GCT Semiconductor Holding (GCTS) 10-Q 14 Aug 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Aug. 07, 2024
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 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		47,297,182
Entity Central Index Key	0001851961
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
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		Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents		$ 4,035	$ 258
Accounts receivable, net		5,166	4,920
Inventory		1,997	1,486
Contract assets		4,615	3,439
Prepaid expenses and other current assets		4,835	2,906
Total current assets		20,648	13,009
Property and equipment, net		615	772
Operating lease right-of-use assets		1,149	1,521
Intangibles, net		132	245
Other assets		837	881
Total assets		23,381	16,428
Current liabilities:
Accounts payable		877	17,814
Contract liabilities		23	48
Accrued and other current liabilities		22,196	23,956
Common stock forward liability		535
Borrowings		33,616	44,509
Convertible promissory notes, current		5,006	27,794
Operating lease liabilities, current		664	680
Total current liabilities		62,917	114,801
Convertible promissory notes, net of current		4,667	6,239
Net defined benefit liabilities		7,366	7,689
Long-term operating lease liabilities		496	850
Income taxes payable		2,120	2,178
Warrant liabilities		3,956
Other liabilities		176	108
Total liabilities		81,698	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 June 30, 2024 and December 31, 2023, respectively; no shares issued and outstanding as of June 30, 2024 and December 31, 2023
Common stock, par value $0.0001 per share; 400,000 and 200,000 shares authorized as of June 30, 2024 and December 31, 2023, respectively; 46,679 and 24,166 shares issued and outstanding as of June 30, 2024 and December 31, 2023, respectively(1)	[1]	5	3
Additional paid-in capital(1)	[1]	491,384	435,752
Accumulated other comprehensive loss		234	(1,538)
Accumulated deficit		(549,940)	(549,654)
Total stockholders' deficit		(58,317)	(115,437)	[1]
Total liabilities and stockholders' deficit		$ 23,381	$ 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.)

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 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	46,679,000	24,166,000
Common stock, shares outstanding	46,679,000	24,166,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net revenues:
Total net revenues		$ 1,468	$ 4,301	$ 4,733	$ 7,363
Cost of net revenues:
Total cost of net revenues		547	1,470	1,859	3,011
Gross profit		921	2,831	2,874	4,352
Operating expenses:
Research and development		4,164	3,985	9,685	4,887
Sales and marketing		976	757	1,972	1,593
General and administrative		2,860	2,627	5,696	4,104
Gain on extinguishment of liability				(14,636)
Total operating expenses		8,000	7,369	2,717	10,584
Income (loss) from operations		(7,079)	(4,538)	157	(6,232)
Interest expense		(760)	(2,723)	(2,842)	(3,658)
Other income (expenses), net		6,863	731	2,525	2,017
Loss before provision for income taxes		(976)	(6,530)	(160)	(7,873)
Provision for income taxes		67	37	126	87
Net loss		$ (1,043)	$ (6,567)	$ (286)	$ (7,960)
Net loss per common share - basic	[1]	$ (0.02)	$ (0.27)	$ (0.01)	$ (0.33)
Net loss per common share - diluted		$ (0.02)	$ (0.27)	$ (0.01)	$ (0.33)
Weighted average number of common shares used in computing net loss per common share - basic	[1]	44,060	23,883	34,764	23,873
Weighted average number of common shares used in computing net loss per common share - diluted		44,060	23,883	34,764	23,873
Product
Net revenues:
Total net revenues		$ 18	$ 4,042	$ 2,396	$ 4,641
Cost of net revenues:
Total cost of net revenues		158	991	812	1,969
Service
Net revenues:
Total net revenues		1,450	259	2,337	2,722
Cost of net revenues:
Total cost of net revenues		$ 389	$ 479	$ 1,047	$ 1,042
[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.)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Comprehensive loss, net of taxes:
Net loss	$ (1,043)	$ (6,567)	$ (286)	$ (7,960)
Foreign currency translation adjustment	708	175	1,772	849
Comprehensive loss	$ (335)	$ (6,392)	$ 1,486	$ (7,111)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Deficit - USD ($) $ in Thousands		Common Stock Previously reported	Common Stock Revision of prior period, adjustment	Common Stock		Additional Paid-in Capital Previously reported	Additional Paid-in Capital Revision of prior period, adjustment	Additional Paid-in Capital		Accumulated Other Comprehensive Income (Loss) Previously reported	Accumulated Other Comprehensive Income (Loss)		Accumulated Deficit Previously reported	Accumulated Deficit		Previously reported	Total
Balance as at beginning at Dec. 31, 2022		$ 128	$ (126)	$ 2	[1]	$ 433,990	$ 126	$ 434,116	[1]	$ (1,862)	$ (1,862)	[1]	$ (527,185)	$ (527,185)	[1]	$ (94,929)	$ (94,929)	[1]
Balance as at beginning (in shares) at Dec. 31, 2022		127,761,000	(103,900,000)	23,861,000	[1]
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	[1]							2									2
Foreign currency translation adjustment											674						674
Net loss														(1,393)			(1,393)
Balance as at end at Mar. 31, 2023	[1]			$ 2				434,119			(1,188)			(528,578)			(95,645)
Balance as at end (in shares) at Mar. 31, 2023	[1]			23,866,000
Balance as at beginning at Dec. 31, 2022		$ 128	$ (126)	$ 2	[1]	433,990	126	434,116	[1]	(1,862)	(1,862)	[1]	(527,185)	(527,185)	[1]	(94,929)	(94,929)	[1]
Balance as at beginning (in shares) at Dec. 31, 2022		127,761,000	(103,900,000)	23,861,000	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment																	849
Net loss																	(7,960)
Balance as at end at Jun. 30, 2023				$ 2				434,198			(1,013)			(535,145)			(101,958)
Balance as at end (in shares) at Jun. 30, 2023				23,903,000
Balance as at beginning at Mar. 31, 2023	[1]			$ 2				434,119			(1,188)			(528,578)			(95,645)
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								4									4
Issuance of common stock from warrant exercise (in shares)				33,000
Issuance of common stock from conversion of convertible promissory notes and accrued interest								72									72
Issuance of common stock from conversion of convertible promissory notes and accrued interest (in shares)				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				$ 2				434,198			(1,013)			(535,145)			(101,958)
Balance as at end (in shares) at Jun. 30, 2023				23,903,000
Balance as at beginning at Dec. 31, 2023		$ 129	$ (126)	$ 3	[1]	435,626	126	435,752	[1]	(1,538)	(1,538)	[1]	(549,654)	(549,654)	[1]	(115,437)	$ (115,437)	[1]
Balance as at beginning (in shares) at Dec. 31, 2023		129,396,000	(105,230,000)	24,166,000	[1]												24,166,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reverse recapitalization transaction, net of transaction costs and acquired liabilities				$ 2				50,031									$ 50,033
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				$ 5				487,006			(474)			(548,897)			(62,360)
Balance as at end (in shares) at Mar. 31, 2024				45,833,000
Balance as at beginning at Dec. 31, 2023		$ 129	$ (126)	$ 3	[1]	$ 435,626	$ 126	435,752	[1]	$ (1,538)	(1,538)	[1]	$ (549,654)	(549,654)	[1]	$ (115,437)	$ (115,437)	[1]
Balance as at beginning (in shares) at Dec. 31, 2023		129,396,000	(105,230,000)	24,166,000	[1]												24,166,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from option exercises (in shares)																	0
Issuance of commitment shares in connection with common stock purchase agreement (in shares)																	56,818
Issuance of common stock to underwriter																	$ 700
Foreign currency translation adjustment																	1,772
Net loss																	(286)
Balance as at end at Jun. 30, 2024				$ 5				491,384			234			(549,940)			$ (58,317)
Balance as at end (in shares) at Jun. 30, 2024				46,679,000													46,679,000
Balance as at beginning at Mar. 31, 2024				$ 5				487,006			(474)			(548,897)			$ (62,360)
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)				679,000													678,462
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				$ 5				$ 491,384			$ 234			$ (549,940)			$ (58,317)
Balance as at end (in shares) at Jun. 30, 2024				46,679,000													46,679,000
[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.)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Operating activities:
Net loss	$ (286)	$ (7,960)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	379	390
Operating lease right-of-use amortization	347	390
Stock-based compensation	1,546	5
Issuance of common stock to underwriter	667
Change in credit loss allowance	(547)	793
Change in fair value of convertible promissory notes	1,189	(1,098)
Change in fair value of warrant liabilities	(2,002)
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	253	(494)
Inventory	(511)	(229)
Contract assets	(1,176)	(1,924)
Prepaid expenses and other current assets	(1,702)	518
Other assets	44	62
Accounts payable	(3,356)	(522)
Contract liabilities	(25)	(601)
Accrued and other current liabilities	(4,407)	4,817
Net defined benefit liabilities	351	94
Income tax payable	(29)	(147)
Lease liabilities	(341)	(464)
Other liabilities	(406)	(1)
Net cash used in operating activities	(24,062)	(6,371)
Investing activities:
Purchases of property and equipment	(131)	(222)
Net cash used in investing activities	(131)	(222)
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	2,815
Proceeds from bank borrowings		6,861
Proceeds from exercise of stock options		5
Repayments of bank borrowings	(7,853)	(23)
Repayments of convertible promissory notes	(630)
Payments of financial lease liabilities		(9)
Net cash provided by financing activities	27,860	6,834
Effect of exchange rate changes on cash and cash equivalents	110	(380)
Net increase (decrease) in cash and cash equivalents	3,777	(139)
Cash and cash equivalents at beginning of period	258	1,398
Cash and cash equivalents at end of period	4,035	1,259
Supplemental disclosure of cash flow information:
Cash paid for interest	2,144	1,084
Cash paid for income taxes	47	8
Cash paid for operating leases	377	386
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	51
Proceeds from issuance of common stock withheld for outstanding payables	$ 488

Organization and Liquidity

Organization and Liquidity	6 Months Ended
	Jun. 30, 2024
Organization and Liquidity
Organization and Liquidity	1. 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. Prior to June 30, 2024, the Company has incurred operating losses and negative cash flows from operating and had an accumulated deficit of $549.9 million as of June 30, 2024. The Company’s existing sources of liquidity as of June 30, 2024 include cash and cash equivalents of $4.0 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 June 30, 2024, the Company received $2.8 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	6 Months Ended
	Jun. 30, 2024
Summary of Significant Accounting Policies and Basis of Presentation
Summary of Significant Accounting Policies and Basis of Presentation	2. 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 six months ended June 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. However, 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 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: 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 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 collectability 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 June 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 June 30, 2024 December 31, 2023 ​ Customer A ​ 32 % — % Customer H ​ 18 % 19 % Customer I ​ 15 % 14 % Customer J ​ 14 % 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 ​ Six Months Ended ​ ​ ​ June 30, ​ June 30, ​ Customer 2024 2023 2024 2023 ​ Customer A ​ — % — % 42 % — % Customer B ​ 80 % — % 25 % — % Customer C ​ — % — % 18 % — % Customer D ​ — % 70 % — % 41 % Customer E ​ — % — % — % 14 % Customer F ​ — % — % — % 12 % Customer G ​ — % — % — % 11 % ​ 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 $0.8 million and $1.9 million foreign currency exchange gains for the three and six months ended June 30, 2024, respectively. The Company recognized $0.2 million and $0.9 million foreign currency exchange gains for the three and six months ended June 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 (expense), net in the condensed consolidated statements of operations. Common Stock Warrants The outstanding common stock warrants are liability-classified as 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 (expense), net in the unaudited condensed consolidated statements of operations. Certain Equity Contracts The Company’s promises to potentially issue additional shares in the future, including the Legacy GCT Earnout Shares and the Sponsor Earnout Shares discussed in Note 3, 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 In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805) Accounting for Contract Assets and Contract Liabilities from Contracts with Customers Recent Accounting Pronouncements Not Yet Adopted 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 In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures 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	6 Months Ended
	Jun. 30, 2024
Reverse Recapitalization
Reverse Recapitalization	3. 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 one one In the event of a future 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 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 June 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 based on the $12.50 per share VWAP Threshold, (ii) one one 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.

Disaggregation of Revenue

Disaggregation of Revenue	6 Months Ended
	Jun. 30, 2024
Disaggregation of Revenue
Disaggregation of Revenue	4. 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 June 30, Six Months Ended June 30, ​ 2024 2023 2024 2023 South Korea ​ $ — ​ $ 3,006 ​ $ 2,000 ​ $ 3,006 United States ​ 1,339 ​ 348 ​ 1,728 ​ 2,316 Germany ​ ​ 74 ​ ​ — ​ ​ 870 ​ ​ — China ​ 55 ​ 472 ​ 135 ​ 1,566 Taiwan ​ — ​ 475 ​ — ​ 475 Total ​ $ 1,468 ​ $ 4,301 ​ $ 4,733 ​ $ 7,363 ​ Contract Assets and Liabilities Net revenues recognized during the six months ended June 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 June 30, 2024 and December 31, 2023, the contract assets were $4.6 million and $3.4 million, respectively. The balances of contract liabilities and capitalized costs related to contract fulfilment were immaterial as of June 30, 2024 and December 31, 2023. ​

Fair Value of Measurements

Fair Value of Measurements	6 Months Ended
	Jun. 30, 2024
Fair Value of Measurements
Fair Value of Measurements	5. Recurring Fair Value Measurements The following financial instruments are measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ Level 1 Level 2 Level 3 Total Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible promissory notes ​ $ — ​ $ — ​ $ 9,673 ​ $ 9,673 Warrant liabilities ​ ​ — ​ ​ — ​ ​ 3,956 ​ ​ 3,956 Common stock forward liability ​ — ​ — ​ 535 ​ 535 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 June 30, 2024 December 31, 2023 Convertible promissory notes, current Discounted Cash Flow Model (“DCF”) Discount rate, risk-free rate, credit spread, contractual cash flows ​ $ 5,006 ​ $ — ​ ​ 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 ​ ​ 535 ​ ​ — Convertible promissory notes, net of current Binomial Lattice Model (“BLM”) Stock price, volatility, remaining term, risk-free rate, credit spread ​ 4,667 ​ — ​ ​ PWERM ​ Scenario of initial public offering (“IPO”) and merger and acquisition (“M&A”) ​ ​ — ​ ​ 6,239 Warrant liabilities Black Scholes Merton Model (“BSM”) or BLM Exercise price, term to expiration, volatility, risk-free rate ​ 3,956 ​ — ​ As of June 30, 2024, the key inputs for the convertible promissory notes valuation using the DCF model were as follows: remaining term of 0.17 years and a discount rate of 10.8%. As of June 30, 2024, the key inputs for the convertible promissory notes, net of current using the BLM were as follows: stock price of $5.21, volatility of 21.3%, remaining term of 1.66 years, risk-free rate of 4.84%, and credit spread of 5.7%. As of June 30, 2024, the key inputs for the common stock forward valuation using the DCF model were as follows: a remaining term of 1.87 years and future risk-free rate estimates of 4.76%-5.47% for this period. As of June 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 expiration of 4.7 years, volatility range of 21.3%, and a risk-free rate of 4.3%. As of June 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 4.7 years. As of June 30, 2024, the key inputs for the other warrant liabilities using the BSM were as follows: an exercise price of $5.00 per share, or $10.00 per share or $18.75 per share, term to expiration ranging from 0.12 years to 2.30 years, volatility ranging from 30.6% to 33.8%, and a risk-free rate ranging from 4.6% to 5.4%. As of December 31, 2023, the PWERM was used as Legacy GCT was a private company. After the Closing, and as of June 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 ​ 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 ​ 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 ​

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2024
Balance Sheet Components
Balance Sheet Components	6. Inventory Inventories consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Raw materials ​ $ 464 ​ $ 448 Work-in-process ​ 630 ​ 601 Finished goods ​ 903 ​ 437 Total inventory ​ $ 1,997 ​ $ 1,486 ​ There were no inventory write-downs during the six months ended June 30, 2024 and 2023. Prepaid expenses and other assets Prepaid expenses and other assets consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Prepaid expenses ​ $ 2,822 ​ $ 433 Prepaid inventory ​ ​ 1,502 ​ ​ 279 Lease deposit ​ 400 ​ 434 Other receivables and current assets ​ 111 ​ 117 Deferred transaction costs ​ — ​ 1,643 Total prepaid expenses and other current assets ​ $ 4,835 ​ $ 2,906 ​ Accrued and other current liabilities Accrued and other current liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Payroll and related expenses ​ $ 9,241 ​ $ 9,880 Accrued payables ​ ​ 6,103 ​ ​ 6,319 Other taxes payable ​ ​ 3,344 ​ ​ 158 Current portion of interest payable ​ ​ 2,871 ​ ​ 6,915 Professional fees ​ 465 ​ 499 Product warranty liabilities ​ 44 ​ 55 Royalty and license fee ​ 42 ​ 58 Other ​ 86 ​ 72 Total accrued and other current liabilities ​ $ 22,196 ​ $ 23,956 ​

Debt

Debt	6 Months Ended
	Jun. 30, 2024
Debt
Debt	7. The Company’s outstanding debt was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 ​ ​ Outstanding ​ ​ ​ Outstanding ​ ​ ​ ​ Principal ​ Fair Value ​ Principal ​ Fair Value Convertible promissory notes: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Historical convertible promissory notes ​ $ 5,000 ​ $ 5,006 ​ $ 35,347 ​ $ 34,033 2023 and 2024 convertible promissory notes ​ 5,000 ​ 4,667 ​ — ​ — Total convertible promissory notes ​ ​ 10,000 ​ ​ 9,673 ​ ​ 35,347 ​ ​ 34,033 Borrowings: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ KEB Hana Bank ​ 6,479 ​ 6,479 ​ 6,980 ​ 6,980 IBK Industrial Bank ​ 6,623 ​ 6,623 ​ 7,135 ​ 7,135 Note payable (one individual investor) ​ 1,000 ​ 1,000 ​ 1,000 ​ 1,000 M-Venture Investment, Inc. ​ 4,319 ​ 4,319 ​ 7,756 ​ 7,756 Anapass, Inc., related party ​ 9,358 ​ 9,358 ​ 10,082 ​ 10,082 i Best Investment Co., Ltd ​ 5,038 ​ 5,038 ​ 10,082 ​ 10,082 Kyeongho Lee, related party ​ 799 ​ 799 ​ 1,474 ​ 1,474 Total debt ​ $ 43,616 ​ 43,289 ​ $ 79,856 ​ 78,542 Less: current portion ​ ​ ​ ​ (38,622) ​ ​ ​ ​ (72,303) Debt, net of current portion ​ ​ ​ ​ $ 4,667 ​ ​ ​ ​ $ 6,239 ​ Expected future minimum principal payments under the Company’s total debt is as follows as of June 30, 2024 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible ​ ​ ​ ​ ​ ​ Notes ​ ​ ​ ​ ​ ​ Years ​ Payable ​ Borrowing ​ Total 2024, remainder ​ $ 5,000 ​ $ 30,737 ​ $ 35,737 2025 ​ — ​ 2,879 ​ 2,879 2026 ​ 5,000 ​ — ​ 5,000 Total debt ​ $ 10,000 ​ $ 33,616 ​ $ 43,616 ​ 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. As of June 30, 2024, the remaining principal and interest amount of $7.1 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 June 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 June 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 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 has 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. 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 has 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. 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. 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 have 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. 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 have 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. 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 has 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	6 Months Ended
	Jun. 30, 2024
Commitments and Contingencies
Commitments and Contingencies	8. 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 June 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 June 30, 2024, the Company had no outstanding noncancelable purchase commitments for these production agreements. 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 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 six months ended June 30, 2024, the Company recorded $1.3 million and $4.8 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 June 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 $6.5 million, $6.6 million and $9.4 million, respectively, as of June 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): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Cash and cash equivalents ​ $ 3,879 ​ $ 254 Accounts receivable ​ ​ 5,200 ​ ​ 4,920 Inventory ​ 1,997 ​ 1,486 Property and equipment ​ 253 ​ 352 Intangible assets and others ​ 942 ​ 199 ​

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2024
Common Stock
Common Stock	9. 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 June 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. 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 a $0.7 million charge to equity and expensed this amount to general and administrative expenses for the three and six months ended June 30, 2024. 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): ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Common stock warrants ​ 26,724 ​ 2,894 Legacy GCT Earnout Shares ​ 20,000 ​ — Shares available for future grant from 2024 plan 3,952 — Convertible promissory notes 767 1,835 Options issued and outstanding 668 668 Shares available for future grant from 2024 ESPP ​ 600 ​ — RSUs outstanding 424 392 Shares available for future grant from 2011 plan — 113 Total 53,135 5,902 ​

Warrants

Warrants	6 Months Ended
	Jun. 30, 2024
Warrants
Warrants	10. 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 June 30, 2024 Exercise Price Expiration August 2021 ​ 299 ​ $ 10.00 - $18.75 ​ August 2024 September 2021 300 ​ $ 5.00 September 2024 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 Tota l 26,724 ​ ​ ​

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2024
Stock-Based Compensation
Stock-Based Compensation	11. 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ Number of ​ Weighted- ​ Remaining ​ ​ ​ ​ ​ Options ​ Average ​ Contractual Life ​ Aggregate ​ ​ Outstanding ​ Exercise Price ​ (in Years) ​ Intrinsic Value 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 Balance as of June 30, 2024 668 ​ 0.11 5.0 ​ 3,411 Vested as of June 30, 2024 668 ​ $ 0.11 5.0 ​ 3,406 Exercisable as of June 30, 2024 642 ​ $ 0.11 4.9 ​ 3,278 (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, exercised or cancelled during the six months ended June 30, 2024 June 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. During the three months ended June 30, 2024, the stock-based compensation was immaterial. 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. As of June 28, 2024, this determination was made for 31,668 shares based on the closing price of the Company’s common stock as of that date. RSUs outstanding under the 2024 Plan were as follows (in thousands, except per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number of RSUs ​ Average Grant ​ ​ Outstanding ​ Date Fair Value 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 32 ​ 5.21 Balance as of June 30, 2024 424 ​ $ 6.09 (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 $0.3 million and $0.7 million of stock-based compensation during the three and six months ended June 30, 2024, respectively, related to the outstanding RSUs. As of June 30, 2024, there was $2.4 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 3.5 years. Any unvested RSUs are forfeited upon separation from the Company, and the Company accounts for forfeitures when 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 June 30, ​ Six Months Ended June 30, ​ 2024 2023 2024 2023 Research and development ​ $ 128 ​ $ 1 ​ $ 254 ​ $ 2 Sales and marketing ​ 36 ​ 1 ​ 72 ​ 2 General and administrative ​ 159 ​ 1 ​ 1,220 ​ 1 Total ​ $ 323 ​ $ 3 ​ $ 1,546 ​ $ 5 ​

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2024
Income Taxes
Income Taxes	12. 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 six months ended June 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 six months ended June 30, 2024 and 2023, the Company recorded income tax of $0.1 million and $0.1 million, respectively. The effective tax rate is (119.4)% and (1.0)% for six months ended June 30, 2024 and 2023, respectively. Through June 30, 2024, the Company was not under examination by any taxing authority. As of June 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 June 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 June 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	6 Months Ended
	Jun. 30, 2024
Employee Benefit Plans
Employee Benefit Plans	13. 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 December 31, 2023 Liability for severance payments, beginning ​ $ 7,627 ​ $ 7,997 Deposit ​ (261) ​ (308) Liability for severance payments, ending ​ $ 7,366 ​ $ 7,689 ​

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2024
Related Party Transactions
Related Party Transactions	14. A summary of balances and transactions with the related parties who are stockholders of the Company were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 December 31, 2023 ​ ​ Anapass Kyeongho Lee ​ Anapass Kyeongho Lee Borrowings ​ $ 9,358 ​ $ 799 ​ $ 10,082 ​ $ 1,474 Other current liabilities ​ 52 ​ 86 ​ 212 ​ 182 ​ For each of the three and six months ended June 30, 2024, the Company recorded $0.1 million and $0.3 million, respectively, of interest expense with Anapass, Inc. in the unaudited condensed consolidated statements of operations. For each of the three and six months ended June 30, 2023, the Company recorded $0.1 million and $0.3 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 six months ended June 30, 2024 and 2023.

Segments and Information

Segments and Information	6 Months Ended
	Jun. 30, 2024
Segments and Information
Segments and Information	15. 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): ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 December 31, 2023 South Korea ​ $ 1,048 ​ $ 1,363 United States ​ 716 ​ 930 Total ​ $ 1,764 ​ $ 2,293 ​

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2024
Net Loss Per Share
Net Loss Per Share	16. 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): ​ ​ ​ ​ ​ ​ ​ June 30, ​ ​ 2024 2023 Warrants 26,724 2,172 Legacy GCT Earnout Shares ​ 20,000 ​ — Sponsor Earnout Shares ​ 1,920 ​ — Convertible promissory notes ​ 767 ​ 1,806 Options 668 848 RSU 424 — Total 50,503 4,826 ​

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2024
Subsequent Events
Subsequent Events	17. i Best Investment Co., Ltd In July 2024, the Company repaid KRW 1.0 billion ($0.7 million) to i Best Investment Co., Ltd. In July 2024, the Company executed an amendment with i Best Investment Co., Ltd. for the three term loans with an aggregate principal amount of KRW 6.0 billion ($4.3 million) outstanding, pursuant to which the maturity date for such loans was extended from August 2024 to February 2025. M-Venture Investment Co., Ltd In July 2024, the Company repaid KRW 1.0 billion ($0.7 million) to M-Venture Investment Co., Ltd. In July 2024, the Company executed an amendment with M-Venture Investment Co., Ltd. and Mujin Electronics Co., Ltd. for the term loan of KRW 5.0 billion ($3.7 million) outstanding as of June 30, 2024. As a result, Mujin Electronics Co., Ltd. assumed the loan from M-Venture Investment Co., Ltd., and the maturity date was extended from July 2024 to January 2025 with an interest rate of 6.8%. KEB Hana Bank In July 2024, the Company executed an amendment with KEB Hana Bank for the term loan of KRW 8.0 billion ($5.8 million) outstanding as of June 30, 2024, pursuant to which the maturity date was extended from July 2024 to July 2025. Anapass, Inc. In July 2024, the Company executed an amendment with Anapass, Inc., for the term note of KRW 6 billion ($4.3 million) outstanding, pursuant to which the maturity date was extended from July 2024 to July 2025. Purchase Agreement In July 2024, the Company sold 544,136 shares of its common stock for gross proceeds of $2.7 million, of which $0.5 million was withheld by B. Riley against the outstanding amount payable, and $2.2 million was received by the Company in cash.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	6 Months Ended
	Jun. 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 six months ended June 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. However, 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 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: 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 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 collectability 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 June 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 June 30, 2024 December 31, 2023 ​ Customer A ​ 32 % — % Customer H ​ 18 % 19 % Customer I ​ 15 % 14 % Customer J ​ 14 % 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 ​ Six Months Ended ​ ​ ​ June 30, ​ June 30, ​ Customer 2024 2023 2024 2023 ​ Customer A ​ — % — % 42 % — % Customer B ​ 80 % — % 25 % — % Customer C ​ — % — % 18 % — % Customer D ​ — % 70 % — % 41 % Customer E ​ — % — % — % 14 % Customer F ​ — % — % — % 12 % Customer G ​ — % — % — % 11 % ​ 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 $0.8 million and $1.9 million foreign currency exchange gains for the three and six months ended June 30, 2024, respectively. The Company recognized $0.2 million and $0.9 million foreign currency exchange gains for the three and six months ended June 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 (expense), net in the condensed consolidated statements of operations.
Common Stock Warrants	Common Stock Warrants The outstanding common stock warrants are liability-classified as 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 (expense), net in the unaudited condensed consolidated statements of operations.
Certain Equity Contracts	Certain Equity Contracts The Company’s promises to potentially issue additional shares in the future, including the Legacy GCT Earnout Shares and the Sponsor Earnout Shares discussed in Note 3, 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 In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805) Accounting for Contract Assets and Contract Liabilities from Contracts with Customers Recent Accounting Pronouncements Not Yet Adopted 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 In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures 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)	6 Months Ended
	Jun. 30, 2024
Summary of Significant Accounting Policies and Basis of Presentation
Schedule of net revenues and accounts receivable concentration	​ ​ ​ ​ ​ ​ ​ Customer June 30, 2024 December 31, 2023 ​ Customer A ​ 32 % — % Customer H ​ 18 % 19 % Customer I ​ 15 % 14 % Customer J ​ 14 % 27 % Customer K ​ — % 10 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ June 30, ​ June 30, ​ Customer 2024 2023 2024 2023 ​ Customer A ​ — % — % 42 % — % Customer B ​ 80 % — % 25 % — % Customer C ​ — % — % 18 % — % Customer D ​ — % 70 % — % 41 % Customer E ​ — % — % — % 14 % Customer F ​ — % — % — % 12 % Customer G ​ — % — % — % 11 %

Reverse Recapitalization (Table

Reverse Recapitalization (Tables)	6 Months Ended
	Jun. 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)	6 Months Ended
	Jun. 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 June 30, Six Months Ended June 30, ​ 2024 2023 2024 2023 South Korea ​ $ — ​ $ 3,006 ​ $ 2,000 ​ $ 3,006 United States ​ 1,339 ​ 348 ​ 1,728 ​ 2,316 Germany ​ ​ 74 ​ ​ — ​ ​ 870 ​ ​ — China ​ 55 ​ 472 ​ 135 ​ 1,566 Taiwan ​ — ​ 475 ​ — ​ 475 Total ​ $ 1,468 ​ $ 4,301 ​ $ 4,733 ​ $ 7,363

Fair Value of Measurements (Tab

Fair Value of Measurements (Tables)	6 Months Ended
	Jun. 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ Level 1 Level 2 Level 3 Total Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible promissory notes ​ $ — ​ $ — ​ $ 9,673 ​ $ 9,673 Warrant liabilities ​ ​ — ​ ​ — ​ ​ 3,956 ​ ​ 3,956 Common stock forward liability ​ — ​ — ​ 535 ​ 535 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 June 30, 2024 December 31, 2023 Convertible promissory notes, current Discounted Cash Flow Model (“DCF”) Discount rate, risk-free rate, credit spread, contractual cash flows ​ $ 5,006 ​ $ — ​ ​ 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 ​ ​ 535 ​ ​ — Convertible promissory notes, net of current Binomial Lattice Model (“BLM”) Stock price, volatility, remaining term, risk-free rate, credit spread ​ 4,667 ​ — ​ ​ PWERM ​ Scenario of initial public offering (“IPO”) and merger and acquisition (“M&A”) ​ ​ — ​ ​ 6,239 Warrant liabilities Black Scholes Merton Model (“BSM”) or BLM Exercise price, term to expiration, volatility, risk-free rate ​ 3,956 ​ —
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 ​ 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 ​ 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 ​

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2024
Balance Sheet Components
Schedule of inventory	Inventories consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Raw materials ​ $ 464 ​ $ 448 Work-in-process ​ 630 ​ 601 Finished goods ​ 903 ​ 437 Total inventory ​ $ 1,997 ​ $ 1,486
Schedule of prepaid expenses and other assets	Prepaid expenses and other assets consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Prepaid expenses ​ $ 2,822 ​ $ 433 Prepaid inventory ​ ​ 1,502 ​ ​ 279 Lease deposit ​ 400 ​ 434 Other receivables and current assets ​ 111 ​ 117 Deferred transaction costs ​ — ​ 1,643 Total prepaid expenses and other current assets ​ $ 4,835 ​ $ 2,906
Schedule of accrued and other current liabilities	Accrued and other current liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Payroll and related expenses ​ $ 9,241 ​ $ 9,880 Accrued payables ​ ​ 6,103 ​ ​ 6,319 Other taxes payable ​ ​ 3,344 ​ ​ 158 Current portion of interest payable ​ ​ 2,871 ​ ​ 6,915 Professional fees ​ 465 ​ 499 Product warranty liabilities ​ 44 ​ 55 Royalty and license fee ​ 42 ​ 58 Other ​ 86 ​ 72 Total accrued and other current liabilities ​ $ 22,196 ​ $ 23,956 ​

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2024
Debt
Schedule of outstanding debt	The Company’s outstanding debt was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 ​ ​ Outstanding ​ ​ ​ Outstanding ​ ​ ​ ​ Principal ​ Fair Value ​ Principal ​ Fair Value Convertible promissory notes: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Historical convertible promissory notes ​ $ 5,000 ​ $ 5,006 ​ $ 35,347 ​ $ 34,033 2023 and 2024 convertible promissory notes ​ 5,000 ​ 4,667 ​ — ​ — Total convertible promissory notes ​ ​ 10,000 ​ ​ 9,673 ​ ​ 35,347 ​ ​ 34,033 Borrowings: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ KEB Hana Bank ​ 6,479 ​ 6,479 ​ 6,980 ​ 6,980 IBK Industrial Bank ​ 6,623 ​ 6,623 ​ 7,135 ​ 7,135 Note payable (one individual investor) ​ 1,000 ​ 1,000 ​ 1,000 ​ 1,000 M-Venture Investment, Inc. ​ 4,319 ​ 4,319 ​ 7,756 ​ 7,756 Anapass, Inc., related party ​ 9,358 ​ 9,358 ​ 10,082 ​ 10,082 i Best Investment Co., Ltd ​ 5,038 ​ 5,038 ​ 10,082 ​ 10,082 Kyeongho Lee, related party ​ 799 ​ 799 ​ 1,474 ​ 1,474 Total debt ​ $ 43,616 ​ 43,289 ​ $ 79,856 ​ 78,542 Less: current portion ​ ​ ​ ​ (38,622) ​ ​ ​ ​ (72,303) Debt, net of current portion ​ ​ ​ ​ $ 4,667 ​ ​ ​ ​ $ 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 June 30, 2024 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Convertible ​ ​ ​ ​ ​ ​ Notes ​ ​ ​ ​ ​ ​ Years ​ Payable ​ Borrowing ​ Total 2024, remainder ​ $ 5,000 ​ $ 30,737 ​ $ 35,737 2025 ​ — ​ 2,879 ​ 2,879 2026 ​ 5,000 ​ — ​ 5,000 Total debt ​ $ 10,000 ​ $ 33,616 ​ $ 43,616

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 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): ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Cash and cash equivalents ​ $ 3,879 ​ $ 254 Accounts receivable ​ ​ 5,200 ​ ​ 4,920 Inventory ​ 1,997 ​ 1,486 Property and equipment ​ 253 ​ 352 Intangible assets and others ​ 942 ​ 199 ​

Common Stock (Tables)

Common Stock (Tables)	6 Months Ended
	Jun. 30, 2024
Common Stock
Summary of reserved shares of common stock for issuance	​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Common stock warrants ​ 26,724 ​ 2,894 Legacy GCT Earnout Shares ​ 20,000 ​ — Shares available for future grant from 2024 plan 3,952 — Convertible promissory notes 767 1,835 Options issued and outstanding 668 668 Shares available for future grant from 2024 ESPP ​ 600 ​ — RSUs outstanding 424 392 Shares available for future grant from 2011 plan — 113 Total 53,135 5,902 ​

Warrants (Tables)

Warrants (Tables)	6 Months Ended
	Jun. 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 June 30, 2024 Exercise Price Expiration August 2021 ​ 299 ​ $ 10.00 - $18.75 ​ August 2024 September 2021 300 ​ $ 5.00 September 2024 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 Tota l 26,724 ​ ​ ​

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ Number of ​ Weighted- ​ Remaining ​ ​ ​ ​ ​ Options ​ Average ​ Contractual Life ​ Aggregate ​ ​ Outstanding ​ Exercise Price ​ (in Years) ​ Intrinsic Value 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 Balance as of June 30, 2024 668 ​ 0.11 5.0 ​ 3,411 Vested as of June 30, 2024 668 ​ $ 0.11 5.0 ​ 3,406 Exercisable as of June 30, 2024 642 ​ $ 0.11 4.9 ​ 3,278 (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): ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number of RSUs ​ Average Grant ​ ​ Outstanding ​ Date Fair Value 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 32 ​ 5.21 Balance as of June 30, 2024 424 ​ $ 6.09 (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	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2024 2023 2024 2023 Research and development ​ $ 128 ​ $ 1 ​ $ 254 ​ $ 2 Sales and marketing ​ 36 ​ 1 ​ 72 ​ 2 General and administrative ​ 159 ​ 1 ​ 1,220 ​ 1 Total ​ $ 323 ​ $ 3 ​ $ 1,546 ​ $ 5 ​

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2024
Employee Benefit Plans
Summary of net liability for severance payments	The net liability for severance payments was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 December 31, 2023 Liability for severance payments, beginning ​ $ 7,627 ​ $ 7,997 Deposit ​ (261) ​ (308) Liability for severance payments, ending ​ $ 7,366 ​ $ 7,689 ​

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 December 31, 2023 ​ ​ Anapass Kyeongho Lee ​ Anapass Kyeongho Lee Borrowings ​ $ 9,358 ​ $ 799 ​ $ 10,082 ​ $ 1,474 Other current liabilities ​ 52 ​ 86 ​ 212 ​ 182

Segments and Information (Table

Segments and Information (Tables)	6 Months Ended
	Jun. 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): ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 December 31, 2023 South Korea ​ $ 1,048 ​ $ 1,363 United States ​ 716 ​ 930 Total ​ $ 1,764 ​ $ 2,293 ​

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 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): ​ ​ ​ ​ ​ ​ ​ June 30, ​ ​ 2024 2023 Warrants 26,724 2,172 Legacy GCT Earnout Shares ​ 20,000 ​ — Sponsor Earnout Shares ​ 1,920 ​ — Convertible promissory notes ​ 767 ​ 1,806 Options 668 848 RSU 424 — Total 50,503 4,826 ​

Organization and Liquidity (Det

Organization and Liquidity (Details) $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Mar. 31, 2024 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 26, 2024	Dec. 31, 2023 USD ($)
Organization and Liquidity
Exchange ratio				0.1868
Accumulated deficit		$ (549,940)	$ (549,940)		$ (549,654)
Cash and cash equivalents		4,035	4,035		$ 258
Cash proceeds from the reverse recapitalization and PIPE Financing	$ 17,200		17,238
Proceeds from Issuance of Common Stock		$ 2,800	$ 2,815
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	Jun. 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		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Revenue | Customer A
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			42%
Revenue | Customer B
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage	80%		25%
Revenue | Customer C
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			18%
Revenue | Customer D
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage		70%		41%
Revenue | Customer E
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage				14%
Revenue | Customer F
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage				12%
Revenue | Customer G
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage				11%
Accounts receivable | Customer A
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			32%
Accounts receivable | Customer H
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			18%		19%
Accounts receivable | Customer I
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			15%		14%
Accounts receivable | Customer J
Summary of Significant Accounting Policies and Basis of Presentation
Concentration risk percentage			14%		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		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Summary of Significant Accounting Policies and Basis of Presentation
Foreign currency gain, net	$ 0.8	$ 0.2	$ 1.9	$ 0.9

Reverse Recapitalization - Busi

Reverse Recapitalization - Business Combination (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 - Numb

Reverse Recapitalization - Number of shares of common stock issued and outstanding post Business Combination (Details) - shares		3 Months Ended
	Mar. 26, 2024	Jun. 30, 2024	Dec. 31, 2023
Reverse Recapitalization
Common stock, shares outstanding		46,679,000	24,166,000
Common stock issued in PIPE Financing		678,462
Total common stock issued and outstanding	45,833,000	46,679,000	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 in PIPE Financing	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 (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 (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 (Details) - shares	1 Months Ended	6 Months Ended
	Nov. 30, 2021	Jun. 30, 2024
Reverse Recapitalization
Number of warrants issued		26,724,000
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 (Details) - Legacy G C T $ / shares in Units, $ in Millions	Mar. 26, 2024 USD ($) $ / shares shares
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 | $	$ 108.8
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 | $ / shares	$ 12.50
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 | $ / 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 | $ / shares	$ 17.50
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 | $	$ 10.4
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 | $ / shares	$ 12.50
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 | $ / 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 | $ / shares	$ 17.50

Disaggregation of Revenue - Net

Disaggregation of Revenue - Net revenues categorized by customer location (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue
Revenues from contracts with customers	$ 1,468	$ 4,301	$ 4,733	$ 7,363
South Korea
Disaggregation of Revenue
Revenues from contracts with customers		3,006	2,000	3,006
Germany
Disaggregation of Revenue
Revenues from contracts with customers	74		870
United States
Disaggregation of Revenue
Revenues from contracts with customers	1,339	348	1,728	2,316
China
Disaggregation of Revenue
Revenues from contracts with customers	$ 55	472	$ 135	1,566
Taiwan
Disaggregation of Revenue
Revenues from contracts with customers		$ 475		$ 475

Disaggregation of Revenue - Con

Disaggregation of Revenue - Contract assets and liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Disaggregation of Revenue
Contract assets	$ 4.6	$ 3.4
Contract liabilities	$ 0.1		$ 0.7

Fair Value of Measurements (Det

Fair Value of Measurements (Details) - Recurring - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value of Measurements
Convertible promissory notes	$ 9,673	$ 34,033
Warrant liabilities	3,956
Common stock forward liability	535
Level 3
Fair Value of Measurements
Convertible promissory notes	9,673	$ 34,033
Warrant liabilities	3,956
Common stock forward liability	$ 535

Fair Value of Measurements - Va

Fair Value of Measurements - Valuation techniques and the inputs (Details) $ in Thousands	Jun. 30, 2024 USD ($) Y $ / shares	Dec. 31, 2023 USD ($)
Binomial Lattice Model ("BLM") | Exercise price | Public warrants
Fair Value of Measurements
Warrant liabilities, measurement input | $ / shares	11.50
Binomial Lattice Model ("BLM") | Term to expiration | Public warrants
Fair Value of Measurements
Warrant liabilities, measurement input	4.7
Black Scholes Merton Model ("BSM") or BLM | Exercise price | Public warrants
Fair Value of Measurements
Warrant liabilities, measurement input | $ / shares	11.50
Black Scholes Merton Model ("BSM") or BLM | Term to expiration | Public warrants
Fair Value of Measurements
Warrant liabilities, measurement input	4.7
Black Scholes Merton Model ("BSM") or BLM | Volatility | Private placement warrants
Fair Value of Measurements
Warrant liabilities, measurement input	0.213
Black Scholes Merton Model ("BSM") or BLM | Risk-free rate | Private placement warrants
Fair Value of Measurements
Warrant liabilities, measurement input	0.043
Convertible promissory notes, current | Discounted Cash Flow Model ("DCF") | Level 3
Fair Value of Measurements
Fair value | $	$ 5,006
Convertible promissory notes, current | Discounted Cash Flow Model ("DCF") | Discount factor
Fair Value of Measurements
Convertible promissory notes, measurement input	0.108
Convertible promissory notes, current | Discounted Cash Flow Model ("DCF") | Remaining term
Fair Value of Measurements
Convertible promissory notes, measurement input	0.17
Convertible promissory notes, current | PWERM | Level 3
Fair Value of Measurements
Fair value | $		$ 27,794
Common stock forward liability | Discounted Cash Flow Model ("DCF") | Level 3
Fair Value of Measurements
Fair value | $	$ 535
Common stock forward liability | Discounted Cash Flow Model ("DCF") | Term to expiration
Fair Value of Measurements
Remaining term, measurement input	1.87
Common stock forward liability | Discounted Cash Flow Model ("DCF") | Risk-free rate | Minimum
Fair Value of Measurements
Remaining term, measurement input	0.0476
Common stock forward liability | Discounted Cash Flow Model ("DCF") | Risk-free rate | Maximum
Fair Value of Measurements
Remaining term, measurement input	0.0547
Convertible promissory notes, net of current | PWERM | Level 3
Fair Value of Measurements
Fair value | $		$ 6,239
Convertible promissory notes, net of current | Binomial Lattice Model ("BLM") | Level 3
Fair Value of Measurements
Fair value | $	$ 4,667
Convertible promissory notes, net of current | Binomial Lattice Model ("BLM") | Stock price
Fair Value of Measurements
Convertible promissory notes, measurement input | $ / shares	5.21
Convertible promissory notes, net of current | Binomial Lattice Model ("BLM") | Remaining term
Fair Value of Measurements
Convertible promissory notes, measurement input	1.66
Convertible promissory notes, net of current | Binomial Lattice Model ("BLM") | Credit spread
Fair Value of Measurements
Convertible promissory notes, measurement input	0.057
Convertible promissory notes, net of current | Binomial Lattice Model ("BLM") | Volatility
Fair Value of Measurements
Convertible promissory notes, measurement input	0.213
Convertible promissory notes, net of current | Binomial Lattice Model ("BLM") | Risk-free rate
Fair Value of Measurements
Convertible promissory notes, measurement input	0.0484
Warrant liabilities - private and public warrants | Black Scholes Merton Model ("BSM") or BLM | Level 3
Fair Value of Measurements
Fair value | $	$ 3,956
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Exercise price | Minimum
Fair Value of Measurements
Warrant liabilities, measurement input | $ / shares	5
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Exercise price | Weighted average
Fair Value of Measurements
Warrant liabilities, measurement input | $ / shares	10
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Exercise price | Maximum
Fair Value of Measurements
Warrant liabilities, measurement input | $ / shares	18.75
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Term to expiration | Minimum
Fair Value of Measurements
Warrant liabilities, measurement input	0.12
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Term to expiration | Maximum
Fair Value of Measurements
Warrant liabilities, measurement input	2.30
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Volatility | Minimum
Fair Value of Measurements
Warrant liabilities, measurement input	0.306
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Volatility | Maximum
Fair Value of Measurements
Warrant liabilities, measurement input	0.338
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Risk-free rate | Minimum
Fair Value of Measurements
Warrant liabilities, measurement input	0.046
Warrant liabilities - other | Black Scholes Merton Model ("BSM") or BLM | Risk-free rate | Maximum
Fair Value of Measurements
Warrant liabilities, measurement input	0.054

Fair Value of Measurements - Ch

Fair Value of Measurements - Changes in the fair value (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2024	Mar. 31, 2024
Fair Value of Measurements
Change in fair value, Extensible list	Other income (expenses), net	Other income (expenses), net
Convertible promissory notes
Fair Value of Measurements
Fair value as of beginning of period	$ 10,317	$ 34,033
Conversion		(41,209)
Borrowing		16,290
Repayment	(630)
Change in fair value	(14)	1,203
Fair value as of end of period	9,673	10,317
Warrant liabilities
Fair Value of Measurements
Fair value as of beginning of period	10,584
Fair value of warrants assumed at closing		5,958
Change in fair value	(6,628)	4,626
Fair value as of end of period	3,956	$ 10,584
Common stock forward liability
Fair Value of Measurements
Conversion	(51)
Change in fair value	586
Fair value as of end of period	$ 535

Balance Sheet Components - Inve

Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Inventory
Raw materials	$ 464		$ 448
Work-in-process	630		601
Finished goods	903		437
Total inventory	1,997		$ 1,486
Write-downs of inventory	$ 0	$ 0

Balance Sheet Components - Prep

Balance Sheet Components - Prepaid expenses and other assets (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Balance Sheet Components
Prepaid expenses	$ 2,822	$ 433
Prepaid inventory	1,502	279
Lease deposit	400	434
Other receivables and current assets	111	117
Deferred transaction costs		1,643
Total prepaid expenses and other current assets	$ 4,835	$ 2,906

Balance Sheet Components - Accr

Balance Sheet Components - Accrued and other current liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Balance Sheet Components
Payroll and related expenses	$ 9,241	$ 9,880
Accrued payables	6,103	6,319
Other taxes payable	3,344	158
Current portion of interest payable	2,871	6,915
Professional fees	465	499
Product warranty liabilities	44	55
Royalty and license fee	42	58
Other	86	72
Total accrued and other current liabilities	$ 22,196	$ 23,956

Debt - Outstanding debt (Detail

Debt - Outstanding debt (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Borrowings
Borrowings	$ 43,616	$ 79,856
Fair Value	43,289	78,542
Less: current portion	(38,622)	(72,303)
Debt, net of current portion	4,667	6,239
Convertible promissory notes
Borrowings
Borrowings	10,000	35,347
Fair Value	9,673	34,033
Historical convertible promissory notes
Borrowings
Borrowings	5,000	35,347
Fair Value	5,006	34,033
2023 & 2024 convertible promissory notes
Borrowings
Borrowings	5,000
Fair Value	4,667
Borrowings
Borrowings
Borrowings	33,616
Borrowings | KEB Hana Bank
Borrowings
Borrowings	6,479	6,980
Fair Value	6,479	6,980
Borrowings | IBK Industrial Bank
Borrowings
Borrowings	6,623	7,135
Fair Value	6,623	7,135
Borrowings | Note payable (one individual investor)
Borrowings
Borrowings	1,000	1,000
Fair Value	1,000	1,000
Borrowings | M-Venture Investment, Inc.
Borrowings
Borrowings	4,319	7,756
Fair Value	4,319	7,756
Borrowings | Anapass, Inc, related party
Borrowings
Borrowings	9,358	10,082
Fair Value	9,358	10,082
Borrowings | i Best Investment Co., Ltd
Borrowings
Borrowings	5,038	10,082
Fair Value	5,038	10,082
Borrowings | Kyeongho Lee
Borrowings
Borrowings	799	1,474
Fair Value	$ 799	$ 1,474

Debt - Expected future minimum

Debt - Expected future minimum principal payments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Borrowings
2024, remainder	$ 35,737
2025	2,879
2026	5,000
Total debt	43,616	$ 79,856
Convertible Notes
Borrowings
2024, remainder	5,000
2025	0
2026	5,000
Total debt	10,000
Borrowings
Borrowings
2024, remainder	30,737
2025	2,879
Total debt	$ 33,616

Debt - Convertible Promissory N

Debt - Convertible Promissory Notes (Details) $ / shares in Units, $ in Thousands	1 Months Ended		6 Months Ended
	Apr. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) item $ / shares	Feb. 29, 2024 USD ($)	Dec. 31, 2023 USD ($)
Borrowings
Amount outstanding			$ 43,616		$ 79,856
Repayment of convertible net			630
Historical convertible promissory notes
Borrowings
Amount of debt converted		$ 32,100
Number of shares issued on conversion of debt | shares		4,258,223
Amount of principal and interest outstanding			$ 7,100
Number of noteholders | item			1
Conversion price | $ / shares			$ 3.50
Amount outstanding			$ 5,000		$ 35,347
Repayment of convertible net	$ 600
Historical convertible promissory notes | Minimum
Borrowings
Interest rate (as a percent)			4%
Historical convertible promissory notes | Maximum
Borrowings
Interest rate (as a percent)			7%
2023 & 2024 convertible promissory notes
Borrowings
Amount outstanding			$ 5,000
2023 & 2024 convertible promissory notes | CVT Investors
Borrowings
Principal amount			$ 13,300
Interest rate (as a percent)			5%
Amount of debt converted		$ 13,400
Number of shares issued on conversion of debt | shares		2,004,535
Conversion price | $ / shares		$ 6.67
Amount outstanding			$ 0
2023 & 2024 convertible promissory notes | Strategic investor
Borrowings
Principal amount			$ 5,100	$ 5,000
Interest rate (as a percent)			5%
Term for conversion			6 months
Conversion price | $ / shares		$ 10	$ 10

Debt - Borrowings Pursuant to T

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

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

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 (₩)

Jun. 30, 2024 USD ($)

Dec. 31, 2022 USD ($)

Dec. 31, 2022 KRW (₩)

Dec. 31, 2017 USD ($)

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

$ 43,616

$ 79,856

$ 43,616

Borrowings

Borrowings

Amount outstanding

33,616

33,616

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

$ 6,479

6,980

$ 6,479

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

$ 6,800

₩ 9,200

Interest rate (as a percent)

4.90%

4.90%

Amount outstanding

$ 6,623

7,135

$ 6,623

Note payable (one individual investor) | Borrowings

Borrowings

Principal amount

$ 1,000

Interest rate (as a percent)

4%

4%

Amount outstanding

$ 1,000

1,000

$ 1,000

M-Venture Investment, Inc. | Borrowings

Borrowings

Amount outstanding

$ 4,319

7,756

$ 4,319

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

Borrowings

Principal amount

$ 3,700

₩ 5,000

Interest rate (as a percent)

6.50%

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%

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%

8.70%

Principal amount of loan extended maturity date

$ 3,700

₩ 5,000

Anapass, Inc, related party | Borrowings

Borrowings

Amount outstanding

$ 9,358

10,082

$ 9,358

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%

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

$ 5,038

$ 10,082

$ 5,038

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

$ 799

$ 1,474

$ 799

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 - Purchase Commitment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Feb. 29, 2024	Dec. 31, 2023
Purchase Commitment
Research and development expense	$ 4,164	$ 3,985	$ 9,685	$ 4,887
Unpaid recorded expenses included in accounts payable	877		877			$ 17,814
Research and development agreement with Samsung
Purchase Commitment
Outstanding purchase commitments	0		0
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	1,300		4,800
Aggregated unpaid amount	$ 4,900		$ 4,900

Commitments and Contingencies_2

Commitments and Contingencies - Assets Pledged as Collateral (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Borrowings
Borrowings	$ 43,616	$ 79,856
Cash and cash equivalents	4,035	258
Accounts receivable	5,166	4,920
Inventory	1,997	1,486
Property and equipment	615	772
KEB Hana Bank | Related party | Assets pledged as collateral | Borrowings
Borrowings
Borrowings	6,500	7,000
IBK Industrial Bank | Related party | Assets pledged as collateral | Borrowings
Borrowings
Borrowings	6,600	7,100
Anapass, Inc. | Related party | Assets pledged as collateral | Borrowings
Borrowings
Borrowings	9,400	10,100
Cash and cash equivalents	3,879	254
Accounts receivable	5,200	4,920
Inventory	1,997	1,486
Property and equipment	253	352
Intangible assets and others	$ 942	$ 199

Common Stock (Details)

Common Stock (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	6 Months Ended
	Apr. 30, 2024	Mar. 31, 2024	Jun. 30, 2024	Jun. 30, 2024
Common Stock
Common stock forward liability	$ 600		$ 535	$ 535
Commitment shares				56,818
Reimbursement of commitment amount				$ 250
Common stock issued in PIPE Financing			678,462
Shares issued values			$ 3,388
Amount withheld for outstanding payables			500
Proceeds from Issuance of Common Stock			2,800	2,815
Issuance of common stock to underwriter (in shares)	110,000
Issuance of common stock to underwriter			667	$ 700
B. Riley Principal Capital II, LLC
Common Stock
Stock Sale Commitment Amount		$ 50,000
Percentage of volume weighted average price		98%
Shares issued values			$ 3,300
B. Riley Principal Capital II, LLC | Maximum
Common Stock
Stock Sale Commitment Amount		$ 50,000

Common Stock - Shares authorize

Common Stock - Shares authorized (Details) - shares	Jun. 30, 2024	Dec. 31, 2023
Common Stock
Shares of authorized but unissued common stock	53,135,000	5,902,000
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
Options issued and outstanding
Common Stock
Shares of authorized but unissued common stock	668,000	668,000
RSUs outstanding
Common Stock
Shares of authorized but unissued common stock	424,000	392,000
Shares available for future grant from 2024 plan
Common Stock
Shares of authorized but unissued common stock	3,952,000
Shares available for future grant from 2024 ESPP
Common Stock
Shares of authorized but unissued common stock	600,000
Shares available for future grant from 2011 plan
Common Stock
Shares of authorized but unissued common stock		113,000
Common stock warrants
Common Stock
Shares of authorized but unissued common stock	26,724,000	2,894,000
Legacy GCT Earnout Shares
Common Stock
Shares of authorized but unissued common stock	20,000,000
Convertible promissory notes
Common Stock
Shares of authorized but unissued common stock	767,000	1,835,000

Warrants (Details)

Warrants (Details) shares in Thousands	6 Months Ended
	Jun. 30, 2024 $ / shares shares
Warrants
Number of warrants issued | shares	26,724
August 2021
Warrants
Number of warrants issued | shares	299
August 2021 | Maximum
Warrants
Exercise price of warrants	$ 18.75
August 2021 | Minimum
Warrants
Exercise price of warrants	$ 10
September 2021
Warrants
Number of warrants issued | shares	300
Exercise price of warrants	$ 5
February 2023 ~ June 2023
Warrants
Number of warrants issued | shares	2,115
February 2023 ~ June 2023 | Maximum
Warrants
Exercise price of warrants	$ 18.75
February 2023 ~ June 2023 | Minimum
Warrants
Exercise price of warrants	$ 10
July 2023
Warrants
Number of warrants issued | shares	80
Exercise price of warrants	$ 10
October 2023
Warrants
Number of warrants issued | shares	100
Exercise price of warrants	$ 10
:Public And Private Placement Warrants [Member]
Warrants
Number of warrants issued | shares	23,830
Exercise price of warrants	$ 11.50

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - shares	Mar. 31, 2024	Dec. 31, 2021
Stock-Based Compensation
Additional shares of common stock reserved for issuance (in shares)		90,000
2024 Incentive Compensation Plan
Stock-Based Compensation
Number of shares of common stock reserved for issuance (in shares)	3,983,334

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Number of Options Outstanding
Balance as of beginning (in shares)	3,579,000
Balance as of end (in shares)	668,000	3,579,000
Vested as of end (in shares)	668,000
Exercisable as of end (in shares)	642,000
Weighted-Average Exercise Price
Balance as of beginning (in dollars per share)	$ 0.02
Balance as of end (in dollars per share)	0.11	$ 0.02
Vested as of end (in dollars per share)	0.11
Exercisable as of end (in dollars per share)	$ 0.11
Weighted Average Remaining Contractual Life (Years)
Outstanding - Weighted Average Remaining Contractual Life (in years)	5 years	5 years 6 months
Vested - Weighted Average Remaining Contractual Life (in years)	5 years
Exercisable - Weighted Average Remaining Contractual Life (in years)	4 years 10 months 24 days
Balance outstanding - Aggregate Intrinsic Value	$ 3,411	$ 4,045
Vested - Aggregate Intrinsic Value	3,406
Exercisable - Aggregate Intrinsic Value	$ 3,278
Granted during the period (in shares)	0
Exercised during the period (in shares)	0
Cancelled during the period (in shares)	0
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)	$ 0.11
Reverse recapitalization (in dollars per share)		0.09
Balance as of end (in dollars per share)		$ 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 - Rest

Stock-Based Compensation - Restricted Stock Units (Details) - RSU - $ / shares shares in Thousands	1 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Number of Shares
Balance at the beginning		2,100
Balance at the end	424	424
Granted	700	32
Weighted Average shares
Balance at beginning (in dollars per share)		$ 1.15
Balance at end (in dollars per share)	$ 6.09	6.09
Granted ( in dollars per share)		$ 5.21
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 - Re_2

Stock-Based Compensation - Restricted Stock Units - Narratives (Details) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 28, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Stock-Based Compensation
Stock-based compensation			$ 900	$ 323	$ 3	$ 1,546	$ 5
Granted						0
Common Stock
Stock-Based Compensation
Closing price of company's common stock	31,668
RSUs outstanding
Stock-Based Compensation
Stock-based compensation				300		$ 700
Unrecognized compensation cost related to RSUs		$ 2,400		$ 2,400		$ 2,400
Expected weighted average period for recognition of unrecognized compensation cost related to RSUs (in years)						3 years 6 months
Share based fixed monetary amount		700,000				32,000
Granted								392,000

Stock-Based Compensation - Allo

Stock-Based Compensation - Allocation (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Stock-Based Compensation
Stock-based compensation	$ 900	$ 323	$ 3	$ 1,546	$ 5
Research and development
Stock-Based Compensation
Stock-based compensation		128	1	254	2
Sales and marketing
Stock-Based Compensation
Stock-based compensation		36	1	72	2
General and administrative
Stock-Based Compensation
Stock-based compensation		$ 159	$ 1	$ 1,220	$ 1

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Taxes
Income tax expense	$ 67	$ 37	$ 126	$ 87
Effective tax rate (in %)			(119.40%)	(1.00%)
Unrecognized tax benefits	3,100		$ 3,100
Unrecognized tax benefits that would impact the effective tax rate if recognized	1,700		1,700
Unrecognized tax benefits - Interest expense or penalties accrued	$ 0		$ 0

Employee Benefit Plans - Net li

Employee Benefit Plans - Net liability for severance payments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Employee Benefit Plans
Liability for severance payments, beginning	$ 7,627	$ 7,997
Deposit	(261)	(308)
Liability for severance payments, ending	$ 7,366	$ 7,689

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Related Party Transactions
Other current liabilities	$ 86		$ 86		$ 72
Interest expense	760	$ 2,723	2,842	$ 3,658
Related party | Anapass
Related Party Transactions
Borrowings	9,358		9,358		10,082
Other current liabilities	52		52		212
Interest expense	100	$ 100	300	$ 300
Related party | Kyeongho Lee
Related Party Transactions
Borrowings	799		799		1,474
Other current liabilities	$ 86		$ 86		$ 182

Segments and Information (Detai

Segments and Information (Details)	6 Months Ended
	Jun. 30, 2024 segment
Segments and Information
Number of operating segment	1

Segments and Information - Long

Segments and Information - Long-lived assets by geographic region (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Segments and Information
Total tangible long-lived assets	$ 1,764	$ 2,293
South Korea
Segments and Information
Total tangible long-lived assets	1,048	1,363
United States
Segments and Information
Total tangible long-lived assets	$ 716	$ 930

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of outstanding potentially dilutive common stock (Details) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 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)	50,503	4,826
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)	26,724	2,172
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)	1,920
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)	767	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)	668	848
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)	424

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands, ₩ in Billions	1 Months Ended		3 Months Ended	6 Months Ended
	Jul. 31, 2024 USD ($) shares	Jul. 31, 2024 KRW (₩) shares	Jun. 30, 2024 USD ($) shares	Jun. 30, 2024 USD ($) shares	Jul. 31, 2024 KRW (₩)
Subsequent Events
Issuance of common stock under common stock purchase agreement (in shares) | shares			678,462
Shares issued values			$ 3,388
Proceeds from issuance of common stock under common stock purchase agreement			2,800	$ 2,815
Commitment shares | shares				56,818
Proceeds from common stock			2,800	$ 2,815
Amount withheld for outstanding payables			500
B. Riley Principal Capital II, LLC
Subsequent Events
Shares issued values			$ 3,300
Subsequent event
Subsequent Events
Issuance of common stock under common stock purchase agreement (in shares) | shares	544,136	544,136
Shares issued values	$ 2,700
Proceeds from issuance of common stock under common stock purchase agreement	2,200
Proceeds from common stock	2,200
Amount withheld for outstanding payables	500
Subsequent event | M-Venture Investment, Inc. | Term loans
Subsequent Events
Term loan outstanding	3,700				₩ 5
Repayment of short term loan	$ 700	₩ 1
Interest rate (as a percent)	6.80%				6.80%
Subsequent event | i Best Investment Co., Ltd.
Subsequent Events
Term loan outstanding	$ 4,300				₩ 6
Subsequent event | i Best Investment Co., Ltd. | Term loans
Subsequent Events
Repayment of short term loan	700	₩ 1
Subsequent event | KEB Hana Bank | Term loans
Subsequent Events
Term loan outstanding	5,800				8
Subsequent event | Anapass, Inc. | Term loans
Subsequent Events
Term loan outstanding	$ 4,300				₩ 6