Allurion (ALUR) S-1/A 13 Jan 25 IPO registration (amended) Financial data

Cover Page

Cover Page	9 Months Ended
	Sep. 30, 2024
Document Information [Line Items]
Document Type	S-1/A
Amendment Flag	true
Entity Registrant Name	ALLURION TECHNOLOGIES, INC.
Entity Central Index Key	0001964979
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Incorporation, State or Country Code	DE
Entity Primary SIC Number	3841
Entity Tax Identification Number	92-2182207
Entity Address, Address Line One	11 Huron Drive
Entity Address, City or Town	Natick
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01760
City Area Code	508
Local Phone Number	647-4000
Amendment Description	Amendment No. 2
Business Contact
Document Information [Line Items]
Contact Personnel Name	Shantanu Gaur
Entity Address, Address Line One	11 Huron Drive
Entity Address, City or Town	Natick
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01760
City Area Code	508
Local Phone Number	647-4000

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 28,654	$ 38,037	$ 7,685
Accounts receivable, net of allowance of doubtful accounts	9,935	18,194	29,346
Inventory, net	4,568	6,171	3,865
Prepaid expenses and other current assets	1,672	2,414	2,487
Total current assets	44,829	64,816	43,383
Property and equipment, net	3,080	3,381	2,382
Right-of-use asset	2,283	3,010	2,899
Other long-term assets	507	505	2,706
Total assets	50,699	71,712	51,370
Current liabilities:
Accounts payable	10,393	10,379	5,809
Current portion of term loan	0	38,643	53,360
Current portion of lease liabilities	878	908	905
Accrued expenses and other current liabilities	7,973	15,495	15,793
Total current liabilities	19,244	65,425	75,867
Warrant liabilities	7,381	6,765
Revenue Interest Financing liability	38,500	36,200
Earn-out liabilities	1,850	23,990
Convertible notes payable	36,090	0	3,103
Lease liabilities, net of current portion	1,578	2,306	2,163
Other liabilities	9,867	7,513	2,551
Total liabilities	114,510	142,199	83,684
Commitments and Contingencies (Note 16)
Redeemable Convertible Preferred Stock (Note 12):
Series A redeemable convertible preferred stock, $0.0001 par value - 100,000,000 shares authorized as of September 30, 2024; and 2,260,159 and zero shares issued and outstanding as of September 30, 2024 and December 31, 2023	979	0
Stockholders' deficit:
Preferred stock, $0.0001 par value - 100,000,000 shares authorized as of June 30, 2024; and no shares issued and outstanding as of June 30, 2024 and December 31, 2023		0	0
Common stock	3	2	1
Additional paid-in capital	150,696	143,010	99,877
Accumulated other comprehensive income (loss)	2,890	(700)
Accumulated deficit	(218,379)	(212,799)	(132,192)
Total stockholders' deficit	(64,790)	(70,487)	(32,314)
Total liabilities, redeemable convertible preferred stock, and stockholders' deficit	$ 50,699	71,712	$ 51,370
Previously Reported
Current liabilities:
Warrant liabilities		5,943
Other liabilities		$ 8,335

UNAUDITED CONDENSED CONSOLIDA_2

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Allowance of doubtful accounts	$ 8,243	$ 12,671	$ 741
Series A redeemable convertible preferred stock, par value	$ 0.0001	$ 0.0001
Series A redeemable convertible preferred stock, shares authorized	100,000,000	100,000,000
Series A redeemable convertible preferred stock, shares issued	2,260,159	0
Series A redeemable convertible preferred stock, shares outstanding	2,260,159	0
Preferred stock, par value		$ 0.0001	$ 0.0001
Preferred stock, shares authorized	100,000,000	100,000,000	100,000,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized	1,000,000,000	1,000,000,000	1,000,000,000
Common stock, shares issued	2,574,783	1,907,529	1,083,196
Common stock, shares outstanding	2,574,783	1,907,529	1,083,196

UNAUDITED CONDENSED CONSOLIDA_3

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023		Dec. 31, 2022
Income Statement [Abstract]
Revenue	$ 5,367	$ 18,200	$ 26,519	$ 45,232	$ 53,467		$ 64,211
Cost of revenue	2,256	4,232	7,549	10,165	11,970		13,485
Gross profit	3,111	13,968	18,970	35,067	41,497		50,726
Operating expenses:
Sales and marketing	5,197	13,989	18,060	36,127	46,857		50,405
Research and development	3,212	7,191	13,247	21,623	27,694		16,966
General and administrative	7,043	18,942	20,746	30,657	46,024		15,365
Total operating expenses:	15,452	40,122	52,053	88,407	120,575		82,736
Loss from operations	(12,341)	(26,154)	(33,083)	(53,340)	(79,078)		(32,010)
Other income (expense):
Interest expense		(2,586)	(2,264)	(7,331)	(10,566)		(4,426)
Changes in fair value of warrants	9,703	3,868	14,210	2,189	8,364		(821)
Changes in fair value of debt	1,790	(6,008)	10,020	(3,751)	(3,751)
Changes in fair value of Revenue Interest Financing and PIPE Conversion Option	(11,104)	(2,040)	(9,608)	(2,040)	(2,192)
Change in fair value of earn-out liabilities	2,260	24,330	22,140	24,330	29,050
Loss on extinguishment of debt		(3,929)	(8,713)	(3,929)	(3,929)
Termination of convertible note side letters		(9,466)		(17,598)	(17,598)
Other income (expense), net	757	389	1,928	133	(643)		(344)
Total other income (expense):	3,406	4,558	27,713	(7,997)	(1,265)		(5,591)
Loss before income taxes	(8,935)	(21,596)	(5,370)	(61,337)	(80,343)		(37,601)
Provision for income taxes	(69)	(34)	(210)	(90)	(264)		(143)
Net loss	(9,004)	(21,630)	(5,580)	(61,427)	(80,607)		(37,744)
Cumulative undeclared preferred dividends	0	(255)	0	(1,697)	(1,697)		(2,907)
Net loss attributable to common shareholders	$ (9,004)	$ (21,885)	$ (5,580)	$ (63,124)	$ (82,304)		$ (40,651)
Net loss per share, basic	$ (3.51)	$ (13.56)	$ (2.62)	$ (50.01)	$ (57.83)	[1]	$ (37.75)	[1]
Net loss per share, diluted	$ (3.51)	$ (13.56)	$ (2.62)	$ (50.01)	$ (57.83)	[1]	$ (37.75)	[1]
Weighted-average shares outstanding - Basic	2,563,459	1,613,425	2,132,416	1,262,346	1,423,275		1,076,743
Weighted-average shares outstanding - diluted	2,563,459	1,613,425	2,132,416	1,262,346	1,423,275		1,076,743
[1]The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods prior to the Business Combination have been retrospectively adjusted to the equivalent number of shares outstanding immediately after the Business Combination to effect the reverse capitalization. See Note 3 for further information. The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods have also been retrospectively adjusted to give effect to the Reverse Stock Split. See Note 1 for further information.

UNAUDITED CONDENSED CONSOLIDA_4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Net loss	$ (9,004)	$ (21,630)	$ (5,580)	$ (61,427)	$ (80,607)	$ (37,744)
Other comprehensive income (loss):
Change in fair value due to change in credit risk	5,800		600		(700)
Comprehensive Income	(134)	$ (21,630)	(1,990)	$ (61,427)	$ (81,307)	$ (37,744)
Revenue Interest Financing
Other comprehensive income (loss):
Change in fair value due to change in credit risk	5,800		600
RTW Convertible Notes
Other comprehensive income (loss):
Change in fair value due to change in credit risk	$ 3,070		$ 2,990

UNAUDITED CONDENSED CONSOLIDA_5

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Series A-1 Convertible Preferred Stock	Series B Convertible Preferred Stock	Redeemable Preferred Stock	Common Stock	Common Stock Series A-1 Convertible Preferred Stock	Common Stock Series B Convertible Preferred Stock	Additional Paid-in Capital	Additional Paid-in Capital Series A-1 Convertible Preferred Stock	Additional Paid-in Capital Series B Convertible Preferred Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ 4,837				$ 1			$ 99,284				$ (94,448)
Beginning Balance (in shares) at Dec. 31, 2021					1,072,294
Exercise of stock options	128							128
Exercise of stock options, (in shares)					5,143
Stock-based compensation expense	437							437
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants		$ 24	$ 4						$ 24	$ 4
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)						225	42
Issuance of common stock for the exercise of Public Warrants (in shares)					5,492
Net loss	(37,744)											(37,744)
Ending Balance at Dec. 31, 2022	(32,314)				$ 1			99,877				(132,192)
Ending Balance (in shares) at Dec. 31, 2022					1,083,196
Exercise of stock options	20							20
Exercise of stock options, (in shares)					616
Stock-based compensation expense	409							409
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants	29							29
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)					143
Net loss	(17,801)											(17,801)
Ending Balance at Mar. 31, 2023	(49,657)				$ 1			100,335				(149,993)
Ending Balance (in shares) at Mar. 31, 2023					1,083,955
Beginning Balance at Dec. 31, 2022	(32,314)				$ 1			99,877				(132,192)
Beginning Balance (in shares) at Dec. 31, 2022					1,083,196
Net loss	(61,427)
Ending Balance at Sep. 30, 2023	(52,756)				$ 2			140,861				(193,619)
Ending Balance (in shares) at Sep. 30, 2023					1,898,446
Beginning Balance at Dec. 31, 2022	(32,314)				$ 1			99,877				(132,192)
Beginning Balance (in shares) at Dec. 31, 2022					1,083,196
Exercise of stock options	145							145
Exercise of stock options, (in shares)					11,943
Stock-based compensation expense	8,357							8,357
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants		$ 6	$ 89						$ 6	$ 89
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)						20	342
Reverse recapitalization, net of transaction costs	58,573				$ 1			58,572
Reverse recapitalization, net of transaction costs (in shares)					549,435
Recognition of warrant liabilities in connection with the Merger	(13,762)							(13,762)
Issuance of common stock in connection with vesting of RSU awards (in shares)					36,737
Issuance of common stock for the conversion of convertible notes	25,570							25,570
Issuance of common stock for the conversion of convertible notes (in shares)					132,049
Recognition of earn-out liabilities (Note 3)	(53,040)							(53,040)
Reclassification of Legacy Allurion liabilitiy classified warrants to equity classification	929							929
Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and the additional RTW and Fortress shares and issuance of related shares	16,098							16,098
Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and the additional RTW and Fortress shares and issuance of related shares (in shares)					91,508
Issuance of common stock for the exercise of Public Warrants	46							46
Issuance of common stock for the exercise of Public Warrants (in shares)					878
Issuance of common stock for commitment shares for equity line financing	123							123
Issuance of common stock for commitment shares for equity line financing (in shares)					1,421
Other comprehensive income (loss)	(700)										$ (700)
Net loss	(80,607)											(80,607)
Ending Balance at Dec. 31, 2023	$ (70,487)				$ 2			143,010			(700)	(212,799)
Ending Balance (in shares) at Dec. 31, 2023					1,907,529
Temporary Equity, Balance (in Shares) at Dec. 31, 2023	0
Beginning Balance at Mar. 31, 2023	$ (49,657)				$ 1			100,335				(149,993)
Beginning Balance (in shares) at Mar. 31, 2023					1,083,955
Exercise of stock options	28							28
Exercise of stock options, (in shares)					1,106
Stock-based compensation expense	401							401
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants	6							6
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)					20
Net loss	(21,996)											(21,996)
Ending Balance at Jun. 30, 2023	(71,218)				$ 1			100,770				(171,989)
Ending Balance (in shares) at Jun. 30, 2023					1,085,081
Exercise of stock options	83							83
Exercise of stock options, (in shares)					3,089
Stock-based compensation expense	5,539							5,539
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants	60							60
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)					200
Reverse recapitalization, net of transaction costs	58,573				$ 1			58,572
Reverse recapitalization, net of transaction costs (in shares)					549,435
Recognition of warrant liabilities in connection with the Merger	(13,762)							(13,762)
Issuance of common stock in connection with vesting of RSU awards (in shares)					36,263
Issuance of common stock for the conversion of convertible notes	25,570				$ 0			25,570
Issuance of common stock for the conversion of convertible notes (in shares)					132,049
Recognition of earn-out liabilities (Note 3)	(53,040)							(53,040)
Reclassification of Legacy Allurion liabilitiy classified warrants to equity classification	929							929
Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and the additional RTW and Fortress shares and issuance of related shares	16,098							16,098
Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and the additional RTW and Fortress shares and issuance of related shares (in shares)					91,508
Issuance of common stock for the exercise of Public Warrants	42							42
Issuance of common stock for the exercise of Public Warrants (in shares)					821
Net loss	(21,630)											(21,630)
Ending Balance at Sep. 30, 2023	(52,756)				$ 2			140,861				(193,619)
Ending Balance (in shares) at Sep. 30, 2023					1,898,446
Ending Balance, temporary stocks	0
Beginning Balance at Dec. 31, 2023	(70,487)				$ 2			143,010			(700)	(212,799)
Beginning Balance (in shares) at Dec. 31, 2023					1,907,529
Exercise of stock options	9							9
Exercise of stock options, (in shares)					186
Stock-based compensation expense	552							552
Stock issued during period value	378							378
Stock isssued during the period (in shares)					5,730
Issuance of common stock in connection with vesting of RSU awards (in shares)					2,505
Issuance of common stock for the exercise of Public Warrants (in shares)					6
Other comprehensive income (loss)	(2,200)										(2,200)
Net loss	5,586											5,586
Ending Balance at Mar. 31, 2024	(66,162)				$ 2			143,949			(2,900)	(207,213)
Ending Balance (in shares) at Mar. 31, 2024					1,915,956
Beginning Balance at Dec. 31, 2023	(70,487)				$ 2			143,010			(700)	(212,799)
Beginning Balance (in shares) at Dec. 31, 2023					1,907,529
Net loss	(5,580)
Ending Balance at Sep. 30, 2024	$ (64,790)				$ 3			150,696			2,890	(218,379)
Ending Balance (in shares) at Sep. 30, 2024					2,574,783
Temporary Equity, Balance (in Shares) at Sep. 30, 2024	2,260,159			2,260,159
Beginning Balance at Mar. 31, 2024	$ (66,162)				$ 2			143,949			(2,900)	(207,213)
Beginning Balance (in shares) at Mar. 31, 2024					1,915,956
Exercise of stock options	16							16
Exercise of stock options, (in shares)					460
Stock-based compensation expense	805							805
Issuance of common stock in connection with vesting of RSU awards (in shares)					2,505
Issuance of common stock for the exercise of Public Warrants	1							1
Issuance of common stock for the exercise of Public Warrants (in shares)					6
Other comprehensive income (loss)	(3,080)										(3,080)
Net loss	(2,162)											(2,162)
Ending Balance at Jun. 30, 2024	(70,582)				$ 2			144,771			(5,980)	(209,375)
Ending Balance (in shares) at Jun. 30, 2024					1,918,927
Stock-based compensation expense	860							860
Stock issued during period value	5,066				$ 1			5,065
Stock isssued during the period (in shares)					653,351
Issuance of common stock in connection with vesting of RSU awards (in shares)					2,505
Other comprehensive income (loss)	8,870										8,870
Net loss	(9,004)											(9,004)
Ending Balance at Sep. 30, 2024	$ (64,790)				$ 3			$ 150,696			$ 2,890	$ (218,379)
Ending Balance (in shares) at Sep. 30, 2024					2,574,783
Temporary Equity, Balance (in Shares) at Sep. 30, 2024	2,260,159			2,260,159
Issuance of preferred stock in connection with Private Placement, net of issuance costs (in shares)				2,260,159
Issuance of preferred stock in connection with Private Placement, net of issuance costs				$ 979
Ending Balance, temporary stocks	$ 979			$ 979

UNAUDITED CONDENSED CONSOLIDA_6

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Operating Activities:
Net loss	$ (5,580)	$ (61,427)	$ (80,607)	$ (37,744)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Non-cash lease expense	561	618	824	1,104
Depreciation and amortization	778	558	746	895
Stock-based compensation	2,217	6,349	8,357	437
Provision for uncollectible accounts	1,065	4,953	12,675	436
Unrealized exchange (gain) or loss	(29)	253	(180)	(113)
Provision for inventory	1,052	743	1,399
Change in fair value of warrant liabilities	(14,210)	(2,189)	(8,364)	820
Change in fair value of derivative liabilities	(1,895)	(165)	1,730	19
Change in fair value of Revenue Interest Financing and PIPE Conversion Option	9,608	2,040	2,192
Change in fair value of earn-out liabilities	(22,140)	(24,330)	(29,050)
Interest paid on debt recorded at fair value	(2,458)		(1,092)
Change in fair value of debt	(10,020)	3,751	3,751
Debt issuance costs associated with debt recorded at fair value	1,357	1,210	1,210
Non-cash interest expense	1,464	1,117	2,083	953
Non-cash termination of convertible note side letters		16,098	16,098
Loss on extinguishment of debt/ term loan	8,713	3,929	3,929
Issuance costs associated with warrants recorded at fair value	942
Non-cash issuance of common stock for commitment shares			123
Changes in operating assets and liabilities:
Accounts receivable	7,199	(3,883)	(1,318)	(22,817)
Inventory	551	(899)	(3,705)	(1,150)
Prepaid expenses, other current and long-term assets	747	409	285	(577)
Lease liabilities	(593)	(617)	(789)	(733)
Accounts payable	(578)	3,492	4,664	3,324
Accrued expenses and other current liabilities	(7,777)	4,879	1,057	8,165
Net cash used in operating activities	(29,026)	(43,111)	(63,982)	(46,981)
Investing Activities:
Purchases of property and equipment	(611)	(1,208)	(1,606)	(1,550)
Net cash used in investing activities	(611)	(1,208)	(1,606)	(1,550)
Financing Activities:
Proceeds from issuance of convertible notes	48,000	28,700	28,700	1,103
Proceeds from Fortress Term Loan—net		59,780	59,780	29,850
Payment of debt issuance costs			(3,450)	(262)
Proceeds from Business Combination, net of transaction costs		62,078	61,652
Proceeds from revenue interest financing		40,000	40,000
Proceeds from option and warrant exercises	26	195	213	132
Proceeds from equity line financing	378
Repayment of convertible notes		(10,750)	(10,750)
Proceeds from Private Placement, net of issuance costs	2,685
Proceeds from Public Offering, net of issuance costs	18,249
Payment of debt issuance costs	(1,357)	(3,450)
Repayment of promissory note assumed in Business Combination		(2,500)	(2,500)
Payment of deferred financing costs				(286)
Net cash provided by financing activities	20,261	116,394	95,986	30,537
Net (decrease) increase in cash and cash equivalents and restricted cash	(9,376)	72,075	30,398	(17,994)
Cash and cash equivalents and restricted cash at beginning of period	38,421	8,023	8,023	26,017
Cash and cash equivalents and restricted cash at end of period	29,045	80,098	38,421	8,023
Supplemental disclosure of cash flow information
Cash paid for interest	2,672	5,022	8,035	3,476
Supplemental cash flow information on non-cash investing and financing activities
Purchase of property and equipment included in accounts payable		270	134	13
Issuance of warrants in connection with financing				834
Deferred financing costs in accounts payable and accrued expenses	1,004	1,006	580	$ 1,919
Recognition of assumed warrant liability		13,762	13,762
Recognition of earn-out liabilities		53,040	53,040
Issuance of common stock upon conversion of convertible notes		25,569	25,569
Change in fair value of Revenue Interest Financing through other comprehensive income	600		(700)
Change in fair value of RTW Convertible Notes through other comprehensive income	2,990
2021 Term Loan
Financing Activities:
Repayment of Term Loan		$ (57,659)	(57,659)
Fortress Term Loan
Financing Activities:
Repayment of Term Loan	$ (47,720)		$ (20,000)

UNAUDITED CONDENSED CONSOLIDA_7

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - Reconciliation of Cash and Cash Equivalents and Restricted Cash - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 28,654	$ 38,037	$ 7,685
Restricted cash included in other long-term assets	$ 391	$ 384	$ 338
Restricted Cash and Cash Equivalents, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent	Other Assets, Noncurrent
Cash and cash equivalents and restricted cash shown in the statement of cash flows	$ 29,045	$ 38,421	$ 8,023

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Organization Allurion Technologies, Inc. (“Allurion” or the “Company”) is a vertically integrated medical device company that is developing, manufacturing, and commercializing innovative weight loss experiences centered around its Allurion ™ ™ The Company also offers tiered access to artificial intelligence (“AI”)-powered remote patient monitoring tools, a mobile app for patients and a clinic dashboard for providers, referred to as the Allurion Virtual Care Suite (“VCS”) and, collectively with the Allurion Balloon, referred to as the “Allurion Program”. The base tier of the VCS is free of charge to those purchasing the Allurion Balloon, as well as customers looking for a weight-loss management platform for patients utilizing other weight loss treatments, including anti-obesity medications and bariatric surgery. More full-scale versions of the VCS are available to health care providers on an upgrade basis. Allurion currently markets the Allurion Program in over 50 countries, and the Company operates subsidiaries in the United States, France, the United Arab Emirates, the United Kingdom, Italy, Spain, Australia and Mexico. Business Combination Agreement On February 9, 2023, Allurion Technologies Opco, Inc. (formerly Allurion Technologies, Inc., “Legacy Allurion”) and Allurion Technologies, Inc. (formerly Allurion Technologies Holdings, Inc.) entered into the Business Combination Agreement (as subsequently amended on May 2, 2023, the “Business Combination Agreement”) with Compute Health Acquisition Corp. (“CPUH” or “Compute Health”), Compute Health Corp. (“Merger Sub I”) and Compute Health LLC (“Merger Sub II” and, together with Merger Sub I, the “Merger Subs”). Pursuant to the Business Combination Agreement, on August 1, 2023 (the “Closing Date”), the Mergers (as defined below) were consummated in three steps: (a) Compute Health merged with and into Allurion (the “CPUH Merger”), with Allurion surviving the CPUH Merger as a publicly listed entity (the time at which the CPUH Merger became effective, the “CPUH Merger Effective Time”) and becoming the sole owner of the Merger Subs; (b) three hours following the consummation of the CPUH Merger, Merger Sub I merged with and into Legacy Allurion (the “Intermediate Merger” and the time at which the Intermediate Merger became effective, the “Intermediate Merger Effective Time”), with Legacy Allurion surviving the Intermediate Merger and becoming a direct, wholly-owned subsidiary of Allurion; and (c) thereafter, Legacy Allurion merged with and into Merger Sub II (the “Final Merger” and, collectively with the CPUH Merger and the Intermediate Merger, the “Mergers”, and together with all other transactions contemplated by the Business Combination Agreement, the “Business Combination”), with Merger Sub II surviving the Final Merger and remaining a direct, wholly-owned subsidiary of Allurion (the time at which the Final Merger became effective, the “Final Merger Effective Time”). Shares of Allurion’s Common Stock (defined below) began trading on the New York Stock Exchange (“NYSE”) under the ticker symbol “ALUR” on August 2, 2023. Upon completion of the Business Combination, Legacy Allurion’s business operations continued as our business operations. The Business Combination was accounted for as a reverse capitalization in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Under this method of accounting, Compute Health was treated as the “acquired” company for financial reporting purposes and Legacy Allurion was the accounting “acquirer”. Accordingly, the Business Combination was treated as the equivalent of Legacy Allurion issuing stock for the net assets of Compute Health, accompanied by a recapitalization. As a result of the reverse recapitalization, the assets and liabilities of the Company are presented at their historical carrying values, and the assets and liabilities of Compute Health are recognized on the acquisition date and measured on the basis of the net proceeds from the capital transaction, with no goodwill or other intangible assets recorded. This determination is primarily based on the fact that, immediately following the Business Combination, Legacy Allurion stockholders had a majority of the voting power of Allurion, Legacy Allurion controlled the majority of the board seats of Allurion, and Legacy Allurion senior management comprised all of the senior management of Allurion. The equity structure has been restated in all comparative periods up to the Closing Date to reflect the number of shares of the Company’s common stock, $0.0001 par value per share (“Common Stock,” “Allurion Common Stock” or the “Company’s Common Stock”), issued to Legacy Allurion stockholders in connection with the Business Combination. As such, the shares and corresponding capital amounts and earnings per share related to Legacy Allurion’s convertible preferred stock and Legacy Allurion common stock prior to the Business Combination have been retroactively restated as shares reflecting the exchange ratio of approximately 0.9780 (the “Exchange Ratio”) established in the Business Combination. The Exchange Ratio established in the Business Combination is prior to the Reverse Stock Split (as defined below) and did not change as a result of the Reverse Stock Split. As a result of this retrospective application, certain prior period balances within the condensed consolidated financial statements have changed. Refer to Note 3, Business Combination Unless otherwise indicated, references in this Quarterly Report on Form 10-Q to the “Company”, “our”, and “Allurion” refer to the condensed consolidated operations of Allurion Technologies, Inc. and its subsidiaries. References to CPUH and Compute Health refer to Compute Health Acquisition Corp. and its subsidiaries prior to the consummation of the Business Combination and references to “Legacy Allurion” refer to Allurion Technologies, Inc. prior to the consummation of the Business Combination. Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. GAAP and the rules and regulations of the Securities and Exchange Commission (“SEC”). Any reference in these notes to the applicable accounting guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”), and Accounting Standards Update (“ASU”), of the Financial Accounting Standards Board (“FASB”). They should be read in conjunction with our audited financial statements as of and for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K, 10-K”). Our foreign operations are subject to exchange rate fluctuations and foreign currency transaction costs. The functional currency for all of our foreign subsidiaries is the United States dollar except Allurion Australia Pty Ltd., which uses the Australian dollar. When remeasuring from a local currency to the functional currency, assets and liabilities are remeasured into U.S. dollars at exchange rates in effect at the balance sheet dates and results of operations transacted in local currency are remeasured into U.S. dollars using average exchange rates for the period presented. A gain from remeasurement of less than $0.1 million and a loss from remeasurement of $0.3 million for the nine months ended September 30, 2024 and 2023, respectively, and a gain from remeasurement of $0.4 million and loss from remeasurement of $0.3 million for the three months ended September 30, 2024 and 2023, respectively, are recorded in the statements of operations within Other income, net. The Company translates the foreign functional currency financial statements to U.S. dollars for Allurion Australia Pty Ltd. using the exchange rates at the balance sheet date for assets and liabilities, the period average exchange rates for revenues and expenses, and the historical exchange rates for equity transactions. The effects of foreign currency translation adjustments were immaterial for the three and nine months ended September 30, 2024 and 2023. Reverse Stock Split The Company held its annual meeting of stockholders on December 16, 2024 (the “Annual Meeting”), and upon the recommendation of the Board of Directors (the “Board”) of the Company, the Company’s stockholders approved a certificate of amendment (the “Charter Amendment”) to the Company’s Amended and Restated Certificate of Incorporation to effect a reverse stock split of the Company’s common stock, par value $0.0001 per share (the “Common Stock”), at a ratio between 1-for-10 and 1-for-25, with the final ratio to be determined by the Board in its sole discretion. On December 23, 2024, following the Annual Meeting, the Board approved a reverse stock split of the Common Stock at a ratio of 1-for-25 (the “Reverse Stock Split”). Effective as of 12:01 a.m. Eastern Time on January 3, 2025, the Company filed an amendment (the “Certificate of Amendment”) to its Amended and Restated Certificate of Incorporation, as amended and/or restated from time to time, to effectuate the Reverse Stock Split. As a result of the Reverse Stock Split, every 25 shares of the Company’s Common Stock issued or outstanding will be automatically reclassified into one validly issued, fully-paid and non-assessable new share of Common Stock, subject to the treatment of fractional shares as described below, without any action on the part of the holders. Trading of the Common Stock on the NYSE commenced on a split-adjusted basis at market open on January 3, 2025, under the existing trading symbol “ALUR.” No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who would otherwise be entitled to receive fractional shares as a result of the Reverse Stock Split were automatically entitled to receive an additional fraction of a share of Common Stock to round up to the next whole share. Proportional adjustments were also made to the number of shares of Common Stock awarded and available for issuance under the Company’s equity incentive plans, as well as the exercise price and the number of shares issuable upon the exercise or conversion of the Company’s outstanding stock options, restricted stock units and other equity securities under the Company’s equity incentive plans. Additionally, all outstanding convertible notes were adjusted in accordance with their terms, which will, among other changes to the convertible note terms, result in proportionate adjustments being made to the number of shares issuable upon exercise of such convertible notes and to the exercise and redemption prices of such convertible notes. All outstanding warrants were also adjusted in accordance with their terms, which will, among other changes to the warrant terms, result in proportionate adjustments being made to the number of shares issuable upon exercise of such warrants and to the exercise and redemption prices of such warrants. Specifically, following the effectiveness of the reverse stock split, every twenty five (25) shares of Common Stock that may be purchased pursuant to the exercise of public warrants will represent one (1) share of Common Stock that may be purchased pursuant to such warrants. Accordingly, for the Company’s warrants trading under the symbol “ALUR WS” on the NYSE, each whole public warrant will be exercisable for 0.056818 shares of common stock at an exercise price of $202.50 per share of Common Stock, which is based on each public warrant being exercisable for 1.420455 shares of common stock before the reverse stock split, adjusted for the 25:1 reverse stock split ratio. Unless otherwise indicated, all authorized, issued, and outstanding shares and per share amounts contained in the accompanying consolidated financial statements have been adjusted to reflect the 1-for-25 Reverse Stock Split for all periods presented. As a result, net loss per share was also retrospectively adjusted for periods ended prior to the Reverse Stock Split. Proportionate adjustments for the Reverse Stock Split were also made to the exercise prices and number of shares issuable under the Company’s equity incentive plans, and the number of shares underlying outstanding equity awards, as applicable. Going Concern The Company has evaluated whether there are certain events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the interim condensed consolidated financial statements are issued. The Company has incurred recurring losses since inception, anticipates net losses and negative operating cash flows for the near future, and may be unable to remain in compliance with certain financial covenants required under its credit facilities. Through September 30, 2024, the Company has funded its operations primarily with proceeds from the sale of its Common Stock, convertible preferred stock, issuance of convertible notes, issuance of term loans, and funds received upon consummation of the Business Combination. The Company has incurred recurring losses and cash outflows from operating activities since its inception, including losses from operations of $33.1 million and $53.3 million and cash outflows from operating activities of $29.0 million and $43.1 million for the nine months ended September 30, 2024 and 2023, respectively. As of September 30, 2024, the Company had an accumulated deficit of $218.4 million. The Company expects to continue to generate significant operating losses for the foreseeable future. Based on the Company’s recurring losses from operations incurred since inception, its expectation of continuing operating losses for the foreseeable future, the potential need to raise additional capital to finance its future operations, and the potential of being unable to remain in compliance with certain financial covenants under its credit facilities, the Company has concluded that there is substantial doubt about its ability to continue as a going concern for a period of one year from the date that these condensed consolidated financial statements are issued. The accompanying unaudited condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business.	1. Organization and Basis of Presentation Organization Allurion Technologies, Inc. (“Allurion” or the “Company”) is a vertically Business Combination Agreement On February 9, 2023, Allurion Technologies Opco, Inc. (formerly Allurion Technologies, Inc., “Legacy Allurion”) and Allurion Technologies, Inc. (formerly Allurion Technologies Holdings, Inc.), entered into the Business Combination Agreement (as subsequently amended on May 2, 2023, the “Business Combination Agreement”) with Compute Health Acquisition Corp. (“CPUH” or “Compute Health”), Compute Health Corp. (“Merger Sub I”) and Compute Health LLC (“Merger Sub II” and, together with Merger Sub I, the “Merger Subs”). Pursuant to the Business Combination Agreement, on August 1, 2023 (the “Closing Date”), the Mergers (as defined below) were consummated in three steps: (a) Compute Health merged with and into Allurion (the “CPUH Merger”), with Allurion surviving the CPUH Merger as a publicly listed entity (the time at which the CPUH Merger became effective, the “CPUH Merger Effective Time”) and becoming the sole owner of the Merger Subs; (b) three hours following the consummation of the CPUH Merger, Merger Sub I merged with and into Legacy Allurion (the “Intermediate Merger” and the time at which the Intermediate Merger became effective, the “Intermediate Merger Effective Time”), with Legacy Allurion surviving the Intermediate Merger and becoming a direct, wholly-owned subsidiary of Allurion; and (c) thereafter, Legacy Allurion merged with and into Merger Sub II (the “Final Merger” and, collectively with the CPUH Merger and the Intermediate Merger, the “Mergers”, and together with all other transactions contemplated by the Business Combination Agreement, the “Business Combination”), with Merger Sub II surviving the Final Merger and remaining a direct, wholly-owned subsidiary of Allurion (the time at which the Final Merger became effective, the “Final Merger Effective Time”). Allurion shares began trading on the New York Stock Exchange (“NYSE”) under the ticker symbol “ALUR” on August 2, 2023. Upon completion of the Business Combination, Legacy Allurion’s business operations continued as our business operations. The Business Combination was accounted for as a reverse capitalization in accordance with accounting principles generally accepted in the United States of America. Under this method of accounting, Compute Health was treated as the “acquired” company for financial reporting purposes and Legacy Allurion was the accounting “acquirer”. Accordingly, the Business Combination was treated as the equivalent of Legacy Allurion issuing stock for the net assets of Compute Health, accompanied by a recapitalization. As a result of the reverse recapitalization, the assets and liabilities of the Company are presented at their historical carrying values, and the assets and liabilities of Compute Health are recognized on the acquisition date and measured on the basis of the net proceeds from the capital transaction, with no goodwill or other intangible assets recorded. This determination is primarily based on the fact that, immediately following the Business Combination, Legacy Allurion stockholders had a majority of the voting power of Allurion, Legacy Allurion controlled the majority of the board seats of Allurion, and Legacy Allurion senior management comprised all of the senior management of Allurion. The equity structure has been restated in all comparative periods up to the Closing Date to reflect the number of shares of the Company’s common stock, $0.0001 par value per share (“Allurion Common Stock” or the “Company’s Common Stock”), issued to Legacy Allurion stockholders in connection with the Business Combination. As such, the shares and corresponding capital amounts and earnings per share related to Legacy Allurion’s convertible preferred stock and Legacy Allurion common stock prior to the Business Combination have been retroactively restated as shares reflecting the exchange ratio of approximately 0.9780 (the “Exchange Ratio”) established in the Business Combination. The Exchange Ratio established in the Business Combination is prior to the Reverse Stock Split (as defined below) and did not change as a result of the Reverse Stock Split. As a result of this retrospective application, certain prior period balances within the consolidated financial statements have changed. Refer to Note 3, Business Combination Unless otherwise indicated, references in this prospectus to the “Company,” “our,” and “Allurion” refer to the consolidated operations of Allurion Technologies, Inc. and its subsidiaries. References to CPUH and Compute Health refer to Compute Health Acquisition Corp. and its subsidiaries prior to the consummation of the Business Combination and references to “Legacy Allurion” refer to Allurion Technologies, Inc. prior to the consummation of the Business Combination. Basis of Presentation The accompanying consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“US GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”). Any reference in these notes to the applicable accounting guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”), and Accounting Standards Update (“ASU”), of the Financial Accounting Standards Board (“FASB”). In connection with the Business Combination, the Company’s equity structure has been restated in prior periods to reflect the number of shares of the Allurion Common Stock, $0.0001 par value per share, issued to Legacy Allurion stockholders. As such, the shares and corresponding capital amounts presented in the consolidated balance sheet and consolidated statement of redeemable convertible preferred stock and stockholders’ deficit have been retroactively restated as shares reflecting the Exchange Ratio established in the Business Combination. All then-existing Legacy Allurion redeemable convertible preferred stock and Legacy Allurion convertible preferred stock were converted into shares of Allurion Common Stock at the closing of the Business Combination. The consolidated financial statements include Allurion; and its consolidated subsidiaries, Allurion France SAS, and Allurion Middle East, LLC, which were both incorporated in 2017; Allurion Hong Kong Ltd., which was incorporated in 2019; Allurion UK Ltd., which was incorporated in 2021; Allurion Italy, Srl, Allurion Spain, Srl, Allurion Australia Pty Ltd. and Allurion Mexico S. de R.L de C.V, which were incorporated in 2022; and Allurion Technologies, LLC, which was incorporated in 2023. The Company’s operations are located in Europe, the Middle East, Africa, Latin America, Canada and the Asia-Pacific region, and it operates in one business segment. Our foreign operations are subject to exchange rate fluctuations and foreign currency transaction costs. The functional currency for all of our foreign subsidiaries is the United States dollar except Allurion Australia Pty Ltd., which uses the Australian dollar. When remeasuring from a local currency to the functional currency, assets and liabilities are remeasured into U.S. dollars at exchange rates in effect at the balance sheet dates and results of operations transacted in local currency are remeasured into U.S. dollars using average exchange rates for the period presented. Gains (losses) from remeasurement of $0.1 million and $(0.7) million for the years ended December 31, 2023 and 2022, respectively, are recorded in the statements of operations and comprehensive loss within other expense, net. The Company translates the foreign functional currency financial statements equity transactions. The effects of foreign currency translation adjustments were immaterial for the years ended December 31, 2023 and 2022. Reverse Stock Split The Company held its annual meeting of stockholders on December 16, 2024 (the “Annual Meeting”), and upon the recommendation of the Board of Directors (the “Board”) of the Company, the Company’s stockholders approved a certificate of amendment (the “Charter Amendment”) to the Company’s Amended and Restated Certificate of Incorporation to effect a reverse stock split of the Company’s common stock, par value $0.0001 per share (the “Common Stock”), at a ratio between 1-for-10 and 1-for-25, with the final ratio to be determined by the Board in its sole discretion. On December 23, 2024, following the Annual Meeting, the Board approved a reverse stock split of the Common Stock at a ratio of 1-for-25 (the “Reverse Stock Split”). Effective as of 12:01 a.m. Eastern Time on January 3, 2025, the Company filed an amendment (the “Certificate of Amendment”) to its Amended and Restated Certificate of Incorporation, as amended and/or restated from time to time, to effectuate the Reverse Stock Split. As a result of the Reverse Stock Split, every 25 shares of the Company’s Common Stock issued or outstanding will be automatically reclassified into one validly issued, fully-paid and non-assessable new share of Common Stock, subject to the treatment of fractional shares as described below, without any action on the part of the holders. Trading of the Common Stock on the NYSE commenced on a split-adjusted basis at market open on January 3, 2025, under the existing trading symbol “ALUR.” No fractional shares will be issued in connection with the Reverse Stock Split. Stockholders who would otherwise be entitled to receive fractional shares as a result of the Reverse Stock Split will automatically be entitled to receive an additional fraction of a share of Common Stock to round up to the next whole share. Proportional adjustments will also be made to the number of shares of Common Stock awarded and available for issuance under the Company’s equity incentive plans, as well as the exercise price and the number of shares issuable upon the exercise or conversion of the Company’s outstanding stock options, restricted stock units and other equity securities under the Company’s equity incentive plans. Additionally, all outstanding convertible notes will be adjusted in accordance with their terms, which will, among other changes to the convertible note terms, result in proportionate adjustments being made to the number of shares issuable upon exercise of such convertible notes and to the exercise and redemption prices of such convertible notes. All outstanding warrants will also be adjusted in accordance with their terms, which will, among other changes to the warrant terms, result in proportionate adjustments being made to the number of shares issuable upon exercise of such warrants and to the exercise and redemption prices of such warrants. Specifically, following the effectiveness of the reverse stock split, every twenty five (25) shares of Common Stock that may be purchased pursuant to the exercise of public warrants will represent one (1) share of Common Stock that may be purchased pursuant to such warrants. Accordingly, for the Company’s warrants trading under the symbol “ALUR WS” on the NYSE, each whole public warrant will be exercisable for 0.056818 shares of common stock at an exercise price of $202.50 per share of Common Stock, which is based on each public warrant being exercisable for 1.420455 shares of common stock before the reverse stock split, adjusted for the 25:1 Unless otherwise indicated, all authorized, issued, and outstanding shares and per share amounts contained in the accompanying consolidated financial statements have been adjusted to reflect the 1-for-25 Reverse Stock Split for all periods presented. As a result, net loss per share was also retrospectively adjusted for periods ended prior to the Reverse Stock Split. Proportionate adjustments for the Reverse Stock Split were also made to the exercise prices and number of shares issuable under the Company’s equity incentive plans, and the number of shares underlying outstanding equity awards, as applicable. Going Concern The Company has evaluated whether there are certain events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. The Company has incurred recurring losses since inception and anticipates net losses and negative operating cash flows for the near future and may be unable to remain in compliance with certain financial covenants required under the Fortress Term Loan. Through December 31, 2023, the Company has funded its operations primarily with proceeds from the sale of its convertible preferred stock, issuance of convertible notes, issuance of term loans and funds received upon consummation of the Business Combination. The Company has incurred recurring losses and cash outflows from operating activities since its inception, including net losses of $80.6 million and $37.7 million and cash outflows from operating activities of $64.0 million and $47.0 million for the years ended December 31, 2023 and 2022, respectively. As of December Based on the Company’s recurring losses from operations incurred since inception, its expectation of continuing operating losses for the foreseeable future, the potential need to raise additional capital to finance its future operations and debt service payments, and the potential of being unable to remain in compliance with certain financial covenants under the Fortress Term Loan, the Company has concluded that there is substantial doubt about its ability to continue as a going concern for a period of one year from the date that these consolidated financial statements are issued. The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. Due to the substantial doubt about the Company’s ability to continue operating as a going concern for twelve months from the issuance date of these financial statements and the liquidity and revenue covenant clauses within the Fortress Term Loan, the amounts due as of December 31, 2023, have been classified as current liabilities in the consolidated financial statements. The lender under the Fortress Term Loan has not invoked the material adverse change clause and the Company has met the liquidity covenant as of the date of issuance of these financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies There have been no significant changes, except as described below, to the significant accounting policies disclosed in Note 2 of the “Notes to Consolidated Financial Statements” to the consolidated audited financial statements as of and for the year ended December 31, 2023 included in our Annual Report on Form 10-K. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Management considers many factors in selecting appropriate financial accounting policies and controls in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ from those estimates. RTW Convertible Notes The Company accounted for the RTW Convertible Notes (defined below) under the fair value option (“FVO”) election of ASC Topic 825, Financial Instruments Reclassification of Prior Year Presentation Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations. Adjustment has been made to the condensed consolidated balance sheet as of December 31, 2023, to present the Legacy Allurion common stock warrant liabilities as part of the Warrant liabilities line item. These amounts were part of the Other liabilities line item in prior years. Mezzanine Equity Mezzanine equity represents the Series A Preferred Stock (defined below) issued by the Company. The shares of Series A Preferred Stock are redeemable at a determinable price on a fixed date, which results in mezzanine equity classification (outside of permanent equity) on the Company’s consolidated balance sheet. Refer to Note 12, Redeemable Convertible Preferred Stock and Stockholder’s Deficit, Risk of Concentration of Credit, Significant Customers and Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents and accounts receivable, net. The Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company maintains its cash, cash equivalents and restricted cash with financial institutions that management believes to be of high credit quality. The Company has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Significant customers are those which represent more than 10% of the Company’s total revenue for the three and nine months ended September 30, 2024 and 2023 or accounts receivable, net balance as of September 30, 2024 and December 31, 2023. The following table presents customers that represent 10% or more of the Company’s total revenue and accounts receivable, net: Revenue Revenue Accounts Receivable Three Months Nine Months September 30, December 31, 2024 2023 2024 2023 2024 2023 Customer A 18 % 19 % N/A 12 % 15 % 16 % Customer B N/A 11 % N/A N/A N/A N/A The Company relies on third parties for the supply of parts and components for its products as well as third-party logistics providers. In instances where these parties fail to perform their obligations, the Company may be unable to find alternative suppliers of parts and components to satisfactorily deliver its products to its customers on time, if at all, which could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships. Recently Adopted Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt with Conversion and Other Options and Derivatives and Hedging-Contracts in Entity’s Own Equity, 2020-06 2020-06 Recently Issued Accounting Pronouncements Not Yet Adopted 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	2. Summary of Significant Accounting Policies Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Management considers many factors in selecting appropriate financial accounting policies and controls in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ from those estimates. Reclassification of Prior Year Presentation Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations. Adjustments have been made to the consolidated statement of operations and comprehensive loss for the year ended December 31, 2022 to present the change in fair value of derivative liabilities as part of Other income (expense), net, and to present the change in fair value of warrants as its own line item. The change in fair value of derivative liabilities was a separate line item in prior years and the change in fair value of warrants was part of Other income (expense), net in prior years. Risk of Concentration of Credit, Significant Customers and Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents and accounts receivable, net. The Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company maintains its cash, cash equivalents and restricted cash with financial institutions that management believes to be of high credit quality. The Company has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Significant customers are those which represent more than 10% of the Company’s total revenue for the years ended December 31, 2023 and 2022 or accounts receivable, net balance as of December 31, 2023 and 2022. The following table presents customers that represent 10% or more of the Company’s total revenue and accounts receivable, net: Revenue Accounts Receivable Years Ended December 31 December 31, 2023 2022 2023 2022 Customer A 10 % N/A 16 % N/A Customer B N/A 11 % N/A N/A Customer C N/A N/A N/A 13 % Customer D N/A N/A N/A 12 % The Company relies on third parties for the supply of parts and components for its products as well as third-party logistics providers. In instances where these parties fail to perform their obligations, the Company may be unable to find alternative suppliers of parts and components to satisfactorily deliver its products to its customers on time, if at all, which could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships. Leases Effective January 1, 2022, the Company adopted ASC 842, Leases right-of-use non-current At the lease commencement date, operating lease liabilities and their corresponding ROU assets are recorded at the present value of future lease payments over the expected remaining lease term using the discount rate implicit in the lease, if it is readily determinable, or the Company’s incremental borrowing rate. The Company’s incremental borrowing rate reflects the fixed rate at which the Company could borrow the amount of the lease payments in the same currency on a collateralized basis, for a similar term in a similar economic environment. Lease cost for operating leases is recognized on a straight-line basis over the lease term as an operating expense. In addition, certain adjustments to the ROU asset may be required for items such as lease prepayments, incentives received or initial direct costs. The Company enters into contracts that contain both lease and non-lease Non right-of-use Cash and Cash Equivalents and Restricted Cash Cash consists of amounts held in bank savings and checking accounts. Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase. Cash equivalents consist of money market funds. The Company’s restricted cash consists of cash that the Company is contractually obligated to maintain and deposits of cash collateral held in accordance with the terms of various corporate credit cards. Restricted cash is included within other long-term assets on the consolidated balance sheets. A reconciliation of the amounts of cash and cash equivalents and restricted cash in the consolidated balance sheets to the amount in the consolidated statements of cash flows is as follows (in thousands): December 31, 2023 2022 Cash and cash equivalents $ 38,037 $ 7,685 Restricted cash included in other long-term assets 384 338 Cash and cash equivalents and restricted cash shown in the statement of cash flows $ 38,421 $ 8,023 Segment Reporting The Company operates in a single operating and reportable segment. Operating segments are defined as components of an enterprise for which discrete financial information is available and is regularly reviewed by the chief operating decision maker (“CODM”) in order to make decisions regarding resource allocation and performance assessment. The Company has determined that its CODM is its Chief Executive Officer. The Company’s CODM reviews financial information presented on a regular basis at the consolidated level for purposes of allocating resources and evaluating financial performance. Since the Company operates as one operating segment, all required financial segment information can be found in the consolidated financial statements. The Company’s products include the Allurion Balloon and related accessories. See Note 4, Revenue Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or an exit price that would be 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. The carrying value of the Company’s financial instruments such as cash and cash equivalents, accounts payable, and accrued expenses approximate their fair values due to their short-term maturity. The carrying value of the Company’s term loan approximates its fair value as the interest rate and other terms are that which are currently available to the Company. The Company’s assets and liabilities recorded at fair value have been categorized based upon a fair value hierarchy, which is distinguished between observable and unobservable inputs in accordance with authoritative accounting guidance: Level 1 inputs: Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date Level 2 inputs: Other than quoted prices included in Level 1, inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability Level 3 inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that the observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset. Inventories Inventories, which include the costs of material, labor, and overhead, are stated at the lower of cost or net realizable value, with cost generally computed using the first-in, Property and Equipment Property and equipment include computers, laboratory equipment, machinery, and leasehold improvements. Property and equipment are recorded at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets, except for leasehold improvements, which are depreciated on a straight-line basis over the shorter of the estimated life or the lease term. Expenditures for repairs and maintenance are expensed as incurred. Capitalized Internal-Use Software development costs consist of certain consulting costs and compensation expenses for employees who devote time to the development projects of our internal-use internal-use The Company determined the amount of internal software costs to be capitalized based on the amount of time spent by our developers on projects in the application stage of development. There is judgment in estimating the time allocated to a particular project in the application stage. A significant change in the time spent on each project could have a material impact on the amount capitalized and related amortization expense in subsequent periods. As of December 31, 2023 and 2022, capitalized internal-use Impairment of Long-Lived Assets The Company evaluates its long-lived assets, which consist primarily of property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds the fair value of the asset. To date, no impairments have occurred. Debt Issuance Costs The Company defers costs directly associated with acquiring third-party financing. Fees incurred to issue debt are generally deferred and amortized as a component of interest expense over the estimated term of the related debt using the effective interest rate method. Fees incurred in connection with a modification are deferred and amortized as a component of interest expense over the remaining life of the loan if due to the creditor. Third-party fees incurred in connection with a modification Deferred Offering Costs Deferred offering costs include certain legal, accounting, consulting and other third-party fees incurred directly related to the Business Combination. The Company deferred offering costs classified as a long-term asset until the closing or termination of the transaction. At the closing of the Business Combination, these costs were recorded in stockholders’ deficit as a reduction of additional paid-in Warrants The Company determines the accounting classification of warrants it issues, as either liability or equity classified, by first assessing whether the warrants meet liability classification in accordance with ASC 480-10, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity (“ASC 480-10”), 815-40, Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock 815-40”). 480-10, ASC 480-10, 815-40, 815-40, 815-40 Derivative Liabilities The Company evaluates its convertible instruments and other contracts, including warrants, to determine if those contracts or embedded components of those contracts are required to be accounted for as derivatives, either in whole or in part. If an embedded derivative is bifurcated from a debt host contract, changes in the fair value of the bifurcated derivative are recorded in the accompanying consolidated statements of operations. 2023 Convertible Notes The Company accounted for the convertible notes issued between February 2023 and August 2023 (the “2023 Convertible Notes”) under the fair value option (“FVO”) election of ASC Topic 825, Financial Instruments recorded as a component of Other (expense) income in the consolidated statements of operations. As a result of electing the FVO, direct costs and fees related to the 2023 Convertible Notes were expensed as incurred. The convertible notes issued in 2020, 2021 and 2022 are accounted for as disclosed in Note 8, Debt Earn-Out In connection with the Business Combination, certain holders of Legacy Allurion common stock “Earn-Out earn-out earn-out Earn-Out earn-out fixed-for-fixed Distinguishing Liabilities from Equity The fair value of the earn-out earn-out earn-out earn-out Revenue Interest Financing and PIPE Conversion Option In connection with the Business Combination, the Company entered into a revenue interest financing agreement, dated as of February 9, 2023 (the “Revenue Interest Financing Agreement”) with certain entities that have engaged RTW Investments, LP as investment manager (collectively, “RTW”), under which the Company received $40.0 million upfront (the “Revenue Interest Financing”). In exchange, the Company is obligated to remit to RTW certain revenue interest payments on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries at a rate up to 6.0% of annual net sales prior to December 31, 2026. On or after January 1, 2027, the Company will remit revenue interest payments at a rate up to 10.0% of annual net sales, and it will continue to make revenue interest payments to RTW until December 31, 2030. The Company accounts for the Revenue Interest Financing Agreement under the fair value option election of ASC 825. The Revenue Interest Financing Agreement accounted for under the FVO election is a debt host financial instrument that contains embedded features. The embedded features include requirements to settle the Revenue Interest Financing prior to maturity upon the occurrence of certain contingent events, a change in royalty rates upon the occurrence of certain contingent events, and the Company’s ability to prepay the Revenue Interest Financing. As the Company has elected the FVO, these embedded features would not meet the criteria for bifurcation and separate accounting as the entire financial instrument is initially measured at its issue-date estimated fair value and then subsequently remeasured at estimated fair value on a recurring basis on each reporting period date. Changes in the estimated fair value of the Revenue Interest Financing Agreement are recorded as a component of Other (expense) income in the consolidated statements of operations. A portion of the estimated change in fair value must be reported in other comprehensive loss to the extent that it is attributable to instrument-specific credit risk. As a result of electing the FVO, direct costs and fees related to the Revenue Interest Financing are expensed as incurred. In connection with the Company entering in the Revenue Interest Financing, the Company and RTW entered into the RTW side letter under which RTW may elect to convert up to $7.5 million of its initial PIPE (as defined in Note 3, Business Combination Derivatives and Hedging Accounts Receivable Accounts receivable are unsecured and are carried at net realizable value, including an allowance for doubtful accounts. Trade credit is generally extended on a short-term basis; trade receivables do not bear interest, although a finance charge may be applied to such receivables that are past due. The allowance for doubtful accounts is based on the Company’s assessment of the collectability of customer accounts. The Company regularly reviews the allowance by considering factors that may affect a customer’s ability to pay, such as historical expense, credit quality, the The following table summarizes activity in the allowance for doubtful accounts: Year Ended December 31,   2023     2022   Balance at beginning of period $ (741 ) $ (354 ) Provision for uncollectible accounts (12,675 ) (436 ) Uncollectible accounts written off 745 49 Balance at end of period $ (12,671 ) $ (741 ) Revenue Recognition The Company recognizes revenue under ASU No. 2014-09, Revenue from Contracts with Customers The Company recognizes revenue when control of its products is transferred to customers at an amount that reflects the consideration it expects to receive in exchange for those products. The Company’s revenue recognition process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the transaction price, allocating the transaction price to the distinct performance obligations in the contract, and recognizing revenue as performance obligations are satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. Performance obligations are considered satisfied once the Company has transferred control of a good or service to the customer, meaning that such customer has the ability to use and obtain the benefit of the good or service. The Company has provided customers purchasing the Allurion Balloon with an implied license for access to its VCS software. This implied software license was given to customers for no additional consideration and was not negotiated as part of the customer’s contracts. Further, the customer contracts and related purchase orders do not include nor specify rights or obligations associated with the VCS software. Based on this assessment, the Company determined the implied license to be immaterial in the context of the contract with customers purchasing the Allurion Balloon, and as such did not allocate any value to the implied VCS license. The Company generates revenue from sales of its Allurion Balloon to distributors and health care providers. Customers typically The Company recognizes revenue at the transaction price, which reflects the consideration it believes it is entitled to receive. Transaction price includes estimates of variable consideration for promotions and prompt pay discounts, which are recorded as a reduction of transaction price in the period the related product revenue is recognized. The Company may also make payments to customers for marketing programs. Payments to customers for a distinct good or service that reasonably estimate the fair value of the distinct benefit received, such as marketing programs, are recorded as a marketing expense on the consolidated statement of operations and comprehensive loss. Shipping and logistics costs inclusive of these payments to customers and other costs included in sales and marketing expense for the years ended December 31, 2023 and 2022 were $3.3 million and $3.6 million, respectively. The Company expenses incremental costs of obtaining a contract, such as sales commissions, when incurred because the amortization period would have been one year or less. These costs are recorded within sales and marketing expenses in the Company’s consolidated statement of operations and comprehensive loss. The Company has also elected the sales tax practical expedient; therefore, sales and other taxes assessed by a governmental authority that are collected concurrently with revenue-producing activities are excluded from the transaction price. The Company has also elected the significant financing component practical expedient, which allows management to not assess whether the contract has a significant financing component in circumstances where, at contract inception, the expected contract duration is less than one year. Product Warranty The Company does not provide general rights of return of products sold to its customers. However, the Company does provide for rights of exchange to its distributors and end-use body These instances of nonconformity have been immaterial, and the Company’s management expects instances of nonconformity to be extremely rare. Research and Development Costs The Company expenses research and development costs as incurred. Research and development expenses consist of costs associated with performing research and development activities, including salaries and benefits, stock-based compensation, product development costs, materials and supplies, clinical trial activities, depreciation of equipment, and contract and other outside services. Payments for activities that are provided by outside vendors are based upon the terms of the individual arrangements with each vendor. Costs of certain of these activities are expensed based upon an evaluation of the progress to completion of specific tasks and actual costs incurred, using information provided to the Company by its vendors. As payments for these activities may differ from the pattern of costs actually incurred, additional costs are reflected in the consolidated financial statements as prepaid or accrued research and development expenses. Advertising and Marketing Costs The Company expenses advertising and marketing costs as incurred. Advertising and marketing expenses are included in sales and marketing operating expenses. Advertising and marketing costs for the years ended December 31, 2023 and 2022 were $10.8 million and $16.0 million, respectively. Intellectual Property Prosecution Costs The Company incurs registration and prosecution costs related to its intellectual property. The related costs are expensed as incurred and are classified as a component of general and administrative expenses. Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company’s consolidated financial statements and tax returns. Deferred tax assets and liabilities are determined based upon the differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities and for net operating loss and tax credit carryforwards, using enacted tax rates expected to be in effect in the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that these assets may not be realized. The Company determines whether a tax position will be sustained upon examination. If it is not more likely than not that a position will be sustained, none of the benefit attributable to the position is recognized. The tax benefit to be recognized for any tax position that meets the more likely than not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. As of December 31, 2023 and 2022, the Company has not identified any uncertain tax positions for which reserves would be required. Net Loss Per Share The Company applies the two-class two-class two-class Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders less the cumulative undeclared dividend by the weighted average number of common shares outstanding for the period. Diluted net loss attributable to common stockholders is computed by adjusting net loss attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing the diluted net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents. The holders of the Legacy Allurion Series D convertible preferred stock were contractually entitled to receive a cumulative dividend, whether or not declared, and therefore, Legacy Allurion Series D convertible preferred stocks were participating securities. The holders of all other redeemable and convertible preferred stock were not entitled to cumulative dividends. The preferred equity holders were also not contractually required to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss, such losses are not allocated to such participating securities. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. In connection with the Business Combination with Compute Health, the Company’s equity in previous periods has been retroactively adjusted to the earliest period presented to reflect the equivalent number of shares of Allurion Common Stock issued to the Company’s stockholders in connection with the Business Combination. As a result, net loss per share was also retrospectively adjusted for periods ended prior to the Business Combination. See Note 3, Business Combination Stock-Based Compensation The Company recognizes compensation expense for awards based on the grant-date fair value of stock-based No. 2018-07, Compensation—Stock Compensation (“Topic 718”): Improvements to Nonemployee Share-Based Payment Accounting Comprehensive Loss For the year ended December 31, 2023, comprehensive loss consists of net loss and other comprehensive loss, which includes changes in the fair value attributable to instrument-specific credit risk related to the Revenue Interest Financing with RTW. There were no differences between net loss and comprehensive loss presented in the statements of operations and comprehensive loss for the year ended December 31, 2022. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326) adopted ASU 2016-13 2016-13 Recently Issued Accounting Pronouncements Not Yet Adopted In August 2020, the FASB issued ASU 2020-06, Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity’s Own Equity No. 2020-06 2020-06 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

Business Combination

Business Combination	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Business Combinations [Abstract]
Business Combination	3. Business Combination As discussed in Note 1, Organization and Basis of Presentation Upon the closing of the Business Combination, (a) holders of Legacy Allurion common stock received shares of Allurion Common Stock in an amount determined by application of the Exchange Ratio of approximately 0.9780 , (the Exchange Ratio established in the Business Combination is prior to the Reverse Stock Split and did not change as a result of the Reverse Stock Split) (b) each then-outstanding share of Legacy Allurion preferred stock was converted into the right to receive shares of Allurion Common Stock equal to the number of shares of Legacy Allurion common stock that would be issued upon conversion of such outstanding share of Legacy Allurion preferred stock based on the applicable conversion ratio multiplied by the Exchange Ratio, (c) each then-outstanding and unexercised Legacy Allurion option was converted into a new Allurion option on the same terms and conditions as were applicable to such Legacy Allurion option based on the Exchange Ratio, (d) each then-outstanding Legacy Allurion warrant was converted into a new Allurion warrant based on the Exchange Ratio (“Rollover Warrant”), (e) each then-outstanding Legacy Allurion restricted stock unit was converted into a rollover restricted stock unit based on the Exchange Ratio, and (f) certain amounts of loans made by Compute Health Sponsor LLC (the “Sponsor”) to CPUH, which balance was $ Further, upon the closing of the Business Combination and after giving effect to the Reverse Stock Split, each then-outstanding share of Compute Health Class A common stock was canceled and extinguished and was converted into the right to receive In connection with the Business Combination, the Company incurred approximately $22.7 million of transaction costs, consisting of legal and other professional fees, of which $15.2 million was recorded to additional paid-in loss. Of the $5.0 million recorded as general and administrative expenses, $3.6 million relates to a one-time The following table reconciles the elements of the Business Combination to the condensed consolidated statement of cash flows and the condensed consolidated statement of changes in equity: December 31, Cash – CPUH trust (net of redemptions) $ 38,395 Cash – PIPE Investors 37,922 Gross Proceeds 76,317 Less: transaction costs paid (14,665 ) Net proceeds from the Business Combination 61,652 Less: warrant liabilities assumed (13,762 ) Less: repayment of note assumed in the Business Combination (2,500 ) Less: accrued transaction costs at December 31, 2023 (580 ) Business Combination, net of transaction costs $ 44,810 The number of shares of Allurion Common Stock outstanding immediately following the consummation of the Business Combination and after giving effect to the Reverse Stock Split was as follows: Common Stock Legacy Allurion Equityholders (1) 1,115,896 CPUH Stockholders (2) 206,628 Shares Issued to PIPE Investors (2) 215,468 Shares issued to RTW and Fortress (3) 76,000 Shares issued to convertible note holders 132,049 CPUH Sponsor Shares (2) 130,509 Side Letter Termination Shares (3) 15,508 Total shares of Common Stock immediately after Business Combination 1,892,058 (1) Consists of Legacy Allurion common stock and Legacy Allurion preferred stock, plus the issuance of common stock in connection with the vesting of RSUs at closing, less the Gaur Trust Contributed Shares (as defined below). (2) The CPUH Stockholders shares, PIPE shares, and CPUH Sponsor shares are presented combined within the condensed consolidated statements of stockholders deficit on the “Reverse recapitalization, net of transaction costs” line, which is less the Gaur Trust Contributed Shares. (3) The shares issued to RTW and Fortress and the Side Letter Termination shares are presented combined within the condensed consolidated statements of stockholders deficit on the “Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and additional RTW and Fortress shares and issuance of related shares” line. PIPE Investment In connection with the execution of the Business Combination Agreement, Allurion and Compute Health entered into subscription agreements, each dated February 9, 2023, with certain accredited investors and qualified institutional buyers (the “PIPE Investors”), pursuant to which, upon the terms and subject to the conditions set forth therein, the PIPE Investors, among other things, purchased an aggregate of 215,468 shares of Allurion Common Stock at a purchase price of $176.00 per share (other than as set forth in the Amended and Restated RTW Side Letter, as defined below), for an aggregate purchase price of $37.9 million, following the CPUH Merger Effective Time (the “PIPE Investment”). Revenue Interest Financing Agreement, Side Letter and PIPE Conversion Option On February 9, 2023, concurrently with the execution of the Business Combination Agreement, the Company entered into the Revenue Interest Financing Agreement (the “Revenue Interest Financing Agreement”) with certain entities that engaged RTW Investments, LP (together with its affiliates, “RTW”) as investment manager. Pursuant to the Revenue Interest Financing Agreement, at the closing of the Business Combination, RTW paid Allurion an aggregate of $40.0 million (the “Investment Amount”). In exchange for the Investment Amount, Allurion will remit revenue interest payments on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries at a rate up to 6.0% of annual net sales prior to December 31, 2026. On or after January 1, 2027, the Company will remit revenue interest payments at a rate up to 10.0% of annual net sales, and it will continue to make revenue interest payments to RTW until December 31, 2030. The Revenue Interest Financing Agreement was amended pursuant to the RIFA Amendment (as defined below) on April 14, 2024. The RIFA Amendment, among other things, increased the rate of revenue interest payments to be paid to RTW on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries. Refer to Note 9, Revenue Interest Financing, Side Letter, and PIPE Conversion Option Additionally, in connection with the Company entering into the Revenue Interest Financing Agreement, the Company, Compute Health, Legacy Allurion, Merger Sub II and RTW entered into a side letter (the “RTW Side Letter”) on February 9, 2023 under which RTW may elect to convert up to $7.5 million of its initial PIPE Investment into an additional revenue interest financing by forfeiting a number of shares of Allurion Common Stock acquired by its PIPE Investment. Refer to Note 9, Revenue Interest Financing, Side Letter, and PIPE Conversion Option On May 2, 2023, the parties amended and restated the RTW Side Letter (as amended, the “Amended and Restated RTW Side Letter”), in connection with the Backstop Agreement (defined below), pursuant to which, among other things, Allurion issued 10,000 shares of Allurion Common Stock to RTW immediately prior to the Intermediate Merger Effective Time. On October 22, 2024, funds affiliated with RTW provided notice to the Company of their election under the Amended and Restated RTW Side Letter, to surrender 30,000 shares of Common Stock of the Company representing $7.5 million in consideration for the New RIFA (as defined below). Refer to Note 19, Subsequent Events Fortress Credit Agreement In connection with the closing of the Business Combination, the Company entered into a term loan facility (the “Fortress Term Loan”) pursuant to a Credit Agreement and Guaranty, dated as of August 1, 2023 (the “Fortress Credit Agreement”), with Fortress Credit Corp. (“Fortress”), as administrative agent for the lenders party thereto from time to time (the “Lenders”). Under the terms of the Fortress Term Loan, we borrowed $60.0 million, which was used to repay the outstanding principal, accrued and unpaid interest, and other obligations with respect to the 2021 Term Loan (as defined below). Additionally, per the terms of the Fortress Term Loan and Backstop Agreement (as defined below), Allurion issued an aggregate of 38,000 shares of Allurion Common Stock to an affiliate of Fortress pursuant to a subscription agreement between Allurion and such affiliate. Refer to Note 8, Debt Backstop Agreement On May 2, 2023, CFIP2 ALLE LLC, an affiliate of Fortress Credit Corp., and RTW (collectively, the “Backstop Purchasers”), Legacy Allurion, Allurion and Hunter Ventures Limited (“HVL”) entered into the backstop agreement (the “Backstop Agreement”). Pursuant to the Backstop Agreement, immediately prior to the Intermediate Merger Closing, (a) each Backstop Purchaser purchased $2 million of the aggregate principal amount outstanding of HVL’s Legacy Allurion convertible note issued in February 2023, (b) Allurion canceled the existing HVL Legacy Allurion Convertible Note and issued a new Allurion Convertible Note to HVL for the remaining balance together with all unpaid interest accrued since the date of issuance thereof, (c) Allurion issued new Allurion Convertible Notes to each Backstop Purchaser with an issuance date of August 1, 2023 and an original principal amount of $2 million each and (d) Allurion issued 28,000 shares of Allurion Common Stock to each Backstop Purchaser. Refer to Note 8, Debt HVL Termination Agreement On May 2, 2023, HVL and Legacy Allurion entered into a letter agreement (the “HVL Termination Agreement”), terminating the side letter agreement entered into between Legacy Allurion and HVL in connection with the issuance of HVL’s Legacy Allurion convertible note on February 15, 2023. Pursuant to the HVL Termination Agreement, among other things, at the closing of the Business Combination, upon the terms and subject to the conditions set forth therein, Allurion issued to HVL 15,508 shares of Allurion Common Stock. Refer to Note 8, Debt Gaur Contribution Agreement On May 2, 2023, Shantanu K. Gaur and Neha Gaur, trustees of The Shantanu K. Gaur Revocable Trust of 2021 (the “Gaur Trust”) and Allurion entered into a contribution agreement (the “Gaur Contribution Agreement”), pursuant to which, among other things, upon the terms and subject to the conditions set forth therein, the Gaur Trust contributed to Allurion, as a contribution of capital, 3,170 shares of Allurion Common Stock (the “Gaur Trust Contributed Shares”). The Gaur Trust’s contribution of the Gaur Trust Contributed Shares was effective immediately following the consummation of the Business Combination and the issuance of shares of Allurion Common Stock to the Gaur Trust pursuant to the terms of the Business Combination Agreement. RSU Forfeiture Agreement On May 2, 2023, Krishna Gupta, a member of the Company’s Board of Directors (the “Board” or “Board of Directors”), entered into a letter agreement with Legacy Allurion (the “RSU Forfeiture Agreement”), pursuant to which, among other things, upon the terms and subject to the conditions set forth therein, Mr. Gupta agreed to forfeit 3,170 restricted stock units of Allurion (the “Forfeited RSUs”). The Forfeited RSUs were terminated and cancelled without consideration therefor immediately following the closing of the Business Combination Agreement. Sponsor Contribution Agreement On May 2, 2023, the Sponsor and Compute Health entered into a letter agreement (the “Sponsor Contribution Agreement”) pursuant to which, among other things, upon the terms and subject to the conditions set forth therein, the Sponsor agreed to contribute to Compute Health, as a contribution of capital, 161,379 shares of Compute Health Class A Common Stock (“Sponsor Contributed Shares”), prior to giving effect to the Reverse Stock Split. The Sponsor’s contribution of the Sponsor Contributed Shares was made immediately following the CPUH Recapitalization (defined below) and immediately prior to the CPUH Merger Effective Time. Sponsor Support Agreement On February 9, 2023, Allurion entered into a support agreement (the “Sponsor Support Agreement”), pursuant to which immediately prior to the CPUH Merger Effective time, (a) the Sponsor recapitalized each of the Sponsor’s 21,442,500 shares of Compute Health Class B Common Stock, and all 12,833,333 of the Sponsor’s warrants to purchase shares of Class A Common Stock, into 2,088,327 shares of Compute Health Class A Common Stock and (b) the additional Class B Holders set forth on Schedule I of the Sponsor Support Agreement recapitalized his or her 30,000 shares of Compute Health Class B Common Stock into 21,120 shares of Compute Health Class A Common Stock (the “CPUH Recapitalization”). Subsequently, at the CPUH Merger Effective Time, each such share of Compute Health Class A Common Stock was converted into shares of Allurion Common Stock at an exchange ratio of 1.420455 (the “CPUH Exchange Ratio”). Conversion of Convertible Notes In connection with the closing of the Business Combination, outstanding Legacy Allurion Convertible Notes with an aggregate principal amount together with accrued but unpaid interest of approximately $21.8 million were converted into 132,049 shares of Allurion Common Stock with a corresponding recognition of additional paid-in Debt Public Warrants and Warrant Amendment In connection with the closing of the Business Combination, the Company assumed 528,277 outstanding public warrants (the “Public Warrants”) to purchase an aggregate 750,394 shares of Allurion Common Stock at $202.50 per share following the Warrant Amendment (defined below). The total value of the liability associated with the Public Warrants was $13.8 million measured at fair value based on the public warrant quoted price. The Company concluded the warrants met the definition of a liability based on the settlement provision that allows the warrant holders to net-share Redeemable Convertible Preferred Stock and Stockholders Deficit Fair Value Measurements Earn-Out In connection with the closing of the Business Combination, Legacy Allurion equity holders are entitled to receive additional shares of Allurion Common Stock if the share price achieves certain targets (the “Earn-Out Earn-Out Fair Value Measurements earn-out	3. Business Combination As discussed in Note 1, Organization and Basis of Presentation Upon the closing of the Business Combination, (a) holders of Legacy Allurion common stock received shares of Allurion Common Stock in an amount determined by application of the Exchange Ratio of approximately 0.9780, (the Exchange Ratio established in the Business Combination is prior to the Reverse Stock Split and did not change as a result of the Reverse Stock Split) (b) each then-outstanding share of Legacy Allurion preferred stock was converted into the right to receive shares of Allurion Common Stock equal to the number of shares of Allurion Common Stock that would be issued upon conversion of such outstanding share of Legacy Allurion preferred stock based on the applicable conversion ratio multiplied by the Exchange Ratio, (c) each then-outstanding and unexercised Legacy Allurion option was converted into a new Allurion option on the same terms and conditions as were applicable to such Legacy Allurion option based on the Exchange Ratio (“Rollover Option”), (d) each then-outstanding Legacy Allurion warrant was converted into a new Allurion warrant based on the Exchange Ratio (“Rollover Warrant”), (e) each then-outstanding Legacy Allurion restricted stock unit was converted into a rollover restricted stock unit based on the Exchange Ratio, and (f) certain amounts of loans made by Compute Health Sponsor LLC (the “Sponsor”) to CPUH, which balance was $ million at the time of the Business Combination (the “Sponsor Loan Excess”), was converted into shares of Allurion Common Stock (the “Sponsor Loan Equity Issuance”). For periods prior to the Business Combination, the reported share and per share amounts have been retroactively converted by applying the Exchange Ratio. The consolidated assets, liabilities, and results of operations prior to the Business Combination are those of Legacy Allurion. Further, upon the closing of the Business Combination and after giving effect to the Reverse Stock Split, each then-outstanding share of Compute Health Class A common stock was canceled and extinguished and was converted into the right to receive shares of Allurion Common Stock. Additionally, the Company assumed 528,277 outstanding public warrants to purchase an aggregate 750,394 shares of Allurion Common Stock at $202.50 per share. In connection with the Business Combination, the Company incurred approximately $22.7 million of transaction costs, consisting of legal and other professional fees, $15.2 million of which were recorded to additional paid-in one-time The following table reconciles the elements of the Business Combination to the consolidated statement of cash flows and the consolidated statement of changes in equity: December 31, Cash – CPUH trust (net of redemptions) $ 38,395 Cash – PIPE Investors 37,922 Gross Proceeds 76,317 Less: transaction costs paid (14,665 ) Net proceeds from the Business Combination (1) 61,652 Less: warrant liabilities assumed (2) (13,762 ) Less: repayment of note assumed in the Business Combination (1) (2,500 ) Less: accrued transaction costs at December 31, 2023 (1) (580 ) Business Combination, net of transaction costs $ 44,810 (1) The Net proceeds from the Business Combination, less the repayment of note assumed in the Business Combination, less the accrued transaction costs at December 31, 2023 are presented net in the consolidated statements of stockholders deficit within line “Reverse recapitalization, net of transaction costs (Note 3)”. (2) The warrant liabilities assumed are presented separately from the “Reverse recapitalization, net of transaction costs (Note 3)” line within the consolidated statements of stockholders deficit. The number of shares of Allurion Common Stock outstanding immediately following the consummation of the Business Combination and after giving effect to the Reverse Stock Split was as follows: Common Stock Legacy Allurion Equityholders (1) 1,115,896 CPUH Stockholders (2) 206,628 Shares Issued to PIPE Investors (2) 215,468 Shares issued to RTW and Fortress (3) 76,000 Shares issued to convertible note holders 132,049 CPUH Sponsor Shares (2) 130,509 Side Letter Termination Shares (3) 15,508 Total shares of Common Stock immediately after Business Combination 1,892,058 (1) Consists of Legacy Allurion common stock and Legacy Allurion preferred stockholders, plus the issuance of common stock in connection with the vesting of RSUs at closing, less the Gaur Contributed (2) The CPUH Stockholders shares, PIPE shares, and CPUH Sponsor shares are presented combined within the consolidated statements of redeemable convertible preferred stock and stockholders deficit on the “Reverse recapitalization, net of transaction costs” line, which is less the Gaur Contributed Shares (as defined below). (3) The shares issued to RTW and Fortress and the Side Letter Termination shares are presented combined within the consolidated statements of redeemable convertible preferred stock and stockholders deficit on the “Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and additional RTW and Fortress shares and issuance of related shares” line. PIPE Investment In connection with the execution of the Business Combination Agreement, Allurion and Compute Health entered into subscription agreements, each dated February 9, 2023 (the “PIPE Subscription Agreements”), with certain accredited investors and qualified institutional buyers (the “PIPE Investors”), pursuant to which, upon the terms and subject to the conditions set forth therein, the PIPE Investors, among other things, purchased an aggregate of 215,468 shares of Allurion Common Stock at a purchase price of $176.00 per share (other than as set forth in the Amended and Restated RTW Side Letter, as defined below), for an aggregate purchase price of $37.9 million, following the CPUH Merger Effective Time (the “PIPE Investment”). Revenue Interest Financing Agreement, Side Letter and PIPE Conversion Option On February 9, 2023, concurrently with the execution of the Business Combination Agreement, the Company entered into the Revenue Interest Financing Agreement with RTW. Pursuant to the Revenue Interest Financing Agreement, at the closing of the Business Combination, RTW paid Allurion an aggregate of $40.0 million (the “Investment Amount”). In exchange for the Investment Amount, Allurion will remit revenue interest payments on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries at a rate up to 6.0% of annual net sales prior to December 31, 2026. On or after January 1, 2027, the Company will remit revenue interest payments at a rate up to 10.0% of annual net sales, and it will continue to make revenue interest payments to RTW until December 31, 2030. Additionally, in connection with the Company entering in the Revenue Interest Financing, the Company, Compute Health, Legacy Allurion, Merger Sub II and RTW entered into a side letter (the “RTW Side Letter”) on February 9, 2023 under which RTW may elect to convert up to $7.5 million of its initial PIPE subscription into an additional revenue interest financing by forfeiting a number of shares of Allurion common stock acquired by its PIPE Investment. Refer to Note 9, Revenue Interest Financing, Side Letter, and PIPE Conversion Option On May 2, 2023, the parties amended and restated the RTW Side Letter (as amended, the “Amended and Restated RTW Side Letter”), in connection with the Backstop Agreement (defined below), pursuant to which, among other things, Allurion issued 10,000 shares of Allurion Common Stock to RTW immediately prior to the Intermediate Merger Effective Time. Fortress Credit Agreement In connection with the closing of the Business Combination, the Company entered into a term loan facility (the “Fortress Term Loan”) pursuant to a credit agreement and guaranty, dated as of August 1, 2023 (the “Fortress Credit Agreement”), with Fortress Credit Corp. (“Fortress”), as administrative agent for the lenders party thereto from time to time (the “Lenders”). Under the terms of the Fortress Term Loan, we borrowed $60.0 million which was used to repay the outstanding principal, accrued and unpaid interest, and other obligations with respect to the 2021 Term Loan (as defined below). Additionally, per the terms of the Fortress Term Loan and Backstop Agreement, Allurion issued an aggregate of 38,000 shares of Allurion Common Stock to an affiliate of Fortress pursuant to a subscription agreement between Allurion and such affiliate. Refer to Note 8, Debt Backstop Agreement On May 2, 2023, CFIP2 ALLE LLC, an affiliate of Fortress Credit Corp., and RTW (collectively, the “Backstop Purchasers”), Legacy Allurion, Allurion and Hunter Ventures Limited (“HVL”) entered into the backstop agreement (the “Backstop Agreement”). Pursuant to the Backstop Agreement, immediately prior to the Intermediate Merger Closing (a) each Backstop Purchaser purchased $2 million of the aggregate principal amount outstanding of HVL’s Legacy Allurion convertible note issued in February 2023, (b) Allurion canceled the existing HVL Legacy Allurion Convertible Note and issued a new Allurion Convertible Note to HVL for the remaining balance together with all unpaid interest accrued since the date of issuance thereof, (c) Allurion issued new Allurion Convertible Notes to each Backstop Purchaser with an issuance date of August 1, 2023 and an original principal amount of $2 million each and (d) Allurion issued 28,000 shares of Allurion Common Stock to each Backstop Purchaser. Refer to Note 8, Debt HVL Termination Agreement On May 2, 2023, HVL and Legacy Allurion entered into a letter agreement (the “HVL Termination Agreement”), terminating the side letter agreement entered into between Legacy Allurion and HVL in connection with the issuance of HVL’s Legacy Allurion convertible note on February 15, 2023. Pursuant to the HVL Termination Agreement, among other things, at the closing of the Business Combination, upon the terms and subject to the conditions set forth therein, Allurion issued to HVL 15,508 shares of Allurion Common Stock. Refer to Note 8, Debt Gaur Contribution Agreement On May 2, 2023, Shantanu K. Gaur and Neha Gaur, trustees of The Shantanu K. Gaur Revocable Trust of 2021 (the “Gaur Trust”) and Allurion entered into a contribution agreement (the “Gaur Contribution Agreement”), pursuant to which, among other things, upon the terms and subject to the conditions set forth therein, the Gaur Trust contributed to Allurion, as a contribution of capital, 3,170 shares of Allurion Common Stock (the “Gaur Trust Contributed Shares”). The Gaur Trust’s contribution of the Gaur Trust Contributed Shares was effective immediately following the consummation of the Business Combination and the issuance of shares of Allurion Common Stock to the Gaur Trust pursuant to the terms of the Business Combination Agreement. RSU Forfeiture Agreement On May 2, 2023, Krishna Gupta, a member of our Board of Directors, entered into a letter agreement with Legacy Allurion (the “RSU Forfeiture Agreement”), pursuant to which, among other things, upon the terms and subject to the conditions set forth therein, Mr. Gupta agreed to forfeit 3,170 restricted stock units of Allurion (the “Forfeited RSUs”). The Forfeited RSUs were terminated and cancelled without consideration therefore immediately following the closing of the Business Combination Agreement. Sponsor Contribution Agreement On May 2, 2023, the Sponsor and Compute Health entered into a letter agreement (the “Sponsor Contribution Agreement”) pursuant to which, among other things, upon the terms and subject to the conditions set forth therein, the Sponsor agreed to contribute to Compute Health, as a contribution of capital, 161,379 shares of Compute Health Class A Common Stock (“Sponsor Contributed Shares”), prior to giving effect to the Reverse Stock Split. The Sponsor’s contribution of the Sponsor Contributed Shares was made immediately following the CPUH Recapitalization (defined below) and immediately prior to the CPUH Merger Effective Time. Sponsor Support Agreement On February 9, 2023, Allurion entered into a support agreement (the “Sponsor Support Agreement”), pursuant to which immediately prior to the CPUH Merger Effective time, (a) the Sponsor recapitalized each of the Sponsor’s 21,442,500 shares of Compute Health Class B Common Stock, and all 12,833,333 of the Sponsor’s warrants to purchase shares of Class A Common Stock, into 2,088,327 shares of Compute Health Class A Common Stock and (b) the additional Class B Holders set forth on Schedule I of the Sponsor Support Agreement (the “Additional Class B Holders”) recapitalized his or her 30,000 shares of Compute Health Class B Common Stock into 21,120 shares of Compute Health Class A Common Stock (the “CPUH Recapitalization”). Subsequently, at the CPUH Merger Effective Time, each such share of Compute Health Class A Common Stock was converted into shares of Allurion Common Stock at an exchange ratio of 1.420455 (the “CPUH Exchange Ratio”), prior to giving effect to the Reverse Stock Split. Conversion of Convertible Notes In connection with the closing of the Business Combination, outstanding Legacy Allurion Convertible Notes with an aggregate principal amount together with accrued but unpaid interest of approximately $21.8 million were converted into 132,049 shares of Allurion Common Stock with a corresponding recognition of additional paid-in Debt Public Warrants and Warrant Amendment In connection with the closing of the Business Combination, the Company assumed 528,277 outstanding Public Warrants (defined below) to purchase an aggregate 750,394 shares of Allurion Common Stock at $202.50 per share following the Warrant Amendment (defined below). The total value of the liability associated with the Public Warrants was $13.8 million measured at fair value based on the public warrant quoted price. The Company concluded the warrants met the definition of a liability based on the settlement provision that allows the warrant holders to net-share Capital Stock and Stockholders’ Deficit Fair Value Measurements Earn-Out In connection with the closing of the Business Combination, Legacy Allurion equity holders are entitled to receive additional shares of Allurion Common Stock if the shares price achieves certain targets. The Company accounts for the potential issuance of the Earn-Out Fair Value Measurements earn-out

Revenue

Revenue	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Revenue	4. Revenue Revenue by geographic region is based on the country in which our customer is located and is summarized by geographic area as follows (in thousands): Three Months Ended 2024 2023 Turkey $ 966 $ 3,517 Australia $ 543 $ 979 Italy 511 626 Chile —  1,956 All Other Countries 3,347 11,122 Total Revenues $ 5,367 $ 18,200 For the three months ended September 30, 2024, $1.8 million of revenue was generated in five countries included within All Other Countries in the table above, representing approximately 34% of Total Revenues, with each country responsible for approximately 5% to 8% of the total. Remaining revenue was generated by sales in 36 other countries included within All Other Countries. For the three months ended September 30, 2023, $5.9 million of revenue was generated in five countries included within All Other Countries, representing approximately 33% of Total Revenues, with each country responsible for approximately 5% to 7% of the total. Remaining revenue was generated by sales in 45 other countries included within All Other Countries. Nine Months Ended 2024 2023 Spain $ 3,001 $ 3,715 United Kingdom 2,534 3,456 France 2,431 4,423 Turkey 1,573 5,495 All Other Countries 16,980 28,143 Total Revenues $ 26,519 $ 45,232 For the nine months ended September 30, 2024, $7.2 million of revenue was generated in five countries included within All Other Countries in the table above, representing approximately 27% of Total Revenues, with each country responsible for approximately 4% to 8% of the total. Remaining revenue was generated by sales in 49 other countries included within All Other Countries. For the nine months ended September 30, 2023, $11.1 million of revenue was generated in five countries included within All Other Countries, representing approximately 25% of Total Revenues, with each country responsible for approximately 4% to 7% of the total. Remaining revenue was generated by sales in 58 other countries included within All Other Countries. No revenue was generated in the United States for the three and nine months ended September 30, 2024.	4. Revenue Revenue by geographic region is based on the country in which our customer is domiciled and is summarized by geographic area as follows (in thousands): Year Ended December 31,   2023     2022   France $ 5,569 $ 6,032 Turkey 5,494 4,079 Spain 4,618 6,852 Chile 2,708 5,008 All other countries 35,078 42,240 Total Revenues $ 53,467 $ 64,211 There is currently no revenue generated in the United States. For the year ended December 31, 2023, $13.3 million of revenue was generated in four countries included within All other countries in the table above, representing approximately 25% of Total Revenues, with each country responsible for approximately 5%-9% 6%-7%

Inventory

Inventory	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Disclosure Text Block [Abstract]
Inventory	5. Inventory Inventory consists of the following (in thousands): September 30, December 31, Finished goods $ 2,748 $ 3,427 Work in progress 1,005 967 Raw materials 815 1,777 Total Inventory $ 4,568 $ 6,171 Inventory is stated net of $0.7 million and less than $0.1 million for the provision for excess and obsolete inventory as of September 30, 2024 and December 31, 2023, respectively.	5. Inventory Inventory consists of the following (in thousands): December 31, 2023 2022 Finished goods $ 3,427 $ 2,096 Work in progress 967 213 Raw materials 1,777 1,556 Total Inventory $ 6,171 $ 3,865 Inventory is stated net of less than $0.1 million and zero for the provision of excess and obsolete inventory as of December 31, 2023 and 2022, respectively.

Property and Equipment, net

Property and Equipment, net	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, net	6. Property and Equipment, net Property and equipment consist of the following (in thousands): Estimated Useful Life September 30, December 31, Computers and purchased software 3 $ 618 $ 618 Leasehold improvements Shorter of useful life 1,943 1,943 Furniture and fixtures 5 291 291 Machinery and equipment 3-5 3,507 2,893 Property and equipment—at cost 6,359 5,745 Less accumulated depreciation and amortization (4,169 ) (3,559 ) Construction in progress 890 1,195 Property and equipment—net $ 3,080 $ 3,381 Depreciation expense was $0.2 million for each of the three months ended September 30, 2024 and 2023, and $0.8 million and $0.6 million for the nine months ended September 30, 2024 and 2023, respectively, recorded as follows (in thousands): Three Months Ended Nine Months Ended  2024   2023   2024   2023  Cost of revenue $ 119 $ 63 $ 433 $ 280 Research and development 63 48 161 131 General and administrative 19 34 104 104 Sales and marketing 14 15 80 43 Total depreciation and amortization expense $ 215 $ 160 $ 778 $ 558	6. Property and Equipment, net Property and equipment consist of the following (in thousands): Estimates Useful Life December 31, 2023 2022 Computers and purchased software 3 $ 618 $ 575 Leasehold improvements Shorter of useful life 1,943 1,822 Furniture and fixtures 5 291 251 Machinery and equipment 3-5 2,893 2,002 Property and equipment—at cost 5,745 4,650 Less accumulated depreciation and amortization (3,559 ) (2,851 ) Construction in progress 1,195 583 Property and equipment—net $ 3,381 $ 2,382 Depreciation expense was $0.7 million and $0.9 million for the years ended December Year Ended December 31,   2023     2022   Cost of revenue $ 367 $ 568 Research and development 179 90 General and administrative 138 160 Sales and marketing 62 57 Total depreciation and amortization expense $ 746 $ 875

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Accrued Liabilities and Other Liabilities [Abstract]
Accrued Expenses and Other Current Liabilities	7. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Marketing reimbursement $ 930 $ 2,834 Accrued compensation 1,733 1,687 Accrued clinical trials and R&D 81 3,694 Accrued selling and marketing 592 1,110 Accrued professional fees 493 1,505 Accrued warranty 16 44 Accrued restructuring —  655 Other accrued expenses 4,128 3,966 Total accrued expenses and other current liabilities $ 7,973 $ 15,495 In connection with strategic initiatives implemented during the year ended December 31, 2023, the Company’s management approved and initiated plans to reduce its cost structure. During the nine months ended September 30, 2024, the Company recorded less than $0.1 million in restructuring charges and paid $0.7 million in restructuring charges. No restructuring charges were incurred or paid during the three months ended September 30, 2024.	7. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2023 2022 Distributor fees and marketing reimbursements $ 2,834 $ 6,348 Accrued compensation 1,687 3,453 Accrued clinical trials and R&D 3,694 228 Accrued selling and marketing 1,110 481 Accrued professional fees 1,505 2,105 Accrued interest —  489 Accrued warranty 44 48 Accrued restructuring 655 —  Other accrued expenses 3,966 2,641 Total accrued expenses and other current liabilities $ 15,495 $ 15,793 In connection with strategic initiatives implemented during the period ended December 31, 2023, the Company’s management approved and initiated plans to reduce its cost structure. The Company recorded $1.0 million of restructuring charges during the year ended December 31, 2023, of which $0.4 million has been paid as of December 31, 2023. The restructuring charges are included in operating expenses in the statement of operations. Substantially all of this charge represents the severance cost of terminated employees.

Debt

Debt	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	8. Debt The components of the Company’s third-party debt consist of the following (in thousands): September 30, December 31, Fortress Term Loan $ —  $ 43,100 RTW Convertible Notes 49,320 —  Total principal amount of debt 49,320 43,100 Change in fair value (13,230 ) —  Plus: Accretion —  148 Less: current portion of long-term debt, net of discounts —  (38,643 ) Less: unamortized deferred financing costs and debt discounts —  (4,605 ) Long-term debt, net of current portion and discounts $ 36,090 $ —  As of December 31, 2023, the fair value for the Company’s Fortress Term Loan approximated the carrying amount. Term Loans 2021 Term Loan In March 2021, the Company entered into a loan and security agreement (as amended, the “2021 Term Loan” and the “2021 Term Loan Agreement”) with Runway Growth Credit Fund, Inc. (“Runway”) that provided for borrowings up to $25.0 million. In December 2021, the 2021 Term Loan Agreement was amended (the “Amendment”) to extend the maturity date of the 2021 Term Loan to December 30, 2025 and provide for an additional $20.0 million of borrowings. In December 2021, the Company issued warrants exercisable for 132,979 shares of Legacy Allurion Series C preferred stock as consideration for the Amendment and the draw down related to the 2021 Term Loan Agreement. The fair value of these warrants was determined to be $0.3 million upon issuance and are classified as a warrant liability on the condensed consolidated balance sheet as of September 30, 2024 and December 31, 2023 (see Note 10, Fair Value Measurements 5,203 shares of Allurion Common Stock. In June 2022, the 2021 Term Loan Agreement was amended to revise definitional terms for certain milestone events, the final payment amount and certain financial covenants. In September 2022, the 2021 Term Loan Agreement was further amended to, among other things, increase additional borrowing up to $15.0 million. During June through December of 2022, the Company drew an additional $30.0 million of the 2021 Term Loan and warrants exercisable for 88,440 shares of Series D-1 million upon issuance and are classified as a warrant liability on the consolidated balance sheets as of September 30, 2024 and December 31, 2023 (see Note 10, Fair Value Measurements D-1 On August 1, 2023, the 2021 Term Loan was paid off using the proceeds from the Fortress Term Loan (see below). The total payoff amount was $58.0 million, consisting of $55.0 million repayment of principal, a $1.1 million prepayment fee, and a $1.6 million final payment fee. The prepayment fee was calculated as 2% of the outstanding principal balance as of August 1, 2023. The final payment fee was calculated as the 3% of the outstanding principal balance as of August 1, 2023 less the original final payment of $0.1 million. The Company recorded a $3.9 million loss on extinguishment of debt in connection with the 2021 Term Loan repayment. Interest expense for the three months ended September 30, 2023 related to the 2021 Term Loan was $0.8 million, consisting of $0.7 million of contractual interest, and $0.1 million of amortization of the debt discount, amortization of warrant, and term loan accretion. Interest expense for the nine months ended September 30, 2023 related to the 2021 Term Loan was $5.0 million, consisting of $4.7 million of contractual interest, $0.1 million amortization of the debt discount, $0.1 million of amortization of the warrant, and $0.1 million of term loan accretion. Fortress Term Loan On August 1, 2023, the Company entered into the Fortress Term Loan pursuant to the Fortress Credit Agreement with Fortress that provided gross proceeds of $60 million. The Fortress Term Loan had a maturity date of June 30, 2027 and accrued interest per annum at a rate of 6.44% plus the greater of (i) the Wall Street Journal Prime Rate and (ii) 3.0%, which interest was payable in arrears on a monthly basis. The Fortress Term Loan provided for an exit payment equal to 3.0% of the Fortress Term Loan (the “Exit Fee”) due upon prepayment or the maturity date of the Fortress Term Loan, in addition to any early prepayment fee. The Exit Fee is treated as additional interest expense and is accreted over the life of the loan using the effective interest method. Proceeds of the Fortress Term Loan were used, in part, to repay all amounts outstanding under the 2021 Term Loan. In connection with the issuance of the Fortress Term Loan, the Company paid issuance costs of $2.5 million, which were recorded as a debt discount and will be amortized over the remaining life of the loan. On December 29, 2023, the Company entered into an amendment to the Fortress Credit Agreement (the “Fortress Amendment”). The Fortress Amendment waived the December 31, 2023 minimum revenue covenant under the Fortress Credit Agreement and modified the minimum liquidity covenant by increasing the minimum liquidity amount from $12.5 million to $33.5 million until March 31, 2024, $23.5 million from April 1, 2024 to June 30, 2024, $16.9 million from July 1, 2024 to September 30, 2024 and $12.5 million on October 1, 2024 and thereafter. The Fortress Amendment also provided that at any time after March 31, 2024, each lender had the right to convert a portion of the outstanding principal amount, not to exceed the lender’s proportionate share of a maximum of $20.0 million in aggregate outstanding principal amount, into shares of Allurion Common Stock at a conversion price based on the 30-day paid-in-kind Debt The Company assessed the terms and features of the Fortress Credit Agreement in order to identify any potential embedded features that would require bifurcation or any beneficial conversion features. The terms and features assessed include, under certain circumstances, a default interest rate of 3% that will apply to all outstanding obligations during the occurrence and continuance of an event of default. In accordance with ASC 815, Derivatives and Hedging re-measured fair valued to zero in connection with the repayment of the Fortress Term Loan, with a corresponding $2.0 million gain recorded in other income, net On April 16, 2024, the Company repaid all outstanding obligations under the Fortress Term Loan with proceeds from the Amended Note Purchase Agreement (as defined below) with RTW. The total payoff amount was $48.0 million, consisting of $43.1 million repayment of principal, a $2.7 million prepayment fee, a $1.3 million exit fee, $0.6 million of other fees paid directly to Fortress, and $0.3 million of accrued interest. The Company recorded an $8.7 million loss on extinguishment of debt in connection with the Fortress Term Loan repayment in the condensed consolidated statement of operations for nine months ended September 30, 2024. Interest expense for the three and nine months ended September 30, 2023 related to the Fortress Term Loan was $1.7 million, consisting of $1.5 million of contractual interest, $0.1 million amortization of the debt discount, and term loan accretion of $0.1 million. The average interest rate during the three months ended September 30, 2023 was 14.94%. Interest expense for the nine months ended September 30, 2024 related to the Fortress Term Loan was $2.3 million, consisting of $1.9 million of contractual interest, $0.3 million amortization of the debt discount, and term loan accretion of $0.1 million. There was no interest expense for the three months ended September 30, 2024 due to the extinguishment of the Fortress Term Loan on April 16, 2024. The average interest rate through April 16, 2024 was 14.94%. Convertible Notes 2021 Convertible Notes In December 2021, the Company entered into a convertible note agreement with investors for gross proceeds of $2.0 million with a stated interest rate of 5.0% per annum (the “2021 Convertible Notes”) and a maturity date 36 months from the date of issuance unless previously converted pursuant to their terms of the agreement. No issuance costs were incurred. The 2021 Convertible Notes provided that, effective upon either a Special Purpose Acquisition Company (i.e. “deSPAC”) transaction, closing of a qualified financing, or closing of a non-qualified Interest expense for each of the three and nine months ended September 30, 2023 related to the 2021 Convertible Notes was less than $0.1 million and $0.1 million, respectively, consisting entirely of contractual interest. Interest expense related to the 2021 Convertible Notes is recorded within Interest expense on the condensed consolidated statement of operations. On August 1, 2023, in connection with the closing of the Business Combination and after giving effect to the Reverse Stock Split, the outstanding 2021 Convertible Notes were converted into an aggregate 2022 Convertible Notes In January 2022, the Company entered into a convertible note purchase agreement with investors for gross proceeds of $1.1 million with a stated interest rate of 5.0% per annum (the “2022 Convertible Notes”). The 2022 Convertible Notes were to mature 36 months from the issuance date unless previously converted pursuant to the terms of the agreement. Issuance costs were de minimis. The 2022 Convertible Notes had the same terms as the 2021 Convertible Notes. Interest expense for each of the three and nine months ended September 30, 2023 related to the 2022 Convertible Notes was less than $0.1 million, consisting entirely of contractual interest. Interest expense related to the 2022 Convertible Notes is recorded within Interest expense on the condensed consolidated statement of operations. On August 1, 2023, in connection with the closing of the Business Combination and after giving effect to the Reverse Stock Split, the outstanding 2022 Convertible Notes were converted into an aggregate 3,329 shares of Allurion Common Stock with a corresponding recognition of APIC of $1.2 million, and are no longer outstanding. 2023 Convertible Notes Between February and August 2023, the Company entered into a convertible note purchase agreement, and related side letters, for the sale of convertible notes (the “2023 Convertible Notes”) to certain investors for gross proceeds of $28.7 million, with a stated interest rate of 7.0% per annum. The 2023 Convertible Notes provided that they would mature on December 31, 2026 unless previously converted pursuant to the terms of the note purchase agreement. The 2023 Convertible Notes also provided that, effective upon a deSPAC transaction, all of the outstanding principal and interest would automatically convert into a number of shares of Legacy Allurion common stock equal to the balance of the 2023 Convertible Notes on the date of conversion divided by the discounted capped conversion price, which is calculated by dividing $217.3 million by the fully diluted capitalization of the Company immediately prior to the conversion of the 2023 Convertible Notes. Additionally, the 2023 Convertible Notes provided that, effective upon the closing of a qualified financing, holders of the 2023 Convertible Notes could optionally accelerate repayment of the principal and interest of the 2023 Convertible Notes or convert all of the outstanding principal and interest into shares of Legacy Allurion common stock or shares of the same class or series of capital stock issued in the qualified financing equal to the balance of the 2023 Convertible Notes on the date of conversion divided by the greater of the capped price or the discounted price. The capped price is calculated by dividing $260.0 million by the fully diluted capitalization of the Company immediately prior to the conversion of the 2023 Convertible Notes, and the discounted price is calculated as 85% of the cash price of the same class or series of capital stock issued in the qualified financing. The 2023 Convertible Notes are accounted for under the fair FVO election of ASC 825 as the notes contain embedded derivatives, including the automatic conversion upon a deSPAC transaction prior to the deSPAC deadline, voluntary conversion upon a qualified financing, automatic repayment upon a sale event, and conversion rate adjustment, which would require bifurcation and separate accounting. These convertible notes are initially measured at their issue-date estimated fair value and subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. Interest expense for each of the three and nine months ended September 30, 2023 related to the 2023 Convertible Notes was $0.1 million and $0.5 million, respectively, consisting entirely of contractual interest. Interest expense related to the 2023 Convertible Notes is recorded within Interest expense on the condensed consolidated statement of operations. On May 2, 2023 the Company entered into termination agreements (the “Termination Agreements”) with respect to side letters entered into with certain holders of the 2023 Convertible Notes. With respect to the Termination Agreement with HVL, the Company had the right to prepay, in one or more transactions, all or a portion of the outstanding principal amount, plus accrued interest, under such holder’s 2023 Convertible Note (the “HVL Bridge Note”), including by way of (a) a $2 million payment in cash by the Company to HVL on May 2, 2023, $1.5 million of which was deemed a prepayment penalty and recorded as other expense on the income statement, with the remaining $0.5 million recorded as a reduction of the principal amount, (b) immediately prior to the consummation of the transactions contemplated by the Business Combination Agreement, an additional payment of at least $6 million, up to the then-outstanding principal amount, plus accrued interest, under the HVL Bridge Note by way of (i) payment in cash by the Company and/or (ii) the sale and transfer of all or any portion of the HVL Bridge Note, equivalent in value to the portion of the additional payment to be repaid pursuant to this clause (b)(ii), to any person or persons designated in writing by the Company. The Termination Agreements were accounted for as a modification of debt and the modified convertible notes continued to be accounted for under the FVO with any change in fair value recognized in other expense on the income statement. In addition, under the Termination Agreement executed with HVL, the Company agreed to issue to HVL a number of shares of Allurion Common Stock (“PubCo Additional Shares”) equal to (a) the outstanding principal and accrued interest under the HVL Bridge Note immediately prior to the consummation of the transactions contemplated by the Business Combination Agreement (after giving effect to the payment of the repayments) divided by $125.00, plus (b) 12,000 shares of Allurion Common Stock. The PubCo Additional Shares were accounted for as a freestanding financing liability. The liability for the PubCo Additional Shares was initially measured at its issue-date estimated fair value and subsequently remeasured at fair value at each reporting period, with changes in fair value reflected in earnings until the PubCo Additional Shares were issued. A $3.4 million liability was recorded at issuance for the PubCo Additional Shares as Other liabilities on the balance sheet. On August 1, 2023, upon closing of the Business Combination and after giving effect to the Reverse Stock Split, HVL was issued Further on May 2, 2023, RTW and Fortress as the Backstop Purchasers entered into the Backstop Agreement with the Company, Legacy Allurion and HVL. Pursuant to the Backstop Agreement, each Backstop Purchaser agreed that to the extent any HVL Bridge Notes remained outstanding prior to the consummation of the Business Combination, such Backstop Purchaser would, at the closing of the Business Combination, purchase up to $2.0 million of the HVL Bridge Notes from HVL in exchange for shares of Allurion Common Stock (the “Base PubCo Shares”, “Backstop Shares” and “Conditional Additional PubCo Shares”). The Base PubCo Shares and Backstop Shares were accounted for as a freestanding financing liability. The Base PubCo Shares and Backstop Shares liability was initially measured at its issue-date estimated fair value and subsequently remeasured at fair value at each reporting period with changes in fair value reflected in earnings until the Base PubCo Shares and Backstop Shares were issued. A $3.3 On August 1, 2023, immediately prior to the closing of the Business Combination and after giving effect to the Reverse Stock Split, the Company repaid $ RTW Convertible Notes On April 14, 2024, the Company entered into a note purchase agreement (the “Original Note Purchase Agreement”) with RTW as agent for the purchasers (the “Purchasers”) party thereto from time to time (RTW in such capacity, the “Principal Purchaser”), and Acquiom Agency Services LLC (“Acquiom”) as collateral agent for the Purchasers. Subsequently, on April 16, 2024, the Company, the Principal Purchaser, the Purchasers, and Acquiom entered into the First Amendment to the Original Note Purchase Agreement (the Original Note Purchase Agreement as amended, the “Amended Note Purchase Agreement”). Pursuant to the Amended Note Purchase Agreement, the Company issued and sold $48.0 million of convertible senior secured notes (the “RTW Convertible Notes”). The RTW Convertible Notes bear interest at an annual rate of 6%, which interest is paid quarterly in cash or, at the Company’s option, in kind for the first three years. The RTW Convertible Notes will mature on April 16, 2031 unless previously converted pursuant to the terms of the Amended Note Purchase Agreement. The RTW Convertible Notes are convertible into shares of Allurion Common Stock, at a Purchaser’s election at any time after the earliest of (i) the date on which Stockholder Approval (as defined below) is obtained, (ii) December 31, 2025, (iii) the date of a Fundamental Change Company Notice (as defined in the Amended Note Purchase Agreement), and (iv) the Make-Whole Fundamental Change Effective Date (as defined in the Amended Note Purchase Agreement), subject to certain terms and limitations in the Amended Note Purchase Agreement, based on a conversion rate of 24.6920 shares of common stock per $1,000 principal amount of Notes (equivalent to a conversion price of approximately $40.50 per share, which represents a 35% premium to the lowest price per share in an equity financing for capital raising purposes ending on the date on which the Company has raised aggregate gross offering proceeds of at least $15,000,000 (the “Next Equity Financing”). On July 1, 2024, we consummated the Public Offering, as described elsewhere in this Quarterly Report on Form 10-Q, The RTW Convertible Notes are accounted for under the FVO election of ASC 825 as the notes contain embedded derivatives, including the conversion upon Stockholder Approval, the conversion upon a Fundamental Change Company Notice, the conversion upon a Make-Whole Fundamental Change, redemption upon the event of default, and redemption upon a Fundamental Change, which would require bifurcation and separate accounting. The RTW Convertible Notes were initially measured at their issue-date estimated fair value and subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. The fair value of the RTW Convertible Notes at issuance was $49.1 million, with a corresponding $1.1 million loss recognized in Other income, net in the condensed consolidated statement of operations. In connection with the issuance of the RTW Convertible Notes and RIFA Amendment (as defined below), we incurred $1.4 million in issuance costs, which were directly expensed through general and administrative expense due to the FVO election of the RTW Convertible Notes and Revenue Interest Financing. For the three months ended September 30, 2024, the Company recorded gains of $1.8 million and $3.1 million through the condensed consolidated statements of operations and other comprehensive income (loss), respectively. For the nine months ended September 30, 2024, the Company recorded gains of $10.0 million and $3.0 million through the condensed consolidated statements of operations and other comprehensive income (loss), respectively. The Amended Note Purchase Agreement contains financial maintenance covenants, which require (i) the Company maintain not less than $12,500,000 in unrestricted cash in controlled accounts in the U.S. at all times, (ii) the Company to receive minimum trailing twelve-month consolidated revenue at amounts designated in the Amended Note Purchase Agreement, tested quarterly beginning with the twelve-month period ending March 31, 2025, and (iii) the Company’s and its subsidiaries’ consolidated business operations outside the United States to be profitable for the trailing three-month period, tested quarterly beginning with the three-month period ending December 31, 2025. The Company is in compliance with the covenants in the Amended Note Purchase Agreement as of September 30, 2024. The Company elected paid in kind interest for the three and nine months ended September 30, 2024 related to the RTW Convertible Notes.	8. Debt The components of the Company’s third-party debt consisted of the following (in thousands): December 31, 2023 2022 Fortress Term Loan $ 43,100 $ —  2021 Term Loan —  55,000 Convertible Notes —  3,103 Total principal amounts of debt 43,100 58,103 Plus: Accretion 148 213 Less: current portion of long-term debt, net of discounts (38,643 ) (53,360 ) Less: unamortized deferred financing costs and debt discounts (4,605 ) (1,853 ) Long-term debt, net of current portion and discounts $ —  $ 3,103 As of December 31, 2023 and 2022, the fair value for the Company’s Fortress Term Loan and 2021 Term Loan approximated the respective carrying amounts. Term Loans 2021 Term Loan In March 2021, the Company entered into a loan and security agreement (as amended, the “2021 Term Loan” and the “2021 Term Loan Agreement”) with Runway Growth Credit Fund, Inc. (“Runway”) that provided initial cash proceeds of $15.0 million, all of which was drawn down in March 2021 and provided for additional borrowings of up to $10.0 million, in $5.0 million increments, based upon the achievement of certain revenue thresholds within specified time periods, as defined in the 2021 Term Loan Agreement. In December 2021, the 2021 Term Loan Agreement was amended (the “Amendment”) to extend the maturity date of the 2021 Term Loan to December 30, 2025 and provide for an additional $20.0 million of borrowings, of which $15.0 million (the “Term C Loan”) was available based upon the achievement of certain revenue thresholds within specified time periods as defined in 2021 Term Loan Agreement as amended. The agreement provided for equal monthly principal payments to commence on December 30, 2024 such that the borrowed principal amounts would be repaid in full on December 30, 2025. However, if certain revenue thresholds were achieved prior to April 15, 2023, the borrowed principal amounts would be repaid in full on December 30, 2025. The revenue thresholds were achieved in June 2022. In connection with the 2021 Term Loan, the Company paid issuance costs of $0.7 million which were amortized over the remaining life of the loan. In December 2021, the Company issued warrants exercisable for 132,979 shares of Legacy Allurion Series C preferred stock as consideration for the Amendment and the draw down related to the 2021 Term Loan Agreement. The fair value of these warrants was determined to be $0.3 million upon issuance and are classified as a warrant liability on the consolidated balance sheet as of December 31, 2023 and 2022 (see Note 10, Fair Value Measurements shares of Allurion Common Stock. In June 2022, the 2021 Term Loan Agreement was amended to revise definitional terms for certain milestone events, the final payment amount and financial covenant. In September 2022, the 2021 Term Loan Agreement was further amended to, among other things: (1) change the interest rate to the higher of the prime rate or 3.25% plus During June through September of 2022, the Company drew an additional $15.0 million of the Term C Loan based upon the achievement of certain revenue thresholds under the amended and restated provisions of the 2021 Term Loan. In connection with the Term C Loan under the 2021 Term Loan, the Company paid issuance costs of $0.3 million, which were amortized over the remaining life of the loan. Upon the additional $15.0 million draw on the Term C Loan, warrants exercisable for 44,220 shares of Series D-1 D-1 million upon issuance and are classified as a warrant liability on the consolidated balance sheets as of December 31, 2023 and 2022 (see Note 10, Fair Value Measurements 88,440 shares of Series D-1 During October through December of 2022, the Company drew an additional $15.0 million of the Term D Loan based upon the achievement of certain revenue thresholds under the amended and restated provisions of the 2021 Term Loan. On August 1, 2023, the 2021 Term Loan was paid off using the proceeds from the Fortress Term Loan (see below). The total payoff amount was $58.0 million, consisting of $55.0 million repayment of principal, a $1.1 million prepayment fee, and a $1.6 million final payment fee. The prepayment fee was calculated as 2% of the outstanding principal balance as of August 1, 2023. The final payment fee was calculated as 3% of the outstanding principal balance as of August 1, 2023 less the original final payment of $0.1 million. The Company recorded a $3.9 million loss on extinguishment of debt in connection with the 2021 Term Loan repayment. Interest expense for the year ended December 31, 2023 related to the 2021 Term Loan was $5.0 million, consisting of $4.7 million of contractual interest, $0.1 million amortization of debt discount, $0.1 million amortization 2022 was $4.3 million, consisting of $3.8 million of contractual interest, $0.2 million amortization of debt discount, $0.1 million amortization of warrant, and $0.2 million term loan accretion.  Fortress Term Loan On August 1, 2023, the Company entered into the Fortress Term Loan pursuant to the Fortress Credit Agreement with Fortress that provided gross proceeds of $60 million. The Fortress Term Loan has a maturity date of June 30, 2027 and accrues interest per annum at a rate of 6.44% plus the greater of (i) the Wall Street Journal Prime Rate and (ii) 3.0%, which interest is payable in arrears on a monthly basis. An exit payment equal to 3.0% of the Fortress Term Loan (the “Exit Fee”) is due upon prepayment or the maturity date of the Fortress Term Loan, in addition to any early prepayment fee. The Exit Fee is treated as additional interest expense and is accreted over the life of the loan using the effective interest method. Proceeds of the Fortress Term Loan were used, in part, to repay all amounts outstanding under the 2021 Term Loan. In connection with the issuance of the Fortress Term Loan, the Company paid issuance costs of $2.5 million, which were recorded as a debt discount and will be amortized over the remaining life of the loan. On December 29, 2023, the Company entered into an amendment to the Fortress Credit Agreement (the “Fortress Amendment”). The Fortress Amendment waived the December 31, 2023 minimum revenue covenant under the Fortress Credit Agreement and modified the minimum liquidity covenant by increasing the minimum liquidity amount from $12.5 million to $33.5 million until March 31, 2024, $23.5 million from April 1, 2024 to June 30, 2024, $16.9 million from July 1, 2024 to September 30, 2024 and $12.5 million on October 1, 2024 and thereafter. The Fortress Amendment also provides that at any time after March 31, 2024, each lender will have the right to convert a portion of the outstanding principal amount, not to exceed the lender’s proportionate share of a maximum of $20.0 million in aggregate outstanding principal amount, into shares of Common Stock of the Company at a conversion price based on the 30-day paid-in-kind The Fortress Credit Agreement contains certain financial reporting and other covenants, including the maintenance of a minimum liquidity amount and maintenance of minimum product revenues over trailing twelve-month periods. Upon the occurrence of an event of default, the Lenders may declare all outstanding obligations immediately due and payable as well as increase the interest rate 3.0% above the rate that is otherwise applicable. The Company has determined that there is substantial doubt about the Company’s ability to continue as a going concern (see Note 1, Organization and Basis of Presentation The Company assessed the terms and features of the Fortress Credit Agreement in order to identify any potential embedded features that would require bifurcation or any beneficial conversion features. The terms and features assessed include, under certain circumstances, a default interest rate of 3% which will apply to all outstanding obligations during the occurrence and continuance of an event of default. In accordance with ASC 815, the Company concluded that this feature is not clearly and closely related to the host instrument and represents an embedded derivative (the “Term Loan Derivative Liability”) that is required to be re-remeasured derivative was determined to be immaterial. The fair value of the Term Loan Derivative Liability was $1.9 million as of December 31, 2023, with a corresponding recognition of Other income (expense), net in the consolidated statement of operations. The Company classified the Term Loan Derivative Liability as a non-current Interest expense from August 1, 2023 through December 31, 2023 related to the Fortress Term Loan was $4.1 million Scheduled future maturities of the Fortress Term Loan for years subsequent to December 31, 2023 are as follows (in thousands): December 31, 2024 —  December 31, 2025 —  December 31, 2026 8,979 December 31, 2027 34,121 $ 43,100 Convertible Notes 2021 Convertible Notes In December 2021, the Company entered into a convertible note agreement with an investor for gross proceeds of $2.0 million with a stated interest rate of 5.0% per annum (the “2021 Convertible Notes”) and a maturity date 36 months from the date of issuance unless previously converted pursuant to their terms of the agreement. No issuance costs were incurred. The 2021 Convertible Notes provided that, effective upon either a Special Purpose Acquisition Company (i.e. “deSPAC”) transaction, closing of a qualified financing, or closing of a non-qualified Interest expense for the years ended December 31, 2023 and 2022 related to the 2021 Convertible Notes was $0.1 million, consisting entirely of contractual interest. Interest expense related to the 2021 Convertible Notes is recorded within Interest expense on the consolidated statement of operations and comprehensive loss. On August 1, 2023, in connection with the closing of the Business Combination, and after giving effect to the Reverse Stock Split, the outstanding 2021 Convertible Notes were converted into an aggregate 2022 Convertible Notes In January 2022, the Company entered into a convertible note agreement with investors for gross proceeds of $1.1 million with a stated interest rate of 5.0% per annum (the “2022 Convertible Notes”). The 2022 Convertible Notes mature 36 months from the issuance date unless previously converted pursuant to their terms of the agreement. Issuance costs were de minimis. The 2022 Convertible Notes had the same terms as the 2021 Convertible notes. Interest expense for the years ended December 31, 2023 and 2022 related to the 2022 Convertible Notes was less than $0.1 million and $0.2 million, respectively, consisting entirely of contractual interest. Interest expense related to the 2022 Convertible Notes is recorded within Interest expense on the consolidated statement of operations and comprehensive loss. On August 1, 2023, in connection with the closing of the Business Combination, and after giving effect to the Reverse Stock Split, the outstanding 2022 Convertible Notes were converted into an aggregate 2023 Convertible Notes Between February and August 2023, the Company entered into a convertible note purchase agreement, and related side letters, for the sale of the 2023 Convertible Notes to certain investors for gross proceeds of $28.7 million, with a stated interest rate of 7.0% per annum. The 2023 Convertible Notes provided that they would mature on December 31, 2026 unless previously converted pursuant to the terms of their agreement. The 2023 Convertible Notes also provided that, effective upon a deSPAC transaction, all of the outstanding principal and interest would automatically convert into a number of shares of common stock equal to the balance of the 2023 Convertible Notes on the date of conversion divided by the discounted capped conversion price, which is calculated by dividing $217.3 million by the fully diluted capitalization of the Company immediately prior to the conversion of the 2023 Convertible Notes. Additionally, the 2023 Convertible Notes provide that, effective upon the closing of a qualified financing, holders of the 2023 Convertible Notes could optionally accelerate repayment of the principal and interest of the 2023 Convertible Notes or convert all of the outstanding principal and interest into common shares or shares of the same class or series of capital stock issued in the qualified financing equal to the balance of the 2023 Convertible Notes on the date of conversion divided by the greater of the capped price or the discounted price. The capped price is calculated by dividing $260.0 million by the fully diluted capitalization of the Company immediately prior to the conversion of the 2023 Convertible Notes, and the discounted price is calculated as 85% of the cash price of the same class or series of capital stock issued in the qualified financing. The 2023 Convertible Notes are accounted for under the FVO election of ASC 825 as the notes contain embedded derivatives including the automatic conversion upon a deSPAC transaction prior to the deSPAC deadline, voluntary conversion upon a qualified financing, automatic repayment upon a sale event, and conversion rate adjustment, which would require bifurcation and separate accounting. These convertible notes are initially measured at their issue-date estimated fair value and subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. Interest expense for the year ended December 31, 2023 related to the 2023 Convertible Notes was $0.5 million, consisting entirely of contractual interest. Interest expense related to the 2023 Convertible Notes is recorded within Interest expense on the consolidated statement of operations and comprehensive loss. On May 2, 2023 the Company entered into termination agreements (the “Termination Agreements”) with respect to side letters entered into with certain holders of Legacy Allurion Convertible Notes. With respect to the Termination Agreement with one of the side letter holders (the “Side Letter Holder”), the Company had the right to prepay, in one or more transactions, all or a portion of the outstanding principal amount, plus accrued interest, under the 2023 Convertible Note (the “Side Letter Holder Bridge Note”), including by way of (a) a $2 million payment in cash by the Company to the Side Letter Holder on May 2, 2023, $1.5 million of which is deemed a prepayment penalty and recorded as other expense on the income statement, with the remaining $0.5 million recorded as a reduction of the principal amount, (b) immediately prior to the consummation of the transactions contemplated by the Business Combination Agreement, an additional payment of at least $6 million, up to the then-outstanding principal amount, plus accrued interest, under the Side Letter Holder Bridge Note by way of (i) payment in cash by the Company and/or (ii) the sale and transfer of all or any portion of the Side Letter Holder Bridge Note, equivalent in value to the portion of the additional payment to be repaid pursuant to this clause (b)(ii), to any person or persons designated in writing by the Company. The Termination Agreements were accounted for as a modification of debt and the modified convertible notes continued to be accounted for under the FVO with any change in fair value recognized in other expense on the income statement. In addition, under the Termination Agreement executed with the Side Letter Holder, the Company agreed to issue to the Side Letter Holder a number of shares of Allurion Common Stock (“PubCo Additional Shares”) equal to (a) the outstanding principal and accrued interest under the Side Letter Holder Bridge Note immediately prior to the consummation of the transactions contemplated by the Business Combination Agreement (after giving effect to the payment of the repayments) divided by $125.00, plus (b) 12,000 shares of Allurion Common Stock. The PubCo Additional Shares were accounted for as a freestanding financing liability. The liability for the PubCo Additional Shares is initially measured at its issue-date estimated fair value and subsequently remeasured at fair value at each reporting period with changes in fair value reflected in earnings until the PubCo Additional Shares are issued. A $3.4 million liability was recorded at issuance for the PubCo Additional Shares as Other liabilities on the consolidated balance sheet and the related expense recorded through Other income (expense) on the consolidated statement of operations and comprehensive loss for the year ended December 31, 2023. On August 1, 2023, upon closing of the Business Combination and after giving effect to the Reverse Stock Split, the Side Letter Holder was issued Further on May 2, 2023, RTW and Fortress (the “Backstop Purchasers”) entered into the Backstop Agreement with the Company, Legacy Allurion and the Side Letter Holder. Pursuant to the Backstop Agreement, each Backstop Purchaser agreed that to the extent any Side Letter Holder Bridge Notes remain outstanding prior to the consummation of the Business Combination, such Backstop Purchaser will, at the closing of the Business Combination, purchase up to $2.0 million of the Side Letter Holder Bridge Notes from the Side Letter Holder in exchange for shares of Allurion Common Stock (the “Base PubCo Shares”, “Backstop Shares” and “Conditional Additional PubCo Shares”). The Base PubCo Shares and Backstop Shares were accounted for as a freestanding financing liability. The Base PubCo Shares and Backstop Shares liability is initially measured at its issue-date estimated fair value and subsequently remeasured at fair value at each reporting period with changes in fair value reflected in earnings until the Base PubCo Shares and Backstop Shares are issued. A $3.3 million liability was recorded at issuance for the Base PubCo Shares and Backstop Shares liability as Other liabilities on the consolidated balance sheet. On August 1, 2023, upon closing of the Business Combination and after giving effect to the Reverse Stock Split, per the terms of the Fortress Term Loan, the Amended and Restated RTW Side Letter and the Backstop Agreement, the Backstop Purchasers were each issued On August 1, 2023, immediately prior to the closing of the Business Combination and after giving effect to the Reverse Stock Split, the Company repaid $

Revenue Interest Financing, Sid

Revenue Interest Financing, Side Letter, and PIPE Conversion Option	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Contract with Customer, Liability [Abstract]
Revenue Interest Financing, Side Letter, and PIPE Conversion Option	9. Revenue Interest Financing, Side Letter, and PIPE Conversion Option On February 9, 2023, Legacy Allurion entered into the Revenue Interest Financing Agreement. Pursuant to the Revenue Interest Financing, at the closing of the Business Combination, RTW paid Allurion an aggregate of $40.0 million Investment Amount. In exchange for the Investment Amount, Allurion will remit revenue interest payments on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries at a rate up to 6.0% of annual net sales prior to December 31, 2026. On or after January 1, 2027, the Company will remit revenue interest payments at a rate up to 10.0% of annual net sales, and it will continue to make revenue interest payments to RTW until December 31, 2030. If RTW has not received aggregate revenue interest payments equal to at least 100% of the Investment Amount by December 31, 2027, the Company must make a cash payment in an amount sufficient to catch RTW up to 100% of the Investment Amount. If RTW has not received revenue interest payments equal to at least 240% of the Investment Amount by December 31, 2030, the Company must make a cash payment in an amount sufficient to catch RTW up to 240% of the Investment Amount. In any event, RTW shall not receive aggregated revenue interest payments in excess of 260% of the Investment Amount (the “Hard Cap”). In addition, prior to December 31, 2025, the Company may prepay a pre-specified The Revenue Interest Financing is accounted for under the FVO election of ASC 825 as the Revenue Interest Financing contains embedded derivatives, including the requirements to settle the Revenue Interest Financing prior to maturity upon the occurrence of certain contingent events and our ability to prepay the Revenue Interest Financing, which would require bifurcation and separate accounting. The Revenue Interest Financing was initially measured at its issue-date estimated fair value and subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. Changes in fair value are recorded as a component of Other income (expense) in the condensed consolidated statements of operations. A portion of the estimated change in fair value must be reported in other comprehensive loss to the extent that it is attributable to instrument-specific credit risk. In connection with the issuance of the Investment Amount, we paid $1.2 million in issuance costs in August 2023, which were directly expensed through general and administrative expense due to the FVO election. As of September 30, 2024, the Company has made $3.6 million in royalty payments to RTW. Refer to Note 10, Fair Value Measurements Concurrently, and in connection with the Amended Note Purchase Agreement, the Revenue Interest Financing Agreement was amended pursuant to the Omnibus Amendment (the “RIFA Amendment”) by and among the Company, Allurion Opco, Allurion Australia Pty Ltd, a proprietary limited company organized under the laws of Australia and a wholly-owned subsidiary of the Company, the Original RIFA Investors (as defined therein) and RTW, on April 14, 2024. The RIFA Amendment, among other things, increased the rate of revenue interest payments to be paid to RTW on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries for net sales less than or equal to $100 million prior to December 31, 2026 from 6% to 12% and increased the rate on net sales in less than or equal to $100 million on or after January 1, 2027 from 10% to 12%. Additionally, the Prepayment Amount was modified such that, prior to March 31, 2026, the Company is entitled to settle the Revenue Interest Financing for a prepayment amount that would allow the investors to yield a 20% internal rate of return. In connection with the Company entering into the Revenue Interest Financing, if, at any time beginning 12 months and ending 24 months following the closing of the Mergers, the VWAP per share of Allurion Common Stock is less than $176.00 for the average of 20 trading days within any 30 trading day period (“Stock Price Drop”); and the absolute value of the percentage decrease of such Stock Price Drop measured from a reference price of $250.00 per share of Allurion Common Stock is greater than the absolute value of the percentage decrease in the VWAP of a comparable publicly traded peer index as defined in the Amended and Restated RTW Side Letter over the same time period, then RTW may elect to convert up to $7.5 million of its initial PIPE Investment into additional revenue interest financing to be added to the Investment Amount by forfeiting a number of shares of Allurion Common Stock acquired in the PIPE Investment. Such additions to the Investment Amount would result in proportional increases to the minimum aggregate revenue interest payments described above. The PIPE Conversion Option is accounted for as a derivative under ASC 815. The PIPE Conversion Option was initially measured at its issue-date estimated fair value of $3.3 million within Other liabilities on the condensed consolidated balance sheets with corresponding recognition of expense at inception as there is no right received by the Company that meets the definition of an asset and the transaction did not involve a distribution or a dividend. The PIPE Conversion Option liability is subsequently remeasured at its estimated fair value on a recurring basis at each reporting period date, with a gain or loss recognized within Other income (expense). The RIFA Amendment was accounted for as a modification with the change in fair value of the PIPE Conversion Option treated as an exchange between the Company and RTW as part of the RIFA Amendment. As such, the Revenue Interest Financing and PIPE Conversion Option were remeasured as of April 16, 2024 just prior to the RIFA Amendment, to $33.0 million and $6.6 million, respectively. The Revenue Interest Financing and PIPE Conversion Option were subsequently remeasured as of April 16, 2024 under the terms of the RIFA Amendment, to $39.0 million and $4.6 million, respectively. As of September 30, 2024, the fair value of the Revenue Interest Financing and PIPE Conversion Option were $38.5 million and $9.9 million, respectively. For the three months ended September 30, 2024, the Company recorded a $6.7 million loss and a $5.8 million gain on the Revenue Interest Financing through the condensed consolidated statements of operations and other comprehensive income (loss), respectively. For the nine months ended September 30, 2024, the Company recorded a $5.4 million loss and a $0.6 million gain on the Revenue Interest Financing through the condensed consolidated statements of operations and other comprehensive income (loss), respectively. The changes in fair value were recorded in the Changes in fair value of Revenue Interest Financing and PIPE Conversion Option in the condensed consolidated statement of operations.	9. Revenue Interest Financing, Side Letter, and PIPE Conversion Option On February 9, 2023, Legacy Allurion entered into the Revenue Interest Financing Agreement. Pursuant to the Revenue Interest Financing, at the closing of the Business Combination, RTW paid Allurion an aggregate of $40.0 million Investment Amount. In exchange for the Investment Amount, Allurion will remit revenue interest payments on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries at a rate up to 6.0% of annual net sales prior to December 31, 2026. On or after January 1 If RTW has not received aggregate revenue interest payments equal to at least 100% of the Investment Amount by December 31, 2027, the Company must make a cash payment in an amount sufficient to catch RTW up to 100% of the Investment Amount. If RTW has not received revenue interest payments equal to at least 240% of the Investment Amount by December 31, 2030, the Company must make a cash payment in an amount sufficient to catch RTW up to 240% of the Investment Amount. In any event, RTW shall not receive aggregated revenue interest payments in excess of 260% of the Investment Amount (the “Hard Cap”). In addition, prior to December 31, 2025, the Company may prepay a pre-specified The Revenue Interest Financing is accounted for under the FVO election of ASC 825 as the Revenue Interest Financing contains embedded derivatives, including the requirements to settle the Revenue Interest Financing prior to maturity upon the occurrence of certain contingent events and our ability to prepay the Revenue Interest Financing, which would require bifurcation and separate Concurrently and in connection with the Revenue Interest Financing and PIPE Subscription Agreement (as discussed in Note 3, Business Combination Debt In connection with the Company entering into the Revenue Interest Financing, if, at any time beginning 12 months and ending 24 months following the closing of the Mergers, the VWAP per share of Allurion Common Stock is less than $176.00 for the average of 20 trading days within any 30 trading day period (“Stock Price Drop”); and the absolute value of the percentage decrease of such Stock Price Drop measured from a reference price of $250.00 per share of Allurion Common Stock is greater than the absolute value of the percentage decrease in the VWAP of a comparable publicly traded peer index as defined in the Amended and Restated RTW Side Letter over the same time period, then RTW may elect to convert up to $7.5 million of its initial PIPE subscription into additional revenue interest financing to be added to the Investment Amount by forfeiting a number of shares of Allurion Common Stock acquired in the PIPE subscription. Such additions to the Investment Amount would result in proportional increases to the minimum aggregate revenue interest payments described above. The PIPE Conversion Option is accounted for as a derivative under ASC 815. The PIPE Conversion Option was initially measured at its issue-date estimated fair value of $3.3 million within Other liabilities on the consolidated balance sheet with corresponding recognition of expense at inception as there is no right received by the Company that meets the definition of an asset and the transaction did not involve a distribution or a dividend. The PIPE Conversion Option liability is subsequently remeasured at its estimated fair value on a recurring basis at each reporting period date, with a gain or loss recognized within Other income The components of the Company’s Revenue Interest Financing consist of the following (in thousands): December 31, Revenue Interest Financing liability $ 40,000 Total principal amounts of debt 40,000 Less: Royalty payments (1,092 ) Less: Change in fair value of debt (2,708 ) Long-term Revenue Interest Financing liability $ 36,200

Fair Value Measurements

Fair Value Measurements	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	10. Fair Value Measurements The following tables present the fair value hierarchy for the Company’s assets and liabilities that are measured at fair value at issuance date and on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value (in thousands): Fair Value Measurement as of September 30, 2024 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 23,749 $ 23,749 $ —  $ —  Total assets $ 23,749 $ 23,749 $ —  $ —  Liabilities: Legacy Allurion Common Stock Warrant Liabilities $ 71 $ —  $ —  $ 71 Public Warrants 531 531 —  —  Public Offering Warrants 5,970 —  —  5,970 Private Placement Warrants 810 —  —  810 Revenue Interest Financing 38,500 —  —  38,500 PIPE Conversion Option 9,850 —  —  9,850 Earn-out 1,850 —  —  1,850 RTW Convertible Notes 36,090 —  —  36,090 Success Fee Derivative Liability 14 —  —  14 Total Liabilities $ 93,686 $ 531 $ —  $ 93,155 Fair Value Measurement as of December 31, 2023 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 30,582 $ 30,582 $ —  $ —  Total assets $ 30,582 $ 30,582 $ —  $ —  Liabilities: Legacy Allurion Common Stock Warrant Liabilities $ 821 $ —  $ —  $ 821 Public Warrants 5,943 5,943 —  —  Revenue Interest Financing 36,200 —  —  36,200 PIPE Conversion Option 5,600 —  —  5,600 Earn-out 23,990 —  —  23,990 Term Loan Derivative Liability 1,895 —  —  1,895 Success Fee Derivative Liability 14 —  —  14 Total Liabilities $ 74,463 $ 5,943 $ —  $ 68,520 Public Warrants As a result of the Business Combination on August 1, 2023, the Company recorded a liability for Public Warrants to purchase the Company’s Common Stock. The Public Warrants are traded on the NYSE and are recorded at fair value using the closing price as September 30, 2024 of $1.00, which is a Level 1 input. Legacy Allurion Warrants, Public Offering Warrants, and Private Placement Warrants The Company has classified the Legacy Allurion Common Stock Warrants, Public Offering Warrants (defined below), and Private Placement Warrants (defined below) within Level 3 of the hierarchy as the fair value is derived using the Black-Scholes option pricing model, which uses a combination of observable (Level 2) and unobservable (Level 3) inputs. See table below for the assumptions used in the pricing model of the Legacy Allurion Common Stock Warrants, Public Offering Warrants, and Private Placement Warrants: Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series C Preferred Stock warrants (as converted to Common) September 30, 2024 3.65 % $ 168.25 $ 15.25 90 % 6.50 Legacy Allurion Other Common Stock September 30, 2024 3.59% 26.25 15.25 90 % 2.94 Legacy Allurion Series D-1 September 30, 2024 3.65% - 303.50 15.25 90 % 6.5 - 7.96 Public Offering Warrants September 30, 2024 3.58% 30.00 15.25 90 % 4.75 Private Placement Warrants September 30, 2024 3.58% 30.00 15.25 90 % 4.75 Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series C Preferred Stock warrants (as converted to Common) December 31, 2023 3.88 % $ 168.25 $ 93.50 100 % 7.25 Legacy Allurion Other Common Stock December 31, 2023 3.95 % 26.25 93.50 100 % 3.69 Legacy Allurion Series D-1 December 31, 2023 3.88 % 303.50 93.50 100 % 7.25 - 8.71 Expected dividend yield for all calculations is 0.00%. The following table reconciles the changes in fair value for the three and nine months ended September 30, 2024 and 2023 of the warrant liabilities valued using Level 3 inputs: Preferred Stock Warrants Common Stock Public Offering Private Placement Total Balance – June 30, 2023 $ 2,679 $ 1,351 —  —  $ 4,030 Change in fair value (1,571 ) (555 ) —  —  (2,126 ) Exercise of warrants (53 ) —  —  —  (53 ) Derecognition of liability to equity (340 ) (589 ) —  —  (929 ) Balance – September 30, 2023 $ 715 $ 207 $ —  $ —  $ 922 Balance – June 30, 2024 $ 110 $ 35 —  —  $ 145 Fair value at issuance —  —  13,157 1,670 14,827 Change in fair value (55 ) (19 ) (7,187 ) (860 ) (8,121 ) Balance – September 30, 2024 $ 55 $ 16 $ 5,970 $ 810 $ 6,851 Preferred Stock Warrants Common Stock Public Offering Private Placement Total Balance – January 1, 2023 $ 1,777 $ 596 $ —  $ —  $ 2,373 Change in fair value (647 ) 200 —  —  (447 ) Exercise of warrants (75 ) —  —  —  (75 ) Derecognition of liability to equity (340 ) (589 ) —  —  (929 ) Balance – September 30, 2023 $ 715 $ 207 $ —  $ —  $ 922 Balance – January 1, 2024 $ 642 $ 179 $ —  $ —  $ 821 Fair value at issuance —  —  —  13,157 1,670 14,827 Change in fair value (587 ) (163 ) (7,187 ) (860 ) (8,797 ) Balance – September 30, 2024 $ 55 $ 16 $ 5,970 $ — $ 810 $ 6,851 2019 Term Loan Success Fee Derivative Liability The derivative liability for the success fee associated with Legacy Allurion’s November 2019 loan and security agreement with Western Alliance Bank (the “2019 Term Loan” and such fee, the “Success Fee”) was recorded at fair value as of September 30, 2024 and December 31, 2023 using the following assumptions: weighted-average probability for the likelihood of a change in control or liquidity event within four years from the initial valuation date of the derivative liability and a market-based discount rate that will increase or decrease each period based on changes in the probability in the future cash flows. 2023 Convertible Notes The 2023 Convertible Notes were accounted for using the FVO election. Under the FVO election, the financial instrument is initially measured at its issue-date estimated fair value and subsequently re-measured Revenue Interest Financing and PIPE Conversion Option The Revenue Interest Financing is accounted for using the FVO election. Under the FVO election, the financial instrument is initially measured at its issue-date estimated fair value and subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. The fair value of the Revenue Interest Financing was remeasured as of September 30, 2024 and December 31, 2023 using a discounted cash flow (“DCF”) method under the income approach utilizing future revenue projections and a discount rate of 23.5% and 24.4%, respectively. The fair value of the PIPE Conversion Option was accounted for as a derivative under ASC 815. The instrument is measured using a Monte Carlo Simulation Method (“MCSM”) using the number of shares convertible of 42,614 and the following assumptions: September 30, December 31, Stock Price $ 15.25 $ 93.50 Risk-free interest rate 4.03 % 4.46 % Expected term (in years) 0.8 1.6 Expected volatility 130.0 % 82.5 % Earn-Out Upon the closing of the Business Combination, the Earn-Out earn-out Earn-Out September 30, December 31, Stock Price $ 15.25 $ 93.50 Risk-free interest rate 3.6 % 3.9 % Expected term (in years) 3.8 4.6 Expected volatility 105.0 % 87.0 % Term Loan Derivative Liability The Term Loan derivative liability associated with the Fortress Term Loan was derecognized during the second quarter of 2024 as the Fortress Term Loan was repaid on April 16, 2024. RTW Convertible Notes The RTW Convertible Notes are accounted for using the FVO election. Under the FVO election, the financial instrument is initially measured at its issue-date estimated fair value and subsequently measured at estimated fair value on a recurring basis at each reporting period date. The fair value of the RTW Convertible Notes was remeasured as of September 30, 2024 using a DCF method under the income approach with a MCSM applied to determine the simulated stock price at each payment date and event that may trigger conversion of the RTW Convertible Notes. The fair value was measured using the $ million principal amount of the RTW Convertible Notes and the following assumptions: September 30, Stock Price $ 15.25 Risk-free interest rate 3.6 % Expected term (in years) 6.5 Expected volatility 90.0 % The changes in the fair values of the Success Fee derivative liability, 2023 Convertible Notes, Revenue Interest Financing, PIPE Conversion Option, Earn-out Success 2023 Revenue PIPE Earn-Out Term RTW PubCo Base Total Balance – June 30, 2023 $ 213 $ 16,793 $ —  $ —  $ —  $ —  $ —  $ 3,327 $ 3,305 $ 23,638 Fair value upon issuance —  9,150 $ 40,000 3,340 53,040 —  —  —  —  $ 105,530 Change in fair value (201 ) 6,008 (3,400 ) 2,100 (24,330 ) —  —  (599 ) 10,065 $ (10,357 ) Repayments of debt —  (10,250 ) —  —  —  —  —  —  —  $ (10,250 ) Derecognition of liability to equity —  (21,701 ) —  —  —  —  —  (2,728 ) (13,370 ) $ (37,799 ) Balance – September 30, 2023 $ 12 $ —  $ 36,600 $ 5,440 $ 28,710 $ —  $ —  $ —  $ —  $ 70,762 Balance – June 30, 2024 $ 14 $ —  $ 39,000 $ 5,450 $ 4,110 $ —  $ 40,950 $ —  $ —  $ 89,524 Change in fair value —  —  6,704 4,400 (2,260 ) —  (1,790 ) —  —  7,054 Change in fair value – OCI —  —  (5,800 ) —  —  —  (3,070 ) —  —  (8,870 ) Repayments of debt —  —  (1,404 ) —  —  —  —  —  —  (1,404 ) Balance – September 30, 2024 $ 14 $ —  $ 38,500 $ 9,850 $ 1,850 $ —  $ 36,090 $ —  $ —  $ 86,304 Balance – January 1, 2023 $ 178 $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ 178 Fair value upon issuance —  28,700 $ 40,000 3,340 53,040 —  —  3,370 3,264 131,714 Change in fair value (166 ) 3,751 (3,400 ) 2,100 (24,330 ) —  —  (642 ) 10,106 (12,581 ) Repayments of debt —  (10,750 ) —  —  —  —  —  —  —  (10,750 ) Derecognition of liability to equity —  (21,701 ) —  —  —  —  —  (2,728 ) (13,370 ) (37,799 ) Balance – September 30, 2023 $ 12 $ —  $ 36,600 $ 5,440 $ 28,710 $ —  $ —  $ —  $ —  $ 70,762 Balance – January 1, 2024 $ 14 $ —  $ 36,200 $ 5,600 $ 23,990 $ 1,895 $ —  $ —  $ —  $ 67,699 Fair value upon issuance —  —  —  —  —  —  49,100 —  —  49,100 Change in fair value —  —  5,358 4,250 (22,140 ) (1,895 ) (10,020 ) —  —  (24,447 ) Change in fair value – OCI —  —  (600 ) —  —  —  (2,990 ) —  —  (3,590 ) Repayments of debt —  —  (2,458 ) —  —  —  —  —  —  (2,458 ) Balance – September 30, 2024 $ 14 $ —  $ 38,500 $ 9,850 $ 1,850 $ —  $ 36,090 $ —  $ —  $ 86,304 The change in fair value of the Success Fee derivative liability, 2023 Convertible Notes, Revenue Interest Financing, PIPE Conversion Option, Earn-Out Other income (expense) in the condensed consolidated statements of operations, with the exception of the changes in fair value associated with the change in credit risk related to the Revenue Interest Financing and RTW Convertible Notes, which is recorded as a component of other comprehensive loss.	10. Fair Value Measurements The following tables present the fair value hierarchy for assets and liabilities that are measured at fair value at issuance date and on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value (in thousands): Fair Value Measurement as of December 31, 2023 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 30,582 $ 30,582 $ —  $ —  Total assets $ 30,582 $ 30,582 $ —  $ —  Liabilities: Legacy Allurion Common Stock Warrant Liabilities $ 821 $ —  $ —  $ 821 Public Warrants 5,943 5,943 —  —  Revenue Interest Financing 36,200 —  —  36,200 PIPE Conversion Option 5,600 —  —  5,600 Earn-out 23,990 —  —  23,990 Term Loan Derivative Liability 1,895 —  —  1,895 Success Fee Derivative Liability 14 —  —  14 Total Liabilities $ 74,463 $ 5,943 $ —  $ 68,520 Fair Value Measurement as of December 31, 2022 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 4,925 $ 4,925 $ —  $ —  Total assets $ 4,925 $ 4,925 $ —  $ —  Liabilities: Legacy Allurion Series C Common Stock Warrant Liability $ 340 $ —  $ —  $ 340 Legacy Allurion Series B Preferred Stock Warrant Liability 303 —  —  303 Legacy Allurion Series A-1 82 —  —  82 Other Common Stock Warrant Liabilities 255 —  —  255 Legacy Allurion Series C Preferred Stock Warrant Liability 684 —  —  684 Derivative Liability—Success Fee 180 —  —  180 Legacy Allurion Series D-1 707 —  —  707 Total Liabilities $ 2,551 $ —  $ —  $ 2,551 Public Warrants As a result of the Business Combination on August 1, 2023, the Company Legacy Allurion Warrants The Company has classified the warrants within Level 3 of the hierarchy as the fair value is derived using Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series C Preferred Stock warrants (as converted to Common) December 31, 2023 3.88 % $ 168.25 $ 93.50 100 % 7.25 Other Common Stock December 31, 2023 3.95 % 26.25 93.50 100 % 3.69 Legacy Allurion Series D-1 December 31, 2023 3.88 % 303.50 93.50 100 % 7.25 8.71 Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series A-1 December 31, 2022 4.42 % 47.50 168.75 69 % 0.25 Legacy Allurion Series B Preferred Stock warrants (as converted to Rollover warrants) December 31, 2022 4.41 % 59.50 172.75 65 % 2.00 Legacy Allurion Series C Common Stock warrants (as converted to Rollover warrants) December 31, 2022 4.11 % 0.25 113.50 63 % 4.00 Legacy Allurion Series C Preferred Stock warrants (as converted to Rollover warrants) December 31, 2022 3.92 % 164.50 181.00 63 % 8.20 Other Common Stock Warrants December 31, 2022 3.99 % 25.50 113.50 63 % 4.6 4.7 Legacy Allurion Series D-1 December 31, 2022 3.88 3.92 % 296.75 282.75 63 % 8.2 9.7 Expected dividend yield for all calculations is 0.00%. The following table reconciles the changes in fair value for the years ended December 31, 2023 and 2022 of the warrant liabilities Preferred Stock Warrants Common Stock Total Balance – January 1, 2022 $ 510 $ 231 $ 741 Fair value upon issuance 834 —  834 Change in fair value 456 365 821 Exercise of warrants (23 ) —  (23 ) Balance – December 31, 2022 $ 1,777 $ 596 $ 2,373 Change in fair value (720 ) 172 (548 ) Exercise of warrants (75 ) —  (75 ) Derecognition of liability to equity (340 ) (589 ) (929 ) Balance – December 31, 2023 $ 642 $ 179 $ 821 2019 Term Loan Success Fee Derivative Liability The derivative liability for the success fee associated with Legacy Allurion’s November 2019 loan and security agreement with Western Alliance Bank (the “2019 Term Loan” and such fee, the “Success Fee”) was recorded at fair value as of December 31, 2023 using the following assumptions: weighted-average probability for the likelihood of a change in control or liquidity event within four years from the initial valuation date of the derivative liability and a market-based discount rate that will increase or decrease each period based on changes in the probability in the future cash flows. 2023 Convertible Notes The 2023 Convertible Notes were accounted for using the FVO election. Under the FVO election, the financial instrument is initially measured at its issue-date estimated fair value and subsequently re-measured PubCo Additional Shares Liability The PubCo Additional Shares liability was initially recorded at fair value as of May 2, 2023 and revalued as of August 1, 2023, just prior to the close of the Business Combination, using the number of shares issued at the close of the Business Combination and after giving effect to the Reverse Stock Split of Base PubCo Shares and Backstop Shares Liability The Base PubCo Shares and Backstop Shares liability was initially recorded at fair value as of May 2, 2023 and revalued as of August 1, 2023, just prior to the close of the Business Combination, using the number of shares for each Backstop Purchaser at the close of the Business Combination and after giving effect to the Reverse Stock Split of Revenue Interest Financing and PIPE Conversion Option The Revenue Interest Financing was accounted for using the FVO election. Under the FVO election, the financial instrument is initially measured at its issue-date estimated fair value and subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. The fair value of the Revenue Interest Financing was remeasured as of December 31, 2023 using a discounted cash flow (“DCF”) method under the income approach utilizing future revenue projections and a discount rate of 24.4%. The fair value of the PIPE Conversion Option was accounted for as a derivative under ASC 815. The instrument is measured using a Monte Carlo Simulation Method using the number of shares convertible of 42,614 and the following assumptions: December 31, Stock Price 93.50 Risk-free interest rate 4.46 % Expected term (in years) 1.6 Expected volatility 82.5 % Earn-Out Upon the closing of the Business Combination, the Earn-Out Common earn-out earn-out December 31, Stock Price 93.50 Risk-free interest rate 3.9 % Expected term (in years) 4.6 Expected volatility 87.0 % Term Loan Derivative Liability The Term Loan Derivative Liability associated with the Fortress Term Loan was recorded at fair value as of December 31, 2023 using a DCF model that includes default interest payments expected to be made based on future revenue projections and cash flow assumptions and a discount rate of 24.4%. The changes in the fair values of the Success Fee derivative liability, 2023 Convertible Notes, PubCo Additional Shares liability, Base PubCo Shares and Backstop Shares liability, Revenue Interest Financing, PIPE Conversion Option, Earn-out Success 2023 PubCo Base Revenue PIPE Earn-Out Term Total Balance – January 1, 2022 $ 159 $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ 159 Fair value upon issuance —  —  —  —  —  —  —  —  —  Change in fair value 19 —  —  —  —  —  —  —  19 Exercise of warrants —  —  —  —  —  —  —  —  —  Balance – December 31, 2022 $ 178 $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ 178 Fair value upon issuance —  $ 28,700 3,370 3,264 40,000 3,340 53,040 1,895 133,609 Change in fair value (164 ) 3,751 (642 ) 10,106 (3,408 ) 2,260 (29,050 ) —  (17,147 ) Change in fair value – OCI —  —  —  —  700 —  —  —  700 Payments —  (10,750 ) —  —  (1,092 ) —  —  —  (11,842 ) Derecognition of liability to equity —  (21,701 ) (2,728 ) (13,370 ) —  —  —  —  (37,799 ) Balance – December 31, 2023 $ 14 $ —  $ —  $ —  $ 36,200 $ 5,600 $ 23,990 $ 1,895 $ 67,699 The change in fair value of the Success Fee derivative liability, 2023 Convertible Notes, PubCo Additional Earn-Out Assets and Liabilities Not Carried at Fair Value The Company’s Fortress term loan is carried at amortized cost. The fair value of the Fortress term loan was estimated to be $43.2 million on December 31, 2023. The fair value was determined using a discounted cash flow approach. We classified the fair value disclosures for the Fortress Term Loan within level 3 of the fair value hierarchy because the fair value is derived using a significant unobservable input, which includes a discount rate.

Income Taxes

Income Taxes	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The Company recorded income tax expense of $0.1 million and $0.2 million for the three and nine months ended September 30, 2024, respectively, representing effective tax rates of (0.8%) and (3.9%), respectively. The Company recorded income tax expense for the three and nine months ended September 30, 2023 of less than $0.1 million and $0.1 million, respectively, representing effective tax rates of (0.2%) and (0.1%), respectively. The tax expense recorded relates to the earnings of the Company’s profitable foreign subsidiaries. As of September 30, 2024 and 2023, the Company maintained a full valuation allowance against its net deferred tax assets as the Company has incurred significant operating losses since inception and has concluded that its net deferred tax asset is not more-likely-than-not As of September 30, 2024 and 2023, the Company has not recorded tax reserves for any uncertain tax provisions.	11. Income Taxes The components of net loss before income taxes are as follows (in thousands): Year Ended December 31,   2023     2022   U.S. $ (81,259 ) $ (38,267 ) Foreign 916 666 Loss before income taxes $ (80,343 ) $ (37,601 ) The reconciliation between the effective tax rate and the statutory federal income tax rate for the years ended D e e m b r Year Ended December 31,   2023     2022   U.S. statutory federal income tax rate 21.0 % 21.0 % State income taxes, net of federal income tax benefit 7.1 % 6.9 % Change in fair value of financial instruments 3.0 % 0.0 % Tax credits 0.4 % 1.0 % Valuation allowance (30.5 )% (29.0 )% Non-deductible (0.9 )% 0.0 % Other (0.4 )% (0.2 )% Effective tax rate (0.3 )% (0.3 )% Significant components of the Company’s deferred tax assets are as follows (in thousands): December 31, 2023 2022 U.S. federal and state net operating loss carryforwards $ 36,092 $ 25,051 Capitalized start-up 10,868 5,377 Research and development tax credits 2,275 1,780 Interest expense 3,918 —  Lease liability 659 838 Depreciation 203 236 Bad debt reserve 3,461 —  Other temporary differences 2,145 994 Total deferred tax assets 59,621 34,276 Valuation allowance (57,985 ) (33,484 ) Net deferred tax assets 1,636 792 Right of use asset (623 ) (792 ) Other deferred tax liability (1,013 ) —  Total deferred tax liabilities (1,636 ) (792 ) Net deferred tax asset $ — $ — The Com pany recorded income tax expense of $ million during the year ended December 31, 2023 due to foreign operating income. The Company recorded $ million of income tax expense during the year ended December 31, 2022. The Company maintains a valuation allowance for the full amount of the net United States deferred tax assets, as the realization of the deferred tax assets is not determined to be more likely than not. The valuation allowance increased for the years ended December 31, 2023 and 2022 by approximately $ million and $ million, respectively, due to an increase in deferred tax assets having a full valuation allowance primarily due to the operating losses incurred, capitalized research and development expenses and tax credits generated. As of December 31, 2023, the Company had $132.2 million and $131.7 million of federal and state NOL carryforwards, respectively. Of the federal NOL carryforwards, $12.8 million expire between 2030 and 2037 and $119.5 million do not expire. The state NOL carryforwards expire between 2030 and 2042. As of December 31, 2023, the Company had $1.5 million and $0.9 million of federal and state research and development tax credits, which expire beginning in 2031 and 2028, respectively. Changes to the Company’s valuation allowance are as follows (in thousands): Year Ended December 31,   2023     2022   Beginning balances $ 33,484 $ 22,579 Additions charged to net loss 24,501 10,905 Ending balances $ 57,985 $ 33,484 Realization of the future tax benefits from these assets is dependent on many factors, including the Company’s ability to generate taxable income within the net operating loss carryforward period. Under the provisions of the Internal Revenue Code, certain substantial changes in the Company’s ownership, including a sale of the Company or significant changes in ownership due to sales of equity, may have limited, or may limit in the future, the amount of net operating loss and research and development credit carryforwards that could be used annually to offset future taxable income. The Company has not completed a study to assess whether a change of control has occurred or whether there have been multiple changes of control since the Company’s formation due to the significant complexity and cost associated with such study and because there could be additional changes in control in the future. As a result, the Company is not able to estimate the effect of the change in control, if any, on the Company’s ability to utilize net operating loss and research and development credit carryforwards in the future. The Company is subject to US federal income tax, state income tax in Massachusetts, and income tax in certain foreign jurisdictions. The Company’s historical income taxes in foreign jurisdictions have been immaterial to the consolidated financial statements. The Company is not currently under examination by the Internal Revenue Service (“IRS”) or any other jurisdictions for any tax years; however, all tax years since inception remain open to examination by the major taxing jurisdictions to which the Company is subject, as carryforward attributes generated in years past may still be adjusted upon examination by the U.S. IRS or other authorities if they have, or will be, used in a future period. As of December 31, 2023 and 2022, the unremitted earnings of the Company’s foreign subsidiaries are immaterial. Interpretive guidance on the accounting for global intangible low-taxed As

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock and Stockholders' Deficit	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Redeemable Convertible Preferred Stock and Stockholders' Deficit	12. Redeemable Convertible Preferred Stock and Stockholders’ Deficit Preferred Equity On June 28, 2024, the Company entered into a subscription agreement (the “Subscription Agreement”) with RTW, pursuant to which the Company agreed to sell to RTW 2,260,159 shares of a newly created series of preferred stock, the Series A non-voting The Private Placement Warrants met the definition of a derivative under ASC 815. The gross proceeds from the Private Placement were first allocated to the Private Placement Warrants based on its issue-date estimated fair value of $1.7 million. The Private Placement Warrants are subsequently remeasured at their estimated fair value on a recurring basis at each reporting period date, with a gain or loss recognized within Other income (expense). The remaining gross proceeds of $1.0 million were allocated to the Series A Preferred Stock. Of the $0.2 million in offering costs, $0.1 million was recorded against the Series A Preferred Stock as a reduction of proceeds and $0.1 million was expensed as general and administrative expenses in the condensed consolidated statement of operations and comprehensive loss. The Allurion Certificate of Incorporation authorizes the issuance of up to 100,000,000 shares of Allurion preferred stock. As of September 30, 2024, 2,260,159 shares of Allurion Series A Preferred Stock were outstanding. The rights and preferences of the Series A Preferred Shares are as follows: Voting Rights The Series A Preferred Stockholders have no voting rights. Dividend Rights The Series A Preferred Stock participates in dividends with Common Stock on an as-converted Liquidation Preference In the event of any voluntary or involuntary liquidation, dissolution, or winding-up Conversion Rights Each share of Series A Preferred Stock is convertible after the date that the Company’s stockholders approve the conversion of the Series A Preferred Stock into shares of Common Stock in accordance with the listing rules of the NYSE (the “Series A Stockholder Approval”). Upon the Series A Stockholder Approval, each share of Series A Preferred Stock then outstanding shall automatically convert into (i) a number of shares of Common Stock equal to the number of Series A Preferred Stock outstanding at the time of conversion, adjustable for certain dilutive events, and (ii) pre-funded Redemption Each share of Series A Preferred Stock outstanding on December 31, 2026 (the “Redemption Date”) shall be automatically redeemed by the Company for cash at a redemption price equal to the volume-weighted average price per share of the Common Stock on the NYSE during the twenty consecutive trading day period ending and including the trading day immediately preceding the Redemption Date (the “Redemption Price”). The Series A Preferred Stock is redeemable at a determinable price (the Redemption Price) on a fixed date (the Redemption Date), which results in mezzanine equity classification (outside of permanent equity) on the Company’s consolidated balance sheet. Common Equity The Allurion Certificate of Incorporation authorizes the issuance of up to 1,000,000,000 shares of Allurion Common Stock. As of September 30, 2024 and December 31, 2023, 2,574,783 and 1,907,529 shares of Common Stock were outstanding, respectively. On June 28, 2024, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Jefferies LLC and TD Securities (USA) LLC, as representative of the several underwriters (the “Underwriters”), pursuant to which the Company agreed to issue and sell 576,261 shares of the Company’s Common Stock and warrants (“Public Offering Warrants”) to purchase up to 576,261 shares of the Company’s Common Stock at an offering price of $30.00 per share and accompanying warrant (the “Public Offering”). The Public Offering closed on July 1, 2024 with net proceeds received of $15.2 million after deducting underwriting discounts of $1.0 million and offering costs of $1.0 million. The Underwriters fully exercised their option for additional Public Offering Warrants, with 86,440 additional Public Offering Warrants issued at closing, for a total of 662,701 Public Offering Warrants. Further, the Underwriters exercised a portion of the option with respect to the Common Stock (the “Share Overallotment”) on July 5, 2024 for net proceeds of $2.2 million, which resulted in the issuance of 77,091 shares of the Company’s Common Stock at an offering price of $30.00 per share. The Public Offering Warrants met the definition of a derivative under ASC 815 and the Share Overallotment met the requirements for equity classification under ASC 815. The $17.4 million in net proceeds from the Public Offering and exercise of the Share Overallotment were first allocated to the Public Offering Warrants The number of shares of Common Stock that have been reserved for issuance upon the potential conversion or exercise, as applicable, of the Company’s securities as of September 30, 2024, is as follows: Outstanding options to purchase Common Stock 284,332 Restricted Stock Units 21,230 Warrants to purchase Common Stock 769,257 Shares of Common Stock issued upon the exercise of Public Warrants 750,383 Series A Preferred Stock 90,407 Earn-Out 360,000 Convertible Notes 19,168 Total 2,294,777 Warrants to Purchase Common Stock In connection with the closing of the Business Combination, all outstanding warrants to purchase Legacy Allurion preferred stock and Legacy Allurion common stock were converted into Rollover Warrants to purchase Allurion Common Stock using the Exchange Ratio. As of September 30, 2024, there were 16,151 Rollover Warrants outstanding to purchase Common Stock. Upon the closing of the Business Combination, certain Legacy Allurion preferred stock and Legacy Allurion common stock warrants that were converted into Rollover Warrants were determined to be equity classified. In connection with the Public Offering and Private Placement, we issued the Public Offering Warrants and Private Placement Warrants. As of September 30, 2024, there were 662,701 Public Offering Warrants and 90,407 Private Placement Warrants outstanding to purchase Common Stock. September 30, 2024 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.2 Common Stock Equity 1,771 $ 61.00 3/30/2021 6.5 Common Stock Liability 5,203 168.25 9/15/2022 8.0 Common Stock Liability 1,810 303.50 6/4/2022 7.7 Common Stock Liability 1,810 303.50 1/17/2017 2.3 Common Stock Equity 2,934 0.50 8/3/2017 2.8 Common Stock Equity 392 28.25 9/8/2017 2.9 Common Stock Liability 1,151 26.25 6/19/2018 3.7 Common Stock Liability 720 26.25 6/25/2019 4.7 Common Stock Liability 360 26.25 7/1/2024 4.8 Common Stock Liability 753,106 30.00 769,257 December 31, 2023 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.9 Common Stock Equity 1,771 $ 61.00 3/30/2021 7.2 Common Stock Liability 5,203 168.25 9/15/2022 8.7 Common Stock Liability 1,810 303.50 6/4/2022 8.4 Common Stock Liability 1,810 303.50 1/17/2017 3.0 Common Stock Equity 2,934 0.50 8/3/2017 3.6 Common Stock Equity 392 28.25 9/8/2017 3.7 Common Stock Liability 1,151 26.25 6/19/2018 4.5 Common Stock Liability 720 26.25 6/25/2019 5.5 Common Stock Liability 360 26.25 16,151 In Compute Health’s initial public offering, it sold units at a price of $10.00 per unit, which consisted of one share of Class A Common Stock, $0.0001 par value, of Compute Health (“Class A Common Stock”) and one-half per share. On July 26, 2023, Compute Health’s Public Warrant holders approved an amendment (the “Warrant Amendment”) to the warrant agreement that governed all Compute Health’s Public Warrants. Per the terms of the Warrant Amendment, upon completion of the Business Combination after giving effect to the Reverse Stock Split, each of the outstanding Compute Health Public Warrants became exercisable for (prior to giving effect to the Reverse Stock Split) Allurion Public Warrants in the Business Combination. The Public Warrants will expire August 1, 2030, seven years after the completion of the Business Combination, or earlier upon redemption or liquidation. The Company may redeem the outstanding Public Warrants for cash at a price of $0.25 per Public Warrant at any time commencing 90 days after the completion of the Business Combination, and provided that the last sales price the Company’s Common Stock equals or exceeds $316.75 per share of any 20 trading days within a 30-day The Company may redeem the outstanding Public Warrants for shares of our Common Stock at a price of $2.50 per Public Warrant at any time commencing 90 days after the completion of the Business Combination, and provided that the last sales price of the Company’s Common Stock equals or exceeds $176.00 per share of any 20 trading days within a 30-day Chardan Equity Facility On December 18, 2023, we entered into a ChEF Purchase Agreement (the “Purchase Agreement”) and a Registration Rights Agreement, each with Chardan Capital Markets (“Chardan”) related to a “ChEF,” Chardan’s committed equity facility (the “Chardan Equity Facility”). Pursuant to the Purchase Agreement, the Company has the right from time to time at its option to sell to Chardan up to the lesser of (i) $100,000,000 in aggregate gross purchase price of newly issued shares of the Company’s Common Stock, and (ii) 379,299 shares of Common Stock, which number of shares is equal to paid-in non-refundable

Capital Stock and Stockholders'

Capital Stock and Stockholders' Deficit	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Capital Stock and Stockholders' Deficit	12. Capital Stock and Stockholders’ Deficit The Allurion certificate of incorporation authorizes the issuance of up to 100,000,000 shares of Allurion preferred stock. As of December Legacy Allurion Preferred Equity In connection with the Business Combination, the Legacy Allurion preferred stock was retroactively adjusted, converted into common stock at the Exchange Ratio, and reclassified to permanent equity as a result of the reverse recapitalization. As of December 31, 2023, there is no Legacy issued, or outstanding. The following table summarizes details of Legacy Allurion Preferred Stock authorized, issued, and outstanding immediately prior to the Business Combination and prior to giving effect to the Reverse Stock Split (in thousands, except share amounts): Preferred Stock (1) Preferred Stock Carrying Series A Preferred Stock 2,276,786 2,276,786 $ 1,542 Series A-1 1,513,028 1,486,048 2,842 Series B Preferred Stock 2,298,929 2,245,515 5,253 Series C Preferred Stock 8,113,616 7,927,446 39,122 Series D-1 1,684,565 842,283 9,614 Series D-2 3,644,616 3,644,616 24,054 Series D-3 1,498,348 1,498,348 14,789 Total 21,029,888 19,921,042 $ 97,216 Voting Rights The Legacy Allurion preferred stockholders voted as a single class together with holders of all other classes and series of stock of Legacy Allurion on all actions to be taken by the stockholders of the Company. The Legacy Allurion preferred stockholders were entitled to the number of votes equal to the number of shares of Legacy Allurion common stock into which the shares held by each holder were then convertible. The Legacy Allurion Series C Preferred Stockholders were entitled to elect two members of the Board of Directors, and the Legacy Allurion common stockholders were entitled to elect four members of the Board of Directors. Dividend Rights All Legacy Allurion preferred stock participated in dividends with Legacy Allurion common as-converted Liquidation Prefere nce In the event of any voluntary or involuntary liquidation, dissolution, or winding-up A-1, D-1, D-2, D-3 D-1, D-2, D-3 Legacy Allurion Series A Preferred Stock ($1.092), plus any dividends declared but unpaid thereon (the “First Catchup Amount”). Any remaining funds and assets available for distribution to Legacy Allurion stockholders, if any, after the First Catchup Amount would then be distributed on a pro rata basis to the holders of common stock and preferred stock in proportion to the number of shares of common stock or preferred stock hel d. Conversion Rights Each share of Legacy Allurion preferred stock was convertible at any time, at the option of the holder, into one share of Legacy Allurion common stock, based upon a per share conversion factor of each series’ applicable original issuance prices, adjustable for certain dilutive events. Conversion was mandatory upon the closing of an IPO or deSPAC transaction, or upon the election of the holders of a majority of the then-outstanding Legacy Allurion preferred stock. Redemption The holders of Legacy Allurion Series A, Series A-1, D-1, D-2, D-3 Common Equity The Allurion certificate of incorporation authorizes the issuance of up to 1,000,000,000 shares of Allurion Common Stock. As of December 31, 2023 and 2022, 1,907,529 and 1,083,196 shares of common stock were outstanding, respectively, after retrospectively adjusting for the effect of the reverse recapitalization and the Reverse Stock Split. The number of sh ares of Common Stock that have been reserved for the potential conversion or exercise, as applicable, of the Company’s securities as of December 31, 2023, is as follows: Outstanding options to purchase common stock 155,441 Restricted Stock Units 25,745 Warrants to purchase preferred stock (as converted to warrants to purchase common stock) 5,557 Warrants to purchase common stock 10,594 Public warrants to purchase common stock 750,394 Earn-Out 360,000 Total 1,307,731 Warrants to Purchase Common Stock In connection with the closing of the Business Combination, all outstanding warrants to purchase Legacy Allurion preferred stock and Legacy Allurion common stock were converted into Rollover Warrants to purchase Allurion Common Stock using the Exchange Ratio. As of December 31, 2023, there were 16,151 such Rollover Warrants outstanding to purchase Common Stock. Upon the closing of the Business Combination, certain Legacy Allurion preferred stock and Legacy Allurion common stock warrants that were converted into Rollover Warrants were determined to be equity classified. December 31, 2023 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.9 Common stock Equity 1,771 $ 61.00 3/30/2021 7.2 Common stock Liability 5,203 168.25 9/15/2022 8.7 Common stock Liability 1,810 303.50 6/4/2022 8.4 Common stock Liability 1,810 303.50 1/17/2017 3.0 Common stock Equity 2,934 0.50 8/3/2017 3.6 Common stock Equity 392 28.25 9/8/2017 3.7 Common stock Liability 1,151 26.25 6/19/2018 4.5 Common stock Liability 720 26.25 6/25/2019 5.5 Common stock Liability 360 26.25 16,151 December 31, 2022 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 4/1/2013 0.2 Series A-1 Liability 663 $ 48.75 12/1/2014 1.9 Series B Preferred Stock Liability 2,431 61.00 3/30/2021 8.2 Series C Preferred Stock Liability 5,203 168.25 9/15/2022 9.7 Series D-1 Liability 1,810 303.50 6/4/2022 9.4 Series D-1 Liability 1,810 303.50 1/17/2017 4.0 Common stock Liability 2,934 0.50 8/3/2017 4.6 Common stock Liability 392 28.25 9/8/2017 4.7 Common stock Liability 1,151 26.25 6/19/2018 5.5 Common stock Liability 720 26.25 6/25/2019 6.5 Common stock Liability 360 26.25 17,474 In Compute Health’s initial public offering, it sold units at a price of $10.00 per unit, which consisted of one share of Class A Common one-half per share. On July 26, 2023, Compute Health’s Public Warrant holders approved an amendment (the “Warrant Amendment”) to the warrant agreement that governed all Compute Health’s Public Warrants. Per the terms of the Warrant Amendment, upon completion of the Business Combination and after giving effect to the Reverse Stock Split, each of the outstanding Compute Health Public Warrants became exercisable for (prior to giving effect to the Reverse Stock Split) Allurion Public Warrants in the Business Combination. The Public Warrants will expire August 1, 2030, seven years after the completion of the Business Combination, or earlier upon redemption or liquidation. The Company may redeem the outstanding Public Warrants for cash at a price of $0.25 per Public Warrant at any time commencing 90 days after the completion of the Business Combination, and provided that the last sales price of the Company’s Common Stock equals or exceeds $316.75 per share of any 20 trading days within a 30-day The Company may redeem the outstanding Public Warrants for shares of our Common Stock at a price of $2.50 per Public Warrant at any time commencing 90 days after the completion of the Business Combination, and provided that the last sales price of the Company’s Common Stock equals or exceeds $176.00 per share of any 20 trading days within a 30-day Chardan Equity Facility On December 18, 2023, we entered into a ChEF Purchase Agreement (the “Purchase Agreement”) and a Registration Rights Agreement (the “Registration Rights Agreement”), each with Chardan Capital Markets (“Chardan”) related to a “ChEF,” Chardan’s committed equity facility (the “Chardan Equity Facility”). Pursuant to the Purchase Agreement, the Company has the right from time to time at its option to sell to Chardan up to the lesser of (i) $100,000,000 in aggregate gross purchase price of newly issued shares of the Company’s Common Stock, and (ii) 379,299 shares of Common Stock, which number of shares is equal to 19.99% of the shares of the Common Stock outstanding immediately prior to the execution of the Purchase Agreement (the “Exchange Cap”). In consideration for Chardan’s entry into the Purchase Agreement, Allurion agreed to issue to Chardan 1,421 shares of Allurion Common Stock (the “Commitment Shares”). The Company recorded $0.1 million to additional paid-in non-refundable

Net Loss per Share

Net Loss per Share	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share	13. Net Loss per Share Basic and diluted net loss per share was calculated as follows: Three Months Ended Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss $ (9,004 ) $ (21,630 ) $ (5,580 ) $ (61,427 ) Cumulative undeclared preferred dividends to participating securities (Legacy Series D convertible preferred stock) —  (255 ) —  (1,697 ) Net loss attributable to common shareholders $ (9,004 ) $ (21,885 ) $ (5,580 ) $ (63,124 ) Denominator: Basic and diluted weighted-average common stock outstanding 2,563,459 1,613,425 2,132,416 1,262,346 Net loss per share, basic and diluted (3.51 ) (13.56 ) (2.62 ) (50.01 ) The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of shares of Common Stock outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential shares of Common Stock, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: As of September 30, 2024 2023 Outstanding options to purchase Common Stock 284,332 170,810 Restricted Stock Units 21,230 17,173 Series A Preferred Stock 90,407 —  Warrants to purchase Common Stock 769,257 16,200 Shares of Common Stock issued upon the exercise of Public Warrants 750,383 750,394 Earn-Out 360,000 360,000 Convertible Notes 19,168 —  Total 2,294,777 1,314,577	13. Net Loss per Share Basic and diluted net loss per share was calculated as follows: Year Ended December 31, 2023 2022 Numerator: Net loss $ (80,607 ) $ (37,744 ) Cumulative undeclared dividends to participating securities (Legacy Series D convertible preferred stock) (1,697 ) (2,907 ) Net loss attributable to common stockholders $ (82,304 ) $ (40,651 ) Denominator: Basic and diluted weighted-average common stock outstanding 1,423,275 1,076,743 Net loss per share attributable to common stockholders, basic and diluted (1) $ (57.83 ) $ (37.75 ) (1) The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods prior to the Business Combination have been retrospectively adjusted to the equivalent number of shares outstanding immediately after the Business Combination to effect the reverse capitalization. See Note 3 for further information. The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods have also been retrospectively adjusted to give effect to the R everse The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Year Ended 2023 2022 Outstanding options to purchase common stock 155,441 172,079 Restricted Stock Units 25,745 56,605 Warrants to purchase preferred stock (as converted to warrants to purchase common stock) 5,557 11,917 Warrants to purchase common stock 10,594 5,557 Shares of Common Stock issued upon the exercise of Public Warrants 750,394 —  Earn-Out 360,000 —  Convertible notes (as converted to common stock) — 6,851 Total 1,307,731 253,009

Stock Based Compensation

Stock Based Compensation	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock Based Compensation	14. Stock-Based Compensation Stock Incentive Plans The Company’s 2010 Stock Incentive Plan (the “2010 Plan”) provided for the grant of qualified incentive stock options, nonqualified stock options, and other awards to the Company’s employees, officers, directors, advisors, and outside consultants to purchase the Company’s Common Stock. On December 11, 2020, the Company’s Board of Directors adopted the Amended and Restated 2020 Stock Option and Grant Plan (the “2020 Plan”), which provided for the grant of qualified incentive stock options, nonqualified stock options, and other awards to the Company’s employees, officers, directors, advisors, and outside consultants to purchase the Company’s Common Stock. Each stock option from the 2010 Plan and the 2020 Plan that was outstanding immediately prior to the Business Combination, whether vested or unvested, was cancelled and exchanged for a stock option to purchase Allurion Common Stock based on the Exchange Ratio. The per share exercise price for each stock option was divided by the Exchange Ratio. In connection with the closing of the Business Combination, the Company adopted the 2023 Stock Option and Incentive Plan (the “2023 Plan”), which provides for the award of stock options (both incentive and non-qualified), As of September 30, 2024, Stock-based compensation expense included in the condensed consolidated statement of operations was as follows: Three Months Ended Nine Months Ended  2024   2023   2024   2023  Cost of revenue $ 13 $ 16 $ 24 $ 31 Selling, general and administrative 791 5,477 2,109 6,235 Research and development 56 46 84 83 Total stock-based compensation expense $ 860 $ 5,539 $ 2,217 $ 6,349 Stock Options The following table summarizes the option activity under the 2010 Plan, 2020 Plan, and the 2023 Plan during the nine months ended September 30, 2024: Number of Weighted Weighted Aggregate (per option) (in years) (in thousands) Outstanding—January 1, 2024 155,441 $ 66.75 6.9 $ 5,565 Granted 147,443 46.50 Cancellations and forfeitures (17,906 ) 57.00 Exercised (646 ) 34.25 Outstanding—September 30, 2024 284,332 57.00 7.9 —  Exercisable at September 30, 2024 114,913 $ 62.00 5.9 $ —  Total stock compensation expense related to stock option awards during the three and nine months ended September 30, 2024 was $0.6 million and $1.4 million, respectively. As of September 30, 2024, there was approximately $5.6 million of unrecognized compensation costs related to unvested stock options granted under the 2010 Plan, 2020 Plan, and 2023 Plan, which is expected to be recognized over a weighted-average vesting term of 3.0 years. The weighted average grant-date fair value of the stock option awards granted during the nine months ended September 30, 2024 was $32.50 per option. The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model and the assumptions noted in the table below. Expected volatility for the Company’s Common Stock was determined based on an average of the historical volatility of a peer group of public companies that are similar to the Company. The expected term of options granted to employees was calculated using the simplified method, which represents the average of the contractual term of the option and the weighted-average vesting period of the option. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate expected term. The expected term of options granted to non-employees The assumptions used in the Black Scholes option-pricing model for the nine months ended September 30, 2024 and 2023 are as follows: Nine Months 2024 2023 Expected volatility 71 % 86 % Risk-free interest rate 4.36 % 4.50 % Expected dividend yield 0 % 0 % Expected term (in years) 6.1 5.8 Restricted Stock Units In December 2022, the Company issued RSUs to a member of the Board of Directors with vesting subject to both a performance-based closing condition dependent on the successful Business Combination with Compute Health and time-based vesting conditions. See Note 3, Business Combination of the RSUs awarded vested. Thereafter, the remaining The following table summarizes the restricted stock unit activity under the 2020 Plan and 2023 Plan during the three months ended September 30, 2024: Number of RSUs Weighted (per share) Outstanding—January 1, 2024 25,745 $ 111.25 Granted 3,000 65.25 Cancellations and forfeitures —  —  Vested (7,515 ) 112.75 Outstanding—September 30, 2024 21,230 $ 104.00 Total stock compensation expense related to RSUs for the three and nine months ended September 30, 2024 was $0.2 million and $0.8 million, respectively. As of September 30, 2024, there were $1.0 million of unrecognized compensation costs related to nonvested RSUs granted under the 2020 Plan and 2023 Plan, which is expected to be recognized over a remaining weighted-average vesting term of 1.6 years. Employee Stock Purchase Plan In connection with the closing of the Business Combination, the Company adopted the 2023 Employee Stock Purchase Plan (the “2023 ESPP”). Under the 2023 ESPP plan, substantially all employees may voluntarily enroll to purchase the Company’s Common Stock through payroll deductions at a price equal to 85% of the lower of the fair market values of the stock as of the beginning or end of the offering period. An employee’s payroll deductions under the 2023 ESPP are limited to 15% of the employee’s compensation. A total of 89,045 shares of the Company’s Common Stock are reserved and authorized for issuance under the 2023 ESPP. In addition, the number of shares of Common Stock available for issuance under the 2023 ESPP will automatically increase each January 1, beginning on January 1, 2024 and each January thereafter, by the lesser of (i) 1% of the fully diluted outstanding shares of our Common Stock as of the immediately preceding December 31, (ii) 64,000 shares of our Common Stock, or (iii) such lesser number of shares determined by the administrator of the 2023 ESPP. As of September 30, 2024, no shares have been issued under the 2023 ESPP.	14. Stock Based Compensation Stock Incentive Plans The Company’s 2010 Stock Option Plan (the “2010 Plan”) provided for the grant of qualified incentive stock options, nonqualified stock options, and other awards to the Company’s employees, officers, directors, advisors, and outside consultants to purchase the Company’s Common Stock. On December 11, 2020, the Company’s Board of Directors adopted the 2020 Stock Option Plan (the “2020 Plan”), which provided for the grant of qualified incentive stock options, nonqualified stock options, and other awards to the Company’s employees, officers, directors, advisors, and outside consultants to purchase the Company’s Common Stock. Each stock option from the 2010 Plan and the 2020 Plan that was outstanding immediately prior to the Business Combination, whether vested or unvested, was cancelled and exchanged for a stock option to purchase Allurion Common Stock based on the Exchange Ratio. The per share exercise price for each stock option was divided by the Exchange Ratio. In connection with the closing of the Business Combination, the Company adopted the 2023 Stock Option and Incentive Plan (the “2023 Plan”), which provides for the award of stock options (both incentive and non-qualified), As of December 31, 2023, 181,186 options and RSUs were issued and outstanding under the 2010 Plan, 2020 Plan, and 2023 Plan. As of December 31, 2022, 228,684 options and RSUs were issued and outstanding under the 2010 Plan and 2020 Plan. The stock options generally vest over a four-year period and expire 10 years from the date of grant. Stock-based compensation expense included in the consolidated statement of operations and comprehensive loss was as follows: Year Ended December 31,   2023     2022   Cost of revenue $ 32 $ —  Selling, general, and administrative 8,198 400 Research and development 127 37 Total stock-based compensation expense $ 8,357 $ 437 Stock Options The following tables summarizes the option activity under the 2010 Plan, 2020 Plan, and the 2023 Plan during the year ended December 31, 2023: Number Weighted Weighted Aggregate (per option) (in years) (in thousands) Outstanding—January 1, 2023 172,079 $ 58.75 7.7 $ 9,437 Granted 10,308 135.25 Cancellations and forfeitures (15,003 ) 50.00 Exercised (11,943 ) 28.75 Outstanding—December 31, 2023 155,441 $ 66.75 6.9 $ 5,565 Exercisable at December 31, 2023 109,436 $ 55.75 6.2 $ 4,812 Total stock compensation expense related to stock option awards during the year ended December 31, 2023 was $2.7 million. As of December 31, 2023, there was approximately $2.5 million of unrecognized compensation costs related to unvested stock options granted under the 2020 Plan, which is expected to be recognized over a weighted-average The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model and the assumptions noted in the table below. Expected volatility for the Company’s Common Stock was determined based on an average of the historical volatility of a peer group of public companies which are similar to the Company. The expected term of options granted to employees was calculated using the simplified method, which represents the average of the contractual term of the option and the weighted- average vesting period of the option. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate expected term. The expected term of options granted to non-employees The assumptions used in the Black-Scholes option-pricing model are as follows: Year Ended December 31,   2023     2022   Expected volatility 85.8 % 63 % Risk-free interest rate 4.5 % 3.56 % Expected dividend yield —  % —  % Expected term (in years) 5.8 5.8 Restricted Stock Units In December 2022, the Company issued RSUs under the 2020 Plan to a member of the Board of Directors with vesting subject to both a performance-based closing condition dependent on the successful Business Combination with Compute Health and time-based vesting conditions. See Note 1, Organization and Basis of Presentation , Business Combination Number of Weighted Grant (per share) Outstanding—January 1, 2023 56,605 $ 112.75 Granted 9,047 108.00 Cancellations and forfeitures (3,170 ) 112.75 Vested (36,737 ) 112.75 Outstanding—December 31, 2023 25,745 111.25 Total stock compensation expense related to RSUs for the year ended December 31, 2023 was $5.7 million. As of December 31, 2023, there were $1.7 million of unrecognized compensation costs related to nonvested RSUs granted under the 2020 Plan and 2023 Plan, which is expected to be recognized over a remaining weighted-average vesting term of 2.0 years. The weighted average grant-date fair value of time-vested restricted stock units granted during the years ended December 31, 2023 and 2022 was $108.00 and $112.75 per share, respectively. Employee Stock Purchase Plan In connection with the closing of the Business Combination, the Company adopted the 2023 Employee Stock Purchase Plan (the “2023 ESPP”). Under the 2023 ESPP plan, substantially all employees may voluntarily enroll to purchase the Company’s Common Stock through payroll deductions at a price equal to 85% of the lower of the fair market values of the stock as of the beginning or end of the offering period. An employee’s payroll deductions under the 2023 ESPP are limited to 15% of the employee’s compensation. A total of 56,893 shares of the Company’s Common Stock were initially reserved and authorized for issuance under the 2023 ESPP. In addition, the number of shares of Common Stock available for issuance under the 2023 ESPP will automatically increase each January 1, beginning on January 1, 2024 and each January thereafter, by the lesser of (i) 1% of the fully diluted outstanding shares of our Common Stock as of the immediately preceding December 31, (ii) 64,000 shares of our Common Stock, or (iii) such lesser number of shares determined by the administrator of the 2023 ESPP. As of December 31, 2023, no shares have been issued under the 2023 ESPP.

Employee Benefit Plan

Employee Benefit Plan	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Retirement Benefits [Abstract]
Employee Benefit Plan	15. Employee Benefit Plan The Company has a 401(k) retirement plan that covers eligible U.S. employees. Eligible employees may elect to contribute up to the maximum limits, as set by the Internal Revenue Service, of their eligible compensation. The Company may elect to make a discretionary contribution or match a discretionary percentage of employee contributions. During each of the three and nine months ended September 30, 2024 and 2023, the Company’s matching contributions to the plan were less than $0.1 million.	15. Employee Benefit Plan The Company has a 401(k) retirement plan that covers eligible U.S. employees. Eligible employees may elect to contribute up to the maximum limits, as set by the Internal Revenue Service, of their eligible compensation. The Company may elect to make a discretionary contribution or match a discretionary percentage of employee contribution. During the years ended December 31, 2023 and 2022, the Company’s matching contributions to the plan were $0.1 million.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	16. Commitments and Contingencies Leases With respect to contracts involving the use of assets, if the Company has the right to direct the use of the asset and obtain substantially all economic benefits from the use of an asset, it accounts for the service contract as a lease. In February 2023 and August 2023, the Company executed amendments to three of its leases in Natick, Massachusetts and its Hudson, Massachusetts lease, respectively. The amendments were accounted for as a modification of the existing lease agreements, with impacts to the lease term, lease payments, and related lease liability for each of the four leases. As a result of these amendments, the leases in Natick and Hudson will now expire between March 2025 and March 2028, and additional operating lease assets obtained in exchange for lease obligations were $0.9 million. In April 2024, the Company executed an amendment to one of its leases in Natick, Massachusetts. The amendment was accounted for as a modification of the existing lease agreement, with impacts to the lease term, lease payments, and related lease liability for the lease. As a r es As of September 30, 2024, the Company was a party to six different leases for office, manufacturing, and laboratory space under non-cancelable three The components of right-of-use ns Aggregate Lease Information Other pertinent lease information for the three and nine months ended September 30, 2024 and 2023 is as follows (in thousands): Three Months Nine Months 2024 2023 2024 2023 Operating lease costs $ 259 $ 285 $ 794 $ 834 Short-term lease costs 3 5 23 17 Variable lease costs 59 52 194 211 Operating cash flows paid for amounts in the 271 284 826 815 Operating lease assets obtained in exchange —  62 15 936 Future commitments under non-cancelable 2024 $ 273 2025 1,044 2026 739 2027 646 2028 108 Total lease payments $ 2,810 Less: present value adjustment (354 ) Total lease liabilities 2,456 Less: current lease liability (878 ) Long-term operating lease liabilities $ 1,578 The weighted-average remaining lease terms and discount rates related to our leases were as follows: September 30, September 30, Weighted-average remaining lease term 2.9 3.7 Weighted-average discount rate 9.9 % 9.9 % Product Liability The Company has not received any material product liability claims. Notwithstanding this, the Company has obtained insurance related to potential product liability claims. Litigation and Claims In the normal course of operations, the Company may become involved in various claims and legal proceedings related to, for example, the validity or scope of its intellectual property rights, employee-related matters, securities class actions, or adverse patient reactions. Additionally, during the normal course of business, the Company may be a party to legal claims that may not be covered by insurance. As of September 30, 2024 and December 31, 2023, the Company has not recorded accruals for probable losses related to any existing or pending litigation or claims as the Company’s management has determined that there are no matters where a potential loss is probable and reasonably estimable. The Company does not believe that any existing or pending claims would have a material impact on the Company’s consolidated financial statements. French Regulatory Decision On August 6, 2024, it was announced that the Agence Nationale de Sécurité du Médicament (“ANSM”), the French regulatory authority, has suspended sales of the Allurion Balloon in France, and the Company withdrew the device from the French market. The Company has implemented a remediation plan to reduce certain risks associated with the advertising, follow-up NYSE Continued Listing Standards On August 12, 2024, we received a letter from the NYSE notifying us that, as of August 8, 2024, for the last 30 consecutive business days, the average closing price of the Company’s common stock was less than $1.00 per share, the minimum average closing bid price required by the continued listing requirements of Rule 802.01C of the NYSE Listed Company Manual. A company can regain compliance with the minimum share price requirement at any time during the six-month trading-day six-month trading-day On August 29, 2024, we received written notice from the NYSE that we are not in compliance with the con tinu trading-day the	16. Commitments and Contingencies Leases With respect to contracts involving the use of assets, if the Company has the right to direct the use of the asset and obtain substantially In February 2023 and August 2023, the Company executed amendments to three of its leases in Natick, Massachusetts and its Hudson, Massachusetts lease, respectively. The amendments were accounted for as a modification of the existing lease agreements, with impacts to the lease term, lease payments, and related lease liability for each of the four leases. As a result of these amendments, the leases in Natick and Hudson will now expire between June 2024 and March 2028, and additional operating lease assets obtained in exchange for lease obligations were $0.9 million. As of December 31, 2023, the Company was a party to seven different leases for office, manufacturing, and laboratory space under non-cancelable three The components of ROU assets and lease liabilities are included in the consolidated balance sheets. The short-term portion of the Company’s operating lease liability is recorded as part of Accrued expenses and other current liabilities on the consolidated balance sh e Aggregate Lease Information Other pertinent lease information is as follows (in thousands): December 31, December 31, Operating lease costs $ 1,123 $ 918 Short-term lease costs 12 14 Variable operating lease costs 187 191 Operating cash flows paid for amounts in the measurement of lease liabilities 1,084 807 Operating lease assets obtained in exchange for lease obligations 936 1,677 Future commitments under non-cancelable 2024 $ 1,173 2025 1,114 2026 737 2027 645 2028 108 Total lease payments $ 3,777 Less: present value adjustment (563 ) Present value of total lease liabilities 3,214 Less: current lease liability (908 ) Long-term lease liabilities $ 2,306 The weighted-average remaining lease terms and discount rates related to our leases were as follows: 2023 2022 Weighted-average remaining lease term (in years) 3.5 3.9 Weighted-average discount rate 9.9 % 9.5 % Product Liability The Company has not received any material product liability claims. While product defects and adverse patient reactions associated with the Allurion Balloon have occurred, and are expected to continue to occur, the Company does not have a history of product defects or adverse patient reactions that the Company’s management believes would give rise to a material product liability claim. Furthermore, the Company has obtained insurance related to potential product liability claims. Litigation and Claims In the normal course of operations, the Company may become involved in various claims and legal proceedings related to, for example, the validity or scope of its intellectual property rights, employee-related matters, or adverse patient reactions. Additionally, during the normal course of business, the Company may be a party to legal claims that may not be covered by insurance. As of December 31, 2023 and 2022, the Company has not recorded accruals for potential losses related to any existing or pending litigation or claims as the Company’s management has determined that there are no matters where a potential loss is probable and reasonably estimable. The Company does not believe that any existing or pending claims

Geographic Information

Geographic Information	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Segment Reporting [Abstract]
Geographic Information	17. Geogr aphic Information Long-lived assets, consisting of property and equipment, net and ROU assets by geography were as follows (in thousands): September 30, December 31, United States $ 4,690 $ 5,381 France $ 673 1,010 All other countries —  —  Long-lived assets $ 5,363 $ 6,391 Refer to Note 4, Revenue	17. Geographic Information L December 31, 2023 2022 United States $ 5,381 $ 3,999 France 1,010 1,282 All other countries —  —  Long-lived assets $ 6,391 $ 5,281 Refer to Note 4, Revenue

Related-party Transactions

Related-party Transactions	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Related Party Transactions [Abstract]
Related-party Transactions	18. Related-party Transactions Lease Agreement with Related Party In August 2022, the Company entered into an operating lease agreement for additional office space in Paris, France with LNMP JPBC Invest. The Company’s then-Trade Marketing Director was the signor of this lease for LNMP JPBS Invest. Additionally, the Company’s former Chief Commercial Officer is also a partner of LNMP JPBC Invest. The lease agreement included lease payments of approximately $ arm’s-length. Consulting Agreements with KKG Enterprises, LLC and Remus Group Management, LLC In the first quarter of 2023, Allurion entered into consulting agreements with KKG Enterprises, LLC (“KKG Enterprises”) and Remus Group Management, LLC (“Remus Group Management”) to assist Allurion in building out its AI platform, augment its AI advisory board, and provide advisory services related to the Business Combination. These agreements were tied to Allurion Board-related work by Krishna Gupta, who is a director of Allurion, CEO of Remus Group Management, principal at KKG Enterprises, and affiliated with Romulus Capital, a stockholder of Allurion. The agreements included payments of $ Convertible Note with Hunter Ventures Limited On February 15, 2023, Allurion sold $13 million of 2023 Convertible Notes to HVL and entered into a Side Letter with HVL, who is a limited partner of Romulus Growth Allurion L.P., which is a fund affiliated with Krishna Gupta (a director of Allurion; in addition, entities affiliated with him hold more than 5% of our outstanding common stock). Refer to Note 8, Debt Consulting Agreement with Related Party In September 2023, Allurion France, a French société par actions simplifiée and wholly-owned subsidiary of Allurion (“Allurion France”), entered into a corporate officer agreement with the Company’s then-Chief Commercial Officer and Benoit Chardon Consulting, a French société à responsabilité limitée solely owned by Mr. Chardon (“BCC”), pursuant to which BCC agreed to serve as Managing Director of Allurion France. The corporate officer agreement provided that BCC would receive base consulting fees of €28,333.33 per month and additional variable compensation subject to the incentive plan terms issued annually by Allurion and conditional on meeting Allurion France and personal performance attainment defined each year by Allurion. This agreement was terminated on December 12, 2023 by virtue of the termination agreement described below, effective December 31, 2023. Termination Agreement with Related Party On December 12, 2023, Allurion France entered into a termination agreement with the Company’s Chief Commercial Officer, Benoit Chardon, and BCC. Pursuant to the termination agreement, the parties agreed to terminate the corporate officer agreement as of December 31, 2023 and BCC resigned from its duties as managing director of Allurion France effective December 31, 2023. Allurion paid BCC all amounts due to it under the corporate officer agreement through December 31, 2023. In addition, Allurion paid BCC a lump-sum Convertible Note Agreement with RTW Pursuant to the Amended Note Purchase Agreement, on April 16, 2024, we issued and sold $48 million aggregate principal amount of convertible notes to RTW. RTW holds more than 5% of our outstanding Common Stock, has the right to designate an independent director nominee to be elected by our stockholders, is entitled to designate one representative to serve as a non-voting Debt RTW Participation in Public Offering In connection with the Public Offering, the Company issued and sold 9,594 shares of Common Stock and accompanying warrants to funds affiliated with RTW, for an aggregate purchase price of approximately $0.3 million. The Public Offering closed on July 1, 2024. Private Placement with RTW On June 28, 2024, pursuant to the Subscription Agreement, the Company agreed to sell to RTW 2,260,159 shares of Series A Preferred Stock, and 90,407 Private Placement Warrants, for an aggregate purchase price of approximately $2.7 million. The Private Placement closed on July 1, 2024.	18. Related-party Transactions Lease Agreement with Related Party In August 2022, the Company entered into an operating lease agreement for additional office space in Paris, France with LNMP JPBC Invest. The Company’s then-Trade Marketing Director was the signor of this lease for LNMP JPBS Invest. Additionally, the Company’s Chief Commercial Officer is also a partner of LNMP JPBC Invest. The lease agreement included lease payments of approximately $0.1 million per year. The lease commenced August 1, 2022 and was to end on July 31, 2025. The Company concluded that the commercial terms of the lease agreement were competitive, at the current market rate and conducted at arm’s-length. Consulting Agreements with KKG Enterprises, LLC and Remus Group Management, LLC In the first quarter of 2023, Allurion entered into consulting agreements with KKG Enterprises, LLC (“KKG Enterprises”) and Remus Group Management, LLC (“Remus Group Management”) to assist Allurion in building out its AI platform, augment its AI advisory board, and provide advisory services related to the Business Combination. These agreements were tied to Allurion Board-related work by Krishna Gupta, who is a director of Allurion, CEO of Remus Group Management, principal at KKG Enterprises, and affiliated with Romulus Capital, a stockholder of Allurion. The agreements included payments of $0.2 million to KKG Enterprises and $0.3 million to Remus Group Management as board compensation to Krishna Gupta. These agreements were terminated on June 20, 2023. Convertible Note with Hunter Ventures Limited On February 15, 2023, Allurion sold $13 million of 2023 Convertible Notes to HVL and entered into a Side Letter with HVL, who is a limited partner of Romulus Growth Allurion L.P., which is a fund affiliated with Krishna Gupta (a director of Allurion; in addition, entities affiliated with him hold more than 5% of our outstanding Common Stock). Refer to Note 8, Debt Consulting Agreement with Related Party In September 2023, Allurion France, a French société par actions simplifiée and wholly-owned subsidiary of Allurion, entered into a new corporate officer agreement with the Company’s Chief Commercial Officer and Benoit Chardon Consulting, a French société à responsabilité limitée which is solely owned by Mr. Chardon (“BCC”), pursuant to which BCC agreed to serve as Managing Director of Allurion France. The new corporate officer agreement provided that BCC would receive base consulting fees of €28,333.33 per month and additional variable compensation subject to the incentive plan terms issued annually by Allurion and conditional on meeting Allurion France and personal performance attainment defined each year by Allurion. This agreement was terminated on December 12, 2023 by virtue of the termination agreement described below. Termination Agreement with Related Party On December 12, 2023, Allurion France, a French société par actions simplifiée and wholly-owned subsidiary of Allurion, entered into a termination agreement with the Company’s Chief Commercial Officer, Benoit Chardon and BCC. Pursuant to the termination agreement, the parties agreed to terminate the corporate officer agreement as of December 31, 2023 and BCC will resign from its duties as managing director of Allurion France effective December 31, 2023 and Allurion France will pay BCC all amounts due to it under the corporate officer agreement through December 31, 2023. In addition, Allurion France will pay BCC a lump-sum

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2024
Subsequent Events [Abstract]
Subsequent Events	19. Subsequent Events RTW PIPE Conversion On October 22, 2024, funds affiliated with RTW provided notice to the Company of their election under the Amended and Restated RTW Side Letter, to surrender 30,000 shares of Common Stock of the Company representing $7.5 million in consideration for an additional Revenue Interest Financing Agreement. Accordingly, on October 30, 2024, the Company and the funds affiliated with RTW entered into the additional Revenue Interest Financing Agreement (the “New RIFA”). The New RIFA has substantially identical terms and conditions as the Revenue Interest Financing Agreement Restructuring Plan On November 6, 2024, the Company’s board of directors approved a restructuring plan to reduce operating costs and better align its workforce with the needs of its business. The majority of the restructuring is expected to be completed in the fourth quarter of 2024. Under the restructuring plan, the Company is reducing its workforce by approximately 113 roles (approximately 50%). In connection with the restructuring, the Company estimates that it will incur one-time that

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Management considers many factors in selecting appropriate financial accounting policies and controls in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ from those estimates.	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Management considers many factors in selecting appropriate financial accounting policies and controls in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ from those estimates.
RTW Convertible Notes	RTW Convertible Notes The Company accounted for the RTW Convertible Notes (defined below) under the fair value option (“FVO”) election of ASC Topic 825, Financial Instruments	2023 Convertible Notes The Company accounted for the convertible notes issued between February 2023 and August 2023 (the “2023 Convertible Notes”) under the fair value option (“FVO”) election of ASC Topic 825, Financial Instruments recorded as a component of Other (expense) income in the consolidated statements of operations. As a result of electing the FVO, direct costs and fees related to the 2023 Convertible Notes were expensed as incurred. The convertible notes issued in 2020, 2021 and 2022 are accounted for as disclosed in Note 8, Debt
Reclassification of Prior Year Presentation	Reclassification of Prior Year Presentation Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations. Adjustment has been made to the condensed consolidated balance sheet as of December 31, 2023, to present the Legacy Allurion common stock warrant liabilities as part of the Warrant liabilities line item. These amounts were part of the Other liabilities line item in prior years.	Reclassification of Prior Year Presentation Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations. Adjustments have been made to the consolidated statement of operations and comprehensive loss for the year ended December 31, 2022 to present the change in fair value of derivative liabilities as part of Other income (expense), net, and to present the change in fair value of warrants as its own line item. The change in fair value of derivative liabilities was a separate line item in prior years and the change in fair value of warrants was part of Other income (expense), net in prior years.
Mezzanine Equity	Mezzanine Equity Mezzanine equity represents the Series A Preferred Stock (defined below) issued by the Company. The shares of Series A Preferred Stock are redeemable at a determinable price on a fixed date, which results in mezzanine equity classification (outside of permanent equity) on the Company’s consolidated balance sheet. Refer to Note 12, Redeemable Convertible Preferred Stock and Stockholder’s Deficit,
Risk of Concentration of Credit, Significant Customers and Significant Suppliers	Risk of Concentration of Credit, Significant Customers and Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents and accounts receivable, net. The Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company maintains its cash, cash equivalents and restricted cash with financial institutions that management believes to be of high credit quality. The Company has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Significant customers are those which represent more than 10% of the Company’s total revenue for the three and nine months ended September 30, 2024 and 2023 or accounts receivable, net balance as of September 30, 2024 and December 31, 2023. The following table presents customers that represent 10% or more of the Company’s total revenue and accounts receivable, net: Revenue Revenue Accounts Receivable Three Months Nine Months September 30, December 31, 2024 2023 2024 2023 2024 2023 Customer A 18 % 19 % N/A 12 % 15 % 16 % Customer B N/A 11 % N/A N/A N/A N/A The Company relies on third parties for the supply of parts and components for its products as well as third-party logistics providers. In instances where these parties fail to perform their obligations, the Company may be unable to find alternative suppliers of parts and components to satisfactorily deliver its products to its customers on time, if at all, which could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships.	Risk of Concentration of Credit, Significant Customers and Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents and accounts receivable, net. The Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company maintains its cash, cash equivalents and restricted cash with financial institutions that management believes to be of high credit quality. The Company has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Significant customers are those which represent more than 10% of the Company’s total revenue for the years ended December 31, 2023 and 2022 or accounts receivable, net balance as of December 31, 2023 and 2022. The following table presents customers that represent 10% or more of the Company’s total revenue and accounts receivable, net: Revenue Accounts Receivable Years Ended December 31 December 31, 2023 2022 2023 2022 Customer A 10 % N/A 16 % N/A Customer B N/A 11 % N/A N/A Customer C N/A N/A N/A 13 % Customer D N/A N/A N/A 12 % The Company relies on third parties for the supply of parts and components for its products as well as third-party logistics providers. In instances where these parties fail to perform their obligations, the Company may be unable to find alternative suppliers of parts and components to satisfactorily deliver its products to its customers on time, if at all, which could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships.
Leases		Leases Effective January 1, 2022, the Company adopted ASC 842, Leases right-of-use non-current At the lease commencement date, operating lease liabilities and their corresponding ROU assets are recorded at the present value of future lease payments over the expected remaining lease term using the discount rate implicit in the lease, if it is readily determinable, or the Company’s incremental borrowing rate. The Company’s incremental borrowing rate reflects the fixed rate at which the Company could borrow the amount of the lease payments in the same currency on a collateralized basis, for a similar term in a similar economic environment. Lease cost for operating leases is recognized on a straight-line basis over the lease term as an operating expense. In addition, certain adjustments to the ROU asset may be required for items such as lease prepayments, incentives received or initial direct costs. The Company enters into contracts that contain both lease and non-lease Non right-of-use
Cash and Cash Equivalents and Restricted Cash		Cash and Cash Equivalents and Restricted Cash Cash consists of amounts held in bank savings and checking accounts. Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase. Cash equivalents consist of money market funds. The Company’s restricted cash consists of cash that the Company is contractually obligated to maintain and deposits of cash collateral held in accordance with the terms of various corporate credit cards. Restricted cash is included within other long-term assets on the consolidated balance sheets. A reconciliation of the amounts of cash and cash equivalents and restricted cash in the consolidated balance sheets to the amount in the consolidated statements of cash flows is as follows (in thousands): December 31, 2023 2022 Cash and cash equivalents $ 38,037 $ 7,685 Restricted cash included in other long-term assets 384 338 Cash and cash equivalents and restricted cash shown in the statement of cash flows $ 38,421 $ 8,023
Segment Reporting		Segment Reporting The Company operates in a single operating and reportable segment. Operating segments are defined as components of an enterprise for which discrete financial information is available and is regularly reviewed by the chief operating decision maker (“CODM”) in order to make decisions regarding resource allocation and performance assessment. The Company has determined that its CODM is its Chief Executive Officer. The Company’s CODM reviews financial information presented on a regular basis at the consolidated level for purposes of allocating resources and evaluating financial performance. Since the Company operates as one operating segment, all required financial segment information can be found in the consolidated financial statements. The Company’s products include the Allurion Balloon and related accessories. See Note 4, Revenue
Fair Value Measurements		Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or an exit price that would be 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. The carrying value of the Company’s financial instruments such as cash and cash equivalents, accounts payable, and accrued expenses approximate their fair values due to their short-term maturity. The carrying value of the Company’s term loan approximates its fair value as the interest rate and other terms are that which are currently available to the Company. The Company’s assets and liabilities recorded at fair value have been categorized based upon a fair value hierarchy, which is distinguished between observable and unobservable inputs in accordance with authoritative accounting guidance: Level 1 inputs: Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date Level 2 inputs: Other than quoted prices included in Level 1, inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability Level 3 inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that the observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset.
Inventories		Inventories Inventories, which include the costs of material, labor, and overhead, are stated at the lower of cost or net realizable value, with cost generally computed using the first-in,
Property and Equipment		Property and Equipment Property and equipment include computers, laboratory equipment, machinery, and leasehold improvements. Property and equipment are recorded at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets, except for leasehold improvements, which are depreciated on a straight-line basis over the shorter of the estimated life or the lease term. Expenditures for repairs and maintenance are expensed as incurred.
Capitalized Internal-Use Software		Capitalized Internal-Use Software development costs consist of certain consulting costs and compensation expenses for employees who devote time to the development projects of our internal-use internal-use The Company determined the amount of internal software costs to be capitalized based on the amount of time spent by our developers on projects in the application stage of development. There is judgment in estimating the time allocated to a particular project in the application stage. A significant change in the time spent on each project could have a material impact on the amount capitalized and related amortization expense in subsequent periods. As of December 31, 2023 and 2022, capitalized internal-use
Impairment of Long-Lived Assets		Impairment of Long-Lived Assets The Company evaluates its long-lived assets, which consist primarily of property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds the fair value of the asset. To date, no impairments have occurred.
Debt Issuance Costs		Debt Issuance Costs The Company defers costs directly associated with acquiring third-party financing. Fees incurred to issue debt are generally deferred and amortized as a component of interest expense over the estimated term of the related debt using the effective interest rate method. Fees incurred in connection with a modification are deferred and amortized as a component of interest expense over the remaining life of the loan if due to the creditor. Third-party fees incurred in connection with a modification
Deferred Offering Costs		Deferred Offering Costs Deferred offering costs include certain legal, accounting, consulting and other third-party fees incurred directly related to the Business Combination. The Company deferred offering costs classified as a long-term asset until the closing or termination of the transaction. At the closing of the Business Combination, these costs were recorded in stockholders’ deficit as a reduction of additional paid-in
Warrants		Warrants The Company determines the accounting classification of warrants it issues, as either liability or equity classified, by first assessing whether the warrants meet liability classification in accordance with ASC 480-10, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity (“ASC 480-10”), 815-40, Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock 815-40”). 480-10, ASC 480-10, 815-40, 815-40, 815-40
Derivative Liabilities		Derivative Liabilities The Company evaluates its convertible instruments and other contracts, including warrants, to determine if those contracts or embedded components of those contracts are required to be accounted for as derivatives, either in whole or in part. If an embedded derivative is bifurcated from a debt host contract, changes in the fair value of the bifurcated derivative are recorded in the accompanying consolidated statements of operations.
Earn-out Liabilities		Earn-Out In connection with the Business Combination, certain holders of Legacy Allurion common stock “Earn-Out earn-out earn-out Earn-Out earn-out fixed-for-fixed Distinguishing Liabilities from Equity The fair value of the earn-out earn-out earn-out earn-out
Revenue Interest Financing and PIPE Conversion Option		Revenue Interest Financing and PIPE Conversion Option In connection with the Business Combination, the Company entered into a revenue interest financing agreement, dated as of February 9, 2023 (the “Revenue Interest Financing Agreement”) with certain entities that have engaged RTW Investments, LP as investment manager (collectively, “RTW”), under which the Company received $40.0 million upfront (the “Revenue Interest Financing”). In exchange, the Company is obligated to remit to RTW certain revenue interest payments on all current and future products, digital solutions and services developed, imported, manufactured, marketed, offered for sale, promoted, sold, tested or otherwise distributed by Allurion and its subsidiaries at a rate up to 6.0% of annual net sales prior to December 31, 2026. On or after January 1, 2027, the Company will remit revenue interest payments at a rate up to 10.0% of annual net sales, and it will continue to make revenue interest payments to RTW until December 31, 2030. The Company accounts for the Revenue Interest Financing Agreement under the fair value option election of ASC 825. The Revenue Interest Financing Agreement accounted for under the FVO election is a debt host financial instrument that contains embedded features. The embedded features include requirements to settle the Revenue Interest Financing prior to maturity upon the occurrence of certain contingent events, a change in royalty rates upon the occurrence of certain contingent events, and the Company’s ability to prepay the Revenue Interest Financing. As the Company has elected the FVO, these embedded features would not meet the criteria for bifurcation and separate accounting as the entire financial instrument is initially measured at its issue-date estimated fair value and then subsequently remeasured at estimated fair value on a recurring basis on each reporting period date. Changes in the estimated fair value of the Revenue Interest Financing Agreement are recorded as a component of Other (expense) income in the consolidated statements of operations. A portion of the estimated change in fair value must be reported in other comprehensive loss to the extent that it is attributable to instrument-specific credit risk. As a result of electing the FVO, direct costs and fees related to the Revenue Interest Financing are expensed as incurred. In connection with the Company entering in the Revenue Interest Financing, the Company and RTW entered into the RTW side letter under which RTW may elect to convert up to $7.5 million of its initial PIPE (as defined in Note 3, Business Combination Derivatives and Hedging
Accounts Receivable		Accounts Receivable Accounts receivable are unsecured and are carried at net realizable value, including an allowance for doubtful accounts. Trade credit is generally extended on a short-term basis; trade receivables do not bear interest, although a finance charge may be applied to such receivables that are past due. The allowance for doubtful accounts is based on the Company’s assessment of the collectability of customer accounts. The Company regularly reviews the allowance by considering factors that may affect a customer’s ability to pay, such as historical expense, credit quality, the The following table summarizes activity in the allowance for doubtful accounts: Year Ended December 31,   2023     2022   Balance at beginning of period $ (741 ) $ (354 ) Provision for uncollectible accounts (12,675 ) (436 ) Uncollectible accounts written off 745 49 Balance at end of period $ (12,671 ) $ (741 )
Revenue Recognition		Revenue Recognition The Company recognizes revenue under ASU No. 2014-09, Revenue from Contracts with Customers The Company recognizes revenue when control of its products is transferred to customers at an amount that reflects the consideration it expects to receive in exchange for those products. The Company’s revenue recognition process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the transaction price, allocating the transaction price to the distinct performance obligations in the contract, and recognizing revenue as performance obligations are satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. Performance obligations are considered satisfied once the Company has transferred control of a good or service to the customer, meaning that such customer has the ability to use and obtain the benefit of the good or service. The Company has provided customers purchasing the Allurion Balloon with an implied license for access to its VCS software. This implied software license was given to customers for no additional consideration and was not negotiated as part of the customer’s contracts. Further, the customer contracts and related purchase orders do not include nor specify rights or obligations associated with the VCS software. Based on this assessment, the Company determined the implied license to be immaterial in the context of the contract with customers purchasing the Allurion Balloon, and as such did not allocate any value to the implied VCS license. The Company generates revenue from sales of its Allurion Balloon to distributors and health care providers. Customers typically The Company recognizes revenue at the transaction price, which reflects the consideration it believes it is entitled to receive. Transaction price includes estimates of variable consideration for promotions and prompt pay discounts, which are recorded as a reduction of transaction price in the period the related product revenue is recognized. The Company may also make payments to customers for marketing programs. Payments to customers for a distinct good or service that reasonably estimate the fair value of the distinct benefit received, such as marketing programs, are recorded as a marketing expense on the consolidated statement of operations and comprehensive loss. Shipping and logistics costs inclusive of these payments to customers and other costs included in sales and marketing expense for the years ended December 31, 2023 and 2022 were $3.3 million and $3.6 million, respectively. The Company expenses incremental costs of obtaining a contract, such as sales commissions, when incurred because the amortization period would have been one year or less. These costs are recorded within sales and marketing expenses in the Company’s consolidated statement of operations and comprehensive loss. The Company has also elected the sales tax practical expedient; therefore, sales and other taxes assessed by a governmental authority that are collected concurrently with revenue-producing activities are excluded from the transaction price. The Company has also elected the significant financing component practical expedient, which allows management to not assess whether the contract has a significant financing component in circumstances where, at contract inception, the expected contract duration is less than one year.
Product Warranty		Product Warranty The Company does not provide general rights of return of products sold to its customers. However, the Company does provide for rights of exchange to its distributors and end-use body These instances of nonconformity have been immaterial, and the Company’s management expects instances of nonconformity to be extremely rare.
Research and Development Costs		Research and Development Costs The Company expenses research and development costs as incurred. Research and development expenses consist of costs associated with performing research and development activities, including salaries and benefits, stock-based compensation, product development costs, materials and supplies, clinical trial activities, depreciation of equipment, and contract and other outside services. Payments for activities that are provided by outside vendors are based upon the terms of the individual arrangements with each vendor. Costs of certain of these activities are expensed based upon an evaluation of the progress to completion of specific tasks and actual costs incurred, using information provided to the Company by its vendors. As payments for these activities may differ from the pattern of costs actually incurred, additional costs are reflected in the consolidated financial statements as prepaid or accrued research and development expenses.
Advertising and Marketing Costs		Advertising and Marketing Costs The Company expenses advertising and marketing costs as incurred. Advertising and marketing expenses are included in sales and marketing operating expenses. Advertising and marketing costs for the years ended December 31, 2023 and 2022 were $10.8 million and $16.0 million, respectively.
Intellectual Property Prosecution Costs		Intellectual Property Prosecution Costs The Company incurs registration and prosecution costs related to its intellectual property. The related costs are expensed as incurred and are classified as a component of general and administrative expenses.
Income Taxes		Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company’s consolidated financial statements and tax returns. Deferred tax assets and liabilities are determined based upon the differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities and for net operating loss and tax credit carryforwards, using enacted tax rates expected to be in effect in the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that these assets may not be realized. The Company determines whether a tax position will be sustained upon examination. If it is not more likely than not that a position will be sustained, none of the benefit attributable to the position is recognized. The tax benefit to be recognized for any tax position that meets the more likely than not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. As of December 31, 2023 and 2022, the Company has not identified any uncertain tax positions for which reserves would be required.
Net Loss Per Share		Net Loss Per Share The Company applies the two-class two-class two-class Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders less the cumulative undeclared dividend by the weighted average number of common shares outstanding for the period. Diluted net loss attributable to common stockholders is computed by adjusting net loss attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing the diluted net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents. The holders of the Legacy Allurion Series D convertible preferred stock were contractually entitled to receive a cumulative dividend, whether or not declared, and therefore, Legacy Allurion Series D convertible preferred stocks were participating securities. The holders of all other redeemable and convertible preferred stock were not entitled to cumulative dividends. The preferred equity holders were also not contractually required to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss, such losses are not allocated to such participating securities. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. In connection with the Business Combination with Compute Health, the Company’s equity in previous periods has been retroactively adjusted to the earliest period presented to reflect the equivalent number of shares of Allurion Common Stock issued to the Company’s stockholders in connection with the Business Combination. As a result, net loss per share was also retrospectively adjusted for periods ended prior to the Business Combination. See Note 3, Business Combination
Stock-Based Compensation		Stock-Based Compensation The Company recognizes compensation expense for awards based on the grant-date fair value of stock-based No. 2018-07, Compensation—Stock Compensation (“Topic 718”): Improvements to Nonemployee Share-Based Payment Accounting
Comprehensive Loss		Comprehensive Loss For the year ended December 31, 2023, comprehensive loss consists of net loss and other comprehensive loss, which includes changes in the fair value attributable to instrument-specific credit risk related to the Revenue Interest Financing with RTW. There were no differences between net loss and comprehensive loss presented in the statements of operations and comprehensive loss for the year ended December 31, 2022.
Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt with Conversion and Other Options and Derivatives and Hedging-Contracts in Entity’s Own Equity, 2020-06 2020-06 Recently Issued Accounting Pronouncements Not Yet Adopted 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	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326) adopted ASU 2016-13 2016-13 Recently Issued Accounting Pronouncements Not Yet Adopted In August 2020, the FASB issued ASU 2020-06, Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity’s Own Equity No. 2020-06 2020-06 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

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Risk of Concentration of Credit, Significant Customers	The following table presents customers that represent 10% or more of the Company’s total revenue and accounts receivable, net: Revenue Revenue Accounts Receivable Three Months Nine Months September 30, December 31, 2024 2023 2024 2023 2024 2023 Customer A 18 % 19 % N/A 12 % 15 % 16 % Customer B N/A 11 % N/A N/A N/A N/A	The following table presents customers that represent 10% or more of the Company’s total revenue and accounts receivable, net: Revenue Accounts Receivable Years Ended December 31 December 31, 2023 2022 2023 2022 Customer A 10 % N/A 16 % N/A Customer B N/A 11 % N/A N/A Customer C N/A N/A N/A 13 % Customer D N/A N/A N/A 12 %
Reconciliation of Cash and Cash Equivalents and Restricted Cash		A reconciliation of the amounts of cash and cash equivalents and restricted cash in the consolidated balance sheets to the amount in the consolidated statements of cash flows is as follows (in thousands): December 31, 2023 2022 Cash and cash equivalents $ 38,037 $ 7,685 Restricted cash included in other long-term assets 384 338 Cash and cash equivalents and restricted cash shown in the statement of cash flows $ 38,421 $ 8,023
Summary of Activity in Allowance for Doubtful Accounts		The following table summarizes activity in the allowance for doubtful accounts: Year Ended December 31,   2023     2022   Balance at beginning of period $ (741 ) $ (354 ) Provision for uncollectible accounts (12,675 ) (436 ) Uncollectible accounts written off 745 49 Balance at end of period $ (12,671 ) $ (741 )

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Business Combinations [Abstract]
Reconciles of Business Combination to Condensed Consolidated Statement	The following table reconciles the elements of the Business Combination to the condensed consolidated statement of cash flows and the condensed consolidated statement of changes in equity: December 31, Cash – CPUH trust (net of redemptions) $ 38,395 Cash – PIPE Investors 37,922 Gross Proceeds 76,317 Less: transaction costs paid (14,665 ) Net proceeds from the Business Combination 61,652 Less: warrant liabilities assumed (13,762 ) Less: repayment of note assumed in the Business Combination (2,500 ) Less: accrued transaction costs at December 31, 2023 (580 ) Business Combination, net of transaction costs $ 44,810	The following table reconciles the elements of the Business Combination to the consolidated statement of cash flows and the consolidated statement of changes in equity: December 31, Cash – CPUH trust (net of redemptions) $ 38,395 Cash – PIPE Investors 37,922 Gross Proceeds 76,317 Less: transaction costs paid (14,665 ) Net proceeds from the Business Combination (1) 61,652 Less: warrant liabilities assumed (2) (13,762 ) Less: repayment of note assumed in the Business Combination (1) (2,500 ) Less: accrued transaction costs at December 31, 2023 (1) (580 ) Business Combination, net of transaction costs $ 44,810 (1) The Net proceeds from the Business Combination, less the repayment of note assumed in the Business Combination, less the accrued transaction costs at December 31, 2023 are presented net in the consolidated statements of stockholders deficit within line “Reverse recapitalization, net of transaction costs (Note 3)”. (2) The warrant liabilities assumed are presented separately from the “Reverse recapitalization, net of transaction costs (Note 3)” line within the consolidated statements of stockholders deficit.
Number of Shares of Allurion Common Stock Outstanding	The number of shares of Allurion Common Stock outstanding immediately following the consummation of the Business Combination and after giving effect to the Reverse Stock Split was as follows: Common Stock Legacy Allurion Equityholders (1) 1,115,896 CPUH Stockholders (2) 206,628 Shares Issued to PIPE Investors (2) 215,468 Shares issued to RTW and Fortress (3) 76,000 Shares issued to convertible note holders 132,049 CPUH Sponsor Shares (2) 130,509 Side Letter Termination Shares (3) 15,508 Total shares of Common Stock immediately after Business Combination 1,892,058 (1) Consists of Legacy Allurion common stock and Legacy Allurion preferred stock, plus the issuance of common stock in connection with the vesting of RSUs at closing, less the Gaur Trust Contributed Shares (as defined below). (2) The CPUH Stockholders shares, PIPE shares, and CPUH Sponsor shares are presented combined within the condensed consolidated statements of stockholders deficit on the “Reverse recapitalization, net of transaction costs” line, which is less the Gaur Trust Contributed Shares. (3) The shares issued to RTW and Fortress and the Side Letter Termination shares are presented combined within the condensed consolidated statements of stockholders deficit on the “Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and additional RTW and Fortress shares and issuance of related shares” line.	The number of shares of Allurion Common Stock outstanding immediately following the consummation of the Business Combination and after giving effect to the Reverse Stock Split was as follows: Common Stock Legacy Allurion Equityholders (1) 1,115,896 CPUH Stockholders (2) 206,628 Shares Issued to PIPE Investors (2) 215,468 Shares issued to RTW and Fortress (3) 76,000 Shares issued to convertible note holders 132,049 CPUH Sponsor Shares (2) 130,509 Side Letter Termination Shares (3) 15,508 Total shares of Common Stock immediately after Business Combination 1,892,058 (1) Consists of Legacy Allurion common stock and Legacy Allurion preferred stockholders, plus the issuance of common stock in connection with the vesting of RSUs at closing, less the Gaur Contributed (2) The CPUH Stockholders shares, PIPE shares, and CPUH Sponsor shares are presented combined within the consolidated statements of redeemable convertible preferred stock and stockholders deficit on the “Reverse recapitalization, net of transaction costs” line, which is less the Gaur Contributed Shares (as defined below). (3) The shares issued to RTW and Fortress and the Side Letter Termination shares are presented combined within the consolidated statements of redeemable convertible preferred stock and stockholders deficit on the “Derecognition of liabilities associated with the Backstop Shares, Hunter shares, and additional RTW and Fortress shares and issuance of related shares” line.

Revenue (Tables)

Revenue (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Revenues by Geographic Region	Revenue by geographic region is based on the country in which our customer is located and is summarized by geographic area as follows (in thousands): Three Months Ended 2024 2023 Turkey $ 966 $ 3,517 Australia $ 543 $ 979 Italy 511 626 Chile —  1,956 All Other Countries 3,347 11,122 Total Revenues $ 5,367 $ 18,200 Nine Months Ended 2024 2023 Spain $ 3,001 $ 3,715 United Kingdom 2,534 3,456 France 2,431 4,423 Turkey 1,573 5,495 All Other Countries 16,980 28,143 Total Revenues $ 26,519 $ 45,232	Revenue by geographic region is based on the country in which our customer is domiciled and is summarized by geographic area as follows (in thousands): Year Ended December 31,   2023     2022   France $ 5,569 $ 6,032 Turkey 5,494 4,079 Spain 4,618 6,852 Chile 2,708 5,008 All other countries 35,078 42,240 Total Revenues $ 53,467 $ 64,211

Inventory (Tables)

Inventory (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Table Text Block [Abstract]
Schedule of Inventory	Inventory consists of the following (in thousands): September 30, December 31, Finished goods $ 2,748 $ 3,427 Work in progress 1,005 967 Raw materials 815 1,777 Total Inventory $ 4,568 $ 6,171	Inventory consists of the following (in thousands): December 31, 2023 2022 Finished goods $ 3,427 $ 2,096 Work in progress 967 213 Raw materials 1,777 1,556 Total Inventory $ 6,171 $ 3,865

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consist of the following (in thousands): Estimated Useful Life September 30, December 31, Computers and purchased software 3 $ 618 $ 618 Leasehold improvements Shorter of useful life 1,943 1,943 Furniture and fixtures 5 291 291 Machinery and equipment 3-5 3,507 2,893 Property and equipment—at cost 6,359 5,745 Less accumulated depreciation and amortization (4,169 ) (3,559 ) Construction in progress 890 1,195 Property and equipment—net $ 3,080 $ 3,381	Property and equipment consist of the following (in thousands): Estimates Useful Life December 31, 2023 2022 Computers and purchased software 3 $ 618 $ 575 Leasehold improvements Shorter of useful life 1,943 1,822 Furniture and fixtures 5 291 251 Machinery and equipment 3-5 2,893 2,002 Property and equipment—at cost 5,745 4,650 Less accumulated depreciation and amortization (3,559 ) (2,851 ) Construction in progress 1,195 583 Property and equipment—net $ 3,381 $ 2,382
Schedule of Depreciation Expense	Depreciation expense was $0.2 million for each of the three months ended September 30, 2024 and 2023, and $0.8 million and $0.6 million for the nine months ended September 30, 2024 and 2023, respectively, recorded as follows (in thousands): Three Months Ended Nine Months Ended  2024   2023   2024   2023  Cost of revenue $ 119 $ 63 $ 433 $ 280 Research and development 63 48 161 131 General and administrative 19 34 104 104 Sales and marketing 14 15 80 43 Total depreciation and amortization expense $ 215 $ 160 $ 778 $ 558	Depreciation expense was $0.7 million and $0.9 million for the years ended December Year Ended December 31,   2023     2022   Cost of revenue $ 367 $ 568 Research and development 179 90 General and administrative 138 160 Sales and marketing 62 57 Total depreciation and amortization expense $ 746 $ 875

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Accrued Liabilities and Other Liabilities [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Marketing reimbursement $ 930 $ 2,834 Accrued compensation 1,733 1,687 Accrued clinical trials and R&D 81 3,694 Accrued selling and marketing 592 1,110 Accrued professional fees 493 1,505 Accrued warranty 16 44 Accrued restructuring —  655 Other accrued expenses 4,128 3,966 Total accrued expenses and other current liabilities $ 7,973 $ 15,495	Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2023 2022 Distributor fees and marketing reimbursements $ 2,834 $ 6,348 Accrued compensation 1,687 3,453 Accrued clinical trials and R&D 3,694 228 Accrued selling and marketing 1,110 481 Accrued professional fees 1,505 2,105 Accrued interest —  489 Accrued warranty 44 48 Accrued restructuring 655 —  Other accrued expenses 3,966 2,641 Total accrued expenses and other current liabilities $ 15,495 $ 15,793

Debt (Tables)

Debt (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Debt Disclosure [Abstract]
Summary of Components of Third-Party Debt	The components of the Company’s third-party debt consist of the following (in thousands): September 30, December 31, Fortress Term Loan $ —  $ 43,100 RTW Convertible Notes 49,320 —  Total principal amount of debt 49,320 43,100 Change in fair value (13,230 ) —  Plus: Accretion —  148 Less: current portion of long-term debt, net of discounts —  (38,643 ) Less: unamortized deferred financing costs and debt discounts —  (4,605 ) Long-term debt, net of current portion and discounts $ 36,090 $ —	The components of the Company’s third-party debt consisted of the following (in thousands): December 31, 2023 2022 Fortress Term Loan $ 43,100 $ —  2021 Term Loan —  55,000 Convertible Notes —  3,103 Total principal amounts of debt 43,100 58,103 Plus: Accretion 148 213 Less: current portion of long-term debt, net of discounts (38,643 ) (53,360 ) Less: unamortized deferred financing costs and debt discounts (4,605 ) (1,853 ) Long-term debt, net of current portion and discounts $ —  $ 3,103
Schedule of Future Maturities of the Term Loan Facility		Scheduled future maturities of the Fortress Term Loan for years subsequent to December 31, 2023 are as follows (in thousands): December 31, 2024 —  December 31, 2025 —  December 31, 2026 8,979 December 31, 2027 34,121 $ 43,100

Revenue Interest Financing, S_2

Revenue Interest Financing, Side Letter, and PIPE Conversion Option (Tables)	12 Months Ended
	Dec. 31, 2023
Contract with Customer, Liability [Abstract]
Summary of Components of Revenue Interest Financing	The components of the Company’s Revenue Interest Financing consist of the following (in thousands): December 31, Revenue Interest Financing liability $ 40,000 Total principal amounts of debt 40,000 Less: Royalty payments (1,092 ) Less: Change in fair value of debt (2,708 ) Long-term Revenue Interest Financing liability $ 36,200

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Schedule of Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value at Issuance Date and on Recurring Basis	The following tables present the fair value hierarchy for the Company’s assets and liabilities that are measured at fair value at issuance date and on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value (in thousands): Fair Value Measurement as of September 30, 2024 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 23,749 $ 23,749 $ —  $ —  Total assets $ 23,749 $ 23,749 $ —  $ —  Liabilities: Legacy Allurion Common Stock Warrant Liabilities $ 71 $ —  $ —  $ 71 Public Warrants 531 531 —  —  Public Offering Warrants 5,970 —  —  5,970 Private Placement Warrants 810 —  —  810 Revenue Interest Financing 38,500 —  —  38,500 PIPE Conversion Option 9,850 —  —  9,850 Earn-out 1,850 —  —  1,850 RTW Convertible Notes 36,090 —  —  36,090 Success Fee Derivative Liability 14 —  —  14 Total Liabilities $ 93,686 $ 531 $ —  $ 93,155 Fair Value Measurement as of December 31, 2023 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 30,582 $ 30,582 $ —  $ —  Total assets $ 30,582 $ 30,582 $ —  $ —  Liabilities: Legacy Allurion Common Stock Warrant Liabilities $ 821 $ —  $ —  $ 821 Public Warrants 5,943 5,943 —  —  Revenue Interest Financing 36,200 —  —  36,200 PIPE Conversion Option 5,600 —  —  5,600 Earn-out 23,990 —  —  23,990 Term Loan Derivative Liability 1,895 —  —  1,895 Success Fee Derivative Liability 14 —  —  14 Total Liabilities $ 74,463 $ 5,943 $ —  $ 68,520	The following tables present the fair value hierarchy for assets and liabilities that are measured at fair value at issuance date and on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value (in thousands): Fair Value Measurement as of December 31, 2023 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 30,582 $ 30,582 $ —  $ —  Total assets $ 30,582 $ 30,582 $ —  $ —  Liabilities: Legacy Allurion Common Stock Warrant Liabilities $ 821 $ —  $ —  $ 821 Public Warrants 5,943 5,943 —  —  Revenue Interest Financing 36,200 —  —  36,200 PIPE Conversion Option 5,600 —  —  5,600 Earn-out 23,990 —  —  23,990 Term Loan Derivative Liability 1,895 —  —  1,895 Success Fee Derivative Liability 14 —  —  14 Total Liabilities $ 74,463 $ 5,943 $ —  $ 68,520 Fair Value Measurement as of December 31, 2022 Total Carrying Value Level 1 Level 2 Level 3 Assets: Cash equivalents Money market funds $ 4,925 $ 4,925 $ —  $ —  Total assets $ 4,925 $ 4,925 $ —  $ —  Liabilities: Legacy Allurion Series C Common Stock Warrant Liability $ 340 $ —  $ —  $ 340 Legacy Allurion Series B Preferred Stock Warrant Liability 303 —  —  303 Legacy Allurion Series A-1 82 —  —  82 Other Common Stock Warrant Liabilities 255 —  —  255 Legacy Allurion Series C Preferred Stock Warrant Liability 684 —  —  684 Derivative Liability—Success Fee 180 —  —  180 Legacy Allurion Series D-1 707 —  —  707 Total Liabilities $ 2,551 $ —  $ —  $ 2,551
Schedule of Assumptions used in Pricing Model	The Company has classified the Legacy Allurion Common Stock Warrants, Public Offering Warrants (defined below), and Private Placement Warrants (defined below) within Level 3 of the hierarchy as the fair value is derived using the Black-Scholes option pricing model, which uses a combination of observable (Level 2) and unobservable (Level 3) inputs. See table below for the assumptions used in the pricing model of the Legacy Allurion Common Stock Warrants, Public Offering Warrants, and Private Placement Warrants: Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series C Preferred Stock warrants (as converted to Common) September 30, 2024 3.65 % $ 168.25 $ 15.25 90 % 6.50 Legacy Allurion Other Common Stock September 30, 2024 3.59% 26.25 15.25 90 % 2.94 Legacy Allurion Series D-1 September 30, 2024 3.65% - 303.50 15.25 90 % 6.5 - 7.96 Public Offering Warrants September 30, 2024 3.58% 30.00 15.25 90 % 4.75 Private Placement Warrants September 30, 2024 3.58% 30.00 15.25 90 % 4.75 Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series C Preferred Stock warrants (as converted to Common) December 31, 2023 3.88 % $ 168.25 $ 93.50 100 % 7.25 Legacy Allurion Other Common Stock December 31, 2023 3.95 % 26.25 93.50 100 % 3.69 Legacy Allurion Series D-1 December 31, 2023 3.88 % 303.50 93.50 100 % 7.25 - 8.71	The Company has classified the warrants within Level 3 of the hierarchy as the fair value is derived using Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series C Preferred Stock warrants (as converted to Common) December 31, 2023 3.88 % $ 168.25 $ 93.50 100 % 7.25 Other Common Stock December 31, 2023 3.95 % 26.25 93.50 100 % 3.69 Legacy Allurion Series D-1 December 31, 2023 3.88 % 303.50 93.50 100 % 7.25 8.71 Measurement Date Interest Exercise Estimated Fair Expected Expected Life Legacy Allurion Series A-1 December 31, 2022 4.42 % 47.50 168.75 69 % 0.25 Legacy Allurion Series B Preferred Stock warrants (as converted to Rollover warrants) December 31, 2022 4.41 % 59.50 172.75 65 % 2.00 Legacy Allurion Series C Common Stock warrants (as converted to Rollover warrants) December 31, 2022 4.11 % 0.25 113.50 63 % 4.00 Legacy Allurion Series C Preferred Stock warrants (as converted to Rollover warrants) December 31, 2022 3.92 % 164.50 181.00 63 % 8.20 Other Common Stock Warrants December 31, 2022 3.99 % 25.50 113.50 63 % 4.6 4.7 Legacy Allurion Series D-1 December 31, 2022 3.88 3.92 % 296.75 282.75 63 % 8.2 9.7
Schedule of Changes in Fair Values	The following table reconciles the changes in fair value for the three and nine months ended September 30, 2024 and 2023 of the warrant liabilities valued using Level 3 inputs: Preferred Stock Warrants Common Stock Public Offering Private Placement Total Balance – June 30, 2023 $ 2,679 $ 1,351 —  —  $ 4,030 Change in fair value (1,571 ) (555 ) —  —  (2,126 ) Exercise of warrants (53 ) —  —  —  (53 ) Derecognition of liability to equity (340 ) (589 ) —  —  (929 ) Balance – September 30, 2023 $ 715 $ 207 $ —  $ —  $ 922 Balance – June 30, 2024 $ 110 $ 35 —  —  $ 145 Fair value at issuance —  —  13,157 1,670 14,827 Change in fair value (55 ) (19 ) (7,187 ) (860 ) (8,121 ) Balance – September 30, 2024 $ 55 $ 16 $ 5,970 $ 810 $ 6,851 Preferred Stock Warrants Common Stock Public Offering Private Placement Total Balance – January 1, 2023 $ 1,777 $ 596 $ —  $ —  $ 2,373 Change in fair value (647 ) 200 —  —  (447 ) Exercise of warrants (75 ) —  —  —  (75 ) Derecognition of liability to equity (340 ) (589 ) —  —  (929 ) Balance – September 30, 2023 $ 715 $ 207 $ —  $ —  $ 922 Balance – January 1, 2024 $ 642 $ 179 $ —  $ —  $ 821 Fair value at issuance —  —  —  13,157 1,670 14,827 Change in fair value (587 ) (163 ) (7,187 ) (860 ) (8,797 ) Balance – September 30, 2024 $ 55 $ 16 $ 5,970 $ — $ 810 $ 6,851	The following table reconciles the changes in fair value for the years ended December 31, 2023 and 2022 of the warrant liabilities Preferred Stock Warrants Common Stock Total Balance – January 1, 2022 $ 510 $ 231 $ 741 Fair value upon issuance 834 —  834 Change in fair value 456 365 821 Exercise of warrants (23 ) —  (23 ) Balance – December 31, 2022 $ 1,777 $ 596 $ 2,373 Change in fair value (720 ) 172 (548 ) Exercise of warrants (75 ) —  (75 ) Derecognition of liability to equity (340 ) (589 ) (929 ) Balance – December 31, 2023 $ 642 $ 179 $ 821
Schedule of Estimated Fair Value was Measured Using a Monte Carlo Simulation Method	The assumptions used in the Black Scholes option-pricing model for the nine months ended September 30, 2024 and 2023 are as follows: Nine Months 2024 2023 Expected volatility 71 % 86 % Risk-free interest rate 4.36 % 4.50 % Expected dividend yield 0 % 0 % Expected term (in years) 6.1 5.8	The assumptions used in the Black-Scholes option-pricing model are as follows: Year Ended December 31,   2023     2022   Expected volatility 85.8 % 63 % Risk-free interest rate 4.5 % 3.56 % Expected dividend yield —  % —  % Expected term (in years) 5.8 5.8
Public Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Schedule of Changes in Fair Values	The changes in the fair values of the Success Fee derivative liability, 2023 Convertible Notes, Revenue Interest Financing, PIPE Conversion Option, Earn-out Success 2023 Revenue PIPE Earn-Out Term RTW PubCo Base Total Balance – June 30, 2023 $ 213 $ 16,793 $ —  $ —  $ —  $ —  $ —  $ 3,327 $ 3,305 $ 23,638 Fair value upon issuance —  9,150 $ 40,000 3,340 53,040 —  —  —  —  $ 105,530 Change in fair value (201 ) 6,008 (3,400 ) 2,100 (24,330 ) —  —  (599 ) 10,065 $ (10,357 ) Repayments of debt —  (10,250 ) —  —  —  —  —  —  —  $ (10,250 ) Derecognition of liability to equity —  (21,701 ) —  —  —  —  —  (2,728 ) (13,370 ) $ (37,799 ) Balance – September 30, 2023 $ 12 $ —  $ 36,600 $ 5,440 $ 28,710 $ —  $ —  $ —  $ —  $ 70,762 Balance – June 30, 2024 $ 14 $ —  $ 39,000 $ 5,450 $ 4,110 $ —  $ 40,950 $ —  $ —  $ 89,524 Change in fair value —  —  6,704 4,400 (2,260 ) —  (1,790 ) —  —  7,054 Change in fair value – OCI —  —  (5,800 ) —  —  —  (3,070 ) —  —  (8,870 ) Repayments of debt —  —  (1,404 ) —  —  —  —  —  —  (1,404 ) Balance – September 30, 2024 $ 14 $ —  $ 38,500 $ 9,850 $ 1,850 $ —  $ 36,090 $ —  $ —  $ 86,304 Balance – January 1, 2023 $ 178 $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ 178 Fair value upon issuance —  28,700 $ 40,000 3,340 53,040 —  —  3,370 3,264 131,714 Change in fair value (166 ) 3,751 (3,400 ) 2,100 (24,330 ) —  —  (642 ) 10,106 (12,581 ) Repayments of debt —  (10,750 ) —  —  —  —  —  —  —  (10,750 ) Derecognition of liability to equity —  (21,701 ) —  —  —  —  —  (2,728 ) (13,370 ) (37,799 ) Balance – September 30, 2023 $ 12 $ —  $ 36,600 $ 5,440 $ 28,710 $ —  $ —  $ —  $ —  $ 70,762 Balance – January 1, 2024 $ 14 $ —  $ 36,200 $ 5,600 $ 23,990 $ 1,895 $ —  $ —  $ —  $ 67,699 Fair value upon issuance —  —  —  —  —  —  49,100 —  —  49,100 Change in fair value —  —  5,358 4,250 (22,140 ) (1,895 ) (10,020 ) —  —  (24,447 ) Change in fair value – OCI —  —  (600 ) —  —  —  (2,990 ) —  —  (3,590 ) Repayments of debt —  —  (2,458 ) —  —  —  —  —  —  (2,458 ) Balance – September 30, 2024 $ 14 $ —  $ 38,500 $ 9,850 $ 1,850 $ —  $ 36,090 $ —  $ —  $ 86,304	The changes in the fair values of the Success Fee derivative liability, 2023 Convertible Notes, PubCo Additional Shares liability, Base PubCo Shares and Backstop Shares liability, Revenue Interest Financing, PIPE Conversion Option, Earn-out Success 2023 PubCo Base Revenue PIPE Earn-Out Term Total Balance – January 1, 2022 $ 159 $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ 159 Fair value upon issuance —  —  —  —  —  —  —  —  —  Change in fair value 19 —  —  —  —  —  —  —  19 Exercise of warrants —  —  —  —  —  —  —  —  —  Balance – December 31, 2022 $ 178 $ —  $ —  $ —  $ —  $ —  $ —  $ —  $ 178 Fair value upon issuance —  $ 28,700 3,370 3,264 40,000 3,340 53,040 1,895 133,609 Change in fair value (164 ) 3,751 (642 ) 10,106 (3,408 ) 2,260 (29,050 ) —  (17,147 ) Change in fair value – OCI —  —  —  —  700 —  —  —  700 Payments —  (10,750 ) —  —  (1,092 ) —  —  —  (11,842 ) Derecognition of liability to equity —  (21,701 ) (2,728 ) (13,370 ) —  —  —  —  (37,799 ) Balance – December 31, 2023 $ 14 $ —  $ —  $ —  $ 36,200 $ 5,600 $ 23,990 $ 1,895 $ 67,699
Earn-Out Liability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Schedule of Estimated Fair Value was Measured Using a Monte Carlo Simulation Method	The estimated fair value of the Earn-Out September 30, December 31, Stock Price $ 15.25 $ 93.50 Risk-free interest rate 3.6 % 3.9 % Expected term (in years) 3.8 4.6 Expected volatility 105.0 % 87.0 %	The estimated fair value of the earn-out December 31, Stock Price 93.50 Risk-free interest rate 3.9 % Expected term (in years) 4.6 Expected volatility 87.0 %
Revenue Interest Financing and PIPE Conversion Option
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Schedule of Estimated Fair Value was Measured Using a Monte Carlo Simulation Method	The fair value of the PIPE Conversion Option was accounted for as a derivative under ASC 815. The instrument is measured using a Monte Carlo Simulation Method (“MCSM”) using the number of shares convertible of 42,614 and the following assumptions: September 30, December 31, Stock Price $ 15.25 $ 93.50 Risk-free interest rate 4.03 % 4.46 % Expected term (in years) 0.8 1.6 Expected volatility 130.0 % 82.5 %	The fair value of the PIPE Conversion Option was accounted for as a derivative under ASC 815. The instrument is measured using a Monte Carlo Simulation Method using the number of shares convertible of 42,614 and the following assumptions: December 31, Stock Price 93.50 Risk-free interest rate 4.46 % Expected term (in years) 1.6 Expected volatility 82.5 %
RTW Convertible Notes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Schedule of Estimated Fair Value was Measured Using a Monte Carlo Simulation Method	The fair value was measured using the $ million principal amount of the RTW Convertible Notes and the following assumptions: September 30, Stock Price $ 15.25 Risk-free interest rate 3.6 % Expected term (in years) 6.5 Expected volatility 90.0 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Domestic and Foreign Components of Net Loss Before Income Taxes	The components of net loss before income taxes are as follows (in thousands): Year Ended December 31,   2023     2022   U.S. $ (81,259 ) $ (38,267 ) Foreign 916 666 Loss before income taxes $ (80,343 ) $ (37,601 )
Reconciliation of Effective Tax Rate and Statutory Federal Income Tax Rate	The reconciliation between the effective tax rate and the statutory federal income tax rate for the years ended D e e m b r Year Ended December 31,   2023     2022   U.S. statutory federal income tax rate 21.0 % 21.0 % State income taxes, net of federal income tax benefit 7.1 % 6.9 % Change in fair value of financial instruments 3.0 % 0.0 % Tax credits 0.4 % 1.0 % Valuation allowance (30.5 )% (29.0 )% Non-deductible (0.9 )% 0.0 % Other (0.4 )% (0.2 )% Effective tax rate (0.3 )% (0.3 )%
Schedule of Deferred Tax Assets	Significant components of the Company’s deferred tax assets are as follows (in thousands): December 31, 2023 2022 U.S. federal and state net operating loss carryforwards $ 36,092 $ 25,051 Capitalized start-up 10,868 5,377 Research and development tax credits 2,275 1,780 Interest expense 3,918 —  Lease liability 659 838 Depreciation 203 236 Bad debt reserve 3,461 —  Other temporary differences 2,145 994 Total deferred tax assets 59,621 34,276 Valuation allowance (57,985 ) (33,484 ) Net deferred tax assets 1,636 792 Right of use asset (623 ) (792 ) Other deferred tax liability (1,013 ) —  Total deferred tax liabilities (1,636 ) (792 ) Net deferred tax asset $ — $ —
Summary of Valuation Allowance	Changes to the Company’s valuation allowance are as follows (in thousands): Year Ended December 31,   2023     2022   Beginning balances $ 33,484 $ 22,579 Additions charged to net loss 24,501 10,905 Ending balances $ 57,985 $ 33,484

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock and Stockholders' Deficit (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Equity [Abstract]
Summary of Reserved for Issuance Upon the Potential Conversion or Exercise	The number of shares of Common Stock that have been reserved for issuance upon the potential conversion or exercise, as applicable, of the Company’s securities as of September 30, 2024, is as follows: Outstanding options to purchase Common Stock 284,332 Restricted Stock Units 21,230 Warrants to purchase Common Stock 769,257 Shares of Common Stock issued upon the exercise of Public Warrants 750,383 Series A Preferred Stock 90,407 Earn-Out 360,000 Convertible Notes 19,168 Total 2,294,777
Summary of Warrants to Purchase the Classes of Preferred Stock and Common Stock Outstanding	As of September 30, 2024, there were 16,151 Rollover Warrants outstanding to purchase Common Stock. Upon the closing of the Business Combination, certain Legacy Allurion preferred stock and Legacy Allurion common stock warrants that were converted into Rollover Warrants were determined to be equity classified. In connection with the Public Offering and Private Placement, we issued the Public Offering Warrants and Private Placement Warrants. As of September 30, 2024, there were 662,701 Public Offering Warrants and 90,407 Private Placement Warrants outstanding to purchase Common Stock. September 30, 2024 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.2 Common Stock Equity 1,771 $ 61.00 3/30/2021 6.5 Common Stock Liability 5,203 168.25 9/15/2022 8.0 Common Stock Liability 1,810 303.50 6/4/2022 7.7 Common Stock Liability 1,810 303.50 1/17/2017 2.3 Common Stock Equity 2,934 0.50 8/3/2017 2.8 Common Stock Equity 392 28.25 9/8/2017 2.9 Common Stock Liability 1,151 26.25 6/19/2018 3.7 Common Stock Liability 720 26.25 6/25/2019 4.7 Common Stock Liability 360 26.25 7/1/2024 4.8 Common Stock Liability 753,106 30.00 769,257 December 31, 2023 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.9 Common Stock Equity 1,771 $ 61.00 3/30/2021 7.2 Common Stock Liability 5,203 168.25 9/15/2022 8.7 Common Stock Liability 1,810 303.50 6/4/2022 8.4 Common Stock Liability 1,810 303.50 1/17/2017 3.0 Common Stock Equity 2,934 0.50 8/3/2017 3.6 Common Stock Equity 392 28.25 9/8/2017 3.7 Common Stock Liability 1,151 26.25 6/19/2018 4.5 Common Stock Liability 720 26.25 6/25/2019 5.5 Common Stock Liability 360 26.25 16,151	As of December 31, 2023, there were 16,151 such Rollover Warrants outstanding to purchase Common Stock. Upon the closing of the Business Combination, certain Legacy Allurion preferred stock and Legacy Allurion common stock warrants that were converted into Rollover Warrants were determined to be equity classified. December 31, 2023 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.9 Common stock Equity 1,771 $ 61.00 3/30/2021 7.2 Common stock Liability 5,203 168.25 9/15/2022 8.7 Common stock Liability 1,810 303.50 6/4/2022 8.4 Common stock Liability 1,810 303.50 1/17/2017 3.0 Common stock Equity 2,934 0.50 8/3/2017 3.6 Common stock Equity 392 28.25 9/8/2017 3.7 Common stock Liability 1,151 26.25 6/19/2018 4.5 Common stock Liability 720 26.25 6/25/2019 5.5 Common stock Liability 360 26.25 16,151 December 31, 2022 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 4/1/2013 0.2 Series A-1 Liability 663 $ 48.75 12/1/2014 1.9 Series B Preferred Stock Liability 2,431 61.00 3/30/2021 8.2 Series C Preferred Stock Liability 5,203 168.25 9/15/2022 9.7 Series D-1 Liability 1,810 303.50 6/4/2022 9.4 Series D-1 Liability 1,810 303.50 1/17/2017 4.0 Common stock Liability 2,934 0.50 8/3/2017 4.6 Common stock Liability 392 28.25 9/8/2017 4.7 Common stock Liability 1,151 26.25 6/19/2018 5.5 Common stock Liability 720 26.25 6/25/2019 6.5 Common stock Liability 360 26.25 17,474

Capital Stock and Stockholder_2

Capital Stock and Stockholders' Deficit (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Equity [Abstract]
Schedule of Preferred Stock and Common Stock		The following table summarizes details of Legacy Allurion Preferred Stock authorized, issued, and outstanding immediately prior to the Business Combination and prior to giving effect to the Reverse Stock Split (in thousands, except share amounts): Preferred Stock (1) Preferred Stock Carrying Series A Preferred Stock 2,276,786 2,276,786 $ 1,542 Series A-1 1,513,028 1,486,048 2,842 Series B Preferred Stock 2,298,929 2,245,515 5,253 Series C Preferred Stock 8,113,616 7,927,446 39,122 Series D-1 1,684,565 842,283 9,614 Series D-2 3,644,616 3,644,616 24,054 Series D-3 1,498,348 1,498,348 14,789 Total 21,029,888 19,921,042 $ 97,216 The number of sh ares of Common Stock that have been reserved for the potential conversion or exercise, as applicable, of the Company’s securities as of December 31, 2023, is as follows: Outstanding options to purchase common stock 155,441 Restricted Stock Units 25,745 Warrants to purchase preferred stock (as converted to warrants to purchase common stock) 5,557 Warrants to purchase common stock 10,594 Public warrants to purchase common stock 750,394 Earn-Out 360,000 Total 1,307,731
Summary of Warrants to Purchase the Classes of Preferred Stock and Common Stock Outstanding	As of September 30, 2024, there were 16,151 Rollover Warrants outstanding to purchase Common Stock. Upon the closing of the Business Combination, certain Legacy Allurion preferred stock and Legacy Allurion common stock warrants that were converted into Rollover Warrants were determined to be equity classified. In connection with the Public Offering and Private Placement, we issued the Public Offering Warrants and Private Placement Warrants. As of September 30, 2024, there were 662,701 Public Offering Warrants and 90,407 Private Placement Warrants outstanding to purchase Common Stock. September 30, 2024 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.2 Common Stock Equity 1,771 $ 61.00 3/30/2021 6.5 Common Stock Liability 5,203 168.25 9/15/2022 8.0 Common Stock Liability 1,810 303.50 6/4/2022 7.7 Common Stock Liability 1,810 303.50 1/17/2017 2.3 Common Stock Equity 2,934 0.50 8/3/2017 2.8 Common Stock Equity 392 28.25 9/8/2017 2.9 Common Stock Liability 1,151 26.25 6/19/2018 3.7 Common Stock Liability 720 26.25 6/25/2019 4.7 Common Stock Liability 360 26.25 7/1/2024 4.8 Common Stock Liability 753,106 30.00 769,257 December 31, 2023 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.9 Common Stock Equity 1,771 $ 61.00 3/30/2021 7.2 Common Stock Liability 5,203 168.25 9/15/2022 8.7 Common Stock Liability 1,810 303.50 6/4/2022 8.4 Common Stock Liability 1,810 303.50 1/17/2017 3.0 Common Stock Equity 2,934 0.50 8/3/2017 3.6 Common Stock Equity 392 28.25 9/8/2017 3.7 Common Stock Liability 1,151 26.25 6/19/2018 4.5 Common Stock Liability 720 26.25 6/25/2019 5.5 Common Stock Liability 360 26.25 16,151	As of December 31, 2023, there were 16,151 such Rollover Warrants outstanding to purchase Common Stock. Upon the closing of the Business Combination, certain Legacy Allurion preferred stock and Legacy Allurion common stock warrants that were converted into Rollover Warrants were determined to be equity classified. December 31, 2023 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 12/1/2014 0.9 Common stock Equity 1,771 $ 61.00 3/30/2021 7.2 Common stock Liability 5,203 168.25 9/15/2022 8.7 Common stock Liability 1,810 303.50 6/4/2022 8.4 Common stock Liability 1,810 303.50 1/17/2017 3.0 Common stock Equity 2,934 0.50 8/3/2017 3.6 Common stock Equity 392 28.25 9/8/2017 3.7 Common stock Liability 1,151 26.25 6/19/2018 4.5 Common stock Liability 720 26.25 6/25/2019 5.5 Common stock Liability 360 26.25 16,151 December 31, 2022 Issuance Date Remaining Underlying Equity Instrument Balance Sheet Shares Issuable Weighted 4/1/2013 0.2 Series A-1 Liability 663 $ 48.75 12/1/2014 1.9 Series B Preferred Stock Liability 2,431 61.00 3/30/2021 8.2 Series C Preferred Stock Liability 5,203 168.25 9/15/2022 9.7 Series D-1 Liability 1,810 303.50 6/4/2022 9.4 Series D-1 Liability 1,810 303.50 1/17/2017 4.0 Common stock Liability 2,934 0.50 8/3/2017 4.6 Common stock Liability 392 28.25 9/8/2017 4.7 Common stock Liability 1,151 26.25 6/19/2018 5.5 Common stock Liability 720 26.25 6/25/2019 6.5 Common stock Liability 360 26.25 17,474

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Loss per Share	Basic and diluted net loss per share was calculated as follows: Three Months Ended Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss $ (9,004 ) $ (21,630 ) $ (5,580 ) $ (61,427 ) Cumulative undeclared preferred dividends to participating securities (Legacy Series D convertible preferred stock) —  (255 ) —  (1,697 ) Net loss attributable to common shareholders $ (9,004 ) $ (21,885 ) $ (5,580 ) $ (63,124 ) Denominator: Basic and diluted weighted-average common stock outstanding 2,563,459 1,613,425 2,132,416 1,262,346 Net loss per share, basic and diluted (3.51 ) (13.56 ) (2.62 ) (50.01 )	Basic and diluted net loss per share was calculated as follows: Year Ended December 31, 2023 2022 Numerator: Net loss $ (80,607 ) $ (37,744 ) Cumulative undeclared dividends to participating securities (Legacy Series D convertible preferred stock) (1,697 ) (2,907 ) Net loss attributable to common stockholders $ (82,304 ) $ (40,651 ) Denominator: Basic and diluted weighted-average common stock outstanding 1,423,275 1,076,743 Net loss per share attributable to common stockholders, basic and diluted (1) $ (57.83 ) $ (37.75 ) (1) The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods prior to the Business Combination have been retrospectively adjusted to the equivalent number of shares outstanding immediately after the Business Combination to effect the reverse capitalization. See Note 3 for further information. The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods have also been retrospectively adjusted to give effect to the R everse
Summary of Dilutive Securities Excluded from Computation of Basic and Diluted Net Loss Per Common Share	The Company excluded the following potential shares of Common Stock, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: As of September 30, 2024 2023 Outstanding options to purchase Common Stock 284,332 170,810 Restricted Stock Units 21,230 17,173 Series A Preferred Stock 90,407 —  Warrants to purchase Common Stock 769,257 16,200 Shares of Common Stock issued upon the exercise of Public Warrants 750,383 750,394 Earn-Out 360,000 360,000 Convertible Notes 19,168 —  Total 2,294,777 1,314,577	The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Year Ended 2023 2022 Outstanding options to purchase common stock 155,441 172,079 Restricted Stock Units 25,745 56,605 Warrants to purchase preferred stock (as converted to warrants to purchase common stock) 5,557 11,917 Warrants to purchase common stock 10,594 5,557 Shares of Common Stock issued upon the exercise of Public Warrants 750,394 —  Earn-Out 360,000 —  Convertible notes (as converted to common stock) — 6,851 Total 1,307,731 253,009

Stock Based Compensation (Table

Stock Based Compensation (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Stock-based Compensation Expense	Stock-based compensation expense included in the condensed consolidated statement of operations was as follows: Three Months Ended Nine Months Ended  2024   2023   2024   2023  Cost of revenue $ 13 $ 16 $ 24 $ 31 Selling, general and administrative 791 5,477 2,109 6,235 Research and development 56 46 84 83 Total stock-based compensation expense $ 860 $ 5,539 $ 2,217 $ 6,349	Stock-based compensation expense included in the consolidated statement of operations and comprehensive loss was as follows: Year Ended December 31,   2023     2022   Cost of revenue $ 32 $ —  Selling, general, and administrative 8,198 400 Research and development 127 37 Total stock-based compensation expense $ 8,357 $ 437
Summary of Option Activity Under the Plan	The following table summarizes the option activity under the 2010 Plan, 2020 Plan, and the 2023 Plan during the nine months ended September 30, 2024: Number of Weighted Weighted Aggregate (per option) (in years) (in thousands) Outstanding—January 1, 2024 155,441 $ 66.75 6.9 $ 5,565 Granted 147,443 46.50 Cancellations and forfeitures (17,906 ) 57.00 Exercised (646 ) 34.25 Outstanding—September 30, 2024 284,332 57.00 7.9 —  Exercisable at September 30, 2024 114,913 $ 62.00 5.9 $ —	The following tables summarizes the option activity under the 2010 Plan, 2020 Plan, and the 2023 Plan during the year ended December 31, 2023: Number Weighted Weighted Aggregate (per option) (in years) (in thousands) Outstanding—January 1, 2023 172,079 $ 58.75 7.7 $ 9,437 Granted 10,308 135.25 Cancellations and forfeitures (15,003 ) 50.00 Exercised (11,943 ) 28.75 Outstanding—December 31, 2023 155,441 $ 66.75 6.9 $ 5,565 Exercisable at December 31, 2023 109,436 $ 55.75 6.2 $ 4,812
Schedule of Assumptions Used in Black-Scholes Option Pricing Model	The assumptions used in the Black Scholes option-pricing model for the nine months ended September 30, 2024 and 2023 are as follows: Nine Months 2024 2023 Expected volatility 71 % 86 % Risk-free interest rate 4.36 % 4.50 % Expected dividend yield 0 % 0 % Expected term (in years) 6.1 5.8	The assumptions used in the Black-Scholes option-pricing model are as follows: Year Ended December 31,   2023     2022   Expected volatility 85.8 % 63 % Risk-free interest rate 4.5 % 3.56 % Expected dividend yield —  % —  % Expected term (in years) 5.8 5.8
Summary of Restricted Stock Unit Activity Under the Plan	The following table summarizes the restricted stock unit activity under the 2020 Plan and 2023 Plan during the three months ended September 30, 2024: Number of RSUs Weighted (per share) Outstanding—January 1, 2024 25,745 $ 111.25 Granted 3,000 65.25 Cancellations and forfeitures —  —  Vested (7,515 ) 112.75 Outstanding—September 30, 2024 21,230 $ 104.00	The following table summarizes the restricted stock unit activity under the 2020 Plan and 2023 Plan during the year ended December 31, 2023: Number of Weighted Grant (per share) Outstanding—January 1, 2023 56,605 $ 112.75 Granted 9,047 108.00 Cancellations and forfeitures (3,170 ) 112.75 Vested (36,737 ) 112.75 Outstanding—December 31, 2023 25,745 111.25

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of Other Pertinent Lease Information	Other pertinent lease information for the three and nine months ended September 30, 2024 and 2023 is as follows (in thousands): Three Months Nine Months 2024 2023 2024 2023 Operating lease costs $ 259 $ 285 $ 794 $ 834 Short-term lease costs 3 5 23 17 Variable lease costs 59 52 194 211 Operating cash flows paid for amounts in the 271 284 826 815 Operating lease assets obtained in exchange —  62 15 936	Other pertinent lease information is as follows (in thousands): December 31, December 31, Operating lease costs $ 1,123 $ 918 Short-term lease costs 12 14 Variable operating lease costs 187 191 Operating cash flows paid for amounts in the measurement of lease liabilities 1,084 807 Operating lease assets obtained in exchange for lease obligations 936 1,677
Schedule of Future Commitments Under Non-cancelable Operating Lease Agreements	Future commitments under non-cancelable 2024 $ 273 2025 1,044 2026 739 2027 646 2028 108 Total lease payments $ 2,810 Less: present value adjustment (354 ) Total lease liabilities 2,456 Less: current lease liability (878 ) Long-term operating lease liabilities $ 1,578	Future commitments under non-cancelable 2024 $ 1,173 2025 1,114 2026 737 2027 645 2028 108 Total lease payments $ 3,777 Less: present value adjustment (563 ) Present value of total lease liabilities 3,214 Less: current lease liability (908 ) Long-term lease liabilities $ 2,306
Schedule of Weighted-Average Remaining Lease Terms and Discount Rates Related Leases	The weighted-average remaining lease terms and discount rates related to our leases were as follows: September 30, September 30, Weighted-average remaining lease term 2.9 3.7 Weighted-average discount rate 9.9 % 9.9 %	The weighted-average remaining lease terms and discount rates related to our leases were as follows: 2023 2022 Weighted-average remaining lease term (in years) 3.5 3.9 Weighted-average discount rate 9.9 % 9.5 %

Geographic Information (Tables)

Geographic Information (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Segment Reporting [Abstract]
Schedule of Long-lived Assets by Geography	Long-lived assets, consisting of property and equipment, net and ROU assets by geography were as follows (in thousands): September 30, December 31, United States $ 4,690 $ 5,381 France $ 673 1,010 All other countries —  —  Long-lived assets $ 5,363 $ 6,391	L December 31, 2023 2022 United States $ 5,381 $ 3,999 France 1,010 1,282 All other countries —  —  Long-lived assets $ 6,391 $ 5,281

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Details)			3 Months Ended						9 Months Ended		12 Months Ended
	Dec. 23, 2024 $ / shares shares	Aug. 01, 2023 shares	Sep. 30, 2024 USD ($) Country $ / shares shares	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2024 USD ($) Country $ / shares shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) Country $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 16, 2024 $ / shares shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of countries, currently markets the program | Country			50						50		50
Common stock, par value | $ / shares			$ 0.0001						$ 0.0001		$ 0.0001	$ 0.0001
Gains (losses) from foreign currency translation adjustment | $			$ 400,000			$ (300,000)				$ (300,000)	$ 100,000	$ (700,000)
Net losses | $			9,004,000	$ 2,162,000	$ (5,586,000)	21,630,000	$ 21,996,000	$ 17,801,000	$ 5,580,000	61,427,000	80,607,000	37,744,000
Cash outflows from operating activities | $									29,026,000	43,111,000	63,982,000	46,981,000
Losses from operations | $			12,341,000			$ 26,154,000			33,083,000	$ 53,340,000	79,078,000	32,010,000
Accumulated deficit | $			$ 218,379,000						$ 218,379,000		$ 212,799,000	$ 132,192,000
Common stock, shares outstanding | shares		1,892,058	2,574,783						2,574,783		1,907,529	1,083,196
Weighted Average Exercise Price | $ / shares			$ 202.5						$ 202.5		$ 202.5
Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Gains (losses) from foreign currency translation adjustment | $									$ 100,000
Common Stock | Public Warrants
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Public share warrants exercisable | shares		0.056818
Common Stock | Subsequent Event [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stockholders' equity note, stock split	reverse stock split, adjusted for the 25:1 reverse stock split ratio
Common Stock | Subsequent Event [Member] | Public Warrants
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Public share warrants issued | shares	25
Public share warrants exercisable | shares	0.056818
Weighted Average Exercise Price | $ / shares	$ 202.5
Public share warrants exercisable before reverse stock split | shares	1.420455
Common Stock | Reverse Stock Split [Member] | Subsequent Event [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value | $ / shares													$ 0.0001
Common stock, shares outstanding | shares	25												25
Common Stock | Business Combination Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Exchange ratio		0.978
Common stock, par value | $ / shares											$ 0.0001

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)			3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 01, 2023	Feb. 09, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Sales and marketing			$ 5,197,000	$ 13,989,000	$ 18,060,000	$ 36,127,000	$ 46,857,000	$ 50,405,000
Advertising and marketing costs							10,800,000	16,000,000
Uncertain tax positions for which reserves would be required			$ 0	$ 0	$ 0	0	0	0
Proceeds from revenue interest financing						$ 40,000,000	40,000,000
Revenue Interest Financing Agreement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Proceeds from revenue interest financing	$ 40,000,000
Shipping and Logistics
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Sales and marketing							3,300,000	3,600,000
Other Long-Term Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred offering costs							$ 0	$ 2,300,000
New Allurion | Revenue Interest Financing Agreement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Proceeds from revenue interest financing	$ 40,000,000
ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in accounting principle accounting standards update adopted							true
Change in accounting principle accounting standards update adoption date							Jan. 01, 2023
Change in accounting principle accounting standards update immaterial effect							true
ASU 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in accounting principle accounting standards update adopted			true		true
Change in accounting principle accounting standards update adoption date			Jan. 01, 2024		Jan. 01, 2024
Change in accounting principle accounting standards update immaterial effect			true		true
Total Revenue | Customer Concentration Risk | Customers
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk, percentage			10%	10%	10%	10%	10%	10%
Accounts Receivable | Customer Concentration Risk | Customers
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk, percentage					10%		10%	10%
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Earn-out shares receivable	360,000
Maximum | Revenue Interest Financing Agreement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percentage of annual net sales		6%
Remittance of revenue interest payments percentage		10%
Additional revenue interest		$ 7,500,000
Maximum | New Allurion | Revenue Interest Financing Agreement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percentage of annual net sales		6%
Remittance of revenue interest payments percentage		10%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Risk of Concentration of Credit, Significant Customers (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Total Revenue | Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	18%	19%		12%	10%
Total Revenue | Customer B
Concentration Risk [Line Items]
Concentration risk, percentage		11%				11%
Accounts Receivable | Customer A
Concentration Risk [Line Items]
Concentration risk, percentage			15%		16%
Accounts Receivable | Customer C
Concentration Risk [Line Items]
Concentration risk, percentage						13%
Accounts Receivable | Customer D
Concentration Risk [Line Items]
Concentration risk, percentage						12%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Reconciliation of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Cash and cash equivalents	$ 28,654	$ 38,037	$ 7,685
Restricted cash included in other long-term assets	$ 391	$ 384	$ 338
Restricted Cash and Cash Equivalents, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent	Other Assets, Noncurrent
Cash and cash equivalents and restricted cash shown in the statement of cash flows	$ 29,045	$ 38,421	$ 8,023

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Activity in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Balance at beginning of period	$ (12,671)	$ (741)	$ (741)	$ (354)
Provision for uncollectible accounts	$ (1,065)	$ (4,953)	(12,675)	(436)
Uncollectible accounts written off			745	49
Balance at end of period			$ (12,671)	$ (741)

Business Combination - Addition

Business Combination - Additional Information (Details)

3 Months Ended

9 Months Ended

12 Months Ended

Oct. 22, 2024 USD ($) shares

Aug. 01, 2023 USD ($) $ / shares shares

Sep. 30, 2024 USD ($) shares

Mar. 31, 2024 shares

Sep. 30, 2023 shares

Jun. 30, 2023 shares

Mar. 31, 2023 shares

Sep. 30, 2023 USD ($)

Dec. 31, 2023 USD ($) shares

Dec. 23, 2024 shares

Feb. 09, 2023 USD ($)

Dec. 31, 2022 USD ($) shares

Business Acquisition [Line Items]

Proceeds from revenue interest financing | $

$ 40,000,000

$ 40,000,000

Warrants outstanding

16,151

16,151

Warrants converted into warrants exercisable

769,257

16,151

17,474

Outstanding public warrants to purchase

750,394

Transaction costs | $

$ 22,700,000

Additional paid-in capital | $

15,200,000

$ 150,696,000

$ 143,010,000

$ 99,877,000

Business combination expense | $

5,000,000

Business combination one-time insurance payment | $

3,600,000

Warrant liabilities | $

7,381,000

6,765,000

Earn-out liabilities | $

53,000,000

1,850,000

23,990,000

General and Administrative

Business Acquisition [Line Items]

Business combination expense | $

5,000,000

Fortress Term Loan

Business Acquisition [Line Items]

Issuance costs | $

$ 2,500,000

Public Warrants

Business Acquisition [Line Items]

Warrants outstanding

528,277

Warrant liabilities | $

$ 13,800,000

Business Combination Agreement

Business Acquisition [Line Items]

Sponsor loan excess amount | $

3,700,000

Revenue Interest Financing Agreement

Business Acquisition [Line Items]

Proceeds from revenue interest financing | $

40,000,000

Direct costs and fees | $

1,200,000

Issuance costs | $

1,200,000

Revenue Interest Financing Agreement | Maximum

Business Acquisition [Line Items]

Percentage of annual net sales

6%

Remittance of revenue interest payments percentage

10%

Conversion of PIPE subscription to revenue interest finance | $

$ 7,500,000

$ 7,500,000

Conversion of PIPE investment to revenue interest finance | $

$ 7,500,000

$ 7,500,000

Revenue Interest Financing Agreement | New Allurion

Business Acquisition [Line Items]

Proceeds from revenue interest financing | $

$ 40,000,000

Revenue Interest Financing Agreement | New Allurion | Maximum

Business Acquisition [Line Items]

Percentage of annual net sales

6%

Remittance of revenue interest payments percentage

10%

RTW Side Letter | Subsequent Events

Business Acquisition [Line Items]

Number of surrender shares of common stock

30,000

Surrender common stock value | $

$ 7,500,000

Fortress Credit Agreement

Business Acquisition [Line Items]

Shares issued

38,000

Fortress Credit Agreement | Term Loan Facility

Business Acquisition [Line Items]

Term loan borrowed | $

$ 60,000,000

Backstop Agreement

Business Acquisition [Line Items]

Aggregate principal amount | $

$ 2,000,000

Shares issued upon conversion of convertible notes

28,000

RSU Forfeiture Agreement

Business Acquisition [Line Items]

Number of shares forfeited

3,170

PIPE Subscription Agreements

Business Acquisition [Line Items]

Aggregate purchase of shares

215,468

Purchase price per share | $ / shares

$ 176

Aggregate purchase price | $

$ 37,900,000

Common Stock

Business Acquisition [Line Items]

Shares issued

653,351

5,730

Outstanding public warrants to purchase

200

20

143

Common Stock | Public Warrants

Business Acquisition [Line Items]

Public share warrants exercisable

0.056818

Common Stock | Public Warrants | Subsequent Events

Business Acquisition [Line Items]

Public share warrants exercisable

0.056818

Common Stock | Convertible Notes

Business Acquisition [Line Items]

Accured interest | $

$ 21,800,000

Shares issued upon conversion of convertible notes

132,049

Aggregate recognition APIC amount | $

$ 25,600,000

Common Stock | Business Combination Agreement

Business Acquisition [Line Items]

Exchange ratio

0.978

Conversion of shares

21,023

Sale of stock | $ / shares

$ 202.5

Common Stock | Business Combination Agreement | Warrant Amendment

Business Acquisition [Line Items]

Sale of stock | $ / shares

$ 202.5

Common Stock | RTW Side Letter

Business Acquisition [Line Items]

Shares issued

10,000

Common Stock | Backstop Agreement

Business Acquisition [Line Items]

Shares issued

28,000

Common Stock | HVL Termination Agreement

Business Acquisition [Line Items]

Shares issued

15,508

Common Stock | Gaur Contribution Agreement

Business Acquisition [Line Items]

Contribution of capital

3,170

Class A Common Stock | Business Combination Agreement

Business Acquisition [Line Items]

Conversion of shares

1.420455

Class A Common Stock | Sponsor Contribution Agreement

Business Acquisition [Line Items]

Contribution of capital

161,379

Class A Common Stock | Sponsor Support Agreement | CPUH Stockholders

Business Acquisition [Line Items]

Warrants outstanding

12,833,333

Warrants converted into warrants exercisable

2,088,327

Shares issued upon conversion

21,120

Class B Common Stock | Sponsor Support Agreement | CPUH Stockholders

Business Acquisition [Line Items]

Recapitalization of common stock

21,442,500

Recapitalization of additional shares

30,000

Business Combination - Reconcil

Business Combination - Reconciles of Business Combination to Condensed Consolidated Statement (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Business Acquisition [Line Items]
Gross Proceeds	$ 76,317
Less: transaction costs paid	(14,665)
Net proceeds from the Business Combination	61,652
Less: warrant liabilities assumed	(13,762)
Less: repayment of note assumed in the Business Combination	(2,500)
Less: accrued transaction costs at December 31, 2023	(580)
Reverse merger, net of transaction costs	44,810
Cash - CPUH trust
Business Acquisition [Line Items]
Gross Proceeds	38,395
Cash - PIPE Investors
Business Acquisition [Line Items]
Gross Proceeds	$ 37,922

Business Combination - Number o

Business Combination - Number of Shares of Allurion Common Stock Outstanding (Details) - shares	Sep. 30, 2024	Dec. 31, 2023	Aug. 01, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination	2,574,783	1,907,529	1,892,058	1,083,196
Legacy Allurion Equityholders
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination			1,115,896
CPUH Stockholders
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination			206,628
Shares Issued to PIPE Investors
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination			215,468
Shares issued to RTW and Fortress
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination			76,000
Shares Issued to Convertible Note Holders
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination			132,049
CPUH Sponsor Shares
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination			130,509
Side Letter Termination Shares
Business Acquisition [Line Items]
Total shares of Common Stock immediately after Business Combination			15,508

Revenue - Additional Informatio

Revenue - Additional Information (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($) Country	Sep. 30, 2023 USD ($) Country	Sep. 30, 2024 USD ($) Country	Sep. 30, 2023 USD ($) Country	Dec. 31, 2023 USD ($) Country	Dec. 31, 2022 USD ($) Country
Disaggregation of Revenue [Line Items]
Revenue | $	$ 1,800	$ 5,900	$ 7,200	$ 11,100	$ 13,300	$ 16,000
Number of countries generate revenue | Country	5	5	5	5	4	4
United States
Disaggregation of Revenue [Line Items]
Revenue | $	$ 0		$ 0		$ 0
Each Country | Revenue from Contract with Customer Benchmark | Geographic Concentration Risk | Minimum
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	5%	5%	4%	4%	5%	6%
Each Country | Revenue from Contract with Customer Benchmark | Geographic Concentration Risk | Maximum
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	8%	7%	8%	7%	9%	7%
All Other Countries
Disaggregation of Revenue [Line Items]
Number of countries generate revenue by sales | Country	36	45	49	58	55	50
Four Countries Included Within All Other Countries | Revenue from Contract with Customer Benchmark | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	34%	33%	27%	25%	25%	25%

Revenue - Schedule of Revenues

Revenue - Schedule of Revenues by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 5,367	$ 18,200	$ 26,519	$ 45,232	$ 53,467	$ 64,211
Spain
Disaggregation of Revenue [Line Items]
Revenue			3,001	3,715	4,618	6,852
United Kingdom
Disaggregation of Revenue [Line Items]
Revenue			2,534	3,456
France
Disaggregation of Revenue [Line Items]
Revenue			2,431	4,423	5,569	6,032
Turkey
Disaggregation of Revenue [Line Items]
Revenue	966	3,517	1,573	5,495	5,494	4,079
Australia
Disaggregation of Revenue [Line Items]
Revenue	543	979
Italy
Disaggregation of Revenue [Line Items]
Revenue	511	626
Chile
Disaggregation of Revenue [Line Items]
Revenue		1,956			2,708	5,008
All Other Countries
Disaggregation of Revenue [Line Items]
Revenue	$ 3,347	$ 11,122	$ 16,980	$ 28,143	$ 35,078	$ 42,240

Inventory - Schedule of Invento

Inventory - Schedule of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Inventory, Gross [Abstract]
Finished goods	$ 2,748	$ 3,427	$ 2,096
Work in progress	1,005	967	213
Raw materials	815	1,777	1,556
Total Inventory	$ 4,568	$ 6,171	$ 3,865

Inventory - Additional Informat

Inventory - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Inventory [Line Items]
Provision for excess and obsolete inventory	$ 0.7		$ 0
Maximum
Inventory [Line Items]
Provision for excess and obsolete inventory		$ 0.1

Property and Equipment, net - S

Property and Equipment, net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 6,359	$ 5,745	$ 4,650
Less: accumulated depreciation and amortization	(4,169)	(3,559)	(2,851)
Construction in progress	890	1,195	583
Property and equipment net	$ 3,080	$ 3,381	2,382
Computers and purchased software
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years	3 years
Property and equipment at cost	$ 618	$ 618	575
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 1,943	$ 1,943	1,822
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years	5 years
Property and equipment at cost	$ 291	$ 291	251
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 3,507	$ 2,893	$ 2,002
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years	3 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years	5 years

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 0.2	$ 0.2	$ 0.8	$ 0.6	$ 0.7	$ 0.9

Property and Equipment, net -_2

Property and Equipment, net - Schedule of Depreciation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 215	$ 160	$ 778	$ 558	$ 746	$ 895
Cost of Revenue
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	119	63	433	280	367	568
Research and Development
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	63	48	161	131	179	90
General and Administrative
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	19	34	104	104	138	160
Sales and Marketing
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 14	$ 15	$ 80	$ 43	$ 62	$ 57

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
Distributor fees and marketing reimbursements	$ 930	$ 2,834	$ 6,348
Accrued compensation	1,733	1,687	3,453
Accrued clinical trials and R&D	81	3,694	228
Accrued selling and marketing	592	1,110	481
Accrued professional fees	493	1,505	2,105
Accrued interest			489
Accrued warranty	16	44	48
Accrued restructuring		655
Other accrued expenses	4,128	3,966	2,641
Total accrued expenses and other current liabilities	$ 7,973	$ 15,495	$ 15,793

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2024	Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0		$ 1,000,000
Payments for restructuring	$ 0	$ 700,000	$ 400,000
Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 100,000

Debt - Summary of Components of

Debt - Summary of Components of Third-Party Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total principal amount of debt	$ 49,320	$ 43,100	$ 58,103
Change in fair value	(13,230)
Plus: Accretion		148	213
Less: current portion of long-term debt, net of discounts	0	(38,643)	(53,360)
Less: unamortized deferred financing costs and debt discounts		(4,605)	(1,853)
Long-term debt, net of current portion and discounts	36,090		3,103
Convertible Notes
Debt Instrument [Line Items]
Total principal amount of debt			3,103
RTW Convertible Notes
Debt Instrument [Line Items]
Total principal amount of debt	$ 49,320
2021 Term Loan
Debt Instrument [Line Items]
Total principal amount of debt			$ 55,000
Fortress Term Loan
Debt Instrument [Line Items]
Total principal amount of debt		$ 43,100

Debt - Additional Information (

Debt - Additional Information (Details)					1 Months Ended					3 Months Ended		4 Months Ended		5 Months Ended	7 Months Ended		9 Months Ended		12 Months Ended
	Apr. 16, 2024 USD ($)	Apr. 14, 2024 USD ($) $ / shares	Aug. 01, 2023 USD ($) $ / shares shares	May 02, 2023 USD ($)	Aug. 31, 2023	Sep. 30, 2022 USD ($) shares	Jan. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) shares	Mar. 31, 2021 USD ($)	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Apr. 16, 2024 USD ($)	Sep. 30, 2022 USD ($) shares	Dec. 31, 2023 USD ($) shares	Aug. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) shares	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 29, 2023 USD ($)
Debt Instrument [Line Items]
Principal balance										$ 49,320,000				$ 43,100,000		$ 58,103,000	$ 49,320,000		$ 43,100,000	$ 58,103,000
Loss on extinguishment of debt/ term loan											$ 3,929,000						$ 8,713,000	$ 3,929,000	$ 3,929,000
Warrants converted into warrants exercisable | shares										769,257				16,151		17,474	769,257		16,151	17,474
Proceeds from issuance of convertible notes																	$ 48,000,000	28,700,000	$ 28,700,000	$ 1,103,000
Repayment of convertible debt																		10,750,000	10,750,000
Other income, net										$ 757,000	389,000						1,928,000	133,000	(643,000)	(344,000)
Gain in fair value of revenue interest financing										6,700,000							5,400,000
Change in fair value of revenue interest financing										5,800,000							600,000		$ (700,000)
RTW Convertible Notes
Debt Instrument [Line Items]
Principal balance										49,320,000							49,320,000
Issuance costs										1,400,000							1,400,000
Proceeds from issuance of convertible notes																	49,100,000
Other income, net																	1,100,000
Gain in fair value of revenue interest financing										1,800,000							10,000,000
Change in fair value of revenue interest financing										3,100,000							$ 3,000,000
Backstop Agreement
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes			$ 2,000,000
Shares issued upon conversion of outstanding notes | shares			28,000
Fortress Credit Agreement
Debt Instrument [Line Items]
Interest, frequency of payment																	The Fortress Term Loan had a maturity date of June 30, 2027 and accrued interest per annum at a rate of 6.44% plus the greater of (i) the Wall Street Journal Prime Rate and (ii) 3.0%, which interest was payable in arrears on a monthly basis. The Fortress Term Loan provided for an exit payment equal to 3.0% of the Fortress Term Loan (the “Exit Fee”) due upon prepayment or the maturity date of the Fortress Term Loan, in addition to any early prepayment fee.		The Fortress Term Loan has a maturity date of June 30, 2027 and accrues interest per annum at a rate of 6.44% plus the greater of (i) the Wall Street Journal Prime Rate and (ii) 3.0%, which interest is payable in arrears on a monthly basis. An exit payment equal to 3.0% of the Fortress Term Loan (the “Exit Fee”) is due upon prepayment or the maturity date of the Fortress Term Loan, in addition to any early prepayment fee.
2021 Convertible Notes
Debt Instrument [Line Items]
Interest expense																			$ 100,000	100,000
Proceeds from issuance of convertible notes								$ 2,000,000
Interest rate								5%
Debt instrument, term								36 months
Debt instrument maturity date															Dec. 31, 2026
Unamortized debt issuance costs								$ 0
Conversion divided by capped conversion price								600,000,000
2021 Convertible Notes | Common Stock
Debt Instrument [Line Items]
Shares issued upon conversion of outstanding notes | shares			5,345
Aggregate recognition APIC amount			$ 2,200,000
2021 Convertible Notes | Maximum
Debt Instrument [Line Items]
Interest expense											100,000							100,000
2022 Convertible Notes
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes							$ 1,100,000
Interest rate							5%
Debt instrument, term							36 months
2022 Convertible Notes | Common Stock
Debt Instrument [Line Items]
Shares issued upon conversion of outstanding notes | shares			3,329
Aggregate recognition APIC amount			$ 1,200,000
2022 Convertible Notes | Maximum
Debt Instrument [Line Items]
Interest expense											100,000							100,000	100,000	200,000
2023 Convertible Notes
Debt Instrument [Line Items]
Interest expense											100,000							500,000	500,000
Proceeds from issuance of convertible notes															$ 28,700,000
Repayment of principal			500,000
Interest rate					7%										7%
Debt instrument maturity date															Dec. 31, 2026
Conversion divided by discounted capped conversion price															$ 217,300,000
Capped price															$ 260,000,000
Percentage of conversion discounted price is calculated of cash price															85%
Repayment of convertible debt			2,000,000
Debt prepayment penalty			$ 1,500,000
Initial conversion price per share | $ / shares			$ 176
2023 Convertible Notes | Common Stock
Debt Instrument [Line Items]
Shares issued upon conversion of outstanding notes | shares			123,376
Aggregate recognition APIC amount			$ 22,200,000
Side Letter Holder Bridge Note
Debt Instrument [Line Items]
Principal balance			6,300,000
Proceeds from issuance of convertible notes			$ 2,700,000
Shares issued upon conversion of outstanding notes | shares			15,508
Aggregate recognition APIC amount			$ 2,700,000
Repayment of convertible debt			6,300,000
Debt instrument, convertible price for calculating equity securities			$ 125
Deferred liability for issuance of additional shares				$ 3,400,000
Side Letter Holder Bridge Note | Common Stock
Debt Instrument [Line Items]
Shares issued upon conversion of outstanding notes | shares			12,000
Side Letter Holder Bridge Note | Minimum
Debt Instrument [Line Items]
Repayment of convertible debt			$ 6,000,000
Side Letter Holder Bridge Note | Backstop Agreement
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes			2,000,000
Deferred liability for issuance of additional shares				3,300,000
Side Letter Holder Bridge Note | Backstop Agreement | Maximum
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes				2,000,000
Note Purchase Agreement | RTW Convertible Notes
Debt Instrument [Line Items]
Interest rate		6%
Debt instrument maturity date		Apr. 16, 2031
Principal amount		$ 48,000,000
Note Purchase Agreement | Common Stock | RTW Convertible Notes
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes		$ 15,000,000
Initial conversion rate		24.692
Debt instrument, principal amount for conversion into common stock		$ 1,000
Initial conversion price per share | $ / shares		$ 40.5
Premium percentage of stock price trigger		35%
Maximum percentage of number of shares of common stock outstanding		1%
Note Purchase Agreement | Maximum
Debt Instrument [Line Items]
Unrestricted cash		$ 12,500,000
HVL Bridge Note
Debt Instrument [Line Items]
Principal balance			6,300,000
Proceeds from issuance of convertible notes			$ 2,700,000
Shares issued upon conversion of outstanding notes | shares			15,508
Aggregate recognition APIC amount			$ 2,700,000
Repayment of convertible debt			6,300,000
Debt instrument, convertible price for calculating equity securities			$ 125
Deferred liability for issuance of additional shares				3,400,000
HVL Bridge Note | Common Stock
Debt Instrument [Line Items]
Shares issued upon conversion of outstanding notes | shares			12,000
HVL Bridge Note | Minimum
Debt Instrument [Line Items]
Repayment of convertible debt			$ 6,000,000
HVL Bridge Note | Backstop Agreement
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes			2,000,000
Deferred liability for issuance of additional shares				3,300,000
HVL Bridge Note | Backstop Agreement | Maximum
Debt Instrument [Line Items]
Proceeds from issuance of convertible notes				$ 2,000,000
2021 Term Loan
Debt Instrument [Line Items]
Interest expense											800,000							5,000,000	5,000,000	4,300,000
Contractual interest											700,000							4,700,000	4,700,000	3,800,000
Amortization of the debt discount																		100,000	100,000	200,000
Accretion																		100,000	100,000	200,000
Principal balance																$ 55,000,000				55,000,000
Amortization of the warrant																		100,000	100,000	100,000
2021 Term Loan | Maximum
Debt Instrument [Line Items]
Amortization of the debt discount											100,000
2021 Term Loan | 2021 Term Loan Agreement | Runway
Debt Instrument [Line Items]
Initial cash proceeds									$ 15,000,000
Available capacity based upon the achievement of certain revenue thresholds									5,000,000
Loss on extinguishment of debt/ term loan			3,900,000
Total payoff amount			58,000,000
Repayment of principal			55,000,000
Prepayment fee			1,100,000
Final payment fee			$ 1,600,000
Prepayment fee percentage			2%
Original final payment			$ 100,000
Final payment fee percentage			3%
Term loan borrowed									25,000,000
2021 Term Loan | 2021 Term Loan Agreement | Runway | Maximum
Debt Instrument [Line Items]
Additional borrowings									$ 10,000,000
2021 Term Loan | Amended 2021 Term Loan Agreement | Runway
Debt Instrument [Line Items]
Additional borrowings																30,000,000				30,000,000
Term C Loan | Amended 2021 Term Loan Agreement | Runway
Debt Instrument [Line Items]
Additional borrowings						$ 15,000,000		20,000,000					$ 15,000,000
Available capacity based upon the achievement of certain revenue thresholds								$ 15,000,000
Maturity Date								Dec. 30, 2025
Equal monthly principal payments commencing date								Dec. 30, 2024
Issuance costs						$ 300,000		$ 700,000					$ 300,000
Fair value of the warrants										300,000				$ 300,000		300,000	$ 300,000		300,000	300,000
Warrant liability																$ 400,000				400,000
Term C Loan | Amended 2021 Term Loan Agreement | Runway | Legacy Allurion Series C Preferred Stock
Debt Instrument [Line Items]
Warrants exercisable | shares								132,979
Term C Loan | Amended 2021 Term Loan Agreement | Runway | Common Stock
Debt Instrument [Line Items]
Warrants converted into warrants exercisable | shares			5,203
Term C Loan | Amended 2021 Term Loan Agreement | Runway | Series D-1 Preferred Stock
Debt Instrument [Line Items]
Warrants exercisable | shares													44,220			88,440
Term D Loan | Amended 2021 Term Loan Agreement | Runway
Debt Instrument [Line Items]
Additional borrowings																$ 15,000,000				15,000,000
Maturity Date						Dec. 30, 2026
Interest rate						3.25%
Basis spread on variable rate						6.44186%
Fair value of the warrants										800,000				800,000		$ 400,000	800,000		$ 800,000	$ 400,000
Description of interest rate variable																			change the interest rate to the higher of the prime rate or 3.25% plus the applicable margin of 6.44186%,
Term D Loan | Amended 2021 Term Loan Agreement | Runway | Previously Reported
Debt Instrument [Line Items]
Fair value of the warrants														400,000					$ 400,000
Term D Loan | Amended 2021 Term Loan Agreement | Runway | Common Stock
Debt Instrument [Line Items]
Warrants converted into warrants exercisable | shares			3,620
Term D Loan | Amended 2021 Term Loan Agreement | Runway | Series D-1 Preferred Stock
Debt Instrument [Line Items]
Warrants exercisable | shares						44,220
Warrants converted into warrants exercisable | shares			88,440
Term D Loan | Amended 2021 Term Loan Agreement | Runway | Maximum
Debt Instrument [Line Items]
Additional borrowings						$ 15,000,000							$ 15,000,000
Fortress Term Loan
Debt Instrument [Line Items]
Principal balance														43,100,000					$ 43,100,000
Loss on extinguishment of debt/ term loan																	8,700,000
Issuance costs			$ 2,500,000
Fortress Term Loan | Fortress Credit Agreement
Debt Instrument [Line Items]
Initial cash proceeds			$ 60,000,000
Interest expense										0	1,700,000			4,100,000			2,300,000	1,700,000
Contractual interest											1,500,000			3,800,000			1,900,000	1,500,000
Amortization of the debt discount											100,000			200,000			300,000	100,000
Accretion											$ 100,000			$ 100,000			$ 100,000	$ 100,000
Interest rate					6.44%						14.94%	14.94%		14.94%
Basis spread on variable rate			3%
Debt instrument exit payment percentage			3%
Issuance costs			$ 2,500,000
Debt instrument maturity date																	Jun. 30, 2027		Jun. 30, 2027
Minimum Liquidity Amount																					$ 12,500,000
Increase in interest rate			3%
Default interest rate			3%
Fair value of term loan derivative liability			$ 1,900,000							$ 0							$ 0
Gain recorded on derivative																	$ 2,000,000
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]																	Other income, net
Fortress Term Loan | Fortress Amendment
Debt Instrument [Line Items]
Unamortized debt issuance costs																					800,000
Principal amount																					20,000,000
Debt fee amount incurred																					3,100,000
Fortress Term Loan | Fortress Amendment | Until March 31, 2024
Debt Instrument [Line Items]
Minimum Liquidity Amount																					33,500,000
Fortress Term Loan | Fortress Amendment | From April 1, 2024 to June 30, 2024
Debt Instrument [Line Items]
Minimum Liquidity Amount																					23,500,000
Fortress Term Loan | Fortress Amendment | From July 1, 2024 to September 30, 2024
Debt Instrument [Line Items]
Minimum Liquidity Amount																					16,900,000
Fortress Term Loan | Fortress Amendment | On October 1, 2024 and thereafter
Debt Instrument [Line Items]
Minimum Liquidity Amount																					12,500,000
Fortress Term Loan | Fortress Amendment | Maximum | Common Stock
Debt Instrument [Line Items]
Principal balance																					$ 20,000,000
Fortress Term Loan | Side Letter Holder Bridge Note | Backstop Agreement | Common Stock
Debt Instrument [Line Items]
Shares issued upon conversion of outstanding notes | shares			38,000
Aggregate recognition APIC amount			$ 13,400,000
Fortress Term Loan | Note Purchase Agreement
Debt Instrument [Line Items]
Total payoff amount	$ 48,000,000
Repayment of principal	43,100,000
Prepayment fee	2,700,000
Exit fee	1,300,000
Other fees	600,000
Accrued interest	$ 300,000											$ 300,000
Fortress Term Loan | HVL Bridge Note | Backstop Agreement | Common Stock
Debt Instrument [Line Items]
Shares issued upon conversion of outstanding notes | shares			38,000
Aggregate recognition APIC amount			$ 13,400,000

Debt - Schedule of Future Matur

Debt - Schedule of Future Maturities of the Term Loan Facility (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total principal amount of debt	$ 49,320	$ 43,100	$ 58,103
Fortress Term Loan
Debt Instrument [Line Items]
December 31, 2026		8,979
December 31, 2027		34,121
Total principal amount of debt		$ 43,100

Revenue Interest Financing, S_3

Revenue Interest Financing, Side Letter, and PIPE Conversion Option - Additional Information (Details) $ / shares in Units, $ in Thousands

3 Months Ended

9 Months Ended

12 Months Ended

Jan. 02, 2027

Jan. 01, 2027 USD ($)

Dec. 31, 2026

Dec. 30, 2026 USD ($)

Feb. 09, 2023 USD ($) Days $ / shares

Sep. 30, 2024 USD ($)

Sep. 30, 2024 USD ($)

Dec. 31, 2023 USD ($)

Mar. 31, 2026

Apr. 17, 2024 USD ($)

Apr. 16, 2024 USD ($)

Aug. 01, 2023 USD ($)

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Gain in fair value of revenue interest financing

$ 6,700

$ 5,400

Change in fair value of revenue interest financing

5,800

600

$ (700)

Revenue Interest Financing Agreement

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenues interest financing liability

$ 40,000

40,000

$ 40,000

Pre payments percentage

165%

Gain in fair value of revenue interest financing

3,400

Change in fair value of revenue interest financing

(700)

Royalty payments

3,600

3,600

1,092

Issuance costs

1,200

Stock price | $ / shares

$ 250

Revenue Interest Financing Agreement | Previously Reported [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Stock price | $ / shares

$ 250

Revenue Interest Financing Agreement | December 31, 2027

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Cash payments percentage

100%

Revenue Interest Financing Agreement | Maximum

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Percentage of annual net sales

6%

Remittance of revenue interest payments percentage

10%

Revenue interest payments percentage

260%

Volume weighted average price per share | $ / shares

$ 176

Conversion of PIPE subscription to revenue interest finance

$ 7,500

$ 7,500

Trading days | Days

30

Conversion of PIPE investment to revenue interest finance

$ 7,500

7,500

7,500

Revenue Interest Financing Agreement | Maximum | Previously Reported [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Volume weighted average price per share | $ / shares

$ 176

Revenue Interest Financing Agreement | Maximum | December 31, 2030

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Cash payments percentage

240%

Revenue Interest Financing Agreement | Minimum

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenue interest payments percentage

100%

Trading days | Days

20

Revenue Interest Financing Agreement | Minimum | December 31, 2030

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenue interest payments percentage

240%

Revenue Interest Financing Agreement | PIPE Conversion Option

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Issue-date estimated fair value

$ 3,300

RIFA Amendment

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Fair value of revenue interest financing agreement

38,500

38,500

Fair value of pipe conversion option

$ 9,900

$ 9,900

Revenue Interest Financing Agreement Remeasured Value

$ 39,000

$ 33,000

PIPE Conversion Option Remeasured Value

$ 4,600

$ 6,600

RIFA Amendment | Forecast

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Percentage of net sales

12%

6%

Percentage of Increase in Net Sales

12%

10%

Percentage of Internal Rate of Return

20%

RIFA Amendment | Maximum | Forecast

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Sales Revenue Net

$ 100,000

Increase in Sales Revenue Net

$ 100,000

Revenue Interest Financing, S_4

Revenue Interest Financing, Side Letter, and PIPE Conversion Option - Summary of Components of Revenue Interest Financing (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Aug. 01, 2023	Feb. 09, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Less: Change in fair value of debt	$ (13,230)
Long-term Revenue Interest Financing liability	38,500	$ 36,200
Revenue Interest Financing Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues Interest Financing Liability		40,000	$ 40,000	$ 40,000
Total principal amounts of debt		40,000
Less: Royalty payments	$ (3,600)	(1,092)
Less: Change in fair value of debt		(2,708)
Long-term Revenue Interest Financing liability		$ 36,200

Income Taxes - Domestic and For

Income Taxes - Domestic and Foreign Components of Net Loss Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
U.S.					$ (81,259)	$ (38,267)
Foreign					916	666
Loss before income taxes	$ (8,935)	$ (21,596)	$ (5,370)	$ (61,337)	$ (80,343)	$ (37,601)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Effective Tax Rate and Statutory Federal Income Tax Rate (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. statutory federal income tax rate					21%	21%
State income taxes, net of federal income tax benefit					7.10%	6.90%
Change in fair value of financial instruments					3%	0%
Tax credits					0.40%	1%
Valuation allowance					(30.50%)	(29.00%)
Non-deductible expenses					(0.90%)	0%
Other					(0.40%)	(0.20%)
Effective tax rate	(0.80%)	(0.20%)	(3.90%)	(0.10%)	(0.30%)	(0.30%)

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Components of Deferred Tax Assets and Liabilities [Abstract]
U.S. federal and state net operating loss carryforwards	$ 36,092	$ 25,051
Capitalized start-up and research and development expenses	10,868	5,377
Research and development tax credits	2,275	1,780
Interest expense	3,918
Lease liability	659	838
Depreciation	203	236
Bad debt reserve	3,461
Other temporary differences	2,145	994
Total deferred tax assets	59,621	34,276
Valuation allowance	(57,985)	(33,484)	$ (22,579)
Net deferred tax assets	1,636	792
Right of use asset	(623)	(792)
Other deferred tax liability	(1,013)
Total deferred tax liabilities	(1,636)	(792)
Net deferred tax asset	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Income tax expense	$ 69	$ 34	$ 210	$ 90	$ 264	$ 143
Valuation allowance increased					24,501	10,905
Net operating loss carryforwards					$ 36,092	$ 25,051
Effective tax rates	(0.80%)	(0.20%)	(3.90%)	(0.10%)	(0.30%)	(0.30%)
Uncertain tax positions	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Accrued interest and penalties					0	$ 0
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards					131,700
Tax credit carry forwards research and development					$ 900
Tax credits research and development expiration year					2028
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards					$ 132,200
Tax credit carry forwards research and development					$ 1,500
Tax credits research and development expiration year					2031
Earliest Tax Year | State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration period					2030
Earliest Tax Year | Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration period					2030
Latest Tax Year | Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration period					2037
Latest Tax Year | State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration period					2042
Expire between 2030 and 2037 | Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards					$ 12,800
Do not expire | Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards					$ 119,500
Maximum
Operating Loss Carryforwards [Line Items]
Income tax expense		$ 100		$ 100

Income Taxes - Summary of Valua

Income Taxes - Summary of Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Valuation Allowance [Abstract]
Beginning balances	$ 33,484	$ 22,579
Additions charged to net loss	24,501	10,905
Ending balances	$ 57,985	$ 33,484

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Estimated Fair Value was Measured Using a Monte Carlo Simulation Method (Details) - $ / shares	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk-free interest rate	4.36%	4.50%	4.50%	3.56%
Expected term (in years)	6 years 1 month 6 days	5 years 9 months 18 days	5 years 9 months 18 days	5 years 9 months 18 days
Expected volatility	71%	86%	85.80%	63%
Revenue Interest Financing and PIPE Conversion Option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stock price	$ 15.25		$ 93.5
Risk-free interest rate	4.03%		4.46%
Expected term (in years)	9 months 18 days		1 year 7 months 6 days
Expected volatility	130%		82.50%
Earn-Out Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stock price	$ 15.25		$ 93.5
Risk-free interest rate	3.60%		3.90%
Expected term (in years)	3 years 9 months 18 days		4 years 7 months 6 days
Expected volatility	105%		87%
RTW Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stock price	$ 15.25
Risk-free interest rate	3.60%
Expected term (in years)	6 years 6 months
Expected volatility	90%

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Changes in Fair Values (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 145	$ 4,030	$ 821	$ 2,373	$ 2,373	$ 741
Fair value upon issuance	14,827		14,827			834
Change in fair value	$ (8,121)	$ (2,126)	$ (8,797)	$ (447)	$ (548)	$ 821
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Fair Value Adjustment of Warrants	Fair Value Adjustment of Warrants	Fair Value Adjustment of Warrants	Fair Value Adjustment of Warrants	Fair Value Adjustment of Warrants	Fair Value Adjustment of Warrants
Exercise of warrants		$ (53)		$ (75)	$ (75)	$ (23)
Derecognition of liability to equity		(929)		(929)	(929)
Ending Balance	$ 6,851	922	$ 6,851	922	821	2,373
Preferred Stock Warrants (as Converted to Common)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	110	2,679	642	1,777	1,777	510
Fair value upon issuance						834
Change in fair value	(55)	(1,571)	(587)	(647)	(720)	456
Exercise of warrants		(53)		(75)	(75)	(23)
Derecognition of liability to equity		(340)		(340)	(340)
Ending Balance	55	715	55	715	642	1,777
Common Stock Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	35	1,351	179	596	596	231
Change in fair value	(19)	(555)	(163)	200	172	365
Exercise of warrants		0
Derecognition of liability to equity		(589)		(589)	(589)
Ending Balance	16	207	16	207	179	596
Private Placement Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value upon issuance	1,670		1,670
Change in fair value	(860)		(860)
Ending Balance	810		810
Public Offering Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value upon issuance	13,157		13,157
Change in fair value	(7,187)		(7,187)
Ending Balance	5,970		5,970
Public Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	89,524	23,638	67,699	178	178	159
Fair value upon issuance		105,530	49,100	131,714	133,609
Change in fair value	7,054	(10,357)	(24,447)	(12,581)	(17,147)	19
Change in fair value - OCI	(8,870)		(3,590)		700
Repayments of debt	(1,404)	(10,250)	(2,458)	(10,750)
Payments					(11,842)
Derecognition of liability to equity		(37,799)		(37,799)	(37,799)
Ending Balance	86,304	70,762	86,304	70,762	67,699	178
Public Warrants | Success Fee Derivative Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	14	213	14	178	178	159
Change in fair value		(201)		(166)	(164)	19
Ending Balance	14	12	14	12	14	$ 178
Public Warrants | 2023 Convertible Notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		16,793
Fair value upon issuance		9,150		28,700	28,700
Change in fair value		6,008		3,751	3,751
Repayments of debt		(10,250)		(10,750)
Payments					(10,750)
Derecognition of liability to equity		(21,701)		(21,701)	(21,701)
Public Warrants | PubCo Share Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		3,327
Fair value upon issuance				3,370	3,370
Change in fair value		(599)		(642)	(642)
Derecognition of liability to equity		(2,728)		(2,728)	(2,728)
Public Warrants | Base PubCo and Backstop Share Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		3,305
Fair value upon issuance				3,264	3,264
Change in fair value		10,065		10,106	10,106
Derecognition of liability to equity		(13,370)		(13,370)	(13,370)
Public Warrants | Term Loan Derivative Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance			1,895
Fair value upon issuance					1,895
Change in fair value			(1,895)
Ending Balance	0		0		1,895
Public Warrants | Revenue Interest Financing
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	39,000		36,200
Fair value upon issuance		40,000		40,000	40,000
Change in fair value	6,704	(3,400)	5,358	(3,400)	(3,408)
Change in fair value - OCI	(5,800)		(600)		700
Repayments of debt	(1,404)		(2,458)
Payments					(1,092)
Ending Balance	38,500	36,600	38,500	36,600	36,200
Public Warrants | PIPE Conversion Derivative
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	5,450		5,600
Fair value upon issuance		3,340		3,340	3,340
Change in fair value	4,400	2,100	4,250	2,100	2,260
Ending Balance	9,850	5,440	9,850	5,440	5,600
Public Warrants | Earn-Out Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	4,110		23,990
Fair value upon issuance		53,040		53,040	53,040
Change in fair value	(2,260)	(24,330)	(22,140)	(24,330)	(29,050)
Ending Balance	1,850	$ 28,710	1,850	$ 28,710	$ 23,990
Public Warrants | RTW Convertible Notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	40,950
Fair value upon issuance			49,100
Change in fair value	(1,790)		(10,020)
Change in fair value - OCI	(3,070)		(2,990)
Ending Balance	$ 36,090		$ 36,090

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)		9 Months Ended	12 Months Ended
	Aug. 01, 2023 $ / shares shares	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022
Fortress Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan | $			$ 43,200,000
Public Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stock price		$ 1	$ 11.25
Expected Dividend Yield | Level 3 | Black-Scholes Option Pricing Model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrants measurement input		0	0	0
PubCo Additional Shares Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of estimated number of shares | shares	15,508
Fair value of estimated price of shares	$ 176
Base PubCo Shares and Backstop Shares Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of estimated number of shares | shares	38,000
Fair value of estimated price of shares	$ 176
Term Loan Derivative Liability | Estimated Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, measurement input			24.4
2019 Term Loan and Success Fee
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assumptions of liquidity event term		4 years	4 years
2023 Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated share price at conversion	$ 176
Revenue Interest Financing and PIPE Conversion Option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of estimated number of shares | shares		42,614	42,614
Stock price		$ 15.25	$ 93.5
Revenue Interest Financing and PIPE Conversion Option | Estimated Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, measurement input		23.5	24.4
RTW Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stock price		$ 15.25
Principal amount | $		$ 48,000,000

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Assumptions used in Pricing Model (Details) - Black-Scholes Option Pricing Model - Level 3	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest Rate | Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input		0.0395
Interest Rate | Other Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.0399
Interest Rate | Legacy Allurion Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.0359	0.0395
Interest Rate | Private Placement Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.0358
Interest Rate | Public Offering Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.0358
Interest Rate | Legacy Allurion Series A 1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.0442
Interest Rate | Legacy Allurion Series B Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.0441
Interest Rate | Legacy Allurion Series C Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.0411
Interest Rate | Legacy Allurion Series C Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.0365	0.0388	0.0392
Interest Rate | Legacy Allurion Series D-1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input		0.0388
Interest Rate | Legacy Allurion Series D-1 Preferred Stock Warrants | Minimum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.0365		3.88
Interest Rate | Legacy Allurion Series D-1 Preferred Stock Warrants | Maximum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.0371		3.92
Exercise Price | Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input		26.25
Exercise Price | Other Common Stock Warrants | Minimum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			25.5
Exercise Price | Other Common Stock Warrants | Maximum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			27.5
Exercise Price | Legacy Allurion Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	26.25	26.25
Exercise Price | Private Placement Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	30
Exercise Price | Public Offering Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	30
Exercise Price | Legacy Allurion Series A 1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			47.5
Exercise Price | Legacy Allurion Series B Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			59.5
Exercise Price | Legacy Allurion Series C Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.25
Exercise Price | Legacy Allurion Series C Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	168.25	168.25	164.5
Exercise Price | Legacy Allurion Series D-1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	303.5	303.5	296.75
Estimated Fair Value of Underlying Share Price | Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input		93.5
Estimated Fair Value of Underlying Share Price | Other Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			113.5
Estimated Fair Value of Underlying Share Price | Legacy Allurion Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	15.25	93.5
Estimated Fair Value of Underlying Share Price | Private Placement Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	15.25
Estimated Fair Value of Underlying Share Price | Public Offering Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	15.25
Estimated Fair Value of Underlying Share Price | Legacy Allurion Series A 1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			168.75
Estimated Fair Value of Underlying Share Price | Legacy Allurion Series B Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			172.75
Estimated Fair Value of Underlying Share Price | Legacy Allurion Series C Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			113.5
Estimated Fair Value of Underlying Share Price | Legacy Allurion Series C Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	15.25	93.5	181
Estimated Fair Value of Underlying Share Price | Legacy Allurion Series D-1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	15.25	93.5	282.75
Expected Volatility | Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input		1
Expected Volatility | Other Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			63
Expected Volatility | Legacy Allurion Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.90	1
Expected Volatility | Private Placement Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.90
Expected Volatility | Public Offering Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.90
Expected Volatility | Legacy Allurion Series A 1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.69
Expected Volatility | Legacy Allurion Series B Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.65
Expected Volatility | Legacy Allurion Series C Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input			0.63
Expected Volatility | Legacy Allurion Series C Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.90	1	0.63
Expected Volatility | Legacy Allurion Series D-1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants measurement input	0.90	1	63
Expected Life (Years) | Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term		3 years 8 months 8 days
Expected Life (Years) | Other Common Stock Warrants | Minimum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term			4 years 7 months 6 days
Expected Life (Years) | Other Common Stock Warrants | Maximum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term			4 years 8 months 12 days
Expected Life (Years) | Legacy Allurion Other Common Stock
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term	2 years 11 months 8 days	3 years 8 months 8 days
Expected Life (Years) | Private Placement Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term	4 years 9 months
Expected Life (Years) | Public Offering Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term	4 years 9 months
Expected Life (Years) | Legacy Allurion Series A 1 Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term			3 months
Expected Life (Years) | Legacy Allurion Series B Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term			2 years
Expected Life (Years) | Legacy Allurion Series C Common Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term			4 years
Expected Life (Years) | Legacy Allurion Series C Preferred Stock Warrants
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term	6 years 6 months	7 years 3 months	8 years 2 months 12 days
Expected Life (Years) | Legacy Allurion Series D-1 Preferred Stock Warrants | Minimum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term	6 years 6 months	7 years 3 months	8 years 2 months 12 days
Expected Life (Years) | Legacy Allurion Series D-1 Preferred Stock Warrants | Maximum
Fair Value, Assets Measured on Recurring Basis, Observable and Unobservable Input Reconciliation [Line Items]
Warrants term	7 years 11 months 15 days	8 years 8 months 15 days	9 years 8 months 12 days

Fair Value Measurements - Sch_4

Fair Value Measurements - Schedule of Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value at Issuance Date and on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 23,749	$ 30,582	$ 4,925
Total Liabilities	531	5,943
Level 1 | Public Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	531	5,943
Level 1 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	23,749	30,582	4,925
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	93,155	68,520	2,551
Level 3 | Legacy Allurion Common Stock Warrant Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	71	821
Level 3 | Public Offering Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	5,970
Level 3 | Revenue Interest Financing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	38,500	36,200
Level 3 | PIPE Conversion Option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	9,850	5,600
Level 3 | Earn-out Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	1,850	23,990
Level 3 | RTW Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	36,090
Level 3 | Term Loan Derivative Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities		1,895
Level 3 | Success Fee Derivative Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	14	14	180
Level 3 | Legacy Allurion Series C Common Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			340
Level 3 | Legacy Allurion Series B Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			303
Level 3 | Legacy Allurion Series A-1 Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			82
Level 3 | Other Common Stock Warrant Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			255
Level 3 | Legacy Allurion Series C Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			684
Level 3 | Legacy Allurion Series D-1 Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			707
Private Placement Warrants | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	810
Total Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	23,749	30,582	4,925
Total Liabilities	93,686	74,463	2,551
Total Carrying Value | Legacy Allurion Common Stock Warrant Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	71	821
Total Carrying Value | Public Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	531	5,943
Total Carrying Value | Public Offering Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	5,970
Total Carrying Value | Revenue Interest Financing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	38,500	36,200
Total Carrying Value | PIPE Conversion Option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	9,850	5,600
Total Carrying Value | Earn-out Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	1,850	23,990
Total Carrying Value | RTW Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	36,090
Total Carrying Value | Term Loan Derivative Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities		1,895
Total Carrying Value | Success Fee Derivative Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	14	14	180
Total Carrying Value | Legacy Allurion Series C Common Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			340
Total Carrying Value | Legacy Allurion Series B Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			303
Total Carrying Value | Legacy Allurion Series A-1 Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			82
Total Carrying Value | Other Common Stock Warrant Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			255
Total Carrying Value | Legacy Allurion Series C Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			684
Total Carrying Value | Legacy Allurion Series D-1 Preferred Stock Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities			707
Total Carrying Value | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	23,749	$ 30,582	$ 4,925
Total Carrying Value | Private Placement Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Liabilities	$ 810

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock and Stockholders' Deficit - Additional Information (Details) - USD ($)						3 Months Ended					9 Months Ended		12 Months Ended
	Jul. 05, 2024	Jul. 01, 2024	Jun. 28, 2024	Dec. 18, 2023	Aug. 01, 2023	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Dividends declared													$ 0
Preferred stock, shares authorized						100,000,000					100,000,000		100,000,000	100,000,000
Preferred stock, shares outstanding													0	0
Warrants converted into warrants exercisable						769,257					769,257		16,151	17,474
Preferred stock, par value													$ 0.0001	$ 0.0001
Number of shares authorized						1,000,000,000					1,000,000,000		1,000,000,000	1,000,000,000
Par value common stock						$ 0.0001					$ 0.0001		$ 0.0001	$ 0.0001
Number of shares outstanding					1,892,058	2,574,783					2,574,783		1,907,529	1,083,196
Public warrant liabilities						$ 7,381,000					$ 7,381,000		$ 6,765,000
Warrants outstanding						16,151					16,151		16,151
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)					750,394
Warrants exercisable price						$ 202.5					$ 202.5		$ 202.5
General and administrative						$ 7,043,000		$ 18,942,000			$ 20,746,000	$ 30,657,000	$ 46,024,000	$ 15,365,000
Stock issued during period value						5,066,000	$ 378,000
Additional paid-in capital					$ 15,200,000	150,696,000					$ 150,696,000		$ 143,010,000	$ 99,877,000
ChEF Purchase Agreement | Chardan Equity Facility
Class of Stock [Line Items]
Number of shares sold per unit											5,730		0
Amount received on shares sold per unit											$ 400,000
Stock issued during period value				$ 100,000,000
Additional paid-in capital				100,000
Expense of issuance of commitment shares				100,000
Structuring fee payable				$ 100,000
Common Stock
Class of Stock [Line Items]
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)								200	20	143
Stock issued during period value						1,000
Common Stock | ChEF Purchase Agreement | Chardan Equity Facility
Class of Stock [Line Items]
Number of shares outstanding				379,299
Percentage of common stock, shares, outstanding				19.99%
Additional Paid-in Capital
Class of Stock [Line Items]
Stock issued during period value						5,065,000	$ 378,000
Commitment Shares | ChEF Purchase Agreement | Chardan Equity Facility
Class of Stock [Line Items]
Stock issued during period value				$ 1,421
Public Warrant
Class of Stock [Line Items]
Public warrant liabilities						$ 528,269					$ 528,269		$ 528,277
Warrants outstanding						662,701					662,701
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)											750,383		750,394
Public Warrant | Scenario Plan Three
Class of Stock [Line Items]
Stock price						$ 316.75					$ 316.75		$ 316.75
Warrants redumption price per share						0.25					0.25		0.25
Public Warrant | Scenario Plan Four
Class of Stock [Line Items]
Stock price						176					176		176
Warrants redumption price per share						$ 2.5					$ 2.5		2.5
Public Offering
Class of Stock [Line Items]
Warrants converted into warrants exercisable		86,440	576,261
Sale of stock			$ 30
Number of shares sold per unit		662,701	576,261
Net proceeds from offering		$ 15,200,000
Offering cost		1,000,000
Underwriting discounts		1,000,000
Public Offering Warrants and Share Overallotment
Class of Stock [Line Items]
Issue-date estimated fair value		13,200,000
Net proceeds from offering		17,400,000
Offering cost		800,000
Public Offering Warrants and Share Overallotment | Common Stock
Class of Stock [Line Items]
Net proceeds from offering		5,100,000
Public Offering Warrants and Share Overallotment | Additional Paid-in Capital
Class of Stock [Line Items]
Net proceeds from offering		5,100,000
Private Placement Warrants
Class of Stock [Line Items]
Warrants outstanding						90,407					90,407
Private Placement with RTW
Class of Stock [Line Items]
Warrants converted into warrants exercisable			90,407
Net proceeds from offering		2,500,000
Offering cost		$ 200,000
Underwriters
Class of Stock [Line Items]
Warrants exercisable price	$ 30
Number of shares sold per unit	77,091
Net proceeds from offering	$ 2,200,000
Compute Health
Class of Stock [Line Items]
Sale of stock						$ 10					$ 10		$ 10
Compute Health | Public Warrant
Class of Stock [Line Items]
Number of shares sold per unit											0.5		0.5
Compute Health | IPO
Class of Stock [Line Items]
Class of Warrant Exchanged						0.6125					0.6125		0.6125
Number of shares sold per unit											1		1
Class A Common Stock
Class of Stock [Line Items]
Par value common stock						$ 0.0001					$ 0.0001		$ 0.0001
Number of shares sold per unit											1		1
Class A Common Stock | Compute Health | IPO
Class of Stock [Line Items]
Shares issuable for each outstanding warrants exercised						0.056818					0.056818		0.056818
Sale of stock						$ 11.5					$ 11.5		$ 11.5
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock redemption basis											Each share of Series A Preferred Stock outstanding on December 31, 2026 (the “Redemption Date”) shall be automatically redeemed by the Company for cash at a redemption price equal to the volume-weighted average price per share of the Common Stock on the NYSE during the twenty consecutive trading day period ending and including the trading day immediately preceding the Redemption Date (the “Redemption Price”). The Series A Preferred Stock is redeemable at a determinable price (the Redemption Price) on a fixed date (the Redemption Date), which results in mezzanine equity classification (outside of permanent equity) on the Company’s consolidated balance sheet.
Preferred stock liquidation preference											In the event of any voluntary or involuntary liquidation, dissolution, or winding-up of the Company, payment shall be made to the holders of shares of Series A Preferred Stock on a pari passu basis with all holders of Common Stock. Each Series A Preferred Stock holder shall be entitled to receive out of the assets, whether capital or surplus, of the Company the same amount that a holder of Common Stock would receive if such holder’s Series A Convertible Preferred Stock were fully converted to Common Stock plus an additional amount equal to any dividends declared but unpaid to such share.
Preferred stock conversion rights											Each share of Series A Preferred Stock is convertible after the date that the Company’s stockholders approve the conversion of the Series A Preferred Stock into shares of Common Stock in accordance with the listing rules of the NYSE (the “Series A Stockholder Approval”). Upon the Series A Stockholder Approval, each share of Series A Preferred Stock then outstanding shall automatically convert into (i) a number of shares of Common Stock equal to the number of Series A Preferred Stock outstanding at the time of conversion, adjustable for certain dilutive events, and (ii) pre-funded conversion warrants in the form agreed by the holder and the Company, exercisable for a number of shares of Common Stock equal to the number of Series A Preferred Stock outstanding at the time of conversion, adjustable for certain dilutive events.
Preferred stock voting rights											no
Dividends declared											$ 0
Preferred stock, shares outstanding						2,260,159					2,260,159
Series A Preferred Stock | Private Placement with RTW
Class of Stock [Line Items]
Issue-date estimated fair value			$ 1,700,000
Preferred stock, par value			$ 0.0001
Number of shares sold per unit			2,260,159
Gross proceeds from offering			$ 1,000,000
Offering cost			200,000
Reduction in proceeds from offering			100,000
General and administrative			$ 100,000

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock and Stockholders' Deficit - Summary of Reserved for Issuance Upon the Potential Conversion or Exercise (Details) - shares	Sep. 30, 2024	Dec. 31, 2023
Class of Stock [Line Items]
Common stock shares reserved for future issuance	2,294,777	1,307,731
Restricted Stock Units
Class of Stock [Line Items]
Common stock shares reserved for future issuance	21,230	25,745
Outstanding Options to Purchase Common Stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance	284,332	155,441
Warrants to Purchase Common Stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance	769,257	10,594
Shares of Common Stock Issued Upon the Exercise of Public Warrants
Class of Stock [Line Items]
Common stock shares reserved for future issuance	750,383
Earn-Out Shares
Class of Stock [Line Items]
Common stock shares reserved for future issuance	360,000	360,000
Convertible Notes
Class of Stock [Line Items]
Common stock shares reserved for future issuance	19,168
Series A Preferred Stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance	90,407

Redeemable Convertible Prefer_5

Redeemable Convertible Preferred Stock and Stockholders' Deficit - Summary of Warrants to Purchase Classes of Preferred Stock and Common Stock Outstanding (Details) - $ / shares	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Class of Warrant or Right [Line Items]
Shares Issuable Upon Exercise of Warrant	769,257	16,151	17,474
Weighted Average Exercise Price	$ 202.5	$ 202.5
December 1, 2014 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 months 12 days	10 months 24 days
Shares Issuable Upon Exercise of Warrant	1,771	1,771
Weighted Average Exercise Price	$ 61	$ 61
March 30, 2021 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	6 years 6 months	7 years 2 months 12 days
Shares Issuable Upon Exercise of Warrant	5,203	5,203
Weighted Average Exercise Price	$ 168.25	$ 168.25
September 15, 2022 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	8 years	8 years 8 months 12 days
Shares Issuable Upon Exercise of Warrant	1,810	1,810
Weighted Average Exercise Price	$ 303.5	$ 303.5
June 4, 2022 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	7 years 8 months 12 days	8 years 4 months 24 days
Shares Issuable Upon Exercise of Warrant	1,810	1,810
Weighted Average Exercise Price	$ 303.5	$ 303.5
January 17, 2017 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 years 3 months 18 days	3 years	4 years
Shares Issuable Upon Exercise of Warrant	2,934	2,934	2,934
Weighted Average Exercise Price	$ 0.5	$ 0.5	$ 0.5
August 3, 2017 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 years 9 months 18 days	3 years 7 months 6 days	4 years 7 months 6 days
Shares Issuable Upon Exercise of Warrant	392	392	392
Weighted Average Exercise Price	$ 28.25	$ 28.25	$ 28.25
September 8, 2017 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 years 10 months 24 days	3 years 8 months 12 days	4 years 8 months 12 days
Shares Issuable Upon Exercise of Warrant	1,151	1,151	1,151
Weighted Average Exercise Price	$ 26.25	$ 26.25	$ 26.25
June 19, 2018 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	3 years 8 months 12 days	4 years 6 months	5 years 6 months
Shares Issuable Upon Exercise of Warrant	720	720	720
Weighted Average Exercise Price	$ 26.25	$ 26.25	$ 26.25
June 25, 2019 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	4 years 8 months 12 days	5 years 6 months	6 years 6 months
Shares Issuable Upon Exercise of Warrant	360	360	360
Weighted Average Exercise Price	$ 26.25	$ 26.25	$ 26.25
July 01,2024 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	4 years 9 months 18 days
Shares Issuable Upon Exercise of Warrant	753,106
Weighted Average Exercise Price	$ 30

Capital Stock and Stockholder_3

Capital Stock and Stockholders' Deficit - Additional Information (Details) - USD ($)			3 Months Ended					9 Months Ended	12 Months Ended
	Dec. 18, 2023	Aug. 01, 2023	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Preferred stock, shares authorized			100,000,000					100,000,000	100,000,000	100,000,000
Preferred stock, shares outstanding									0	0
Dividends declared									$ 0
Preferred stock, par value									$ 0.0001	$ 0.0001
Original issue price									$ 1.092
Number of shares authorized			1,000,000,000					1,000,000,000	1,000,000,000	1,000,000,000
Number of shares outstanding		1,892,058	2,574,783					2,574,783	1,907,529	1,083,196
Warrants outstanding			16,151					16,151	16,151
Par value common stock			$ 0.0001					$ 0.0001	$ 0.0001	$ 0.0001
Warrants exercisable price			$ 202.5					$ 202.5	$ 202.5
Public warrant liabilities			$ 7,381,000					$ 7,381,000	$ 6,765,000
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)		750,394
Stock issued during period value			5,066,000	$ 378,000
Additional paid-in capital		$ 15,200,000	150,696,000					$ 150,696,000	$ 143,010,000	$ 99,877,000
ChEF Purchase Agreement | Chardan Equity Facility
Class of Stock [Line Items]
Number of shares sold per unit								5,730	0
Stock issued during period value	$ 100,000,000
Expense of issuance of commitment shares	100,000
Additional paid-in capital	100,000
Structuring fee payable	$ 100,000
Common Stock
Class of Stock [Line Items]
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)					200	20	143
Stock issued during period value			$ 1,000
Common Stock | ChEF Purchase Agreement | Chardan Equity Facility
Class of Stock [Line Items]
Number of shares outstanding	379,299
Percentage of common stock, shares, outstanding	19.99%
Commitment Shares | ChEF Purchase Agreement | Chardan Equity Facility
Class of Stock [Line Items]
Stock issued during period value	$ 1,421
Public Warrant
Class of Stock [Line Items]
Warrants outstanding			662,701					662,701
Public warrant liabilities			$ 528,269					$ 528,269	$ 528,277
Issuance of Legacy Allurion convertible preferred stock for the exercise of warrants (in shares)								750,383	750,394
Public Warrant | Scenario Plan Three
Class of Stock [Line Items]
Warrants redumption price per share			$ 0.25					$ 0.25	$ 0.25
Stock price			316.75					316.75	316.75
Public Warrant | Scenario Plan Four
Class of Stock [Line Items]
Warrants redumption price per share			2.5					2.5	2.5
Stock price			176					176	176
Compute Health
Class of Stock [Line Items]
Sale of stock			$ 10					$ 10	$ 10
Compute Health | IPO
Class of Stock [Line Items]
Number of shares sold per unit								1	1
Class of Warrant Exchanged			0.6125					0.6125	0.6125
Compute Health | Public Warrant
Class of Stock [Line Items]
Number of shares sold per unit								0.5	0.5
Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									21,029,888
Preferred stock voting rights									The Legacy Allurion preferred stockholders voted as a single class together with holders of all other classes and series of stock of Legacy Allurion on all actions to be taken by the stockholders of the Company. The Legacy Allurion preferred stockholders were entitled to the number of votes equal to the number of shares of Legacy Allurion common stock into which the shares held by each holder were then convertible. The Legacy Allurion Series C Preferred Stockholders were entitled to elect two members of the Board of Directors
Common stock voting rights									common stockholders were entitled to elect four members of the Board of Directors.
Revenue milestone									$ 65,000,000
Percentage of shares of common stock held									150%
Preferred stock conversion rights									Each share of Legacy Allurion preferred stock was convertible at any time, at the option of the holder, into one share of Legacy Allurion common stock, based upon a per share conversion factor of each series’ applicable original issuance prices, adjustable for certain dilutive events. Conversion was mandatory upon the closing of an IPO or deSPAC transaction, or upon the election of the holders of a majority of the then-outstanding Legacy Allurion preferred stock.
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding			2,260,159					2,260,159
Preferred stock voting rights								no
Dividends declared								$ 0
Preferred stock conversion rights								Each share of Series A Preferred Stock is convertible after the date that the Company’s stockholders approve the conversion of the Series A Preferred Stock into shares of Common Stock in accordance with the listing rules of the NYSE (the “Series A Stockholder Approval”). Upon the Series A Stockholder Approval, each share of Series A Preferred Stock then outstanding shall automatically convert into (i) a number of shares of Common Stock equal to the number of Series A Preferred Stock outstanding at the time of conversion, adjustable for certain dilutive events, and (ii) pre-funded conversion warrants in the form agreed by the holder and the Company, exercisable for a number of shares of Common Stock equal to the number of Series A Preferred Stock outstanding at the time of conversion, adjustable for certain dilutive events.
Series A Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									2,276,786
Preferred stock liquidation preference per share									$ 1.092
Series A-1 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									1,513,028
Preferred stock liquidation preference per share									$ 2.85
Series B Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									2,298,929
Preferred stock liquidation preference per share									$ 3.563
Series C Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									8,113,616
Preferred stock liquidation preference per share									$ 4.935
Preferred Stock redemption value to price									1.5
Series C Preferred Stock | Legacy Allurion | Maximum
Class of Stock [Line Items]
Percentage of outstanding shares of redeemable									50%
Series D Preferred Stock
Class of Stock [Line Items]
Percentage of preferred stock dividend									6%
Series D-1 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									1,684,565
Preferred stock liquidation preference per share									$ 17.809
Preferred stock, par value									$ 11.8725
Series D-2 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									3,644,616
Preferred stock liquidation preference per share									$ 9.338
Preferred stock, par value									$ 6.2256
Series D-3 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred stock, shares authorized									1,498,348
Preferred stock liquidation preference per share									$ 15.137
Preferred stock, par value									$ 10.0916
Class A Common Stock
Class of Stock [Line Items]
Number of shares sold per unit								1	1
Par value common stock			$ 0.0001					$ 0.0001	$ 0.0001
Class A Common Stock | Compute Health | IPO
Class of Stock [Line Items]
Sale of stock			$ 11.5					$ 11.5	$ 11.5
Shares issuable for each outstanding warrants exercised			0.056818					0.056818	0.056818

Capital Stock and Stockholder_4

Capital Stock and Stockholders' Deficit - Schedule of Preferred Stock Details Prior to Business Combination (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Preferred Stock Authorized	100,000,000	100,000,000	100,000,000
Preferred Stock Issued		0	0
Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		21,029,888
Preferred Stock Issued		19,921,042
Carrying Value		$ 97,216
Series A Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		2,276,786
Preferred Stock Issued		2,276,786
Carrying Value		$ 1,542
Series A-1 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		1,513,028
Preferred Stock Issued		1,486,048
Carrying Value		$ 2,842
Series B Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		2,298,929
Preferred Stock Issued		2,245,515
Carrying Value		$ 5,253
Series C Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		8,113,616
Preferred Stock Issued		7,927,446
Carrying Value		$ 39,122
Series D-1 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		1,684,565
Preferred Stock Issued		842,283
Carrying Value		$ 9,614
Series D-2 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		3,644,616
Preferred Stock Issued		3,644,616
Carrying Value		$ 24,054
Series D-3 Preferred Stock | Legacy Allurion
Class of Stock [Line Items]
Preferred Stock Authorized		1,498,348
Preferred Stock Issued		1,498,348
Carrying Value		$ 14,789

Capital Stock and Stockholder_5

Capital Stock and Stockholders' Deficit - Summary of Reserved for Issuance Upon the Potential Conversion or Exercise (Details) - shares	Sep. 30, 2024	Dec. 31, 2023
Class of Stock [Line Items]
Common stock shares reserved for future issuance	2,294,777	1,307,731
Restricted Stock Units
Class of Stock [Line Items]
Common stock shares reserved for future issuance	21,230	25,745
Outstanding Options to Purchase Common Stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance	284,332	155,441
Warrants to Purchase Preferred Stock (as converted to warrants to purchase common stock)
Class of Stock [Line Items]
Common stock shares reserved for future issuance		5,557
Warrants to Purchase Common Stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance	769,257	10,594
Public Warrants to Purchase Common Stock
Class of Stock [Line Items]
Common stock shares reserved for future issuance		750,394
Earn-Out Shares
Class of Stock [Line Items]
Common stock shares reserved for future issuance	360,000	360,000

Capital Stock and Stockholder_6

Capital Stock and Stockholders' Deficit - Summary of Warrants to Purchase Classes of Preferred Stock and Common Stock Outstanding (Details) - $ / shares	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Class of Warrant or Right [Line Items]
Shares Issuable Upon Exercise of Warrant	769,257	16,151	17,474
Weighted Average Exercise Price	$ 202.5	$ 202.5
April 1, 2013 | Series A-1 Preferred Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)			2 months 12 days
Shares Issuable Upon Exercise of Warrant			663
Weighted Average Exercise Price			$ 48.75
December 1, 2014 | Series B Preferred Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)			1 year 10 months 24 days
Shares Issuable Upon Exercise of Warrant			2,431
Weighted Average Exercise Price			$ 61
December 1, 2014 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 months 12 days	10 months 24 days
Shares Issuable Upon Exercise of Warrant	1,771	1,771
Weighted Average Exercise Price	$ 61	$ 61
March 30, 2021 | Series C Preferred Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)			8 years 2 months 12 days
Shares Issuable Upon Exercise of Warrant			5,203
Weighted Average Exercise Price			$ 168.25
March 30, 2021 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	6 years 6 months	7 years 2 months 12 days
Shares Issuable Upon Exercise of Warrant	5,203	5,203
Weighted Average Exercise Price	$ 168.25	$ 168.25
September 15, 2022 | Series D-1 Preferred Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)			9 years 8 months 12 days
Shares Issuable Upon Exercise of Warrant			1,810
Weighted Average Exercise Price			$ 303.5
September 15, 2022 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	8 years	8 years 8 months 12 days
Shares Issuable Upon Exercise of Warrant	1,810	1,810
Weighted Average Exercise Price	$ 303.5	$ 303.5
June 4, 2022 | Series D-1 Preferred Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)			9 years 4 months 24 days
Shares Issuable Upon Exercise of Warrant			1,810
Weighted Average Exercise Price			$ 303.5
June 4, 2022 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	7 years 8 months 12 days	8 years 4 months 24 days
Shares Issuable Upon Exercise of Warrant	1,810	1,810
Weighted Average Exercise Price	$ 303.5	$ 303.5
January 17, 2017 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 years 3 months 18 days	3 years	4 years
Shares Issuable Upon Exercise of Warrant	2,934	2,934	2,934
Weighted Average Exercise Price	$ 0.5	$ 0.5	$ 0.5
August 3, 2017 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 years 9 months 18 days	3 years 7 months 6 days	4 years 7 months 6 days
Shares Issuable Upon Exercise of Warrant	392	392	392
Weighted Average Exercise Price	$ 28.25	$ 28.25	$ 28.25
September 8, 2017 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	2 years 10 months 24 days	3 years 8 months 12 days	4 years 8 months 12 days
Shares Issuable Upon Exercise of Warrant	1,151	1,151	1,151
Weighted Average Exercise Price	$ 26.25	$ 26.25	$ 26.25
June 19, 2018 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	3 years 8 months 12 days	4 years 6 months	5 years 6 months
Shares Issuable Upon Exercise of Warrant	720	720	720
Weighted Average Exercise Price	$ 26.25	$ 26.25	$ 26.25
June 25, 2019 | Common Stock
Class of Warrant or Right [Line Items]
Remaining Contractual Term (in years)	4 years 8 months 12 days	5 years 6 months	6 years 6 months
Shares Issuable Upon Exercise of Warrant	360	360	360
Weighted Average Exercise Price	$ 26.25	$ 26.25	$ 26.25

Net Loss per Share - Summary of

Net Loss per Share - Summary of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023		Dec. 31, 2022
Numerator:
Net Income (Loss)	$ (9,004)	$ (2,162)	$ 5,586	$ (21,630)	$ (21,996)	$ (17,801)	$ (5,580)	$ (61,427)	$ (80,607)		$ (37,744)
Cumulative undeclared preferred dividends to participating securities (Legacy Series D convertible preferred stock)	0			(255)			0	(1,697)	(1,697)		(2,907)
Net loss attributable to common shareholders	$ (9,004)			$ (21,885)			$ (5,580)	$ (63,124)	$ (82,304)		$ (40,651)
Denominator:
Basic weighted-average common stock outstanding	2,563,459			1,613,425			2,132,416	1,262,346	1,423,275		1,076,743
Diluted weighted-average common stock outstanding	2,563,459			1,613,425			2,132,416	1,262,346	1,423,275		1,076,743
Net loss per share, basic	$ (3.51)			$ (13.56)			$ (2.62)	$ (50.01)	$ (57.83)	[1]	$ (37.75)	[1]
Net loss per share, diluted	$ (3.51)			$ (13.56)			$ (2.62)	$ (50.01)	$ (57.83)	[1]	$ (37.75)	[1]
[1]The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods prior to the Business Combination have been retrospectively adjusted to the equivalent number of shares outstanding immediately after the Business Combination to effect the reverse capitalization. See Note 3 for further information. The weighted-average common shares and thus net loss per share calculations and potentially dilutive security amounts for all periods have also been retrospectively adjusted to give effect to the Reverse Stock Split. See Note 1 for further information.

Net Loss per Share - Summary _2

Net Loss per Share - Summary of Dilutive Securities Excluded from Computation of Basic and Diluted Net Loss Per Common Share (Details) - shares	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	2,294,777	1,314,577	1,307,731	253,009
Outstanding Options to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	284,332	170,810	155,441	172,079
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	21,230	17,173	25,745	56,605
Warrants to Purchase Preferred Stock (as converted to warrants to purchase Common Stock)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount			5,557	11,917
Warrants to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	769,257	16,200	10,594	5,557
Shares of Common Stock Issued Upon the Exercise of Public Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	750,383	750,394	750,394
Earn-Out Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	360,000	360,000	360,000
Convertible Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	19,168	0		6,851
Series A Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	90,407	0

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended		12 Months Ended
	Oct. 31, 2023	Sep. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock shares reserved for future issuance		2,294,777	2,294,777		1,307,731
Unrecognized compensation costs		$ 1,000	$ 1,000		$ 1,700
Remaining weighted-average period			1 year 7 months 6 days		2 years
Stock compensation expense			$ 2,217	$ 6,349	$ 8,357	$ 437
Common stock, shares issued		2,574,783	2,574,783		1,907,529	1,083,196
Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			62.50%		62.50%
Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	3 years		2 years		2 years
Stock compensation expense		$ 200	$ 800		$ 5,700
Restricted Stock Units | Board of Director Members
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period			3 years
Restricted Stock Units | Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Remaining vesting percentage			37.50%		37.50%
Stock Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted average grant-date fair value of the stock option awards granted			$ 32.5		$ 99.5	$ 59
Remaining weighted-average period					2 years 1 month 6 days
Stock compensation expense		$ 600	$ 1,400		$ 2,700
Time-Vested Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted average grant-date fair value of time-vested restricted stock units granted					$ 108	$ 112.75
2010 Plan and 2020 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options and RSUs issued and exercisable under the plan					181,186	228,684
2010 Plan, 2020 Plan, and 2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options and RSUs issued and exercisable under the plan		305,562	305,562		181,186
Vesting period			4 years		4 years
Expiration period			10 years		10 years
Unrecognized compensation costs		$ 5,600	$ 5,600
Remaining weighted-average period			3 years
2020 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation costs					$ 2,500
2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock shares reserved for future issuance		326,975	326,975		312,908
Increase (decrease) in percentage of number of shares reserved for future issuance			5%		5%
2023 ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock shares reserved for future issuance		89,045	89,045		56,893
Percentage of price lower of fair value market value			85%		85%
Percentage of employees compensation to payroll deductions			15%		15%
Percentage of diluted shares outstanding			1%		1%
Common stock, shares issued					0
2023 ESPP | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock, shares issued		64,000	64,000		64,000

Stock Based Compensation - Sche

Stock Based Compensation - Schedule of Stock Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 860	$ 5,539	$ 2,217	$ 6,349	$ 8,357	$ 437
Cost of Revenue
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	13	16	24	31	32
Selling, General and Administrative
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	791	5,477	2,109	6,235	8,198	400
Research and Development
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 56	$ 46	$ 84	$ 83	$ 127	$ 37

Stock Based Compensation - Summ

Stock Based Compensation - Summary of Stock Option Activity Under the Plan (Details) - 2010 Plan, 2020 Plan, 2023 Plan - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Options, Beginning balance	155,441	172,079
Number of Options, Granted	147,443	10,308
Number of Options, Cancellations and forfeitures	(17,906)	(15,003)
Number of Options, Exercised	(646)	(11,943)
Number of Options, Ending balance	284,332	155,441	172,079
Number of Options, Exercisable	114,913	109,436
Weighted-Average Exercise Price, Beginning balance	$ 66.75	$ 58.75
Weighted-Average Exercise Price, Granted	46.5	135.25
Weighted-Average Exercise Price, Cancellations and forfeitures	57	50
Weighted-Average Exercise Price, Exercised	34.25	28.75
Weighted-Average Exercise Price, Ending balance	57	66.75	$ 58.75
Weighted-Average Exercise Price, Exercisable	$ 62	$ 55.75
Weighted-Average Remaining Contractual Term	7 years 10 months 24 days	6 years 10 months 24 days	7 years 8 months 12 days
Weighted-Average Remaining Contractual Term, Exercisable	5 years 10 months 24 days	6 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding		$ 5,565	$ 9,437
Aggregate Intrinsic Value, Exercisable		$ 4,812

Stock Based Compensation - Sc_2

Stock Based Compensation - Schedule of Assumptions used in Black-Scholes Option-Pricing Model (Details)	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Expected volatility	71%	86%	85.80%	63%
Risk-free interest rate	4.36%	4.50%	4.50%	3.56%
Expected dividend yield	0%	0%
Expected term (in years)	6 years 1 month 6 days	5 years 9 months 18 days	5 years 9 months 18 days	5 years 9 months 18 days

Stock Based Compensation - Su_2

Stock Based Compensation - Summary of Restricted Stock Unit Activity Under the Plan (Details) - Restricted Stock Units - 2020 Plan and 2023 Plan - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of RSUs, Beginning balance	25,745	56,605
Number of RSUs, Granted	3,000	9,047
Number of RSUs, Cancellations and forfeitures		(3,170)
Number of RSUs, Vested	(7,515)	(36,737)
Number of RSUs, Ending balance	21,230	25,745
Weighted Average Grant Date Fair Value, Beginning balance	$ 111.25	$ 112.75
Weighted Average Grant Date Fair Value, Granted	65.25	108
Weighted Average Grant Date Fair Value, Cancellations and forfeitures		112.75
Weighted Average Grant Date Fair Value, Vested	112.75	112.75
Weighted Average Grant Date Fair Value, Ending balance	$ 104	$ 111.25

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan matching contributions	$ 100,000	$ 100,000	$ 100,000	$ 100,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)

1 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

Aug. 29, 2024 USD ($) TradingDay

Apr. 30, 2024 USD ($)

Aug. 31, 2023

Feb. 28, 2023

Sep. 30, 2024 USD ($) ft²

Sep. 30, 2023 USD ($)

Sep. 30, 2024 USD ($) ft²

Sep. 30, 2023 USD ($)

Dec. 31, 2023 USD ($) ft²

Dec. 31, 2022 USD ($)

Jun. 30, 2024 USD ($)

Mar. 31, 2024 USD ($)

Jun. 30, 2023 USD ($)

Mar. 31, 2023 USD ($)

Dec. 31, 2021 USD ($)

Loss Contingencies [Line Items]

Lease description

In February 2023 and August 2023, the Company executed amendments to three of its leases in Natick, Massachusetts and its Hudson, Massachusetts lease, respectively. The amendments were accounted for as a modification of the existing lease agreements, with impacts to the lease term, lease payments, and related lease liability for each of the four leases.

In February 2023 and August 2023, the Company executed amendments to three of its leases in Natick, Massachusetts and its Hudson, Massachusetts lease, respectively. The amendments were accounted for as a modification of the existing lease agreements, with impacts to the lease term, lease payments, and related lease liability for each of the four leases.

Operating lease assets obtained in exchange for lease obligations

$ 62,000

$ 15,000

$ 936,000

$ 936,000

$ 1,677,000

Lease total area of land | ft²

51,000

51,000

51,000

Lessee, operating lease, right to extend

The Company has a right to extend certain of these leases for periods between three and five years.

The Company has a right to extend certain of these leases for periods between three and five years.

Lessee, operating lease, right to extend [true false]

true

true

Loss contingency for probable losses

$ 0

$ 0

$ 0

0

Reduction to revenues of customer returns

1,200,000

$ 1,200,000

Stock exchange listing requirements description

NYSE Continued Listing Standards On August 12, 2024, we received a letter from the NYSE notifying us that, as of August 8, 2024, for the last 30 consecutive business days, the average closing price of the Company’s common stock was less than $1.00 per share, the minimum average closing bid price required by the continued listing requirements of Rule 802.01C of the NYSE Listed Company Manual. A company can regain compliance with the minimum share price requirement at any time during the six-month cure period if, on the last trading day of any calendar month during the cure period, the company has (i) a closing share price of at least $1.00 and (ii) an average closing share price of at least $1.00 over the 30 trading-day period ending on the last trading day of that month. In the event that at the expiration of the six-month cure period, both a $1.00 closing share price on the last trading day of the cure period and a $1.00 average closing share price over the 30 trading-day period ending on the last trading day of the cure period are not attained, the NYSE will commence suspension and delisting procedures. We intend to monitor the closing bid price of our Common Stock and may, if appropriate, consider available options to regain compliance with the NYSE minimum share price requirement.

Number of consecutive trading day | TradingDay

30

Stockholders equity

$ (64,790,000)

$ (52,756,000)

$ (64,790,000)

$ (52,756,000)

(70,487,000)

$ (32,314,000)

$ (70,582,000)

$ (66,162,000)

$ (71,218,000)

$ (49,657,000)

$ 4,837,000

Natick and Hudson

Loss Contingencies [Line Items]

Operating lease assets obtained in exchange for lease obligations

$ 100,000

$ 900,000

Maximum

Loss Contingencies [Line Items]

Lessee operating lease expiration period

2028-03

Lessee, operating lease, remaining lease term

5 years

5 years

5 years

Average market capitalization amount

$ 50,000,000

Stockholders equity

$ 50,000,000

Maximum | Natick and Hudson

Loss Contingencies [Line Items]

Lessee operating lease expiration period

2028-03

2028-03

Minimum

Loss Contingencies [Line Items]

Lessee operating lease expiration period

2025-03

Lessee, operating lease, remaining lease term

3 years

3 years

3 years

Minimum | Natick and Hudson

Loss Contingencies [Line Items]

Lessee operating lease expiration period

2024-06

2024-06

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Other Pertinent Lease Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating lease costs	$ 259	$ 285	$ 794	$ 834	$ 1,123	$ 918
Short-term lease costs	3	5	23	17	12	14
Variable lease costs	59	52	194	211	187	191
Operating cash flows paid for amounts in the measurement of lease liabilities	$ 271	284	826	815
Operating cash flows paid for amounts in the measurement of finance lease liabilities					1,084	807
Operating lease assets obtained in exchange for lease obligations		$ 62	$ 15	$ 936	$ 936	$ 1,677

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Commitments Under Non-cancelable Operating Lease Agreements (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Total
2024		$ 1,173
2025		1,114
2026		737
2027		645
2028		108
Total lease payments		3,777
Less: present value adjustment		(563)
Present value of total lease liabilities		3,214
Less: current lease liability		(908)
Long-term lease liabilities		2,306
2024	$ 273
2025	1,044
2026	739
2027	646
2028	108
Total lease payments	2,810
Less: present value adjustment	(354)
Total lease liabilities	2,456
Less: current lease liability	(878)	(908)	$ (905)
Long-term operating lease liabilities	$ 1,578	$ 2,306	$ 2,163

Commitments and Contingencies_4

Commitments and Contingencies - Schedule of Weighted-Average Remaining Lease Terms and Discount Rates Related Leases (Details)	Sep. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating leases, weighted -average remaining lease term (in years)	2 years 10 months 24 days	3 years 6 months	3 years 8 months 12 days	3 years 10 months 24 days
Operating leases, weighted-average discount rate	9.90%	9.90%	9.90%	9.50%

Geographic Information - Schedu

Geographic Information - Schedule of Long-lived Assets by Geography (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 5,363	$ 6,391	$ 5,281
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	4,690	5,381	3,999
France
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 673	$ 1,010	$ 1,282

Related-party Transactions - Ad

Related-party Transactions - Additional Information (Details) $ in Thousands

1 Months Ended

3 Months Ended

9 Months Ended

Jun. 28, 2024 USD ($) shares

Apr. 16, 2024 USD ($)

Dec. 12, 2023 USD ($)

Feb. 15, 2023 USD ($)

Sep. 30, 2023 EUR (€)

Aug. 31, 2022 USD ($)

Sep. 30, 2024 USD ($) shares

Sep. 30, 2023 USD ($)

Mar. 31, 2023 USD ($)

Sep. 30, 2024 USD ($) shares

Sep. 30, 2023 USD ($)

Dec. 31, 2023 shares

Dec. 31, 2022 shares

Related Party Transaction [Line Items]

Operating lease, payments

$ 271

$ 284

$ 826

$ 815

Percentage of outstanding capital stock

5%

Conversion of warrants into shares of common stock | shares

769,257

769,257

16,151

17,474

2023 Convertible Notes | Hunter Ventures Limited

Related Party Transaction [Line Items]

Debt instrument issued

$ 13,000

Consulting Agreements

Related Party Transaction [Line Items]

Agreements termination date

Jun. 20, 2023

Convertible Note Agreement with RTW

Related Party Transaction [Line Items]

Principal amount

$ 48,000

Percentage of Outstanding Common Stock

5%

RTW Participation in Public Offering

Related Party Transaction [Line Items]

Sale of stock | shares

9,594

Aggregate purchase price

$ 300

Private Placement with RTW

Related Party Transaction [Line Items]

Conversion of warrants into shares of common stock | shares

90,407

Aggregate purchase price

$ 2,700

Private Placement with RTW | Series A Preferred Stock

Related Party Transaction [Line Items]

Sale of stock | shares

2,260,159

LNMP JPBC Invest

Related Party Transaction [Line Items]

Operating lease, payments

$ 100

Operating lease commencement date

Aug. 01, 2022

Operating lease end date

Jul. 31, 2025

Lease terminated date

2024-02

Operating lease start date

Aug. 01, 2022

KKG Enterprises | Consulting Agreements

Related Party Transaction [Line Items]

Payments of advisory services related to business combination

$ 200

Remus Group Management | Consulting Agreements

Related Party Transaction [Line Items]

Payments of advisory services related to business combination

$ 300

Benoit Chardon Consulting | Consulting Agreements

Related Party Transaction [Line Items]

Agreements termination date

Dec. 12, 2023

Consulting fees | €

€ 28,333.33

Benoit Chardon Consulting | Termination Agreement

Related Party Transaction [Line Items]

Termination fees

$ 200

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Subsequent Events $ in Millions	Nov. 06, 2024 USD ($) Employees	Oct. 22, 2024 USD ($) shares	Oct. 30, 2024 USD ($)
Restructuring Plan
Subsequent Event [Line Items]
Number of employees reduced from workforce | Employees	113
Percentage of employees reduced from workforce	50%
One-time aggregate restructuring charges	$ 3.5
Revenue Interest Financing Agreement | RTW Side Letter
Subsequent Event [Line Items]
Number of surrender shares of common stock | shares		30,000
Surrender common stock value		$ 7.5
Conversion of RTW PIPE investment to revenue interest finance			$ 7.5