company believes that its reserves for income taxes reflect the most likely outcome. The Company adjusts these reserves, as well as the related interest, considering changing facts and circumstances.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2024
Employee Benefit Plans
Employee Benefit Plans	13. Employee Benefit Plans Under Korean law, the Company is required to make severance payments to Korean employees leaving their employment. The Company’s severance pay liability to its Korean employees, which is a function of the employee’s salary, years of employment, and severance factor, is reflected in the accompanying unaudited condensed consolidated balance sheets as the net defined benefit liabilities on an accrual basis. The net liability for severance payments was as follows (in thousands): September 30, 2024 December 31, 2023 Liability for severance payments, gross $ 8,328 $ 7,997 Plan assets ( 276 ) ( 308 ) Liability for severance payments, net $ 8,052 $ 7,689

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2024
Related Party Transactions
Related Party Transactions	14. Related Party Transactions A summary of balances and transactions with the related parties who are stockholders of the Company were as follows (in thousands): September 30, 2024 December 31, 2023 Anapass Kyeongho Lee Anapass Kyeongho Lee Borrowings $ 9,851 $ 841 $ 10,082 $ 1,474 Other current liabilities 9 86 212 182 For each of the three and nine months ended September 30, 2024 , the Company recorded $ 0.1 million and $ 0.4 million, respectively, of interest expense with Anapass, Inc. in the unaudited condensed consolidated statements of operations. For each of the three and nine months ended September 30, 2023 , the Company recorded $ 0.1 million and $ 0.4 million, respectively, of interest expense with Anapass, Inc. in the unaudited condensed consolidated statements of operations. Interest expense related to the Company’s arrangements with Kyeongho Lee was immaterial during the three and nine months ended September 30, 2024 and 2023 .

Segments and Information

Segments and Information	9 Months Ended
	Sep. 30, 2024
Segments and Information
Segments and Information	15. Segments and Information The Company operates in one segment. Revenue information by geographic region is presented in Note 4 to these unaudited condensed consolidated financial statements. Tangible long-lived assets by geographic region were as follows (in thousands): September 30, 2024 December 31, 2023 South Korea $ 1,041 $ 1,363 United States 665 930 Total $ 1,706 $ 2,293

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2024
Net Loss Per Share
Net Loss Per Share	16. Net Loss Per Share The following outstanding potentially dilutive common stock equivalents were excluded from the computation of diluted net loss per share for the periods indicated because including them would have been antidilutive (in thousands): September 30, 2024 2023 Warrants 26,273 2,214 Legacy GCT Earnout Shares 20,000 — Sponsor Earnout Shares 571 — Convertible promissory notes 713 1,806 Options 550 670 RSU 611 — Total 48,718 4,690

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2024
Subsequent Events
Subsequent Events	17. Subsequent Events Mujin Electronics Co., Ltd. In October 2024, the Company executed an amendment with Mujin Electronics Co., Ltd. to extend the maturity date of KRW 5.0 billion ($ 3.7 million) loan from January 2025 to June 2025. i Best Investment Co., Ltd In October 2024, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from February 2025 to May 2025 for its sixth draw. Historical Convertible Promissory Notes In October 2024, the Company repaid one of the convertible promissory notes that was issued in 2017 with a principal amount of $ 1.0 million. Purchase Agreement In October 2024, the Company sold 103,596 shares of its common stock for gross proceeds of $ 0.3 million received by the Company in cash. Kyeongho Lee, Related Party In November 2024, the Company entered into a term loan agreement with Kyeongho Lee, a member of the Company’s board of directors, pursuant to which the Company borrowed KRW 4.0 billion ($ 2.9 million). The loan has a maturity date of December 31, 2024 and bears an annual interest rate of 12.0 %.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2024
Summary of Significant Accounting Policies and Basis of Presentation
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation The unaudited condensed consolidated financial statements and accompanying notes include the accounts of the Company and its wholly owned subsidiaries, after elimination of intercompany balances and transactions. The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and the requirements of the Securities and Exchange Commission (“SEC”) for interim financial information. Certain information and disclosures normally included in unaudited consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. Accordingly, these interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto for the year ended December 31, 2023, which are included in the Company’s Form 8‑K filed with the SEC on April 1, 2024. The information as of December 31, 2023 included in the condensed consolidated balance sheets was derived from the audited consolidated financial statements. Certain amounts reported in the audited consolidated financial statements for the year ended December 31, 2023 have been reclassified to conform to the current year’s presentation. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial information. The unaudited condensed consolidated results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other future annual or interim period.
Use of Estimates	Use of Estimates The preparation of the accompanying unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make judgments, estimates, and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. These judgments, estimates, and assumptions are used for but not limited to revenue recognition, provision for credit losses, deferred income taxes and related valuation allowances, inventory obsolescence, recoverability of long-lived assets, certain accrued expenses, stock-based compensation, determination of the fair value of the Company’s financial instruments, including convertible promissory notes, common stock of Legacy GCT prior to the reverse recapitalization, warrant liabilities, stock options, and common stock forward liability. The Company bases its estimates and judgments on historical experience and on various other assumptions that it believes are reasonable under the circumstances. Actual results could differ from these estimates, and these differences may be material.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amount of certain financial instruments held by the Company, such as cash equivalents, accounts receivable, contract assets and liabilities, accounts payable, and accrued and other current liabilities, approximate fair value due to their short maturities. The carrying amount of the liabilities for the convertible promissory notes and the historical convertible promissory notes (see Note 5) represents their fair value. The carrying amounts of the Company’s bank borrowings and lease liabilities approximate their fair values due to the market interest rates that these obligations bear and interest rates available to the Company. Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows: Level 1 Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 Inputs other than quoted prices included within Level 1 that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity for the related assets or liabilities. A financial instrument's categorization within the valuation hierarchy is based on the lowest level of input that is significant to the fair value measurement. The Company’s Level 3 financial instruments consist of a common stock forward liability, convertible promissory notes, and warrant liabilities.
Risk and Uncertainties	Risk and Uncertainties The Company is subject to certain risks and uncertainties and believes changes in any of the following areas could have a material adverse effect on the Company’s future financial position or results of operations or cash flows: 5G and other new product development, including market receptivity, the ability to satisfy obligations under development agreements with major partners, litigation or claims against the Company based on intellectual property, patent, product regulation or other factors, competition from other products, general economic conditions, the ability to attract and retain qualified employees and ultimately to sustain profitable operations. The semiconductor industry is characterized by rapid technological change, competition, competitive pricing pressures, and cyclical market patterns. The Company’s financial results are affected by a wide variety of factors, such as general economic conditions specific to the semiconductor industry and the Company’s particular market, the timely implementation of new 5G and other new products, new manufacturing process technologies, and the ability to safeguard patents and intellectual property in a rapidly evolving market. In addition, the semiconductor market has historically been cyclical and subject to significant economic downturns. As a result, the Company may experience significant period-to-period fluctuations in unaudited condensed consolidated operating results due to the abovementioned factors. The Company’s revenue may be impacted by its ability to obtain adequate wafer supplies from foundries and back-end production capacity from the Company’s test and assembly subcontractors. The foundries with which the Company currently has arrangements may not be willing or able to satisfy all of the Company’s manufacturing requirements on a timely basis or at favorable prices. The Company is also subject to the risks of service disruptions, raw material shortages and price increases by its foundries. Such disruptions, shortages and price increases could harm the Company’s consolidated operating results.
Provision for Credit Losses	Provision for Credit Losses The provision for credit losses is based on the Company’s assessment of the collectibility of its customer accounts. The Company reviews the provision for credit losses by considering certain factors such as historical experience, industry data, credit quality, age of balances, and current economic conditions that may affect a customer’s ability to pay. Uncollectible receivables are written off when all efforts to collect have been exhausted and recoveries are recognized when they are recovered. The Company determined that provisions for credit losses of approximately $ 1.1 million and $ 1.6 million were necessary as of September 30, 2024 and December 31, 2023 , respectively.
Concentration of Credit Risk	Concentration of Credit Risk The Company’s financial instruments subject to credit risk concentration consist of cash and cash equivalents and accounts receivable. The Company maintains its cash and cash equivalents primarily with one financial institution located in the United States and another located in South Korea, where amounts deposited may exceed Federal Deposit Insurance Corporation or Korea Deposit Insurance Corporation limits. The Company’s accounts receivable balances are primarily derived from revenues recognized from customers located in the United States, China, South Korea, Japan, and Taiwan. The Company performs ongoing credit evaluations of the financial condition of its customers and distributors and generally does not require collateral. The Company’s net revenues and accounts receivable are concentrated among a few significant customers, which could expose the Company to financial risk in the event of adverse developments. The following represents the concentration of the Company’s gross accounts receivable among key customers to the extent their share exceeds 10%: Customer September 30, 2024 December 31, 2023 Customer A 27 % — % Customer H 20 % 19 % Customer I 12 % 14 % Customer J 12 % 27 % Customer K — % 10 % The following table includes customers that individually accounted for more than 10% of the Company’s net revenues in the periods indicated: Three Months Ended Nine Months Ended Customer 2024 2023 2024 2023 Customer A — % — % 27 % — % Customer B 24 % — % 25 % — % Customer C — % — % 12 % — % Customer D — % — % — % 25 % Customer F — % 13 % — % 13 % Customer H 57 % — % 20 % — % Customer I — % 24 % — % — % Customer J — % 47 % — % 20 % Management closely monitors the creditworthiness and performance of these key customers and has established credit limits and terms to mitigate potential credit risks. The Company also continues diversifying its customer base and exploring opportunities to reduce its reliance on a few major customers.
Foreign Currency	Foreign Currency Financial statements of foreign subsidiaries that use the local currency as their functional currency are translated into U.S. dollars at the end-of-period exchange rates or at historical exchange rates for purposes of consolidation. Revenues and expenses are translated using average exchange rates during the reporting period. Translation adjustments are included in accumulated other comprehensive loss within stockholders’ deficit. Gains and losses resulting from transactions denominated in a currency other than the functional currency are included in other income (expenses), net in the unaudited condensed consolidated statements of operations. The Company recognized foreign currency exchange losses of $ 1.1 million and gains of $ 0.8 million for the three and nine months ended September 30, 2024, respectively. The Company recognized $ 0.9 million and $ 1.8 million of foreign currency exchange gains for the three and nine months ended September 30, 2023 , respectively.
Convertible Promissory Notes	Convertible Promissory Notes The Company has elected the fair value option to account for its outstanding convertible promissory notes. Changes in the estimated fair value of the outstanding convertible promissory notes are recognized in other income (expenses), net in the condensed consolidated statements of operations.
Common Stock Warrants	Common Stock Warrants Common stock warrants are classified as liabilities if they do not meet equity classification requirements based on their settlement mechanism upon a change of control and similar transactions. The corresponding liability is remeasured at fair value while the common stock warrants remain outstanding, with changes in fair value recognized in other income (expenses), net in the unaudited condensed consolidated statements of operations. Common stock warrants that meet equity classification requirements are credited to stockholders’ deficit on their issuance dates and are not subsequently remeasured.
Certain Equity Contracts	Certain Equity Contracts The Company’s promises to potentially issue additional shares in the future based on certain market conditions, including the Legacy GCT Earnout Shares and the Sponsor Earnout Shares, are discussed in Note 3. These financial instruments were determined to be equity classified and credited to the stockholders’ deficit upon consummation of the Business Combination.
Emerging Growth Company Status	Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS” Act). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards using private company timelines. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these unaudited condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2020‑06, Debt—Debt with Conversion and Other Options (Subtopic 470‑20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815‑40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020‑06 reduces the number of accounting models for convertible instruments and allows more contracts to qualify for equity classification. The Company adopted this guidance effective January 1, 2024 and noted no material impact on the Company’s unaudited condensed consolidated financial statements. In October 2021, the FASB issued ASU 2021‑08, Business Combinations (Topic 805) : Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (“ASU 2021-08”), which provides an exception to fair value measurement for contract assets and contract liabilities related to revenue contracts acquired in a business combination. ASU 2021-08 requires an acquirer to recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with Topic 606. At the acquisition date, an acquirer should account for the related revenue contracts in accordance with Topic 606 as if it had originated the contracts. The Company adopted this guidance effective January 1, 2024 and noted no material impact on the Company’s unaudited condensed consolidated financial statements. In June 2022, the FASB issued ASU 2022‑03, Fair Value Measurement (Topic 820) : Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions (“ASU 2022-03”). ASU 2022-03 clarifies that a contractual restriction on the sale of an equity security should not be considered in measuring the fair value of the equity security and cannot be recognized as a separate unit of account. ASU 2022-03 also requires the investor to disclose the fair value of equity securities subject to contractual sale restrictions, the nature and remaining duration of the restrictions, and the circumstances that could cause a lapse in the restrictions. ASU 2022-03 is effective for annual and interim periods beginning after December 15, 2024, with early adoption permitted. The Company retrospectively adopted this guidance effective July 1, 2024 and noted no material impact on the Company’s unaudited condensed consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280) : Improvements to Reportable Segment Disclosures (“ASU 2023-07”), which expands annual and interim disclosure requirements for reportable segments, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for annual periods beginning after December 15, 2023 and for interim periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the effect of the adoption of ASU 2023-07 on its unaudited condensed consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740) : Improvements to Income Tax Disclosures (“ASU 2023-09”), which requires companies to disclose, on an annual basis, specific categories in the effective tax rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. In addition, companies are required to disclose additional information about income taxes paid. ASU 2023 -09 is effective for annual periods beginning after December 15, 2024, with early adoption permitted. The standard is required to be adopted on a prospective basis; however, retrospective application is permitted. The Company is currently evaluating the effect of the adoption of ASU 2023-09 on its unaudited condensed consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2024
Summary of Significant Accounting Policies and Basis of Presentation
Schedule of net revenues and accounts receivable concentration	The following represents the concentration of the Company’s gross accounts receivable among key customers to the extent their share exceeds 10%: Customer September 30, 2024 December 31, 2023 Customer A 27 % — % Customer H 20 % 19 % Customer I 12 % 14 % Customer J 12 % 27 % Customer K — % 10 % The following table includes customers that individually accounted for more than 10% of the Company’s net revenues in the periods indicated: Three Months Ended Nine Months Ended Customer 2024 2023 2024 2023 Customer A — % — % 27 % — % Customer B 24 % — % 25 % — % Customer C — % — % 12 % — % Customer D — % — % — % 25 % Customer F — % 13 % — % 13 % Customer H 57 % — % 20 % — % Customer I — % 24 % — % — % Customer J — % 47 % — % 20 %

Reverse Recapitalization (Table

Reverse Recapitalization (Tables)	9 Months Ended
	Sep. 30, 2024
Reverse Recapitalization
Schedule of outstanding common stock	Immediately after the Closing, the Company’s outstanding common stock included the following components (in thousands): Shares Common stock of Concord III outstanding prior to the Business Combination 3,941 Less: redemption of Concord III’s common stock ( 3,766 ) Sponsor earnout common stock outstanding prior to the Business Combination 8,625 Common stock of Concord III issued and outstanding 8,800 Common stock issued in PIPE Financing 4,530 Legacy GCT common stock 32,503 Total common stock issued and outstanding 45,833

Disaggregation of Revenue (Tabl

Disaggregation of Revenue (Tables)	9 Months Ended
	Sep. 30, 2024
Organization and Liquidity
Schedule of disaggregation of revenues from contracts with customers and categorized by customer location	All product revenue presented in the condensed consolidated statement of operations is recognized at a point in time, and all service revenue is recognized over time. Net revenues are categorized by customer location as follows (in thousands): Three Months Ended Nine Months Ended 2024 2023 2024 2023 South Korea $ 1,500 $ 4 $ 3,500 $ 3,010 United States 837 572 2,565 2,888 Germany 46 353 916 353 China 32 3,567 167 5,133 Other 195 ( 20 ) 195 455 Total $ 2,610 $ 4,476 $ 7,343 $ 11,839

Fair Value of Measurements (Tab

Fair Value of Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value of Measurements
Schedule of Financial Instruments are Measured at Fair Value on a Recurring Basis	The following financial instruments are measured at fair value on a recurring basis (in thousands): September 30, 2024 Level 1 Level 2 Level 3 Total Liabilities: Convertible promissory notes $ — $ — $ 8,838 8,838 Warrant liabilities — — 3,197 3,197 Common stock forward liability — — 451 451 December 31, 2023 Level 1 Level 2 Level 3 Total Liabilities: Convertible promissory notes $ — $ — $ 34,033 $ 34,033
Schedule of Valuation Techniques and Inputs Used in the Fair Value Measurement	The table below presents valuation techniques and inputs used in the fair value measurement categorized within Level 3 of the fair value hierarchy (in thousands): Valuation techniques Inputs September 30, 2024 December 31, 2023 Convertible promissory notes, current Discounted Cash Flow Model (“DCF”) Discount rate, risk-free rate, credit spread, contractual cash flows $ 4,008 $ — PWERM Scenario of initial public offering (“IPO”) and merger and acquisition (“M&A”) — 27,794 Common stock forward liability DCF Various utilization scenarios, risk-free rate, remaining term 451 — Convertible promissory notes, net of current Binomial Lattice Model (“BLM”) Stock price, volatility, remaining term, risk-free rate, credit spread 4,830 — PWERM Scenario of initial public offering (“IPO”) and merger and acquisition (“M&A”) — 6,239 Warrant liabilities Black Scholes Merton Exercise price, term to expiration, volatility, risk-free rate 3,197 —
Schedule of Changes in the Fair Value of the Company's Level 3 Financial Liabilities	The following table sets forth a summary of the changes in the fair value of the convertible promissory notes (in thousands): As of December 31, 2023 $ 34,033 Conversion ( 41,209 ) Borrowing 16,290 Change in fair value 1,203 As of March 31, 2024 10,317 Repayment ( 630 ) Change in fair value ( 14 ) As of June 30, 2024 9,673 Repayment ( 1,000 ) Change in fair value 165 As of September 30, 2024 $ 8,838 The following table sets forth a summary of the changes in the fair value of the warrant liabilities (in thousands): As of December 31, 2023 $ — Fair value of warrants assumed at Closing 5,958 Change in fair value 4,626 As of March 31, 2024 10,584 Change in fair value ( 6,628 ) As of June 30, 2024 3,956 Change in fair value ( 759 ) As of September 30, 2024 $ 3,197 The following table sets forth a summary of the changes in the fair value of the common stock forward liability (in thousands): As of March 31, 2024 $ — Loss from initial recognition 586 Settlement in equity ( 51 ) As of June 30, 2024 535 Settlement in equity ( 84 ) As of September 30, 2024 $ 451

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2024
Balance Sheet Components [Abstract]
Schedule of Inventory	Inventories consist of the following (in thousands): September 30, December 31, 2024 2023 Raw materials $ 1,247 $ 448 Work-in-process 504 601 Finished goods 1,359 437 Total inventory $ 3,110 $ 1,486
Schedule of Prepaid Expenses and Other Assets	Prepaid expenses and other assets consist of the following (in thousands): September 30, December 31, 2024 2023 Prepaid expenses $ 1,372 $ 433 Prepaid insurance 566 — Prepaid research and development 565 — Prepaid inventory 524 279 Lease deposit 422 434 Other receivables and current assets 96 117 Deferred transaction costs — 1,643 Total prepaid expenses and other current assets $ 3,545 $ 2,906
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consist of the following (in thousands): September 30, December 31, 2024 2023 Payroll and related expenses $ 9,126 $ 9,880 Accrued payables 6,764 6,319 Other taxes payable 3,191 158 Current portion of interest payable 2,560 6,915 Professional fees 548 499 Product warranty liabilities 37 55 Royalty and license fee 43 58 Other 96 72 Total accrued and other current liabilities $ 22,365 $ 23,956

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2024
Debt
Schedule of outstanding debt	The Company’s outstanding debt was as follows (in thousands): September 30, 2024 December 31, 2023 Outstanding Fair Value Outstanding Fair Value Convertible promissory notes: Historical convertible promissory notes $ 4,000 $ 4,008 $ 35,347 $ 34,033 2024 convertible promissory note 5,000 4,830 — — Total convertible promissory notes 9,000 8,838 35,347 34,033 Borrowings: KEB Hana Bank 6,820 6,820 6,980 6,980 IBK Industrial Bank 6,972 6,972 7,135 7,135 Note payable (one individual investor) — — 1,000 1,000 Mujin Electronics Co., Ltd. 3,789 3,789 — — M-Venture Investment, Inc. — — 7,756 7,756 Anapass, Inc., related party 9,851 9,851 10,082 10,082 i Best Investment Co., Ltd 4,546 4,546 10,082 10,082 Kyeongho Lee, related party 841 841 1,474 1,474 Total debt $ 41,819 41,657 $ 79,856 78,542 Less: current portion ( 36,827 ) ( 72,303 ) Debt, net of current portion $ 4,830 $ 6,239
Schedule of Expected future minimum principal payments under the company's total debt	Expected future minimum principal payments under the Company’s total debt is as follows as of September 30, 2024 (in thousands): Years Convertible Borrowings Total 2024, remainder $ 4,000 $ 7,813 $ 11,813 2025 — 25,006 25,006 2026 5,000 — 5,000 Total debt $ 9,000 $ 32,819 $ 41,819

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies
Schedule of carrying amounts related to collateral provided to Anapass, Inc	The following table includes a summary of the carrying amounts related to collateral provided to Anapass, Inc. (in thousands): September 30, December 31, 2024 2023 Cash and cash equivalents $ 1,732 $ 254 Accounts receivable 6,447 4,920 Inventory 3,110 1,486 Property and equipment 206 352 Intangible assets and others 884 199

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended
	Sep. 30, 2024
Common Stock
Summary of reserved shares of common stock for issuance	September 30, December 31, 2024 2023 Common stock warrants 26,273 2,894 Legacy GCT Earnout Shares 20,000 — Shares available for future grant from 2024 plan 3,762 — Convertible promissory notes 713 1,835 Options issued and outstanding 550 668 Shares available for future grant from 2024 ESPP 600 — RSUs outstanding 611 392 Shares available for future grant from 2011 plan — 113 Total 52,509 5,902

Warrants (Tables)

Warrants (Tables)	9 Months Ended
	Sep. 30, 2024
Warrants
Summary of warrants to purchase shares of the company's common stock that are outstanding	The following table represents a summary of warrants to purchase shares of the Company’s common stock that are outstanding (in thousands, except for exercise price): Issue Date September 30, 2024 Exercise Price Expiration February 2023 - June 2023 2,115 $ 10.00 - $ 18.75 February 2026 – June 2026 July 2023 80 $ 10.00 July 2026 October 2023 100 $ 10.00 October 2026 Private and public warrants 23,830 $ 11.50 March 2029 September 2024 148 $ 3.02 September 2029 Total 26,273

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Stock-Based Compensation
Summary of Stock Option Activity	Stock options outstanding under the 2024 Plan were as follows (in thousands, except per share amounts and years): Number of Weighted Weighted Aggregate Balance as of December 31, 2023 3,579 $ 0.02 5.5 $ 4,045 Reverse recapitalization ( 2,911 ) 0.09 — — Balance as of December 31, 2023 (1) 668 0.11 5.5 4,045 Exercised ( 118 ) 0.11 Balance as of September 30, 2024 550 $ 0.11 4.6 $ 1,785 Vested and expected to vest as of September 30, 2024 550 $ 0.11 4.6 $ 1,785 Exercisable as of September 30, 2024 533 $ 0.11 4.5 $ 1,729 (1) Amounts as of December 31, 2023 differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (see Note 3).
Summary of RSUs Activity	RSUs outstanding under the 2024 Plan were as follows (in thousands, except per share amounts): Number of RSUs Weighted Balance as of December 31, 2023 2,100 $ 1.15 Reverse recapitalization ( 1,708 ) 5.01 Balances as of December 31, 2023 (1) 392 $ 6.16 Granted 221 3.69 Cancelled ( 2 ) 6.16 Balance as of September 30, 2024 611 $ 5.26 (1) Amounts as of December 31, 2023 differ from those in prior year consolidated financial statements as they were retrospectively adjusted as a result of the accounting for the Business Combination (see Note 3).
Schedule of Stock-Based Compensation Allocation	The following table summarizes stock-based compensation included in the Company’s condensed consolidated statements of operations: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Cost of revenues 33 — 33 — Research and development 135 1 389 3 Sales and marketing 36 1 108 3 General and administrative 369 1 1,589 2 Total $ 573 $ 3 $ 2,119 $ 8

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2024
Employee Benefit Plans
Summary of net liability for severance payments	The net liability for severance payments was as follows (in thousands): September 30, 2024 December 31, 2023 Liability for severance payments, gross $ 8,328 $ 7,997 Plan assets ( 276 ) ( 308 ) Liability for severance payments, net $ 8,052 $ 7,689

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2024
Related Party Transactions
Summary of balances and transactions with the related parties	A summary of balances and transactions with the related parties who are stockholders of the Company were as follows (in thousands): September 30, 2024 December 31, 2023 Anapass Kyeongho Lee Anapass Kyeongho Lee Borrowings $ 9,851 $ 841 $ 10,082 $ 1,474 Other current liabilities 9 86 212 182

Segments and Information (Table

Segments and Information (Tables)	9 Months Ended
	Sep. 30, 2024
Segments and Information
Summary of long-lived assets by geographic region	The Company operates in one segment. Revenue information by geographic region is presented in Note 4 to these unaudited condensed consolidated financial statements. Tangible long-lived assets by geographic region were as follows (in thousands): September 30, 2024 December 31, 2023 South Korea $ 1,041 $ 1,363 United States 665 930 Total $ 1,706 $ 2,293

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2024
Net Loss Per Share
Schedule of potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per share	The following outstanding potentially dilutive common stock equivalents were excluded from the computation of diluted net loss per share for the periods indicated because including them would have been antidilutive (in thousands): September 30, 2024 2023 Warrants 26,273 2,214 Legacy GCT Earnout Shares 20,000 — Sponsor Earnout Shares 571 — Convertible promissory notes 713 1,806 Options 550 670 RSU 611 — Total 48,718 4,690

Organization and Liquidity (Det

Organization and Liquidity (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2024 USD ($)	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)	Mar. 26, 2024	Dec. 31, 2023 USD ($)
Organization and Liquidity
Exchange ratio					0.00001868
Accumulated deficit		$ (557,061)		$ (557,061)		$ (549,654)
Cash and cash equivalents		1,812		1,812		$ 258
Cash proceeds from the reverse recapitalization and PIPE Financing	$ 17,200			17,238
Proceeds from Issuance of Common Stock		$ 5,000	$ 2,800	$ 7,814
B. Riley Principal Capital II, LLC
Organization and Liquidity
Stock Sale Commitment Amount	$ 50,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies and Basis of Presentation - Provision for Credit Losses (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Summary of Significant Accounting Policies and Basis of Presentation
Provisions for credit losses	$ 1.1	$ 1.6

Summary of Significant Accoun_5

Summary of Significant Accounting Policies and Basis of Presentation - Concentration of Revenues and Accounts Receivable (Details) - Customer concentration	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Revenue | Customer A
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			27%
Revenue | Customer B
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage	24%		25%
Revenue | Customer C
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			12%
Revenue | Customer D
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage				25%
Revenue | Customer F
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage		13%		13%
Revenue | Customer H
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage	57%		20%
Revenue | Customer I
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage		24%
Revenue | Customer J
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage		47%		20%
Accounts receivable | Customer A
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			27%
Accounts receivable | Customer H
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			20%		19%
Accounts receivable | Customer I
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			12%		14%
Accounts receivable | Customer J
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			12%		27%
Accounts receivable | Customer K
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage					10%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies and Basis of Presentation - Foreign Currency (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Summary of Significant Accounting Policies and Basis of Presentation
Foreign currency (loss) gain, net	$ (1.1)	$ 0.9	$ 0.8	$ 1.8

Summary of Significant Accoun_7

Summary of Significant Accounting Policies and Basis of Presentation - Recent Accounting Pronouncements Adopted (Details)	Sep. 30, 2024
ASU 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
ASU 2021-08
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
ASU 2022-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jul. 01, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true

Reverse Recapitalization - Busi

Reverse Recapitalization - Business Combination - Additional Information (Details) $ / shares in Units, $ in Millions	Mar. 26, 2024 USD ($) $ / shares
Concord III
Reverse Recapitalization
Transaction costs incurred in acquisition	$ 13.1
Concord III | PIPE financing
Reverse Recapitalization
Transaction costs incurred in acquisition	0.9
Legacy G C T
Reverse Recapitalization
Transaction costs incurred in acquisition	$ 8.9
Legacy G C T | Concord III
Reverse Recapitalization
Percentage of ownership acquired	100%
Net proceeds received on acquisition	$ 17.1
Share price in business acquisition | $ / shares	$ 10
Stock exchange ratio	0.1868
Legacy G C T | Concord III | Convertible debt
Reverse Recapitalization
Conversion price | $ / shares	$ 6.67

Reverse Recapitalization - Sche

Reverse Recapitalization - Schedule of outstanding common stock (Details) - shares		3 Months Ended
	Mar. 26, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Reverse Recapitalization
Common stock, shares outstanding		47,611,000		24,166,000
Common stock issued		1,421,715	678,462
Total common stock issued and outstanding	45,833,000	47,611,000		24,166,000
Sponsor Earnout Shares
Reverse Recapitalization
Sponsor earnout common stock outstanding prior to the Business Combination	8,625,000
PIPE financing
Reverse Recapitalization
Common stock issued	4,530,000
Concord III
Reverse Recapitalization
Common stock, shares outstanding	3,941,000
Less: redemption of Concord I I I's common stock	(3,766,000)
Common stock of Concord I I I issued and outstanding	8,800,000
Legacy G C T
Reverse Recapitalization
Legacy GCT common stock	32,503,000

Reverse Recapitalization - Reve

Reverse Recapitalization - Reverse Recapitalization - Additional Information (Details)	Mar. 26, 2024 USD ($)
Concord III | Legacy G C T
Reverse Recapitalization
Goodwill and intangible assets	$ 0

Reverse Recapitalization - PIPE

Reverse Recapitalization - PIPE Financing - Additional Information (Details) - PIPE financing $ / shares in Units, $ in Millions	Mar. 26, 2024 USD ($) $ / shares shares
Reverse Recapitalization
Number of shares issued | shares	4,529,967
Issue price per share | $ / shares	$ 6.67
Value of shares issued	$ 30.2
Net proceeds from PIPE financing	$ 17.1

Reverse Recapitalization -Priva

Reverse Recapitalization -Private Warrants and Public warrants - Additional Information (Details) - shares	1 Months Ended	9 Months Ended
	Nov. 30, 2021	Sep. 30, 2024
Reverse Recapitalization
Number of warrants issued		26,273,000
Concord III | Private placement warrants
Reverse Recapitalization
Number of warrants issued	9,400,000
Concord III | Public warrants
Reverse Recapitalization
Number of warrants issued	17,250,000
Legacy G C T | Private placement and public warrants | Sponsor
Reverse Recapitalization
Number of warrants vested and retained	4,492,650
Number of warrants reallocated to others	2,087,350
Number of warrants forfeited	2,820,000

Reverse Recapitalization - Lega

Reverse Recapitalization - Legacy GCT and Sponsor Earn out Shares - Additional Information (Details) - Legacy G C T - USD ($)		1 Months Ended
	Mar. 26, 2024	Jul. 31, 2024
Earnout shares
Reverse Recapitalization
Number of shares issued	20,000,000
Threshold trading days calculated for issuing shares	20 days
Consecutive threshold trading days calculated for issuing shares	30 days
Fair value of shares issued	$ 108,800,000
Earnout shares | VWAP of the Company's common stock equals or exceeds $12.50 per share
Reverse Recapitalization
Number of shares issued	6,666,666
Threshold VWAP of stock to trigger earn out shares	$ 12.5
Earnout shares | VWAP of the Company's common stock equals or exceeds $15.00 per share
Reverse Recapitalization
Number of shares issued	6,666,667
Threshold VWAP of stock to trigger earn out shares	$ 15
Earnout shares | VWAP of the Company's common stock equals or exceeds $17.50 per share
Reverse Recapitalization
Number of shares issued	6,666,667
Threshold VWAP of stock to trigger earn out shares	$ 17.5
Sponsor Earnout Shares
Reverse Recapitalization
Number of shares issued	1,920,375
Threshold trading days calculated for issuing shares	20 days
Consecutive threshold trading days calculated for issuing shares	30 days
Fair value of shares issued	$ 10,400,000
Market based vesting common stock reduced shares		570,796
Remaining outstanding common stock shares		1,349,579
Adjustments to stockholders' deficit		$ 0
Sponsor Earnout Shares | VWAP of the Company's common stock equals or exceeds $12.50 per share
Reverse Recapitalization
Number of shares issued	640,125
Threshold VWAP of stock to trigger earn out shares	$ 12.5
Sponsor Earnout Shares | VWAP of the Company's common stock equals or exceeds $15.00 per share
Reverse Recapitalization
Number of shares issued	640,125
Threshold VWAP of stock to trigger earn out shares	$ 15
Sponsor Earnout Shares | VWAP of the Company's common stock equals or exceeds $17.50 per share
Reverse Recapitalization
Number of shares issued	640,125
Threshold VWAP of stock to trigger earn out shares	$ 17.5

Disaggregation of Revenue - Sch

Disaggregation of Revenue - Schedule of Disaggregation of Revenues from Contracts with Customers and Categorized by Customer Location (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue
Revenues from contracts with customers	$ 2,610	$ 4,476	$ 7,343	$ 11,839
South Korea
Disaggregation of Revenue
Revenues from contracts with customers	1,500	4	3,500	3,010
United States
Disaggregation of Revenue
Revenues from contracts with customers	837	572	2,565	2,888
Germany
Disaggregation of Revenue
Revenues from contracts with customers	46	353	916	353
China
Disaggregation of Revenue
Revenues from contracts with customers	32	3,567	167	5,133
Other
Disaggregation of Revenue
Revenues from contracts with customers	$ 195	$ (20)	$ 195	$ 455

Disaggregation of Revenue - Con

Disaggregation of Revenue - Contract assets and liabilities - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Contract assets	$ 5.1	$ 3.4
Contract liabilities			$ 0.7
Contract liabilities related to contract fulfillment	0.5
Maximum
Disaggregation of Revenue [Line Items]
Contract liabilities	$ 0.1

Fair Value of Measurements - Sc

Fair Value of Measurements - Schedule of Financial Instruments are Measured at Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value of Measurements
Convertible promissory notes	$ 8,838	$ 34,033
Warrant liabilities	3,197
Common stock forward liability	451
Level 3
Fair Value of Measurements
Convertible promissory notes	8,838	$ 34,033
Warrant liabilities	3,197
Common stock forward liability	$ 451

Fair Value of Measurements - _2

Fair Value of Measurements - Schedule of Valuation Techniques and Inputs Used in the Fair Value Measurement (Details) - Level 3 - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Convertible Promissory Notes, Current | Discounted Cash Flow Model ("DCF")
Fair Value of Measurements
Fair value	$ 4,008
Convertible Promissory Notes, Current | PWERM
Fair Value of Measurements
Fair value		$ 27,794
Common Stock Forward Liability | Discounted Cash Flow Model ("DCF")
Fair Value of Measurements
Fair value	451
Convertible Promissory Notes, Net of Current | PWERM
Fair Value of Measurements
Fair value		$ 6,239
Convertible Promissory Notes, Net of Current | Binomial Lattice Model ("BLM")
Fair Value of Measurements
Fair value	4,830
Warrant Liabilities - Private and Public Warrants | Black Scholes Merton Model ("BSM") or BLM
Fair Value of Measurements
Fair value	$ 3,197

Fair Value of Measurements - Ad

Fair Value of Measurements - Additional Information (Details)	Sep. 30, 2024 shares yr
Stock Price | Convertible Promissory Notes, Net of Current | Binomial Lattice Model ("BLM")
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input | shares	3.35
Discount Factor | Convertible Promissory Notes, Current | Discounted Cash Flow Model ("DCF")
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input	0.1007
Remaining Term | Convertible Promissory Notes, Current | Discounted Cash Flow Model ("DCF") | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input	0.08
Remaining Term | Convertible Promissory Notes, Current | Discounted Cash Flow Model ("DCF") | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input	0.25
Remaining Term | Convertible Promissory Notes, Net of Current | Binomial Lattice Model ("BLM")
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input	1.4
Credit Spread | Convertible Promissory Notes, Net of Current | Binomial Lattice Model ("BLM")
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input	0.056
Exercise Price | Binomial Lattice Model ("BLM") | Public warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input | shares	11.50
Exercise Price | Black Scholes Merton Model ("BSM") or BLM | Private placement warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input | shares	11.50
Exercise Price | Black Scholes Merton Model ("BSM") or BLM | Minimum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input | shares	10
Exercise Price | Black Scholes Merton Model ("BSM") or BLM | Maximum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input | shares	18.75
Term to Expiration | Binomial Lattice Model ("BLM") | Public warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	4.5
Term to Expiration | Black Scholes Merton Model ("BSM") or BLM | Private placement warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	4.5
Term to Expiration | Black Scholes Merton Model ("BSM") or BLM | Minimum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	1.41
Term to Expiration | Black Scholes Merton Model ("BSM") or BLM | Maximum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	2.1
Term to Expiration | Common Stock Forward Liability | Discounted Cash Flow Model ("DCF")
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Remaining term, measurement input	1.6
Volatility | Black Scholes Merton Model ("BSM") or BLM | Private placement warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	0.355
Volatility | Black Scholes Merton Model ("BSM") or BLM | Minimum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	0.381
Volatility | Black Scholes Merton Model ("BSM") or BLM | Maximum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	0.390
Volatility | Convertible Promissory Notes, Net of Current | Binomial Lattice Model ("BLM")
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input	0.355
Risk-Free Rate | Black Scholes Merton Model ("BSM") or BLM | Private placement warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	0.0355
Risk-Free Rate | Black Scholes Merton Model ("BSM") or BLM | Minimum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	0.0362
Risk-Free Rate | Black Scholes Merton Model ("BSM") or BLM | Maximum | Warrant liabilities - other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities, measurement input	0.0381
Risk-Free Rate | Convertible Promissory Notes, Net of Current | Binomial Lattice Model ("BLM")
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Convertible promissory notes, measurement input	0.0385
Risk-Free Rate | Common Stock Forward Liability | Discounted Cash Flow Model ("DCF") | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Remaining term, measurement input	0.0378
Risk-Free Rate | Common Stock Forward Liability | Discounted Cash Flow Model ("DCF") | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Remaining term, measurement input	0.0493

Fair Value of Measurements - _3

Fair Value of Measurements - Schedule of Changes in the Fair Value of the Company's Level 3 Financial Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024
Fair Value of Measurements
Change in fair value, [Extensible List]	Other income (expenses), net	Other income (expenses), net	Other income (expenses), net
Convertible Promissory Notes
Fair Value of Measurements
Fair value as of beginning of period	$ 9,673	$ 10,317	$ 34,033
Conversion			(41,209)
Borrowing			16,290
Repayment	(1,000)	(630)
Change in fair value	165	(14)	1,203
Fair value as of end of period	8,838	9,673	10,317
Warrant Liabilities
Fair Value of Measurements
Fair value as of beginning of period	3,956	10,584
Fair value of warrants assumed at closing			5,958
Change in fair value	(759)	(6,628)	4,626
Fair value as of end of period	3,197	3,956	$ 10,584
Common Stock Forward Liability
Fair Value of Measurements
Fair value as of beginning of period	535
Conversion	(84)	(51)
Change in fair value		586
Fair value as of end of period	$ 451	$ 535

Balance Sheet Components - Inve

Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Inventory, Net [Abstract]
Raw materials	$ 1,247	$ 448
Work-in-process	504	601
Finished goods	1,359	437
Total inventory	$ 3,110	$ 1,486

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Balance Sheet Components [Abstract]
Write-downs of inventory	$ 0	$ 0

Balance Sheet Components - Prep

Balance Sheet Components - Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Balance Sheet Components [Abstract]
Prepaid expenses	$ 1,372	$ 433
Prepaid insurance	566
Prepaid research and development	565
Prepaid inventory	524	279
Lease deposit	422	434
Other receivables and current assets	96	117
Deferred transaction costs		1,643
Total prepaid expenses and other current assets	$ 3,545	$ 2,906

Balance Sheet Components - Accr

Balance Sheet Components - Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Balance Sheet Components [Abstract]
Payroll and related expenses	$ 9,126	$ 9,880
Accrued payables	6,764	6,319
Other taxes payable	3,191	158
Current portion of interest payable	2,560	6,915
Professional fees	548	499
Product warranty liabilities	37	55
Royalty and license fee	43	58
Other	96	72
Total accrued and other current liabilities	$ 22,365	$ 23,956

Debt - Outstanding debt (Detail

Debt - Outstanding debt (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Borrowings
Borrowings	$ 41,819	$ 79,856
Fair Value	41,657	78,542
Less: current portion	(36,827)	(72,303)
Debt, net of current portion	4,830	6,239
Convertible promissory notes
Borrowings
Borrowings	9,000	35,347
Fair Value	8,838	34,033
Historical convertible promissory notes
Borrowings
Borrowings	4,000	35,347
Fair Value	4,008	34,033
2024 convertible promissory note
Borrowings
Borrowings	5,000
Fair Value	4,830
Borrowings
Borrowings
Borrowings	32,819
Borrowings | KEB Hana Bank
Borrowings
Borrowings	6,820	6,980
Fair Value	6,820	6,980
Borrowings | IBK Industrial Bank
Borrowings
Borrowings	6,972	7,135
Fair Value	6,972	7,135
Borrowings | Note payable (one individual investor)
Borrowings
Borrowings		1,000
Fair Value		1,000
Borrowings | Mujin Electronics Co., Ltd.
Borrowings
Borrowings	3,789
Fair Value	3,789
Borrowings | M-Venture Investment, Inc.
Borrowings
Borrowings		7,756
Fair Value		7,756
Borrowings | Anapass, Inc, related party
Borrowings
Borrowings	9,851	10,082
Fair Value	9,851	10,082
Borrowings | i Best Investment Co., Ltd
Borrowings
Borrowings	4,546	10,082
Fair Value	4,546	10,082
Borrowings | Kyeongho Lee
Borrowings
Borrowings	841	1,474
Fair Value	$ 841	$ 1,474

Debt - Expected future minimum

Debt - Expected future minimum principal payments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Borrowings
2024, remainder	$ 11,813
2025	25,006
2026	5,000
Total debt	41,819	$ 79,856
Convertible Notes
Borrowings
2024, remainder	4,000
2025	0
2026	5,000
Total debt	9,000
Borrowings
Borrowings
2024, remainder	7,813
2025	25,006
Total debt	$ 32,819

Debt - Convertible Promissory N

Debt - Convertible Promissory Notes - Additional Information (Details)	1 Months Ended		2 Months Ended	9 Months Ended
	Apr. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2024 USD ($) Item $ / shares shares	Feb. 29, 2024 USD ($)	Dec. 31, 2023 USD ($)
Borrowings
Amount outstanding			$ 41,819,000	$ 41,819,000		$ 79,856,000
Repayment of convertible net				1,630,000
Historical convertible promissory notes
Borrowings
Amount of debt converted		$ 32,100,000
Number of shares issued on conversion of debt | shares		4,258,223
Amount of principal and interest outstanding			$ 5,900,000	$ 5,900,000
Number of noteholders | Item				1
Conversion price | $ / shares			$ 3.5	$ 3.5
Amount outstanding			$ 4,000,000	$ 4,000,000		$ 35,347,000
Repayment of convertible net	$ 600,000		$ 1,000,000	$ 5,100,000
Historical convertible promissory notes | Minimum
Borrowings
Interest rate (as a percent)			4%	4%
Historical convertible promissory notes | Maximum
Borrowings
Interest rate (as a percent)			7%	7%
Historical convertible promissory notes | Strategic investor
Borrowings
Conversion price | $ / shares			$ 10	$ 10
2023 & 2024 convertible promissory notes
Borrowings
Number of shares issued on conversion of debt | shares		2,004,535
Repayment of convertible net		$ 13,400,000
2023 & 2024 convertible promissory notes | CVT Investors
Borrowings
Principal amount			$ 13,300,000	$ 13,300,000
Interest rate (as a percent)			5%	5%
Conversion price | $ / shares			$ 6.67	$ 6.67
Amount outstanding			$ 0	$ 0
2023 & 2024 convertible promissory notes | Strategic investor
Borrowings
Principal amount					$ 5,000,000
Interest rate (as a percent)			5%	5%
Number of shares issued on conversion of debt | shares				10
Term for conversion				6 months

Debt - Borrowings Pursuant to T

Debt - Borrowings Pursuant to Term Loan and Security Agreements - Additional Information (Details) $ in Thousands, ₩ in Millions

1 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

Jul. 31, 2024 USD ($)

Jul. 31, 2024 KRW (₩)

Jun. 30, 2024 USD ($)

Apr. 30, 2024 USD ($)

Apr. 30, 2024 KRW (₩)

Mar. 31, 2024 USD ($)

Mar. 31, 2024 KRW (₩)

Dec. 31, 2023 USD ($)

Jul. 31, 2016 USD ($)

Dec. 31, 2021 USD ($)

Dec. 31, 2021 KRW (₩)

Sep. 30, 2024 USD ($)

Sep. 30, 2023 USD ($)

Dec. 31, 2022 USD ($)

Dec. 31, 2022 KRW (₩)

Dec. 31, 2017 USD ($)

Jul. 31, 2024 KRW (₩)

Apr. 30, 2024 KRW (₩)

Dec. 31, 2023 KRW (₩)

Dec. 31, 2022 KRW (₩)

Sep. 30, 2022 USD ($)

Sep. 30, 2022 KRW (₩)

May 31, 2022 USD ($)

May 31, 2022 KRW (₩)

Apr. 30, 2022 USD ($)

Apr. 30, 2022 KRW (₩)

Dec. 31, 2021 KRW (₩)

Oct. 31, 2021 USD ($)

Oct. 31, 2021 KRW (₩)

Jun. 30, 2021 USD ($)

Dec. 31, 2017 KRW (₩)

Jan. 31, 2017 USD ($)

Jan. 31, 2017 KRW (₩)

Jul. 31, 2016 KRW (₩)

Borrowings

Amount outstanding

$ 79,856

$ 41,819

Amount repaid

14,065

$ 23

Borrowings

Borrowings

Amount outstanding

32,819

KEB Hana Bank | Borrowings

Borrowings

Principal amount

$ 6,700

₩ 9,000

Annual interest rate

2.60%

Additional extension term (in years)

1 year

Principal amount of loan extended maturity date

$ 700

₩ 1,000

Amount outstanding

6,980

$ 6,820

KEB Hana Bank | Borrowings | Minimum

Borrowings

Annual interest rate

3.50%

KEB Hana Bank | Borrowings | Maximum

Borrowings

Annual interest rate

5.20%

IBK Industrial Bank | Borrowings

Borrowings

Principal amount

$ 6,000

₩ 8,000

$ 6,800

₩ 9,200

Interest rate (as a percent)

4.90%

3.50%

4.90%

4.90%

3.50%

Amount outstanding

7,135

$ 6,972

Note payable (one individual investor) | Borrowings

Borrowings

Principal amount

$ 1,000

Interest rate (as a percent)

4%

Amount outstanding

1,000

M-Venture Investment, Inc. | Borrowings

Borrowings

Amount outstanding

7,756

M-Venture Investment, Inc. | Term loan and security agreement, one

Borrowings

Principal amount

$ 3,700

₩ 5,000

Interest rate (as a percent)

6.50%

Amount outstanding

$ 3,000

₩ 4,000

Amount repaid

$ 1,500

₩ 2,000

$ 400

₩ 600

300

₩ 400

M-Venture Investment, Inc. | Term loan and security agreement, two, draw one

Borrowings

Principal amount

$ 700

₩ 1,000

Interest rate (as a percent)

6.50%

Principal amount of loan extended maturity date

700

₩ 1,000

M-Venture Investment, Inc. | Term loan and security agreement, two, draw two

Borrowings

Principal amount

$ 3,700

₩ 5,000

Interest rate (as a percent)

8.70%

Principal amount of loan extended maturity date

$ 3,700

₩ 5,000

M-Venture Investment, Inc. | Term loans

Borrowings

Repayment of short term loan

$ 700

₩ 1,000

Mujin Electronics Co., Ltd. | Borrowings

Borrowings

Amount outstanding

$ 3,789

Mujin Electronics Co., Ltd. | Term loan and security agreement, one

Borrowings

Principal amount

$ 3,700

₩ 5,000

Interest rate (as a percent)

6.80%

6.80%

Anapass, Inc, related party | Borrowings

Borrowings

Amount outstanding

10,082

$ 9,851

Anapass, Inc, related party | Term loan and security agreement, one

Borrowings

Principal amount

$ 4,500

₩ 6,000

Interest rate (as a percent)

5.50%

5.50%

Anapass, Inc, related party | Term loan and security agreement, two

Borrowings

Interest rate (as a percent)

5.50%

Anapass, Inc, related party | Term loan and security agreement, two, draw one

Borrowings

Principal amount

$ 2,200

₩ 3,000

Anapass, Inc, related party | Term loan and security agreement, two, draw two

Borrowings

Principal amount

$ 3,000

₩ 4,000

i Best Investment Co., Ltd | Borrowings

Borrowings

Principal amount

$ 10,300

$ 10,300

₩ 14,000

₩ 14,000

Interest rate (as a percent)

6.50%

6.50%

6.50%

6.50%

Amount outstanding

$ 10,082

$ 4,546

i Best Investment Co., Ltd | Term loan and security agreement, draw two

Borrowings

Amount repaid

800

i Best Investment Co., Ltd | Term loan and security agreement, draw three

Borrowings

Amount repaid

$ 1,400

i Best Investment Co., Ltd | Term loan and security agreement, draw four

Borrowings

Amount repaid

$ 2,300

Kyeongho Lee | Borrowings

Borrowings

Amount outstanding

$ 1,474

$ 841

Kyeongho Lee | Promissory notes

Borrowings

Principal amount

$ 400

$ 400

₩ 500

₩ 500

Kyeongho Lee | Promissory notes | Minimum

Borrowings

Interest rate (as a percent)

7.50%

7.50%

7.50%

7.50%

Kyeongho Lee | Promissory notes | Maximum

Borrowings

Interest rate (as a percent)

9%

9%

9%

9%

Kyeongho Lee | Term loans

Borrowings

Principal amount

$ 100

$ 700

₩ 110

₩ 1,000

Amount repaid

$ 700

₩ 1,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Feb. 29, 2024	Dec. 31, 2023
Purchase Commitment
Research and development expense	$ 4,210	$ 2,367	$ 13,895	$ 7,254
Unpaid recorded expenses included in accounts payable	1,070		1,070			$ 17,814
Borrowings	41,819		41,819			79,856
KEB Hana Bank | Assets pledged as collateral | Borrowings | Related party
Purchase Commitment
Borrowings	6,800		6,800			7,000
IBK Industrial Bank | Assets pledged as collateral | Borrowings | Related party
Purchase Commitment
Borrowings	7,000		7,000			7,100
Anapass, Inc. | Assets pledged as collateral | Borrowings | Related party
Purchase Commitment
Borrowings	9,900		9,900			$ 10,100
Research and development agreement with Samsung
Purchase Commitment
Outstanding purchase commitments	200		200
Total fee amount	21,100		21,100
Fee amount to be paid over development milestones	11,700		11,700
Additional NRE to be paid as fee amount	9,400		$ 9,400
Period for payment of additional NRE			4 years
Gain on release of unconditional liability			$ 14,600
Research And Development Agreement With Alpha Holdings Co., Ltd
Purchase Commitment
Total fee amount					$ 7,600
Research and development expense	1,200		6,000
Aggregated unpaid amount	$ 4,900		$ 4,900

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Carrying Amounts Related to Collateral Provided to Anapass, Inc (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Borrowings
Cash and cash equivalents	$ 1,812	$ 258
Accounts receivable	6,441	4,920
Inventory	3,110	1,486
Property and equipment	641	772
Anapass, Inc. | Related party | Assets pledged as collateral | Borrowings
Borrowings
Cash and cash equivalents	1,732	254
Accounts receivable	6,447	4,920
Inventory	3,110	1,486
Property and equipment	206	352
Intangible assets and others	$ 884	$ 199

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2024	Apr. 30, 2024	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2024	Mar. 31, 2024
Common Stock
Common stock forward liability	$ 451	$ 600	$ 451		$ 451
Commitment shares					56,818
Reimbursement of commitment amount					$ 250
Common stock issued			1,421,715	678,462
Shares issued values			$ 5,541	$ 3,388
Amount withheld for outstanding payables			500	500
Proceeds from issuance of common stock under common stock purchase agreement			$ 5,000	2,800	$ 7,814
Issuance of common stock to underwriter (in shares)		110,000
Issuance of common stock to underwriter				667
Private Placement
Common Stock
Common stock issued	741,603
Shares issued values	$ 2,000
Proceeds from issuance of private placement	$ 2,200
Private Placement | Common stock warrants
Common Stock
Common stock issued	148,320
Shares issued values	$ 200
Exercise price of warrants	$ 3.02		$ 3.02		$ 3.02
Warrants term	5 years		5 years		5 years
B. Riley Principal Capital II, LLC
Common Stock
Stock Sale Commitment Amount						$ 50,000
Percentage of volume weighted average price					98%
Shares issued values			$ 5,500	$ 3,300
B. Riley Principal Capital II, LLC | Maximum
Common Stock
Stock Sale Commitment Amount	$ 50,000		$ 50,000		$ 50,000

Common Stock - Common Stock Res

Common Stock - Common Stock Reserved for Issuance - Additional Information (Details) - shares	Sep. 30, 2024	Dec. 31, 2023
Common Stock
Total Shares Authorized	440,000,000
Common Stock, Shares Authorized	400,000,000	200,000,000
Preferred Stock, Shares Authorized	40,000,000	82,352,000

Common Stock - Common Stock R_2

Common Stock - Common Stock Reserved for Issuance (Details) - shares shares in Thousands	Sep. 30, 2024	Dec. 31, 2023
Common Stock
Shares of authorized but unissued common stock	52,509	5,902
Options issued and outstanding
Common Stock
Shares of authorized but unissued common stock	550	668
RSUs Outstanding
Common Stock
Shares of authorized but unissued common stock	611	392
Shares available for future grant from 2024 plan
Common Stock
Shares of authorized but unissued common stock	3,762
Shares available for future grant from 2024 ESPP
Common Stock
Shares of authorized but unissued common stock	600
Shares available for future grant from 2011 plan
Common Stock
Shares of authorized but unissued common stock		113
Common stock warrants
Common Stock
Shares of authorized but unissued common stock	26,273	2,894
Legacy GCT Earnout Shares
Common Stock
Shares of authorized but unissued common stock	20,000
Convertible promissory notes
Common Stock
Shares of authorized but unissued common stock	713	1,835

Warrants (Details)

Warrants (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Warrants
Number of warrants issued | shares	26,273
February 2023 ~ June 2023
Warrants
Number of warrants issued | shares	2,115
February 2023 ~ June 2023 | Maximum
Warrants
Exercise price of warrants | $ / shares	$ 18.75
February 2023 ~ June 2023 | Minimum
Warrants
Exercise price of warrants | $ / shares	$ 10
July 2023
Warrants
Number of warrants issued | shares	80
Exercise price of warrants | $ / shares	$ 10
October 2023
Warrants
Number of warrants issued | shares	100
Exercise price of warrants | $ / shares	$ 10
Public And Private Placement Warrants
Warrants
Number of warrants issued | shares	23,830
Exercise price of warrants | $ / shares	$ 11.50
September 2024
Warrants
Number of warrants issued | shares	148
Exercise price of warrants | $ / shares	$ 3.02

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2021
Stock-Based Compensation
Granted during the period (in shares)				0
Exercisable - Aggregate Intrinsic Value		$ 1,729		$ 1,729
Exercised during the period (in shares)				117,670
Options exercised, intrinsic value		300
Additional shares of common stock reserved for issuance (in shares)						90,000
Stock-based compensation	$ 900	$ 573	$ 3	$ 2,119	$ 8
2024 Incentive Compensation Plan
Stock-Based Compensation
Number of shares of common stock reserved for issuance (in shares)	3,983,334

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Number of Options Outstanding
Balance as of beginning (in shares)	3,579,000
Exercised (in shares)	(117,670)
Balance as of end (in shares)	550,000	3,579,000
Vested and expected to vest as of end (in shares)	550,000
Exercisable as of end (in shares)	533,000
Weighted-Average Exercise Price
Balance as of beginning (in dollars per share) | $ / shares	$ 0.02
Exercised (in dollars per share) | $ / shares	0.11
Balance as of end (in dollars per share) | $ / shares	0.11	$ 0.02
Vested and expected to vest as of end (in dollars per share) | $ / shares	0.11
Exercisable as of end (in dollars per share) | $ / shares	$ 0.11
Weighted Average Remaining Contractual Life (Years)
Outstanding - Weighted Average Remaining Contractual Life (in years)	4 years 7 months 6 days	5 years 6 months
Vested and expected to vest - Weighted Average Remaining Contractual Life (in years)	4 years 7 months 6 days
Exercisable - Weighted Average Remaining Contractual Life (in years)	4 years 6 months
Balance outstanding - Aggregate Intrinsic Value | $	$ 1,785	$ 4,045
Vested and expected to vest - Aggregate Intrinsic Value | $	1,785
Exercisable - Aggregate Intrinsic Value | $	$ 1,729
Retrospectively Adjusted
Number of Options Outstanding
Balance as of beginning (in shares)	668,000
Reverse recapitalization (in shares)		(2,911,000)
Balance as of end (in shares)		668,000
Weighted-Average Exercise Price
Balance as of beginning (in dollars per share) | $ / shares	$ 0.11
Reverse recapitalization (in dollars per share)		0.09
Balance as of end (in dollars per share) | $ / shares		$ 0.11
Weighted Average Remaining Contractual Life (Years)
Outstanding - Weighted Average Remaining Contractual Life (in years)		5 years 6 months
Balance outstanding - Aggregate Intrinsic Value | $		$ 4,045

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of RSUs Activity (Details) - RSU - $ / shares shares in Thousands	1 Months Ended	9 Months Ended
	Jun. 30, 2024	Sep. 30, 2024	Dec. 31, 2023
Number of Shares
Balance at the beginning		2,100
Granted	700	221
Cancelled		(2)
Balance at the end		611
Weighted Average shares
Balance at beginning (in dollars per share)		$ 1.15
Granted ( in dollars per share)		3.69
Cancelled( in dollars per share)		6.16
Balance at end (in dollars per share)		$ 5.26
Retrospectively Adjusted
Number of Shares
Balance at the beginning		392
Reverse capitalization			(1,708)
Weighted Average shares
Balance at beginning (in dollars per share)		$ 6.16
Reverse capitalization (in dollars per share)			$ 5.01

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Stock-Based Compensation
Granted						0
Stock-based compensation			$ 900	$ 573	$ 3	$ 2,119	$ 8
Common Stock
Stock-Based Compensation
Closing price of company's common stock						80,916
RSUs Outstanding
Stock-Based Compensation
Unrecognized compensation cost related to RSUs				2,300		$ 2,300
Expected weighted average period for recognition of unrecognized compensation cost related to RSUs (in years)						3 years
Share based fixed monetary amount		700,000				221,000
Granted	140,000							392,000
Stock-based compensation				$ 600		$ 1,200

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Allocation (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Stock-Based Compensation
Stock-based compensation	$ 900	$ 573	$ 3	$ 2,119	$ 8
Cost of revenues
Stock-Based Compensation
Stock-based compensation		33		33
Research and Development
Stock-Based Compensation
Stock-based compensation		135	1	389	3
Sales and Marketing
Stock-Based Compensation
Stock-based compensation		36	1	108	3
General and Administrative
Stock-Based Compensation
Stock-based compensation		$ 369	$ 1	$ 1,589	$ 2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Taxes
Income tax expense	$ 61,000	$ 38,000	$ 187,000	$ 125,000
Effective tax rate (in %)			(2.60%)	(1.00%)
Unrecognized tax benefits	3,100,000		$ 3,100,000
Unrecognized tax benefits that would impact the effective tax rate if recognized	1,700,000		1,700,000
Unrecognized tax benefits - Interest expense or penalties accrued	$ 0		$ 0

Employee Benefit Plans - Summar

Employee Benefit Plans - Summary of net liability for severance payments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Employee Benefit Plans
Liability for severance payments, gross	$ 8,328	$ 7,997
Plan assets	(276)	(308)
Liability for severance payments, net	$ 8,052	$ 7,689

Related Party Transactions - Su

Related Party Transactions - Summary of Balances and Transactions with the Related Parties (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Related Party Transactions
Other current liabilities	$ 96	$ 72
Related party | Anapass
Related Party Transactions
Borrowings	9,851	10,082
Other current liabilities	9	212
Related party | Kyeongho Lee
Related Party Transactions
Borrowings	841	1,474
Other current liabilities	$ 86	$ 182

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Related Party Transaction [Line Items]
Interest expense	$ 667	$ 1,220	$ 3,509	$ 4,878
Related Party [Member] | Anapass [Member]
Related Party Transaction [Line Items]
Interest expense	$ 100	$ 100	$ 400	$ 400

Segments and Information - Addi

Segments and Information - Additional information (Details)	9 Months Ended
	Sep. 30, 2024 Segment
Segments and Information
Number of operating segment	1

Segments and Information - Summ

Segments and Information - Summary of Long-lived Assets by Geographic Region (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Segments and Information
Total tangible long-lived assets	$ 1,706	$ 2,293
South Korea
Segments and Information
Total tangible long-lived assets	1,041	1,363
United States
Segments and Information
Total tangible long-lived assets	$ 665	$ 930

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Potentially Dilutive Common Stock Equivalents that were Excluded From the Computation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Net Loss Per Share
Potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per common share (in shares)	48,718	4,690
Warrants
Net Loss Per Share
Potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per common share (in shares)	26,273	2,214
Legacy GCT
Net Loss Per Share
Potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per common share (in shares)	20,000
Sponsor Earnout Shares
Net Loss Per Share
Potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per common share (in shares)	571
Convertible promissory notes
Net Loss Per Share
Potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per common share (in shares)	713	1,806
Options issued and outstanding
Net Loss Per Share
Potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per common share (in shares)	550	670
RSU
Net Loss Per Share
Potentially dilutive common stock equivalents that were excluded from the computation of diluted net loss per common share (in shares)	611

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands, ₩ in Millions

1 Months Ended

2 Months Ended

3 Months Ended

9 Months Ended

Nov. 30, 2024 USD ($)

Oct. 31, 2024 USD ($) shares

Apr. 30, 2024 USD ($)

Sep. 30, 2024 USD ($)

Sep. 30, 2024 USD ($) shares

Jun. 30, 2024 USD ($) shares

Sep. 30, 2024 USD ($)

Nov. 30, 2024 KRW (₩)

Oct. 31, 2024 KRW (₩)

Dec. 31, 2021 USD ($)

Dec. 31, 2021 KRW (₩)

Dec. 31, 2017 USD ($)

Dec. 31, 2017 KRW (₩)

Subsequent Event [Line Items]

Repayments of convertible promissory notes

$ 1,630

Issuance of common stock under common stock purchase agreement (in shares) | shares

1,421,715

678,462

Proceeds from issuance of common stock under common stock purchase agreement

$ 5,000

$ 2,800

7,814

Historical convertible promissory notes

Subsequent Event [Line Items]

Repayments of convertible promissory notes

$ 600

$ 1,000

$ 5,100

Mujin Electronics Co., Ltd.

Subsequent Event [Line Items]

Maturity date description

In October 2024, the Company executed an amendment with Mujin Electronics Co., Ltd. to extend the maturity date of KRW 5.0 billion ($3.7 million) loan from January 2025 to June 2025.

i Best Investment Co., Ltd.

Subsequent Event [Line Items]

Maturity date description

In October 2024, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from February 2025 to May 2025 for its sixth draw.

Kyeongho Lee | Term loans

Subsequent Event [Line Items]

Principal amount

$ 100

₩ 110

$ 700

₩ 1,000

Subsequent event

Subsequent Event [Line Items]

Issuance of common stock under common stock purchase agreement (in shares) | shares

103,596

Proceeds from issuance of common stock under common stock purchase agreement

$ 300

Subsequent event | Historical convertible promissory notes

Subsequent Event [Line Items]

Repayments of convertible promissory notes

1,000

Subsequent event | Mujin Electronics Co., Ltd. | Term loans

Subsequent Event [Line Items]

Term loan outstanding

$ 3,700

₩ 5,000

Subsequent event | Kyeongho Lee | Term loans

Subsequent Event [Line Items]

Principal amount

$ 2,900

₩ 4,000

Loan maturity date

Dec. 31, 2024

Annual interest rate

12%