Fathom Digital Manufacturing Corporation - Ordinary Shares (FATH) 10-Q 14 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Nov. 10, 2023
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Trading Symbol	FATH
Entity Registrant Name	Fathom Digital Manufacturing Corporation
Entity Central Index Key	0001836176
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Current Reporting Status	Yes
Entity File Number	001-39994
Entity Tax Identification Number	40-0023833
Entity Address, Address Line One	1050 Walnut Ridge Drive
Entity Address, City or Town	Hartland
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53029
City Area Code	262
Local Phone Number	367-8254
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Class A common stock, par value $0.0001 per share
Security Exchange Name	NYSE
Document Quarterly Report	true
Document Transition Report	false
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,507,084
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,327,379

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands		Sep. 30, 2023	Dec. 31, 2022
Current assets
Cash		$ 7,821	$ 10,713
Accounts receivable, net	[1]	22,040	28,641
Inventory		16,779	15,718
Prepaid expenses and other current assets		2,403	3,588
Total current assets		49,043	58,660
Property and equipment, net		47,164	47,703
Right-of-use lease assets, net		11,469	12,565
Intangible assets, net		237,807	251,412
Other non-current assets		142	175
Total assets		345,625	370,515
Current liabilities
Accounts payable		9,401	7,982
Accrued expenses		7,691	8,176
Current lease liability		2,143	2,374
Other current liabilities		2,671	4,828
Current portion of debt, net		157,321	42,744
Total current liabilities		179,227	66,104
Long-term debt, net		0	114,327
Fathom earnout shares liability		283	5,960
Sponsor earnout shares liability		49	930
Warrant liability		191	2,780
Payable to related parties pursuant to the tax receivable agreement (includes $4,416 and $4,000 at fair value, respectively)		25,800	25,360
Noncurrent lease liability		9,709	11,083
Total liabilities		215,259	226,544
Commitments and Contingencies:
Contingently Redeemable Preferred Equity:
Redeemable non-controlling interest in Fathom OpCo		76,144	92,207
Shareholders’ equity
Preferred stock, $0.002 par value; 500,000 shares authorized; 0 shares issued and outstanding as of September 30, 2023 and December 31, 2022, respectively		0	0
Additional paid-in-capital		595,785	587,941
Accumulated other comprehensive loss		(107)	(107)
Accumulated deficit		(541,456)	(536,084)
Shareholders' equity attributable to Fathom Digital Manufacturing Corporation		54,222	51,764
Total Liabilities, Shareholders' Equity and Redeemable Non-Controlling Interest		345,625	370,515
Class A Common Stock [Member]
Shareholders’ equity
Common stock	[2]	0	7
Class B Common Stock [Member]
Shareholders’ equity
Common stock	[2]	0	7
Class C Common Stock [Member]
Shareholders’ equity
Common stock		$ 0	$ 0
[1] Inclusive of allowance for expected credit losses of $ 580 as of September 30, 2023 and allowance for doubtful accounts of $ 876 as of December 31, 2022, respectively Periods presented have been adjusted to reflect the 20-for-1 reverse stock split effective on September 28, 2023. Additional information regarding the reverse stock split may be found in Note 2- Basis of Presentation.

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Common stock, shares authorized (in shares)	25,000,000
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Allowance for expected credit losses	$ 580	$ 876
Fair value of payable to related parties pursuant to the tax receivable agreement	$ 4,416	$ 4,000
Class A Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	15,000,000	15,000,000
Common stock, shares issued (in shares)	3,507,084	3,290,438
Common stock, shares outstanding	3,507,084	3,290,438
Class B Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	9,000,000	9,000,000
Common stock, shares issued (in shares)	3,327,379	3,507,653
Common stock, shares outstanding	3,327,379	3,507,653
Class C Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	500,000	500,000
Common stock, shares issued (in shares)	0	0
Common stock, shares outstanding	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue		$ 31,458	$ 40,210	$ 100,939	$ 122,737
Cost of revenue	[1],[2],[3]	23,194	25,144	70,196	80,126
Gross profit		8,264	15,066	30,743	42,611
Operating expenses
Selling, general, and administrative		8,117	11,960	28,335	38,341
Depreciation and amortization		4,627	4,627	13,845	13,595
Restructuring		718	996	2,774	996
Goodwill impairment			1,066,564		1,066,564
Total operating expenses		13,462	1,084,147	44,954	1,119,496
Operating loss		(5,198)	(1,069,081)	(14,211)	(1,076,885)
Interest expense and other expense (income)
Interest expense		3,993	2,406	11,422	5,738
Other expense		435	81	573	276
Other income		(1,049)	(25,548)	(9,152)	(88,771)
Total interest expense and other expense (income), net		3,379	(23,061)	2,843	(82,757)
Net loss before income tax		(8,577)	(1,046,020)	(17,054)	(994,128)
Income tax expense (benefit)		(9)	(7,050)	110	(8,435)
Net loss		(8,568)	(1,038,970)	(17,164)	(985,693)
Net loss attributable to Fathom OpCo non-controlling interest		(4,206)	(556,027)	(11,792)	(561,728)
Net loss attributable to controlling interest		(4,362)	(482,943)	(5,372)	(423,965)
(Loss) Income from foreign currency translation adjustments					(107)
Comprehensive loss, net of tax		$ (4,362)	$ (482,943)	$ (5,372)	$ (424,072)
Class A Common Stock [Member]
Net loss per share attributable to shares of Class A common stock
Basic	[4]	$ (1.24)	$ (153.76)	$ (1.56)	$ (153.2)
Diluted	[4]	$ (1.24)	$ (153.76)	$ (1.56)	$ (153.2)
Weighted average shares outstanding
Basic	[4]	3,504,859	3,140,809	3,448,030	2,767,401
Diluted	[4]	3,504,859	3,140,809	3,448,030	2,767,401
[1] Inclusive of $ 1,621 and $ 1,707 of depreciation and amortization for the three months ended September 30, 2023 and September 30, 2022, respectively; and of $ 4,947 and $ 4,944 for the nine months ended September 30, 2023 and September 30, 2022, respectively; Inclusive of $ 0 and $ 0 of inventory step-up amortization for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 0 and $ 3,241 for the nine months ended September 30, 2023 and September 30, 2022, respectively; and Inclusive of $ 1,611 and $ 2,573 of cost of revenue related to inventory purchases from a related party for the three months ended September 30, 2023 and September 30, 2022, respectively; and $ 5,689 and $ 7,513 for the nine months ended September 30, 2023 and September 30, 2022, respectively; Periods presented have been adjusted to reflect the 20-for-1 reverse stock split effective on September 28, 2023. Additional information regarding the reverse stock split may be found in Note 2- Basis of Presentation.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Cost, depreciation and amortization	$ 1,621	$ 1,707	$ 4,947	$ 4,944
Cost, inventory purchases from related party	1,611	2,573	5,689	7,513
Inventory step up amortization	$ 0	$ 0	$ 0	$ 3,241

Condensed Consolidated Statem_3

Condensed Consolidated Statement of Shareholders' Equity and Redeemable Non-Controlling Interest (Unaudited) - USD ($) $ in Thousands		Total	Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock	Common Stock Class A Common Shares	Common Stock Class B Common Shares	Additional Paid-in Capital		Accumulated Deficit	Accumulated Deficit Revision of Prior Period, Accounting Standards Update, Adjustment	Acumulated Other Comprehensive Loss	Redeemable Non-controlling Interest
Shareholders' equity beginning balance at Dec. 31, 2021		$ 418,777					$ 466,358	[1]	$ (47,581)
Shareholders' equity beginning balance (in shares) at Dec. 31, 2021	[1]				2,539,283	4,214,749
Opening Balance, Value, Redeemable Noncontrolling Interest at Dec. 31, 2021												$ 841,982
Equity based compensation		2,130					2,130	[1]
Accounting Standards Update [Extensible Enumeration]										us-gaap:AccountingStandardsUpdate201602Member
Shareholders' equity ending balance at Mar. 31, 2022			$ 82							$ 82
Net income (loss)		24,258							24,258			(5,259)
Other comprehensive loss		(107)									$ (107)
Shareholders' equity ending balance at Mar. 31, 2022		445,140					468,488	[1]	(23,241)		(107)	836,723
Shareholders' equity ending balance (in shares) at Mar. 31, 2022	[1]				2,539,283	4,214,749
Shareholders' equity beginning balance at Dec. 31, 2021		418,777					466,358	[1]	(47,581)
Shareholders' equity beginning balance (in shares) at Dec. 31, 2021	[1]				2,539,283	4,214,749
Opening Balance, Value, Redeemable Noncontrolling Interest at Dec. 31, 2021												841,982
Shareholders' equity ending balance at Sep. 30, 2022		105,708					577,273		(471,458)
Net income (loss)		(423,965)
Shareholders' equity ending balance at Sep. 30, 2022		105,708					577,273	[1]	(471,458)		(107)
Shareholders' equity ending balance (in shares) at Sep. 30, 2022	[1]				3,276,488	3,507,653
Closing Balance, Value, Redeemable Noncontrolling Interest at Sep. 30, 2022												161,407
Shareholders' equity beginning balance at Mar. 31, 2022		445,140					468,488	[1]	(23,241)		(107)	836,723
Shareholders' equity beginning balance (in shares) at Mar. 31, 2022	[1]				2,539,283	4,214,749
Equity based compensation		1,795					1,795	[1]
Net income (loss)		34,726							34,726			(442)
Vesting of restricted shares, net of tax withholding		(2,258)					(2,258)	[1]
Vesting of restricted shares, net of tax withholding (in shares)	[1]				26,527
Exchange of Class B common stock and Fathom Opco units (in shares)	[1]				514,017	(514,017)
Non-controlling interest remeasurement		86,666					86,666	[1]				(86,666)
Tax receivable agreement liability on capital transactions		(15,870)					(15,870)	[1]
Tax impact of exchange of Class B common stock and Fathom OpCo units		7,415					7,415	[1]
Shareholders' equity ending balance at Jun. 30, 2022		557,614					546,236	[1]	11,485		(107)
Shareholders' equity ending balance (in shares) at Jun. 30, 2022	[1]				3,079,827	3,700,732
Closing Balance, Value, Redeemable Noncontrolling Interest at Jun. 30, 2022												749,615
Equity based compensation		1,762					1,762	[1]
Shareholders' equity ending balance at Sep. 30, 2022		105,708					577,273		(471,458)
Net income (loss)		(482,943)					(482,943)					(556,027)
Vesting of restricted shares, net of tax withholding		(308)					(308)	[1]
Vesting of restricted shares, net of tax withholding (in shares)	[1]			3,582
Exchange of Class B common stock and Fathom Opco units (in shares)	[1]				(193,079)	193,079
Non-controlling interest remeasurement		32,181					32,181	[1]				(32,181)
Tax receivable agreement liability on capital transactions		(5,490)					(5,490)	[1]
Tax impact of exchange of Class B common stock and Fathom OpCo units		2,892					2,892	[1]
Shareholders' equity ending balance at Sep. 30, 2022		105,708					577,273	[1]	(471,458)		(107)
Shareholders' equity ending balance (in shares) at Sep. 30, 2022	[1]				3,276,488	3,507,653
Closing Balance, Value, Redeemable Noncontrolling Interest at Sep. 30, 2022												161,407
Shareholders' equity beginning balance at Dec. 31, 2022		51,764					587,955		(536,084)		(107)
Shareholders' equity beginning balance (in shares) at Dec. 31, 2022	[2]				3,290,438	3,507,653
Opening Balance, Value, Redeemable Noncontrolling Interest at Dec. 31, 2022		92,207										92,207
Equity based compensation		1,093					1,093
Net income (loss)		2,115							2,115			(3,447)
Vesting of restricted shares, net of tax withholding (in shares)	[2]				7,191
Exchange of Class B common stock and Fathom Opco units (in shares)	[2]				173,014	(173,014)
Non-controlling interest remeasurement		4,477					4,477					(4,477)
Tax receivable agreement liability on capital transactions		(2,500)					(2,500)
Shareholders' equity ending balance at Mar. 31, 2023		56,949					591,025		(533,969)		(107)
Shareholders' equity ending balance (in shares) at Mar. 31, 2023	[2]				3,477,326	3,334,639
Closing Balance, Value, Redeemable Noncontrolling Interest at Mar. 31, 2023												84,283
Shareholders' equity beginning balance at Dec. 31, 2022		51,764					587,955		(536,084)		(107)
Shareholders' equity beginning balance (in shares) at Dec. 31, 2022	[2]				3,290,438	3,507,653
Opening Balance, Value, Redeemable Noncontrolling Interest at Dec. 31, 2022		92,207										92,207
Shareholders' equity ending balance at Sep. 30, 2023		54,222
Net income (loss)		(5,372)
Shareholders' equity ending balance at Sep. 30, 2023		54,222					595,785		(541,456)		(107)
Shareholders' equity ending balance (in shares) at Sep. 30, 2023	[2]			3,327,379	3,507,084
Closing Balance, Value, Redeemable Noncontrolling Interest at Sep. 30, 2023		76,144
Shareholders' equity beginning balance at Mar. 31, 2023		56,949					591,025		(533,969)		(107)
Shareholders' equity beginning balance (in shares) at Mar. 31, 2023	[2]				3,477,326	3,334,639
Opening Balance, Value, Redeemable Noncontrolling Interest at Mar. 31, 2023												84,283
Equity based compensation		1,239					1,239
Net income (loss)		(3,125)							(3,125)			(4,139)
Vesting of restricted shares, net of tax withholding (in shares)	[2]				13,874
Issuance of Class A shares under Employee Stock Purchase Plan		86					86
Issuance of Class A shares under Employee Stock Purchase Plan (in shares)	[2]				12,482
Exchange of Class B common stock and Fathom Opco units (in shares)	[2]				7,260
Non-controlling interest remeasurement		85					85					(85)
Tax receivable agreement liability on capital transactions		(353)					(353)
Shareholders' equity ending balance at Jun. 30, 2023		54,881					592,082		(537,094)		(107)
Shareholders' equity ending balance (in shares) at Jun. 30, 2023	[2]				3,504,259	3,327,379
Closing Balance, Value, Redeemable Noncontrolling Interest at Jun. 30, 2023												80,059
Equity based compensation		1,139					1,139
Shareholders' equity ending balance at Sep. 30, 2023		54,222
Net income (loss)		(4,362)							(4,362)			(4,206)
Vesting of restricted shares, net of tax withholding (in shares)	[2]				2,825
Non-controlling interest remeasurement		(291)					(291)					$ 291
Tax receivable agreement liability on capital transactions		2,855					2,855
Shareholders' equity ending balance at Sep. 30, 2023		54,222					$ 595,785		$ (541,456)		$ (107)
Shareholders' equity ending balance (in shares) at Sep. 30, 2023	[2]			3,327,379	3,507,084
Closing Balance, Value, Redeemable Noncontrolling Interest at Sep. 30, 2023		$ 76,144
[1] Periods presented have been adjusted to reflect the 20-for-1 reverse stock split effective on September 28, 2023. Additional information regarding the reverse stock split may be found in Note 2- Basis of Presentation. Periods presented have been adjusted to reflect the 20-for-1 reverse stock split effective on September 28, 2023. Additional information regarding the reverse stock split may be found in Note 2- Basis of Presentation.

Condensed Consolidated Statem_4

Condensed Consolidated Statement of Shareholders' Equity and Redeemable Non-Controlling Interest (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022
Class A Common Shares
Common stock, par value (in dollars per share)	$ 0.0001
Class B Common Shares
Common stock, par value (in dollars per share)	0.0001
Common Stock | Class A Common Shares
Common stock, par value (in dollars per share)	0.0001	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Common Stock | Class B Common Shares
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash Flows from Operating Activities
Net loss attributable to controlling interest	$ (5,372)	$ (423,965)
Adjustments to reconcile net (loss) income to net cash from operating activities:
Depreciation and amortization	18,792	18,539
Amortization of inventory step-up	0	3,241
Goodwill impairment		1,066,564
Gain on disposal of property and equipment	(4)	(164)
Share-based compensation	3,471	5,687
Noncash lease expense, net	313	485
Deferred taxes		(8,449)
Bad debt expense	185	5
Non-controlling interest share of Fathom OpCo net loss	(11,792)	(561,728)
Change in fair value of Fathom earnout shares liability	(5,677)	(52,390)
Change in fair value of Sponsor earnout shares liability	(881)	(7,590)
Change in fair value of warrant liability	(2,589)	(28,000)
Change in fair value of tax receivable agreement	442	(200)
Change in fair value of contingent consideration		(148)
Amortization of debt financing costs	461	299
Changes in operating assets and liabilities that provided cash:
Accounts receivable	6,416	(2,270)
Inventory	(1,061)	(5,907)
Prepaid expenses and other assets	1,218	1,861
Accounts payable	1,049	(1,452)
Accrued liabilities and other	(2,721)	2,185
Net cash provided by operating activities	2,250	6,603
Cash Flows from Investing Activities
Purchase of property and equipment	(4,273)	(10,953)
Net cash used in investing activities	(4,273)	(10,953)
Cash Flows from Financing Activities
Proceeds from revolving credit facility, net	5,000
Payments on debt	(4,689)	(2,344)
Payments on finance leases	(240)	(236)
Payment of debt issuance costs	(524)
Tax payment for shares withheld in lieu of taxes		(2,566)
Proceeds from issuance of common stock under ESPP	86
Cash paid for contingent consideration	(502)	(2,750)
Net cash used in financing activities	(869)	(7,896)
Effect of exchange rate changes on cash, and cash equivalents		(107)
Net decrease in cash	(2,892)	(12,353)
Cash, beginning of period	10,713	20,357
Cash, end of period	7,821	8,004
Supplemental Cash Flows Information:
Cash paid for interest	10,334	3,108
Cash paid for taxes	631	98
Cash paid to related parties	5,501	7,595
Significant Non-Cash Transactions:
Property and equipment noncash transaction		1,485
Right-of-use assets acquired through lease liabilities	$ 788	$ 11,986

Nature of Business

Nature of Business	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Note 1. Nature of Business Fathom Digital Manufacturing Corporation (“Fathom”, "Successor", or the “Company”) was incorporated as a Delaware corporation on December 23, 2021. Fathom was previously named Altimar Acquisition Corp. II ("Altimar II") before deregistering as an exempted company in the Cayman Islands. Fathom, through its consolidated subsidiary, Fathom Holdco, LLC (“Fathom OpCo”), is a leading on-demand digital manufacturing platform in North America, providing comprehensive product development and manufacturing services to many of the largest and most innovative companies in the world. Fathom OpCo was formed on April 16, 2021 , as a limited liability company in accordance with the provisions of the Delaware Limited Liability Company Act, for the purpose of holding a 100 percent equity interest in MCT Group Holdings, LLC and its subsidiaries (“MCT Holdings”) and holding a 100 percent equity interest in Incodema Holdings, LLC and its subsidiaries (“Incodema Holdings”). Capitalized terms used but not otherwise defined herein have the meanings given to such terms in the Company's Annual Report on Form 10-K for the year ended December 31, 2022, as amended by Amendment No.1. thereto (the "2022 Form 10-K").

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Note 2. Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of Fathom Digital Manufacturing Corporation and all majority-owned subsidiaries and entities in which a controlling interest is maintained. All significant intercompany transactions and balances have been eliminated in consolidation. The unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”) applicable to interim reports. Accordingly, they do not include all the information and notes required by GAAP for complete financial statements and should be read in conjunction with the audited financial statements included in our 2022 Form 10-K. The Company's annual reporting period is the calendar year. In the Company’s opinion, the unaudited condensed consolidated financial statements contain all adjustments, consisting of adjustments of a normal, recurring nature, necessary to present fairly the financial position, results of operations and cash flows for the periods presented. The results of operations for the three and nine months ended September 30, 2023, are not necessarily indicative of the results to be expected for the full year. The preparation of financial statements in accordance with GAAP requires management to make estimates, judgments, and assumptions that affect the amounts reported in the financial statements. Actual results may differ from those estimates, judgments, and assumptions. Amounts in the prior years' unaudited condensed consolidated financial statements are reclassified whenever necessary to conform to the current year's presentation. The unaudited condensed consolidated financial statements included in this Form 10-Q have been prepared using the going concern basis of accounting, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. To satisfy the obligation to pay down $ 50,000 of Term Loan debt under the Credit Agreement due March 31, 2024 (or June 30, 2024 in certain circumstances), the Company will need to obtain qualified equity capital or otherwise restructure or refinance the Credit Agreement. At this time, we expect to be able to successfully complete one of these actions; however, there is no assurance that we will be successful, and our inability to obtain such capital or complete such actions would likely have a material adverse effect on the Company. This uncertainty raises substantial doubt about the Company’s ability to continue as a going concern within one year after the issuance date of the accompanying unaudited condensed consolidated financial statements. Recently Adopted Accounting Standards The FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments ("ASC 326"), which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments including trade receivables and available for sale debt securities. ASC 326 is effective for fiscal years beginning after December 15, 2022, with early adoption permitted. The new standard was effective for the Company beginning January 1, 2023, and was applied using a modified retrospective transition method. The FASB subsequently issued other related ASUs that amend ASU No. 2016-13 to provide clarification and additional guidance. The Company concluded that the adoption of ASC 326 did not have a material impact on the condensed consolidated financial statements. Reverse Stock Split On September 15, 2023, the Company’s Board of Directors approved a reverse stock split ratio of 20-for-1 (the “Reverse Stock Split”). On September 28 , 2023, the effective date of the Reverse Stock Split, the number of the Company’s issued and outstanding shares of common stock decreased from 70,113,787 shares to 3,505,689 shares, net of fractional shares redeemed. The number of authorized shares and par value per common share remained unchanged. No fractional shares we re issued as a result of the Reverse Stock Split. Stockholders who would otherwise have been entitled to receive a fractional share received a cash payment in lieu thereof. Prior to the effective date of the Reverse Stock Split, the Company had listed warrants to purchase a total of 18,524,320 shares of Common Stock, with each whole warrant being exercisable for one share of Common Stock at $ 11.50 per share. After the effective date of the Reverse Stock Split, every twenty shares of Common Stock that may have been purchased pursuant to the warrants immediately prior to the Reverse Stock Split represented one share of Common Stock that may be purchased pursuant to such warrants immediately following the Reverse Stock Split. Correspondingly, the exercise price per share of Common Stock attributable to such warrants was proportionately increased, such that the exercise price immediately following the Reverse Stock Split was $ 230.00 , which equals the product of twenty multiplied by $ 11.50 , the exercise price per share immediately prior to the Reverse Stock Split. The number of shares of Common Stock subject to the warrants was proportionately decreased by twenty times, to an aggregate of 926,216 shares. The share, per share and trading price amounts in the unaudited condensed consolidated financial statements and the accompanying notes, have been retrospectively adjusted to reflect the Reverse Stock Split for all periods presented.

Immaterial Error Correction of

Immaterial Error Correction of Previously Issued Financial Statements	9 Months Ended
	Sep. 30, 2023
Condensed Financial Information Disclosure [Abstract]
Immaterial Error Correction of Previously Issued Financial Statements	Note 3. Immaterial Error Correction of Previously Issued Financial Statements The Company has made certain adjustments to previously reported amounts for correcting immaterial errors in our unaudited condensed consolidated financial statements as of and for the three and nine months ended September 30, 2022. These adjustments corrected our income tax benefit (expense) and associated deferred tax liability or deferred tax asset due to completion of a comprehensive review of our opening tax basis acquired in the Business Combination. We evaluated these matters in accordance with SAB No. 99, Materiality and SAB No. 108, Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements and determined that their related impact was not material to the financial statements for any prior annual or interim periods. The Company will correct previously reported financial information for these immaterial errors in our future filings, as applicable. These corrections of immaterial errors do not have any impact on the previously reported financial information for the fiscal year ended December 31, 2022. In addition, we made an adjustment to correct an immaterial presentation error regarding the effect of exchange rate changes on cash in our unaudited condensed consolidated statements of cash flows. A summary of the adjustments to our prior period unaudited condensed consolidated statement of comprehensive loss is presented below: Three Months Ended September 30, 2022 As Reported Adjustments As Adjusted Net loss before income tax $ ( 1,046,020 ) $ - $ ( 1,046,020 ) Income tax expense (benefit) 87 ( 7,137 ) ( 7,050 ) Net loss ( 1,046,107 ) ( 7,137 ) ( 1,038,970 ) Net loss attributable to Fathom OpCo non-controlling interest ( 556,027 ) - ( 556,027 ) Net loss attributable to controlling interest ( 490,080 ) ( 7,137 ) ( 482,943 ) Comprehensive loss: (Loss) Income from foreign currency translation adjustments - - - Comprehensive loss, net of tax $ ( 490,080 ) $ ( 7,137 ) $ ( 482,943 ) Nine Months Ended September 30, 2022 As Reported Adjustments As Adjusted Net loss before income tax $ ( 994,128 ) $ - $ ( 994,128 ) Income tax expense (benefit) 167 ( 8,602 ) ( 8,435 ) Net loss ( 994,295 ) ( 8,602 ) ( 985,693 ) Net loss attributable to Fathom OpCo non-controlling interest ( 561,728 ) - ( 561,728 ) Net loss attributable to controlling interest ( 432,567 ) ( 8,602 ) ( 423,965 ) Comprehensive loss: Loss from foreign currency translation adjustments ( 107 ) - ( 107 ) Comprehensive loss, net of tax $ ( 432,674 ) $ ( 8,602 ) $ ( 424,072 ) The following table presents the effect of the adjustments to our prior period unaudited condensed consolidated statement of cash flows. Nine Months Ended September 30, 2022 As Reported Adjustments As Adjusted Cash Flows from Operating Activities Net (loss) income $ ( 432,567 ) $ 8,602 $ ( 423,965 ) Adjustments to reconcile net loss to net cash from operating activities: Deferred taxes 153 ( 8,602 ) ( 8,449 ) Foreign currency translation adjustment ( 107 ) 107 - Net cash provided by operating activities 6,496 107 6,603 Net cash used in investing activities ( 10,953 ) - ( 10,953 ) Net cash used in financing activities ( 7,896 ) - ( 7,896 ) Effect of exchange rate changes on cash, and cash equivalents - ( 107 ) ( 107 ) Net decrease in cash $ ( 12,353 ) $ - $ ( 12,353 ) The following table presents the effect of the adjustments to our prior period unaudited condensed consolidated statement of shareholders' equity and redeemable non-controlling interest. September 30, 2022 As Reported Adjustments As Adjusted Accumulated earnings (deficit) $ ( 480,167 ) $ 8,709 $ ( 471,458 ) Additional paid-in-capital 584,325 ( 7,052 ) 577,273 Other comprehensive loss - ( 107 ) ( 107 ) Total equity attributable to Fathom 104,158 1,550 105,708

Revenue

Revenue	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Revenue	Note 4. Revenue The Company accounts for revenue in accordance with ASC 606 . Revenue is recognized in five steps. The Company identifies the contract with the customer, identifies the performance obligations in the contract, determines the transaction price, allocates the transaction price to the performance obligations, and recognizes revenue when (or as) each performance obligation is satisfied. Collectability is a required component of a valid contract. The Company assesses collectability based on a number of factors, including the customer’s past payment history and current creditworthiness. If collectability is not considered probable at inception, the Company would recognize revenue upon cash collection. The Company provides high quality, advanced rapid prototyping, precision manufacturing and finishing services in low-to-mid volume production scenarios. The Company’s suite of on-demand digital manufacturing services includes additive manufacturing, machining, and molding technologies as well as sheet metal cutting, etching, and forming solutions for customers in the aerospace and defense, electronics, medical, automotive, consumer, and industrial industries, among others. As a result, the majority of revenue recognized in a reporting period is based on completed, invoiced contracts. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC 606. Substantially all of the Company’s Additive Manufacturing, CNC Machining, Urethane Casting, Precision Sheet Metal, and Chemical Etching contracts have a single performance obligation. The majority of the Company’s injection molding contracts have multiple performance obligations including one obligation to produce the mold and sample part and a second obligation to produce production parts. For injection molding contracts with multiple performance obligations, the Company allocates revenue to each performance obligation based on its relative standalone selling price. For the year ended December 31, 2022, and the three months ended March 31, 2023, the Company was not able to support over time revenue recognition for performance obligations to produce the mold and sample part and therefore recognized revenue for each performance obligation on a point-in time basis upon shipment. During the second quarter of 2023, the Company established additional processes and controls to support recognizing revenue using the input method basis for those performance obligations where appropriate on a go forward basis. This change in revenue recognition policy is immaterial to the overall financial statements in all periods included in this Form 10-Q. Revenue by product line for the three and nine months ended September 30, 2023 and September 30, 2022 are as follows: Three Months Ended Nine Months Ended September 30, 2023 September 30, 2022 September 30, 2023 September 30, 2022 Revenue: Additive Manufacturing $ 2,692 $ 3,154 $ 9,567 $ 11,713 Injection Molding 5,372 5,984 16,114 19,892 CNC Machining 12,486 15,530 39,956 43,441 Precision Sheet Metal 9,542 13,719 30,089 43,153 Ancillary Product Lines 1,366 1,823 5,213 4,538 Total revenue $ 31,458 $ 40,210 $ 100,939 $ 122,737

Inventories

Inventories	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Inventories	Note 5. Inventories Inventory consists primarily of finished goods, raw materials, and work in process, which are recorded at the lower of cost or net realizable value, which approximates first-in, first-out (“FIFO”) cost. The Company periodically reviews its inventory for slow-moving, damaged, and discontinued items and provides allowances to reduce such items identified to their net recoverable amounts. The Company’s inventory consisted of the following at September 30, 2023 and December 31, 2022: September 30, 2023 December 31, 2022 Raw materials $ 8,969 $ 8,496 Work in process 5,802 5,664 Finished goods 2,614 2,464 17,385 16,624 Allowance for obsolescence ( 606 ) ( 906 ) Total $ 16,779 $ 15,718

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	Note 6. Property and Equipment Property and equipment consisted of the following as of September 30, 2023 and December 31, 2022: September 30, December 31, Estimated Useful Life Machinery and equipment $ 42,856 $ 39,516 6 - 10 Furniture and fixtures 3,634 3,100 10 Computer hardware 360 374 5 Property and leasehold improvements 7,142 6,839 3 - 23 Construction in progress 3,650 3,893 n/a Auto / transportation equipment 319 312 3 Total 57,961 54,034 Accumulated depreciation ( 10,797 ) ( 6,331 ) Total $ 47,164 $ 47,703 Depr eciation expense included in operating expenses was $ 306 and $ 307 for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 884 and $ 581 for the nine months ended September 30, 2023 and September 30, 2022, respectively. Depreciation expense included in cost of revenues was $ 1,407 and $ 1,492 for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 4,303 and $ 4,283 for the nine months ended September 30, 2023 and September 30, 2022, respectively.

Intangible Assets, Net

Intangible Assets, Net	9 Months Ended
	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, net	Note 7. Intangible Assets, net Intangible assets, net consisted of the following: September 30, 2023 Gross Accumulated Amortization Net Useful Life (in years) Trade name $ 70,000 $ ( 8,282 ) $ 61,718 15 Customer relationships 180,000 ( 16,813 ) 163,187 19 Developed software 4,300 ( 1,526 ) 2,774 5 Developed technology 15,700 ( 5,572 ) 10,128 5 Total intangible assets $ 270,000 $ ( 32,193 ) $ 237,807 December 31, 2022 Gross Accumulated Amortization Net Useful Life (in years) Trade name $ 70,000 $ ( 4,782 ) $ 65,218 15 Customer relationships 180,000 ( 9,707 ) 170,293 19 Developed software 4,300 ( 881 ) 3,419 5 Developed technology 15,700 ( 3,218 ) 12,482 5 Total intangible assets $ 270,000 $ ( 18,588 ) $ 251,412 Aggregate amortization expense related to intangible assets was $ 4,535 and $ 4,535 for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 13,605 and $ 13,675 for the nine months ended September 30, 2023 and September 30, 2022, respectively. There are no intangible assets with indefinite useful lives . The following table represents the estimated aggregate amortization expense for each of the five succeeding fiscal calendar years and thereafter. Year ended Total Remaining 2023 $ 4,535 2024 18,140 2025 18,140 2026 18,041 2027 14,140 Thereafter 164,811 Total $ 237,807

Reorganization

Reorganization	9 Months Ended
	Sep. 30, 2023
Reorganizations [Abstract]
Reorganization	Note 8. Reorganization In July 2022, the Company's Board of Directors approved a reorganization plan (the "Reorganization") designed to consolidate the Company’s national footprint, streamline legacy leadership, and centralize core business functions following the completion of 13 acquisitions by Fathom since 2019. Pursuant to the Reorganization, the Company intended to: • Consolidate its existing facility in Oakland, California into Fathom headquarters in Hartland, Wisconsin, improving utilization and reducing costs; • Establish a Fathom technology center in Fremont, California that will focus on new and emerging technologies, specifically in the additive market; and • Consolidate leadership and other roles through a net workforce reduction of approximately 6 %, create an accounting shared service organization to streamline company-wide processes and create economies of scale while pursuing additional shared-service systems in other administrative functions. The Company completed the workforce reductions and the relocation of its Oakland, California facility to Hartland, Wisconsin location during the fourth quarter of 2022. On February 17, 2023, the Company committed to additional actions to continue and expand the Reorganization, including consolidating our Austin, Texas facilities, reducing the Company’s workforce by an additional 14 % to respond to market conditions and prioritizing investments and operations in line with near-term revenue generation. During the third quarter, the Company expanded the Reorganization to include further workforce reductions at our Hartland and Miami facilities. The Company expects to complete these activities by the end of the first quarter 2024. Reorganization charges are presented on the face of our condensed consolidated statement of comprehensive loss as an operating expense and were $ 718 , inclusive of inventory write-off of $ 111, and $ 996 for the three months ended September 30, 2023 and September 30, 2022, respectively. Reorganization charges were $ 2,774 , inclusive of inventory write-off of $ 1,302, and $ 996 for the nine months ended September 30, 2023 and September 30, 2022, respectively. The following table summarizes activity in the liability related to the Company's Reorganization. Liability balance at December 31, 2022 $ 412 Charges 668 Payments ( 945 ) Liability balance at September 30, 2023 $ 135 The Reorganization liability is included as part of other c urrent liabilities in the unaudited condensed consolidated balance sheet and as of September 30, 2023 and consists of unpaid employee termination costs of $ 135 .

Warrant Liability

Warrant Liability	9 Months Ended
	Sep. 30, 2023
Warrants and Rights Note Disclosure [Abstract]
Warrant Liability	Note 9. Warrant Liability As of September 30, 2023, the Company had 431,216 Public Warrants outstanding with a fair value price of $ 0.00 per Public Warrant, and 495,000 Private Placement Warrants outstanding with a fair value price of $ 0.39 per Private Placement Warrant. Each reporting period the public and private warrants are fair valued with the change in the fair value being recognized in the unaudited condensed consolidated statement of comprehensive loss. The change in the fair value was $ 409 and $ 7,400 for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 2,589 and $ 28,000 for the nine months ended September 30, 2023 and September 30, 2022, respectively, and is recognized in other income in the unaudited condensed consolidated statement of comprehensive loss. On September 21, 2023, the New York Stock Exchange (“NYSE”) notified the Company, and on September 22, 2023, the Company publicly announced, that the NYSE had determined to (a) commence proceedings to delist the Company’s warrants, each whole warrant exercisable to purchase one share of the Company’s Class A common stock, par value $ 0.0001 per share (the “Class A common stock”), at a price of $ 11.50 per share, and listed to trade on the NYSE under the symbol “FATH.WS”, and (b) immediately suspend trading in the Warrants due to “abnormally low” trading price levels. As such, the Public Warrants were determined to have no value as of September 30, 2023. The below table summarizes the number of outstanding warrants and their fair values as of September 30, 2023 a nd December 31, 2022. See Note 16, Fair Value Measurement, for further information. Fair Value # of Warrants September 30, 2023 Public Warrants $ - 431,216 Private Placement Warrants $ 191 495,000 Fair Value # of Warrants December 31, 2022 Public Warrants $ 720 431,216 Private Placement Warrants $ 2,060 495,000

Debt

Debt	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt	Note 10. Debt On December 23, 2021, Fathom OpCo entered into a new Credit Agreement (as amended, the "Credit Agreement"), which included a $ 50,000 revolving credit facility and a $ 125,000 term loan (the “Term Loan”). The Company's borrowings under the revolving credit facility were $ 42,000 and $ 37,000 at September 30, 2023 and December 31, 2022, respectively. The loans borrowed under the Credit Agreement will mature in December 2026 , except for $ 50,000 principal amount of the Term Loan held by term lenders consenting to the Third Amendment (as defined below) which must be repaid (the “Term Loan Paydown”) no later than March 31, 2024 (or June 30, 2024 in the circumstance described below). The Company expects to be able to satisfy the obligations relating to the Term Loan Paydown, but there is no assurance that it will be successful. Due to this uncertainty, and the ability of our lenders to declare a default and exercise their right to accelerate repayment of our indebtedness under the Credit Agreement in the event of our failure to satisfy such obligations, all of our indebtedness under the Credit Agreement is classified as current-portion of long-term debt as of September 30, 2023. See Note 2. Basis of Presentation. As previously disclosed, the Credit Agreement was amended in November 2022 and again in March 2023, in each case to modify, among other things, certain financial covenants in the Credit Agreement. On November 13, 2023, the Company entered into an amendment to the credit agreement (the “Third Amendment”) to modify among other things, certain financial covenants The Third Amendment requires the interest coverage ratio as of the last day of any fiscal quarter, commencing with the fiscal quarter ending on June 30, 2024 to not be less than the applicable ratio set forth opposite such fiscal quarter below: Fiscal Quarter Interest Coverage Ratio Each fiscal quarter ending on and after June 30, 2024 through and including December 31, 2024 1.20 to 1.00 Each fiscal quarter ending on and after March 31, 2025 through and including December 31, 2025 1.25 to 1.00 Fiscal quarter ending on March 31, 2026 1.35 to 1.00 Fiscal quarter ending on June 30, 2026 1.45 to 1.00 Fiscal quarter ending on September 30, 2026 and thereafter 1.55 to 1.00 In addition, the Third Amendment requires the net leverage ratio as of the last day of any fiscal quarter commencing with the fiscal quarter ending on June 30, 2024, to not exceed the applicable ratio set forth opposite such fiscal quarter below: Fiscal Quarter Net Leverage Ratio Fiscal quarter ending on June 30, 2024 7.00 to 1.00 Fiscal quarter ending on September 30, 2024 6.75 to 1.00 Fiscal quarter ending on December 31, 2024 6.50 to 1.00 Fiscal quarter ending on March 31, 2025 6.25 to 1.00 Fiscal quarter ending on June 30, 2025 6.00 to 1.00 Fiscal quarter ending on September 30, 2025 5.75 to 1.00 Fiscal quarter ending on December 31, 2025 5.50 to 1.00 Fiscal quarter ending on March 31, 2026 5.00 to 1.00 Fiscal quarter ending on June 30, 2026 4.50 to 1.00 Fiscal quarter ending on September 30, 2026 and thereafter 4.00 to 1.00 The Third Amendment also requires Minimum EBITDA (as defined and calculated pursuant to the Third Amendment) commencing with the fiscal quarter ending September 30, 2023 to not be less than the applicable amount set forth opposite such fiscal quarter below (tested on a standalone quarterly basis). Fiscal Quarter Minimum EBITDA Fiscal quarter ending on September 30, 2023 $ 1,500 Fiscal quarter ending on December 31, 2023 $ 2,700 Further, the Third Amendment requires the Company’s minimum unrestricted cash and cash equivalents on account, together with the amounts available to be drawn under the revolving credit facility under the Third Amended Credit Agreement (“Liquidity”) commencing with the month ending September 30, 2023, to not be less than $ 13,500 as of the last day of the months ending on September 30, 2023, October 31, 2023, and November 30, 2023 and not less than $ 10,000 as of the last day of any month ending on and after December 31, 2023 through and including December 31, 2024. Under certain circumstances, the Third Amended Credit Agreement permits the Company, at its election and in its sole discretion, to designate the last day of any fiscal quarter ending on or after March 31, 2025 as the “Covenant Changeover Date”. On and after the Covenant Changeover Date, the Third Amendment will require the interest coverage ratio as of the last day of any fiscal quarter ending on or after the Covenant Changeover Date to not be less than 2.50 to 1.00 and the net leverage ratio as of the last day of any fiscal quarter ending on or after the Covenant Changeover Date to not exceed 3.50 to 1.00, provided that, in the case of the maximum net leverage ratio requirement, if a qualified material acquisition is consummated after the Covenant Changeover Date, the Company may elect to increase the maximum net leverage ratio requirement to 4.00 to 1.00 with respect to the fiscal quarter in which such qualified material acquisition is consummated and each of the three immediately following fiscal quarters, provided that no such election may be made to so increase the maximum net leverage ratio requirement to 4.00 to 1.00 unless, as of the end of at least two consecutive fiscal quarters immediately preceding such election, the net leverage ratio was not greater than 3.50 to 1.00. Following the Covenant Changeover Date, certain additional restrictions on the availability of certain baskets in the Third Amended Credit Agreement relating to restricted payments, restricted debt payments and sale and leaseback transactions will cease to apply. Failure to comply with the covenants contained in the Third Amended Credit Agreement (if not waived or further amended on acceptable terms) could give rise to an event of default and, if not cured, entitle the lenders to accelerate the indebtedness outstanding thereunder and terminate our ability to borrow in the future under the Credit Agreement. The Third Amendment requires the Company to obtain qualified equity capital to make the Term Loan Paydown of $ 50,000 no later than (a) March 31, 2024 with qualified equity capital obtained pursuant to a binding commitment entered into on or before January 31, 2024 or (b) June 30, 2024 in the event a Credit Support (as defined below) is executed and delivered to the Administrative Agent on or before January 31, 2024. “Credit Support” means (a) an unconditional guaranty of payment (and not merely of collection) of the Term Loans held by term lenders consenting to the Third Amendment in an amount equal to the Credit Support Amount (as defined below) provided by CORE Industrial Partners or any investment affiliate thereof having undrawn capital commitments of not less than the Credit Support Amount (and/or provided by (i) an existing equity investor in the Company or any affiliate of such investor or (ii) a third party, in the cases of clauses (i) and (ii), that is reasonably acceptable to the majority in interest of the term lenders consenting to the Third Amendment (such acceptance not to be unreasonably withheld, delayed or conditioned)) or (b) a letter of credit issued by a bank of recognized national reputation in the face amount of the Credit Support Amount, the account party in respect of which is not the Company or any of its subsidiaries, in each case under clauses (a) and (b), in form and substance reasonably acceptable to the majority in interest of the term lenders consenting to the Third Amendment (such acceptance not to be unreasonably withheld, delayed or conditioned), in favor of such term lenders and enforceable or drawable, as applicable, by such term lenders (x) if the Term Loan Paydown is not made when due or (y) upon the occurrence of a bankruptcy event in respect of the Company or any of its subsidiaries (and, to the extent such bankruptcy event is an involuntary proceeding or petition, such bankruptcy event having continued undismissed for 60 days or an order or decree approving or ordering the relief sought therein shall be entered). The “Credit Support Amount” means such amount, which shall not be less than $ 50,000 in the aggregate, as would result in the aggregate Term Loan exposure held by any term lender consenting to the Third Amendment to be reduced by an amount equal to such reduction that would occur had the Term Loan Paydown been made on the date of determination. The Credit Agreement previously permitted the Company to exercise a right to cure financial covenant defaults by means of raising cash through the sale of certain eligible equity interests of the Company as described in the Credit Agreement commencing with the fiscal quarter ending on March 31, 2024. The Third Amendment permits the Company to exercise this right commencing with the fiscal quarter ending on June 30, 2024. The Third Amendment also provides that the margin applicable to Term SOFR Loans increases to 4.25 % until the first business day after the delivery of financial statements and the related compliance certificate required to be delivered under the Third Amended Credit Agreement for the fiscal quarter ending on June 30, 2024, and thereafter to the extent the Company’s net leverage ratio equals or exceeds 5.00 to 1.0 on the applicable date. In connection with the preparation and execution of the Third Amendment, the Company incurred reasonable and documented expenses of the Administrative Agent and $ 936 in customary arranger and lender consent fees, with certain portions thereof being payable on the Third Amendment closing date and the remainder being payable at the earlier of the Term Loan Pay Down, March 31, 2024 and the date on which the loans are accelerated and the commitments are terminated in accordance with the Third Amended Credit Agreement. The Company recorded deferred financing costs of $ 0 and $ 524 , respectively for the three and nine months ended September 30, 2023 in conjunction with the Credit Agreement and subsequent amendments and the applicable principal balances are presented within Long-Term debt, net on the Company's consolidated balance sheets. The Company amortizes the deferred financing costs using the effective interest method. The revolving credit facility under the Credit Agreement is available for working capital and other general corporate purposes and includes a letter of credit sub-facility of up to $ 5,000 . The Credit Agreement also includes an uncommitted incremental facility, which, subject to certain conditions, provides for additional term loan facilities, an increase in commitments under the Credit Agreement and/or an increase in commitments under the revolving credit facility, in an aggregate amount of up to $ 100,000 . The Company’s debt as of September 30, 2023 and December 31, 2022 is as follows: As of September 30, 2023 As of December 31, 2022 Debt Description Interest Rate Amount Interest Rate Amount Credit Agreement Revolver 9.47 % $ 42,000 8.20 % $ 37,000 Credit Agreement Term Loan 9.34 % 117,187 8.43 % 121,875 Total principal long-term debt 159,187 158,875 Debt issuance costs ( 1,866 ) ( 1,804 ) Total debt 157,321 157,071 Less: current portion of long-term debt 157,321 42,744 Long-term debt, net of current portion $ - $ 114,327 Interest on all debt is payable in 90-day increments, with the unpaid amount due upon maturity. Interest expense associated with long-term debt was $ 3,828 and $ 2,337 for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 11,076 and $ 5,253 for the nine months ended September 30, 2023 and September 30, 2022, respectively. Included in interest expense, net on the accompanying unaudited condensed consolidated statements of comprehensive loss is amortization of debt issuance costs was $ 165 , and $ 69 for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 461 and $ 299 for the nine months ended September 30, 2023 and September 30, 2022, respectively. In December 2022, the Company entered into a financing agreement through its insurance broker to spread the payment of its annual director’s and officer’s insurance premium over a ten-month period. Total financed payments of $ 1,265 , including a $ 35 financing fee at 6.13 % annual rate, were made between January 2023 and October 2023. As of September 30, 2023, the Company recognized $ 403 of prepaid assets and $ 126 of other current liabilities in the unaudited condensed consolidated balance sheet. The Company recognized $ 404 and $ 1,211 of insurance expense in selling, general and administrative ("SG&A") expenses for the three and nine months ended September 30, 2023, respectively.

Other (Income) Expense

Other (Income) Expense	9 Months Ended
	Sep. 30, 2023
Other Income and Expenses [Abstract]
Other (Income) Expense	Note 11. Other (Income) Expense Other income and expense, net consists of the following for the three and nine months ended September 30, 2023 and September 30, 2022: Three Months Ended Nine Months Ended September 30, 2023 September 30, 2022 September 30, 2023 September 30, 2022 Change in fair value of TRA $ 392 $ - $ 442 $ - Other 43 81 131 276 Other expense $ 435 $ 81 $ 573 $ 276 Change in fair value of Earnout Shares ( 613 ) ( 18,080 ) ( 6,558 ) ( 59,980 ) Change in fair value of Warrants ( 409 ) ( 7,400 ) ( 2,589 ) ( 28,000 ) Change in fair value of TRA - - - ( 200 ) Other ( 27 ) ( 68 ) ( 5 ) ( 591 ) Other income $ ( 1,049 ) $ ( 25,548 ) $ ( 9,152 ) $ ( 88,771 )

Shared Based Compensation

Shared Based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Shared Based Compensation	Note 12. Shared Based Compensation On December 23, 2021, the Company adopted the Fathom Digital Manufacturing 2021 Omnibus Incentive Plan (the "2021 Omnibus Plan") to encourage the profitability and growth of the Company through short-term and long-term incentives to employees that are consistent with the Company's objectives. The 2021 Omnibus Plan provides that the Company may grant options, stock appreciation rights, restricted shares, restricted stock units, performance-based awards (including performance-based restricted shares and restricted stock units), other share-based awards, other cash-based awards, and any combination of the foregoing. Stock Options The following table represents stock option activity for the period ended September 30, 2023. Number of Shares Weighted Average Exercise Price per Share Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at January 1, 2023 15,853 $ 174.13 6.17 $ - Granted 95,369 11.67 - - Exercised - - - - Forfeited ( 864 ) 177.80 - - Expired - - - - Non-vested at September 30, 2023 110,358 $ 33.71 6.47 $ - Exercisable at September 30, 2023 4,996 $ 173.92 5.42 $ - At September 30, 2023, there was approxima tely $ 1,460 of total unrecognized compensation cost related to unvested stock options granted under the 2021 Omnibus Plan. That cost is expected to be recognized over a weighted average period of 1.89 years as of September 30, 2023. The Company uses authorized and unissued shares to satisfy share award exercises. Restricted Stock Units A summary of the status of the Company's restricted stock unit activity and the changes during the nine months ended September 30, 2023 are as follows: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2023 308,862 $ 185.63 $ - Granted 174,431 208.00 - Vested ( 17,941 ) 168.10 - Forfeited ( 26,881 ) 140.22 - Non-vested at September 30, 2023 438,471 $ 117.20 $ - At September 30, 2023, there was approximatel y $ 6,696 of total unrecognized compensation cost related to unvested restricted stock units granted under the 2021 Omnibus Plan. That cost is expected to be recognized over a weighted average period of 1.76 years as of September 30, 2023. Share Based Compensation Expense Share based compensation was $ 1,139 and $ 1,762 for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 3,471 and $ 5,687 for the nine months ended September 30, 2023 and September 30, 2022, respectively. Employee Stock Purchase Plan The Company's 2022 Employee Stock Purchase Plan ("ESPP") allows eligible employees to purchase a variable number of shares of our common stock during each offering period at a discount through payroll deductions of up to 15 % of their eligible compensation, subject to plan limitations. The ESPP provides for six-month offering periods with a single purchase period. At the end of each offering period, employees are able to purchase shares at 85 % of the lower of the fair market value of our common stock on the first trading day of the offering period or on the last trading day of the offering period. We determine the fair value of stock-based compensation related to our ESPP in accordance with ASC 718 using the component measurement approach and the Black-Scholes standard option pricing model. Employees purchased 12,482 shares of common stock under the ESPP at an average exercise price of $ 6.90 during the nine months ended September 30, 2023. As of September 30, 2023, 48,345 shares remained available for future issuance under the ESPP. We calculate the fair value of the shares under the ESPP using a Black-Scholes option valuation model. Expected volatilities are based upon a selection of public guideline companies. The risk-free rate was based upon U.S. Treasury rates. The fair value of each offering period was estimated using the Black-Scholes option pricing model with the following assumptions: Nine Months Ended September 30, 2023 Expected term (years) 0.5 - 1.5 Expected volatility 77.5 % Expected dividend yield 0.0 % Risk-free interest rate 4.10 % Fair value of share $ 26.40

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2023
Earnings Per Unit [Abstract]
Earnings Per Share	Note 13. Earnings Per Share Basic net earnings per share is computed based on the weighted average number of common shares outstanding. Diluted net earnings per share is computed based on the weighted average number of common shares outstanding, increased by the number of any additional shares that would have been outstanding had any potentially dilutive common shares been issued and reduced by the number of shares the Company could have repurchased from the proceeds from issuance of the potentially dilutive shares. Only the Company's Class A common stock participates in the Company’s undistributed earnings. As such, the Company’s undistributed earnings are allocated entirely to shares of Class A common stock based on the weighted Class A common stock outstanding. The Company's basic and diluted earnings per share calculation is as follows: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Class A Class A Class A Class A Numerator Net loss $ ( 8,568 ) $ ( 1,038,970 ) $ ( 17,164 ) $ ( 985,693 ) Less: Net loss attributable to non-controlling interests ( 4,206 ) ( 556,027 ) ( 11,792 ) ( 561,728 ) Net loss attributable to Class A common stock $ ( 4,362 ) $ ( 482,943 ) $ ( 5,372 ) $ ( 423,965 ) Denominator Basic - weighted-average shares outstanding 3,504,859 3,140,809 3,448,030 2,767,401 Effect of dilutive securities Assumed exchange for shares of Class A common stock - - - - Diluted - weighted-average shares outstanding: 3,504,859 3,140,809 3,448,030 2,767,401 Net loss per share Basic $ ( 1.24 ) $ ( 153.76 ) $ ( 1.56 ) $ ( 153.20 ) Diluted $ ( 1.24 ) $ ( 153.76 ) $ ( 1.56 ) $ ( 153.20 )

Shareholders' Equity and Noncon

Shareholders' Equity and Noncontrolling Interest	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Shareholders' Equity and Noncontrolling Interest	Note 14. Shareholders' Equity and Non-controlling Interest The Company’s equity consists of a total of 25,000,000 authorized shares across all classes of capital stock. The 25,000,000 authorized shares consist of 500,000 authorized shares of preferred stock with a par value of $ 0.0001 per share, 15,000,000 authorized shares of Class A common stock with a par value of $ 0.0001 per share, 9,000,000 shares of Class B common stock with a par value of $ 0.0001 par value per share, and 500,000 shares of Class C common stock with a par value of $ 0.0001 per share. Under its charter, the Company is not permitted to issue any shares of Class C common stock. As of September 30, 2023, the Company had no outstanding shares of Preferred Stock, 3,507,084 outstanding shares of Class A common stock, 3,327,379 outstanding shares of Class B common stock, and no outstanding shares of Class C common stock. The table below demonstrates the calculation of the comprehensive loss attributable to t he non-controlling interest holders for the three and nine months ended September 30, 2023 and September 30, 2022. Three Months Ended Nine Months Ended 2023 2022 2023 2022 Fathom OpCo comprehensive loss $ ( 8,659 ) $ ( 1,070,703 ) $ ( 25,278 ) $ ( 1,079,745 ) Non-controlling interest percentage 48.7 % 51.9 % 48.7 % 51.9 % Comprehensive loss attributable to noncontrolling interest $ ( 4,206 ) $ ( 556,027 ) $ ( 11,792 ) $ ( 561,728 )

Leases

Leases	9 Months Ended
	Sep. 30, 2023
Lessee Disclosure [Abstract]
Leases	Note 15. Leases The Company leases certain manufacturing facilities, office space, and equipment and determines if an arrangement is a lease at inception. Amounts associated with operating leases and financing leases are included in right-of-use lease assets (“ROU assets”), current lease liabilities and long-term lease liabilities in the Company's unaudited condensed consolidated balance sheet. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at the lease commencement date based on the estimated present value of lease payments over the lease term. If the leases do not provide an implicit rate, the Company uses an incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. The incremental borrowing rate is determined using a portfolio approach based on the rate of interest that we would pay to borrow an amount equal to the lease payments on a collateralized basis over a similar term. The Company uses quoted interest rates obtained from financial institutions as an input to derive its incremental borrowing rate as the discount rate for the lease. Leases with an initial term of 12 months or less are not recorded on the balance sheet, and we recognize lease expense for these leases on a straight-line basis over the lease term. For lease agreements entered into or reassessed after the adoption of Topic 842, we combine lease and non-lease components. Certain leases include one or more options to renew, with renewal terms that can extend the lease term from one to 10 years or more, and the exercise of lease renewal options under these leases is at our sole discretion. Lease terms include the non-cancelable portion of the underlying leases along with any reasonably certain lease periods associated with available renewal periods. Certain of the Company’s operating leases include variable rental payments based on a percentage change of certain Consumer Price Index. Variable rental payments are recognized in the condensed consolidated statement of comprehensive loss in the period in which the obligation for those payments is incurred. The depreciable life of assets and leasehold improvements are limited by the expected lease term. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. Balance Sheet Location September 30, 2023 December 31, 2022 Assets Operating Prepaid expenses and other current assets $ 126 $ 143 Operating Right-of-use operating lease assets, net 9,359 10,312 Financing Right-of-use financing lease assets, net 2,110 2,253 Total lease assets $ 11,595 $ 12,708 Liabilities Current Operating Current operating lease liability $ 1,919 $ 2,174 Financing Current financing lease liability 224 200 Non-Current Operating Long-term operating lease liability 7,731 8,958 Financing Long-term financing lease liability 1,978 2,125 Total lease liabilities $ 11,852 $ 13,457 The following table sets forth our lease costs included in our unaudited condensed consolidated statement of comprehensive income: Three Months Ended Nine Months Ended September 30, 2023 September 30, 2022 September 30, 2023 September 30, 2022 Operating lease cost $ 645 $ 837 $ 2,140 $ 2,457 Short-term lease cost - 1 - 9 Financing lease cost: Amortization of ROU assets 60 55 191 162 Interest on lease liabilities 31 34 105 103 Sublease income - ( 34 ) ( 68 ) ( 102 ) Total lease costs $ 736 $ 893 $ 2,368 $ 2,629 September 30, 2023 September 30, 2022 Weighted-average remaining lease term (years) Operating 6.1 6.7 Financing 7.4 8.4 Weighted-average discount rate Operating 5.7 % 5.9 % Financing 5.7 % 5.6 % Maturities of Leases Operating Leases Financing Leases Total Remaining 2023 $ 650 $ 90 $ 740 2024 2,417 345 2,762 2025 2,060 355 2,415 2026 1,634 358 1,992 2027 1,428 366 1,794 Thereafter 3,806 1,200 5,006 Total future lease payments 11,995 2,714 14,709 Less: Discount 2,345 512 2,857 Present value of lease liability $ 9,650 $ 2,202 $ 11,852

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 16. Fair Value Measurement The fair value of the Company’s financial assets and liabilities reflects the Company’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from independent sources) and to minimize the use of unobservable inputs (internal assumptions about how market participants would price assets and liabilities). The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used in order to value the assets and liabilities: Level 1 — Quoted prices in active markets for identical assets or liabilities. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 — Observable inputs other than Level 1 inputs. Examples of Level 2 inputs include quoted prices in active markets for similar assets or liabilities and quoted prices for identical assets or liabilities in markets that are not active. Level 3 — Unobservable inputs based on our assessment of the assumptions that market participants would use in pricing the asset or liability. The following table presents information about the Company’s liabilities that are measured at fair value on a recurring basis as of September 30, 2023. Fair Value Measurements as of September 30, 2023 Description Level 1 Level 2 Level 3 Total Liabilities: Tax Receivable Agreement $ - $ - $ 4,416 $ 4,416 Fathom OpCo acquisitions contingent consideration - - 181 181 Sponsor Earnout Shares Liability - - 49 49 Fathom Earnout Shares Liability - - 283 283 Warrant liability - Public Warrants - - - - Warrant liability - Private Placement Warrants - - 191 191 $ - $ - $ 5,120 $ 5,120 The following table presents information about the Company’s liabilities that are measured at fair value on a recurring basis as of December 31, 2022. Fair Value Measurements as of December 31, 2022 Description Level 1 Level 2 Level 3 Total Liabilities: Tax Receivable Agreement $ - $ - $ 4,000 $ 4,000 Fathom OpCo acquisitions contingent consideration - - 700 700 Sponsor Earnout Shares Liability - - 930 930 Fathom Earnout Shares Liability - - 5,960 5,960 Warrant liability - Public Warrants 720 - - 720 Warrant liability - Private Placement Warrants - - 2,060 2,060 $ 720 $ - $ 13,650 $ 14,370 The following table presents a reconciliation of the beginning and ending balances of recurring Level 3 fair value measurements. Level 3 liabilities Tax Receivable Agreement liability Fathom OpCo acquisitions contingent consideration Sponsor Earnout shares liability Fathom Earnout shares liability Warrant liability – Public Warrants Warrant liability – Private Placement Warrants Total Balance at December 31, 2022 $ 4,000 $ 700 $ 930 $ 5,960 $ 720 $ 2,060 $ 14,370 Payments - ( 502 ) - - - - $ ( 502 ) Net (gain) loss (1) 416 ( 17 ) ( 881 ) ( 5,677 ) ( 720 ) ( 1,869 ) $ ( 8,748 ) Ending balance at September 30, 2023 $ 4,416 $ 181 $ 49 $ 283 $ - $ 191 $ 5,120 (1) Net gains on changes in recurring Level 3 fair value measurements are recognized in Other expense or Other income in our unaudited condensed consolidated statement of comprehensive loss. Valuation Methodologies for Fair Value Measurements Categorized within Level 3 Tax Receivable Agreement ("TRA") The fair value of the TRA is based on multiple inputs and assumptions input into a Monte Carlo simulation model. The significant inputs into this model are the following: a corporate tax rate of 24.8 %, an annual TRA payment date of February 17, existing non-controlling interest percentage of 48.7 %, initial amortization deductions of $ 46,070 , taxable income forecast by 2032 of $ 67,762 , a sell-down schedule which reflects the expected sale of New Fathom Units by legacy Fathom OpCo shareholders, a Class A common stock price as of September 30, 2023 of $ 5.75 , volatility of 78.0 %, correlation between taxable income and the Class A common stock price of 25 %, and a cost of debt of 13.28 %. Legacy Fathom OpCo Acquisitions Contingent Consideration The fair values for contingent consideration payable are determined by using a discounted cash flow approach with unobservable inputs and is classified as a Level 3 liability in the fair value hierarchy. The Company’s assessment of the significance of particular inputs to these fair value measurements requires judgment and considers factors specific to each entity to which the contingent consideration relates to, for example EBITDA targets for a given period. Earnout Shares Liability The Earnout Shares are accounted for as liabilities in the Company's condensed consolidated balance sheet. The fair values for the Earnout Shares are estimated using a Monte Carlo simu lation assuming Geometric Brownian Motion in a risk-neutral framework. The Monte Carlo simulation considers daily simulated stock prices as a proxy for the Company's daily volume-weighted average price ("VWAP"). The key inputs into the valuation of the Earnout Shares are an expected term of 3.23 years, a risk-free rate of 4.71 %, operating asset volatility of 62.2 %, and equity volatility of 91.5 %. The operating asset volatility and the equity volatility assumptions are based on a blended average of operating and equity volatility, respectively, of publicly traded companies within the Company's peer group. Warrant Liability The Public and Private Placement Warrants are accounted for as liabilities in accordance with ASC 815-40 and are presented within Warrant liability in the accompanying unaudited condensed consolidated balance sheet as of September 30, 2023, and December 31, 2022. The Warrant liabilities are measured at fair value at inception and on a recurring basis, with changes in fair value presented within a change in fair value of Warrant liabilities in the statement of comprehensive loss. During the third quarter of 2023 the Company's public warrants were delisted from the NYSE, see Note 9. As such, the Public Warrants were determined to have no value as of September 30, 2023. The Private Placement warrants are valued using a Black-Scholes option pricing approach, which is considered to be a Level 3 fair value measurement. The volatility for the Private Placement warrants, a key input into the valuatio n, was estimated to be 99.0 % based on the publicly traded per share price of the Company's Class A common stock as of September 30, 2023. Other key inputs into the valuation include a term of 3.23 years, a strike price of $ 230.00 per share, and an assumption that the Private Placement warrants will remain outstanding until maturity since, unlike the Public Warrants, the Private Placement warrants are not redeemable. In instances whereby inputs used to measure fair value fall into different levels in the above fair value hierarchy, fair value measurements in their entirety are categorized based on the lowest level input that is significant to the valuation. The Company’s assessment of the significance of particular inputs to these fair value measurements requires judgment and considers factors specific to each asset or liability.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Note 17. Income Taxes The Company calculates the provision for income taxes during interim periods by applying an estimate of the forecasted annual effective tax rate for the full fiscal year to "ordinary" income or loss (pretax income or loss excluding unusual or infrequently occurring discrete items) for the reporting period. The provision for income taxes was $ 110 for the nine months ending September 30, 2023 compared to ($ 8,435 ) for the nine months ended September 30, 2022. The effective tax rate, including discrete items, was ( 0.67 %) for the nine months ended September 30, 2023 compared to 0.82 % for the nine months ended September 30, 2022. The benefit from income taxes was ($ 9 ) for the three months ended September 30, 2023 compared to ($ 7,050 ) for the three months ended September 30, 2022. The effective tax rate, including discrete items, was ( 0.08 %) for the three months ended September 30, 2023 compared to 0.64 % for the three months ended September 30, 2022. The tax provision for the nine months ended September 30, 2023 is impacted by permanent differences with respect to gains and losses recorded on the earn-out share liability, sponsor share liability, and warrant liabilities, partially offset by the changes in valuation allowance and non-controlling interest not subject to taxes. The Company evaluates the realizability of the deferred tax assets on a quarterly basis and establishes a valuation allowance when it is more likely than not that all or a portion of a deferred tax asset may not be realized. For the nine months ended September 30, 2023, the Company made no material adjustments to its assertion that deferred tax assets are not more-likely than not to be realized. As of September 30, 2023, the Company did not recognize income tax expense or benefits associated with uncertain tax positions.

Commitment and Contingencies

Commitment and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 18. Commitments and Contingencies The Company is subject to various claims, lawsuits and other legal proceedings that arise in the ordinary course of business. It is the opinion of management that the disposition or ultimate resolution of such claims and lawsuits will not have a material effect on the Company’s financial condition, comprehensive gain (loss), or cash flows.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2023
Variable Interest Entities [Abstract]
Variable Interest Entities	Note 19. Variable Interest Entities B ased upon the criteria set forth in ASC 810, the Company consolidates variable interest entities (“VIEs”) in which it has a controlling financial interest and is therefore deemed the primary beneficiary. A controlling financial interest will have both of the following characteristics: (a) the power to direct the VIE activities that most significantly impact economic performance; and (b) the obligation to absorb the VIE losses and the right to receive benefits that are significant to the VIE. The Company has determined that Fathom OpCo meets the definition of a VIE and that the Company is the primary beneficiary of Fathom OpCo beginning on the date of the Business Combination, and therefore the Company must consolidate Fathom OpCo from the date of the Business Combination. The following table presents a summary of the total assets, liabilities, and shareholders' equity of the Company’s condensed consolidated VIE, which is comprised solely of Fathom OpCo. Period Ended September 30, 2023 Period Ended December 31, 2022 Total assets $ 345,355 $ 370,245 Total liabilities 188,937 191,514 Total equity 156,418 178,731

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	Note 20 – Subsequent Events The Company evaluated subsequent events and transactions that occurred after the balance sheet date up to the date that the accompanying financial statements were issued. Based upon this review, the Company did not identify any additional subsequent events, outside of the subsequent event that is disclosed in Note 10, that would have required adjustment or disclosure in the unaudited condensed consolidated financial statements.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards The FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments ("ASC 326"), which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments including trade receivables and available for sale debt securities. ASC 326 is effective for fiscal years beginning after December 15, 2022, with early adoption permitted. The new standard was effective for the Company beginning January 1, 2023, and was applied using a modified retrospective transition method. The FASB subsequently issued other related ASUs that amend ASU No. 2016-13 to provide clarification and additional guidance. The Company concluded that the adoption of ASC 326 did not have a material impact on the condensed consolidated financial statements.
Reverse Stock Split	Reverse Stock Split On September 15, 2023, the Company’s Board of Directors approved a reverse stock split ratio of 20-for-1 (the “Reverse Stock Split”). On September 28 , 2023, the effective date of the Reverse Stock Split, the number of the Company’s issued and outstanding shares of common stock decreased from 70,113,787 shares to 3,505,689 shares, net of fractional shares redeemed. The number of authorized shares and par value per common share remained unchanged. No fractional shares we re issued as a result of the Reverse Stock Split. Stockholders who would otherwise have been entitled to receive a fractional share received a cash payment in lieu thereof. Prior to the effective date of the Reverse Stock Split, the Company had listed warrants to purchase a total of 18,524,320 shares of Common Stock, with each whole warrant being exercisable for one share of Common Stock at $ 11.50 per share. After the effective date of the Reverse Stock Split, every twenty shares of Common Stock that may have been purchased pursuant to the warrants immediately prior to the Reverse Stock Split represented one share of Common Stock that may be purchased pursuant to such warrants immediately following the Reverse Stock Split. Correspondingly, the exercise price per share of Common Stock attributable to such warrants was proportionately increased, such that the exercise price immediately following the Reverse Stock Split was $ 230.00 , which equals the product of twenty multiplied by $ 11.50 , the exercise price per share immediately prior to the Reverse Stock Split. The number of shares of Common Stock subject to the warrants was proportionately decreased by twenty times, to an aggregate of 926,216 shares. The share, per share and trading price amounts in the unaudited condensed consolidated financial statements and the accompanying notes, have been retrospectively adjusted to reflect the Reverse Stock Split for all periods presented.

Immaterial Error Correction o_2

Immaterial Error Correction of Previously Issued Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2023
Condensed Financial Information Disclosure [Abstract]
Schedule of Summarized Adjustments of Previously Issued Financial Statements	A summary of the adjustments to our prior period unaudited condensed consolidated statement of comprehensive loss is presented below: Three Months Ended September 30, 2022 As Reported Adjustments As Adjusted Net loss before income tax $ ( 1,046,020 ) $ - $ ( 1,046,020 ) Income tax expense (benefit) 87 ( 7,137 ) ( 7,050 ) Net loss ( 1,046,107 ) ( 7,137 ) ( 1,038,970 ) Net loss attributable to Fathom OpCo non-controlling interest ( 556,027 ) - ( 556,027 ) Net loss attributable to controlling interest ( 490,080 ) ( 7,137 ) ( 482,943 ) Comprehensive loss: (Loss) Income from foreign currency translation adjustments - - - Comprehensive loss, net of tax $ ( 490,080 ) $ ( 7,137 ) $ ( 482,943 ) Nine Months Ended September 30, 2022 As Reported Adjustments As Adjusted Net loss before income tax $ ( 994,128 ) $ - $ ( 994,128 ) Income tax expense (benefit) 167 ( 8,602 ) ( 8,435 ) Net loss ( 994,295 ) ( 8,602 ) ( 985,693 ) Net loss attributable to Fathom OpCo non-controlling interest ( 561,728 ) - ( 561,728 ) Net loss attributable to controlling interest ( 432,567 ) ( 8,602 ) ( 423,965 ) Comprehensive loss: Loss from foreign currency translation adjustments ( 107 ) - ( 107 ) Comprehensive loss, net of tax $ ( 432,674 ) $ ( 8,602 ) $ ( 424,072 ) The following table presents the effect of the adjustments to our prior period unaudited condensed consolidated statement of cash flows. Nine Months Ended September 30, 2022 As Reported Adjustments As Adjusted Cash Flows from Operating Activities Net (loss) income $ ( 432,567 ) $ 8,602 $ ( 423,965 ) Adjustments to reconcile net loss to net cash from operating activities: Deferred taxes 153 ( 8,602 ) ( 8,449 ) Foreign currency translation adjustment ( 107 ) 107 - Net cash provided by operating activities 6,496 107 6,603 Net cash used in investing activities ( 10,953 ) - ( 10,953 ) Net cash used in financing activities ( 7,896 ) - ( 7,896 ) Effect of exchange rate changes on cash, and cash equivalents - ( 107 ) ( 107 ) Net decrease in cash $ ( 12,353 ) $ - $ ( 12,353 ) The following table presents the effect of the adjustments to our prior period unaudited condensed consolidated statement of shareholders' equity and redeemable non-controlling interest. September 30, 2022 As Reported Adjustments As Adjusted Accumulated earnings (deficit) $ ( 480,167 ) $ 8,709 $ ( 471,458 ) Additional paid-in-capital 584,325 ( 7,052 ) 577,273 Other comprehensive loss - ( 107 ) ( 107 ) Total equity attributable to Fathom 104,158 1,550 105,708

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Revenue by Product Line	Revenue by product line for the three and nine months ended September 30, 2023 and September 30, 2022 are as follows: Three Months Ended Nine Months Ended September 30, 2023 September 30, 2022 September 30, 2023 September 30, 2022 Revenue: Additive Manufacturing $ 2,692 $ 3,154 $ 9,567 $ 11,713 Injection Molding 5,372 5,984 16,114 19,892 CNC Machining 12,486 15,530 39,956 43,441 Precision Sheet Metal 9,542 13,719 30,089 43,153 Ancillary Product Lines 1,366 1,823 5,213 4,538 Total revenue $ 31,458 $ 40,210 $ 100,939 $ 122,737

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Schedule of Inventories	September 30, 2023 December 31, 2022 Raw materials $ 8,969 $ 8,496 Work in process 5,802 5,664 Finished goods 2,614 2,464 17,385 16,624 Allowance for obsolescence ( 606 ) ( 906 ) Total $ 16,779 $ 15,718

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following as of September 30, 2023 and December 31, 2022: September 30, December 31, Estimated Useful Life Machinery and equipment $ 42,856 $ 39,516 6 - 10 Furniture and fixtures 3,634 3,100 10 Computer hardware 360 374 5 Property and leasehold improvements 7,142 6,839 3 - 23 Construction in progress 3,650 3,893 n/a Auto / transportation equipment 319 312 3 Total 57,961 54,034 Accumulated depreciation ( 10,797 ) ( 6,331 ) Total $ 47,164 $ 47,703

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	6 Months Ended	9 Months Ended
	Jun. 30, 2023	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets, Net		Intangible assets, net consisted of the following: September 30, 2023 Gross Accumulated Amortization Net Useful Life (in years) Trade name $ 70,000 $ ( 8,282 ) $ 61,718 15 Customer relationships 180,000 ( 16,813 ) 163,187 19 Developed software 4,300 ( 1,526 ) 2,774 5 Developed technology 15,700 ( 5,572 ) 10,128 5 Total intangible assets $ 270,000 $ ( 32,193 ) $ 237,807 December 31, 2022 Gross Accumulated Amortization Net Useful Life (in years) Trade name $ 70,000 $ ( 4,782 ) $ 65,218 15 Customer relationships 180,000 ( 9,707 ) 170,293 19 Developed software 4,300 ( 881 ) 3,419 5 Developed technology 15,700 ( 3,218 ) 12,482 5 Total intangible assets $ 270,000 $ ( 18,588 ) $ 251,412
Schedule of Estimated Aggregate Amortization Expense	The following table represents the estimated aggregate amortization expense for each of the five succeeding fiscal calendar years and thereafter. Year ended Total Remaining 2023 $ 4,535 2024 18,140 2025 18,140 2026 18,041 2027 14,140 Thereafter 164,811 Total $ 237,807

Reorganization (Tables)

Reorganization (Tables)	9 Months Ended
	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Summary of Liability Related to Company's Reorganization	The following table summarizes activity in the liability related to the Company's Reorganization. Liability balance at December 31, 2022 $ 412 Charges 668 Payments ( 945 ) Liability balance at September 30, 2023 $ 135

Warrant Liability (Tables)

Warrant Liability (Tables)	9 Months Ended
	Sep. 30, 2023
Warrants and Rights Note Disclosure [Abstract]
Summary of Number of Outstanding Warrants and Fair Value	The below table summarizes the number of outstanding warrants and their fair values as of September 30, 2023 a nd December 31, 2022. See Note 16, Fair Value Measurement, for further information. Fair Value # of Warrants September 30, 2023 Public Warrants $ - 431,216 Private Placement Warrants $ 191 495,000 Fair Value # of Warrants December 31, 2022 Public Warrants $ 720 431,216 Private Placement Warrants $ 2,060 495,000

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Schedule of Amendment to Credit Agreement	On November 13, 2023, the Company entered into an amendment to the credit agreement (the “Third Amendment”) to modify among other things, certain financial covenants The Third Amendment requires the interest coverage ratio as of the last day of any fiscal quarter, commencing with the fiscal quarter ending on June 30, 2024 to not be less than the applicable ratio set forth opposite such fiscal quarter below: Fiscal Quarter Interest Coverage Ratio Each fiscal quarter ending on and after June 30, 2024 through and including December 31, 2024 1.20 to 1.00 Each fiscal quarter ending on and after March 31, 2025 through and including December 31, 2025 1.25 to 1.00 Fiscal quarter ending on March 31, 2026 1.35 to 1.00 Fiscal quarter ending on June 30, 2026 1.45 to 1.00 Fiscal quarter ending on September 30, 2026 and thereafter 1.55 to 1.00 In addition, the Third Amendment requires the net leverage ratio as of the last day of any fiscal quarter commencing with the fiscal quarter ending on June 30, 2024, to not exceed the applicable ratio set forth opposite such fiscal quarter below: Fiscal Quarter Net Leverage Ratio Fiscal quarter ending on June 30, 2024 7.00 to 1.00 Fiscal quarter ending on September 30, 2024 6.75 to 1.00 Fiscal quarter ending on December 31, 2024 6.50 to 1.00 Fiscal quarter ending on March 31, 2025 6.25 to 1.00 Fiscal quarter ending on June 30, 2025 6.00 to 1.00 Fiscal quarter ending on September 30, 2025 5.75 to 1.00 Fiscal quarter ending on December 31, 2025 5.50 to 1.00 Fiscal quarter ending on March 31, 2026 5.00 to 1.00 Fiscal quarter ending on June 30, 2026 4.50 to 1.00 Fiscal quarter ending on September 30, 2026 and thereafter 4.00 to 1.00 The Third Amendment also requires Minimum EBITDA (as defined and calculated pursuant to the Third Amendment) commencing with the fiscal quarter ending September 30, 2023 to not be less than the applicable amount set forth opposite such fiscal quarter below (tested on a standalone quarterly basis). Fiscal Quarter Minimum EBITDA Fiscal quarter ending on September 30, 2023 $ 1,500 Fiscal quarter ending on December 31, 2023 $ 2,700
Schedule of Long-term Debt Instruments	The Company’s debt as of September 30, 2023 and December 31, 2022 is as follows: As of September 30, 2023 As of December 31, 2022 Debt Description Interest Rate Amount Interest Rate Amount Credit Agreement Revolver 9.47 % $ 42,000 8.20 % $ 37,000 Credit Agreement Term Loan 9.34 % 117,187 8.43 % 121,875 Total principal long-term debt 159,187 158,875 Debt issuance costs ( 1,866 ) ( 1,804 ) Total debt 157,321 157,071 Less: current portion of long-term debt 157,321 42,744 Long-term debt, net of current portion $ - $ 114,327

Other (Income) Expense (Tables)

Other (Income) Expense (Tables)	9 Months Ended
	Sep. 30, 2023
Other Income and Expenses [Abstract]
Schedule of Other (Income) Expense	Other income and expense, net consists of the following for the three and nine months ended September 30, 2023 and September 30, 2022: Three Months Ended Nine Months Ended September 30, 2023 September 30, 2022 September 30, 2023 September 30, 2022 Change in fair value of TRA $ 392 $ - $ 442 $ - Other 43 81 131 276 Other expense $ 435 $ 81 $ 573 $ 276 Change in fair value of Earnout Shares ( 613 ) ( 18,080 ) ( 6,558 ) ( 59,980 ) Change in fair value of Warrants ( 409 ) ( 7,400 ) ( 2,589 ) ( 28,000 ) Change in fair value of TRA - - - ( 200 ) Other ( 27 ) ( 68 ) ( 5 ) ( 591 ) Other income $ ( 1,049 ) $ ( 25,548 ) $ ( 9,152 ) $ ( 88,771 )

Shared Based Compensation (Tabl

Shared Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following table represents stock option activity for the period ended September 30, 2023. Number of Shares Weighted Average Exercise Price per Share Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at January 1, 2023 15,853 $ 174.13 6.17 $ - Granted 95,369 11.67 - - Exercised - - - - Forfeited ( 864 ) 177.80 - - Expired - - - - Non-vested at September 30, 2023 110,358 $ 33.71 6.47 $ - Exercisable at September 30, 2023 4,996 $ 173.92 5.42 $ -
Schedule of Non-vested Restricted Stock Unit Activity	A summary of the status of the Company's restricted stock unit activity and the changes during the nine months ended September 30, 2023 are as follows: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2023 308,862 $ 185.63 $ - Granted 174,431 208.00 - Vested ( 17,941 ) 168.10 - Forfeited ( 26,881 ) 140.22 - Non-vested at September 30, 2023 438,471 $ 117.20 $ -
Schedule of Employee Stock Purchase Plan Valuation Assumptions	The fair value of each offering period was estimated using the Black-Scholes option pricing model with the following assumptions: Nine Months Ended September 30, 2023 Expected term (years) 0.5 - 1.5 Expected volatility 77.5 % Expected dividend yield 0.0 % Risk-free interest rate 4.10 % Fair value of share $ 26.40

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Unit [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The Company's basic and diluted earnings per share calculation is as follows: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Class A Class A Class A Class A Numerator Net loss $ ( 8,568 ) $ ( 1,038,970 ) $ ( 17,164 ) $ ( 985,693 ) Less: Net loss attributable to non-controlling interests ( 4,206 ) ( 556,027 ) ( 11,792 ) ( 561,728 ) Net loss attributable to Class A common stock $ ( 4,362 ) $ ( 482,943 ) $ ( 5,372 ) $ ( 423,965 ) Denominator Basic - weighted-average shares outstanding 3,504,859 3,140,809 3,448,030 2,767,401 Effect of dilutive securities Assumed exchange for shares of Class A common stock - - - - Diluted - weighted-average shares outstanding: 3,504,859 3,140,809 3,448,030 2,767,401 Net loss per share Basic $ ( 1.24 ) $ ( 153.76 ) $ ( 1.56 ) $ ( 153.20 ) Diluted $ ( 1.24 ) $ ( 153.76 ) $ ( 1.56 ) $ ( 153.20 )

Shareholders' Equity and Nonc_2

Shareholders' Equity and Noncontrolling Interest (Tables)	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Schedule Of Calculation Of Comprehensive Loss Attributable To Non-controlling Interest Holders	The table below demonstrates the calculation of the comprehensive loss attributable to t he non-controlling interest holders for the three and nine months ended September 30, 2023 and September 30, 2022. Three Months Ended Nine Months Ended 2023 2022 2023 2022 Fathom OpCo comprehensive loss $ ( 8,659 ) $ ( 1,070,703 ) $ ( 25,278 ) $ ( 1,079,745 ) Non-controlling interest percentage 48.7 % 51.9 % 48.7 % 51.9 % Comprehensive loss attributable to noncontrolling interest $ ( 4,206 ) $ ( 556,027 ) $ ( 11,792 ) $ ( 561,728 )

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Lessee Disclosure [Abstract]
Schedule of balance sheet location disclosure	Balance Sheet Location September 30, 2023 December 31, 2022 Assets Operating Prepaid expenses and other current assets $ 126 $ 143 Operating Right-of-use operating lease assets, net 9,359 10,312 Financing Right-of-use financing lease assets, net 2,110 2,253 Total lease assets $ 11,595 $ 12,708 Liabilities Current Operating Current operating lease liability $ 1,919 $ 2,174 Financing Current financing lease liability 224 200 Non-Current Operating Long-term operating lease liability 7,731 8,958 Financing Long-term financing lease liability 1,978 2,125 Total lease liabilities $ 11,852 $ 13,457
Schedule of lease cost	The following table sets forth our lease costs included in our unaudited condensed consolidated statement of comprehensive income: Three Months Ended Nine Months Ended September 30, 2023 September 30, 2022 September 30, 2023 September 30, 2022 Operating lease cost $ 645 $ 837 $ 2,140 $ 2,457 Short-term lease cost - 1 - 9 Financing lease cost: Amortization of ROU assets 60 55 191 162 Interest on lease liabilities 31 34 105 103 Sublease income - ( 34 ) ( 68 ) ( 102 ) Total lease costs $ 736 $ 893 $ 2,368 $ 2,629 September 30, 2023 September 30, 2022 Weighted-average remaining lease term (years) Operating 6.1 6.7 Financing 7.4 8.4 Weighted-average discount rate Operating 5.7 % 5.9 % Financing 5.7 % 5.6 %
Schedule of weighted average remaining lease term and the weighted average discount rate for the Company's operating leases	September 30, 2023 September 30, 2022 Weighted-average remaining lease term (years) Operating 6.1 6.7 Financing 7.4 8.4 Weighted-average discount rate Operating 5.7 % 5.9 % Financing 5.7 % 5.6 %
Summary of maturities of leases	Maturities of Leases Operating Leases Financing Leases Total Remaining 2023 $ 650 $ 90 $ 740 2024 2,417 345 2,762 2025 2,060 355 2,415 2026 1,634 358 1,992 2027 1,428 366 1,794 Thereafter 3,806 1,200 5,006 Total future lease payments 11,995 2,714 14,709 Less: Discount 2,345 512 2,857 Present value of lease liability $ 9,650 $ 2,202 $ 11,852

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Schedule of Fair Value Measurement of Assets and Liabilities Based on Hierarchy	The following table presents information about the Company’s liabilities that are measured at fair value on a recurring basis as of September 30, 2023. Fair Value Measurements as of September 30, 2023 Description Level 1 Level 2 Level 3 Total Liabilities: Tax Receivable Agreement $ - $ - $ 4,416 $ 4,416 Fathom OpCo acquisitions contingent consideration - - 181 181 Sponsor Earnout Shares Liability - - 49 49 Fathom Earnout Shares Liability - - 283 283 Warrant liability - Public Warrants - - - - Warrant liability - Private Placement Warrants - - 191 191 $ - $ - $ 5,120 $ 5,120 The following table presents information about the Company’s liabilities that are measured at fair value on a recurring basis as of December 31, 2022. Fair Value Measurements as of December 31, 2022 Description Level 1 Level 2 Level 3 Total Liabilities: Tax Receivable Agreement $ - $ - $ 4,000 $ 4,000 Fathom OpCo acquisitions contingent consideration - - 700 700 Sponsor Earnout Shares Liability - - 930 930 Fathom Earnout Shares Liability - - 5,960 5,960 Warrant liability - Public Warrants 720 - - 720 Warrant liability - Private Placement Warrants - - 2,060 2,060 $ 720 $ - $ 13,650 $ 14,370
Reconciliation of Beginning and Ending Balances of Recurring Level 3 Fair Value Measurements	The following table presents a reconciliation of the beginning and ending balances of recurring Level 3 fair value measurements. Level 3 liabilities Tax Receivable Agreement liability Fathom OpCo acquisitions contingent consideration Sponsor Earnout shares liability Fathom Earnout shares liability Warrant liability – Public Warrants Warrant liability – Private Placement Warrants Total Balance at December 31, 2022 $ 4,000 $ 700 $ 930 $ 5,960 $ 720 $ 2,060 $ 14,370 Payments - ( 502 ) - - - - $ ( 502 ) Net (gain) loss (1) 416 ( 17 ) ( 881 ) ( 5,677 ) ( 720 ) ( 1,869 ) $ ( 8,748 ) Ending balance at September 30, 2023 $ 4,416 $ 181 $ 49 $ 283 $ - $ 191 $ 5,120 (1) Net gains on changes in recurring Level 3 fair value measurements are recognized in Other expense or Other income in our unaudited condensed consolidated statement of comprehensive loss.

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2023
Variable Interest Entities [Abstract]
Summary of Total Assets, Liabilities, and Equity of the Company's Consolidated VEI	The following table presents a summary of the total assets, liabilities, and shareholders' equity of the Company’s condensed consolidated VIE, which is comprised solely of Fathom OpCo. Period Ended September 30, 2023 Period Ended December 31, 2022 Total assets $ 345,355 $ 370,245 Total liabilities 188,937 191,514 Total equity 156,418 178,731

Nature of Business - Additional

Nature of Business - Additional Information (Details)	9 Months Ended
	Sep. 30, 2023
Nature Of Business [Line Items]
Limited Liability Company or Limited Partnership, Business, Formation Date	Apr. 16, 2021
MCT Group Holdings LLC | Equity Interest [Member]
Nature Of Business [Line Items]
Ownership Interest	100%
Incodema Holdings LLC | Equity Interest [Member]
Nature Of Business [Line Items]
Ownership Interest	100%

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 29, 2023	Sep. 28, 2023	Dec. 23, 2021
Basis of Presentation [Line Items]
Stockholders' equity, reverse stock split	20-for-1
Warrants to purchase common stock		926,216	18,524,320
Warrant issuance, description	After the effective date of the Reverse Stock Split, every twenty shares of Common Stock that may have been purchased pursuant to the warrants immediately prior to the Reverse Stock Split represented one share of Common Stock that may be purchased pursuant to such warrants immediately following the Reverse Stock Split.
Exercise price of warrants (in dollars per share)		$ 230	$ 11.5
Term Loan [Member]
Basis of Presentation [Line Items]
Term loan Paydown amount				$ 125,000
Term Loan [Member] | Credit Agreement [Member]
Basis of Presentation [Line Items]
Term loan Paydown amount	$ 50,000
Maximum
Basis of Presentation [Line Items]
Common stock, shares issued			70,113,787
Common stock, shares outstanding			70,113,787
Minimum
Basis of Presentation [Line Items]
Common stock, shares issued			3,505,689
Common stock, shares outstanding			3,505,689

Immaterial Error Correction o_3

Immaterial Error Correction of Previously Issued Financial Statements - Unaudited Condensed Consolidated Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended						9 Months Ended
		Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Condensed Financial Statements, Captions [Line Items]
Cost of revenue	[1],[2],[3]	$ 23,194			$ 25,144			$ 70,196	$ 80,126
Gross profit		8,264			15,066			30,743	42,611
Operating loss		(5,198)			(1,069,081)			(14,211)	(1,076,885)
Net loss before income tax		(8,577)			(1,046,020)			(17,054)	(994,128)
Income tax expense (benefit)		(9)			(7,050)			110	(8,435)
Net loss		(8,568)			(1,038,970)			(17,164)	(985,693)
Net loss attributable to Fathom OpCo non-controlling interest		(4,206)			(556,027)			(11,792)	(561,728)
Net loss attributable to controlling interest		(4,362)	$ (3,125)	$ 2,115	(482,943)	$ 34,726	$ 24,258	(5,372)	(423,965)
Comprehensive income (loss):
(Loss) Income from foreign currency translation adjustments									(107)
Comprehensive loss, net of tax		$ (4,362)			(482,943)			$ (5,372)	(424,072)
As Reported
Condensed Financial Statements, Captions [Line Items]
Net loss before income tax					(1,046,020)				(994,128)
Income tax expense (benefit)					87				167
Net loss					(1,046,107)				(994,295)
Net loss attributable to Fathom OpCo non-controlling interest					(556,027)				(561,728)
Net loss attributable to controlling interest					(490,080)				(432,567)
Comprehensive income (loss):
(Loss) Income from foreign currency translation adjustments									(107)
Comprehensive loss, net of tax					(490,080)				(432,674)
Adjustments
Condensed Financial Statements, Captions [Line Items]
Income tax expense (benefit)					(7,137)				(8,602)
Net loss					(7,137)				(8,602)
Net loss attributable to controlling interest					(7,137)				(8,602)
Comprehensive income (loss):
Comprehensive loss, net of tax					$ (7,137)				$ (8,602)
[1] Inclusive of $ 1,621 and $ 1,707 of depreciation and amortization for the three months ended September 30, 2023 and September 30, 2022, respectively; and of $ 4,947 and $ 4,944 for the nine months ended September 30, 2023 and September 30, 2022, respectively; Inclusive of $ 0 and $ 0 of inventory step-up amortization for the three months ended September 30, 2023 and September 30, 2022, respectively, and $ 0 and $ 3,241 for the nine months ended September 30, 2023 and September 30, 2022, respectively; and Inclusive of $ 1,611 and $ 2,573 of cost of revenue related to inventory purchases from a related party for the three months ended September 30, 2023 and September 30, 2022, respectively; and $ 5,689 and $ 7,513 for the nine months ended September 30, 2023 and September 30, 2022, respectively;

Immaterial Error Correction o_4

Immaterial Error Correction of Previously Issued Financial Statements - Unaudited Condensed Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash Flows from Operating Activities
Net income (loss)		$ (423,965)
Adjustments to reconcile net loss to net cash from operating activities:
Deferred taxes		(8,449)
Changes in operating assets and liabilities that used cash:
Net cash provided by operating activities	$ 2,250	6,603
Net cash used in investing activities	(4,273)	(10,953)
Net cash used in financing activities	(869)	(7,896)
Effect of exchange rate changes on cash, and cash equivalents		(107)
Net decrease in cash	$ (2,892)	(12,353)
As Reported
Cash Flows from Operating Activities
Net income (loss)		(432,567)
Adjustments to reconcile net loss to net cash from operating activities:
Deferred taxes		153
Foreign currency translation adjustment		(107)
Changes in operating assets and liabilities that used cash:
Net cash provided by operating activities		6,496
Net cash used in investing activities		(10,953)
Net cash used in financing activities		(7,896)
Net decrease in cash		(12,353)
Adjustments
Cash Flows from Operating Activities
Net income (loss)		8,602
Adjustments to reconcile net loss to net cash from operating activities:
Deferred taxes		(8,602)
Foreign currency translation adjustment		107
Changes in operating assets and liabilities that used cash:
Net cash provided by operating activities		107
Effect of exchange rate changes on cash, and cash equivalents		$ (107)

Immaterial Error Correction o_5

Immaterial Error Correction of Previously Issued Financial Statements - Unaudited Condensed Consolidated Statement of Shareholders' Equity and Redeemable Non-Controlling Interest (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Total equity	$ 54,222	$ 51,764	$ 105,708
Accumulated Earnings (Deficit)
Total equity			(471,458)
Additional Paid-in Capital
Total equity			577,273
As Reported
Total equity			104,158
As Reported | Accumulated Earnings (Deficit)
Total equity			(480,167)
As Reported | Additional Paid-in Capital
Total equity			584,325
Adjustments
Total equity			1,550
Adjustments | Accumulated Earnings (Deficit)
Total equity			8,709
Adjustments | Additional Paid-in Capital
Total equity			(7,052)
Other comprehensive loss
Total equity			(107)
Other comprehensive loss | Adjustments
Total equity			$ (107)

Revenue - Schedule of Revenue b

Revenue - Schedule of Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 31,458	$ 40,210	$ 100,939	$ 122,737
Additive Manufacturing
Disaggregation of Revenue [Line Items]
Total revenue	2,692	3,154	9,567	11,713
Injection Molding
Disaggregation of Revenue [Line Items]
Total revenue	5,372	5,984	16,114	19,892
CNC Machining
Disaggregation of Revenue [Line Items]
Total revenue	12,486	15,530	39,956	43,441
Precision Sheet Metal
Disaggregation of Revenue [Line Items]
Total revenue	9,542	13,719	30,089	43,153
Ancillary Product Lines
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,366	$ 1,823	$ 5,213	$ 4,538

Inventories - Summary of Invent

Inventories - Summary of Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Inventory, Net [Abstract]
Raw materials	$ 8,969	$ 8,496
Work in process	5,802	5,664
Finished goods	2,614	2,464
Inventory, gross	17,385	16,624
Allowance for obsolescence	(606)	(906)
Total	$ 16,779	$ 15,718

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 57,961	$ 54,034
Accumulated depreciation	(10,797)	(6,331)
Total	47,164	47,703
Machinery & Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 42,856	39,516
Machinery & Equipment | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	6 years
Machinery & Equipment | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	10 years
Furniture & Fixtures
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 3,634	3,100
Estimated Useful Life	10 years
Computer hardware
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 360	374
Estimated Useful Life	5 years
Property and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 7,142	6,839
Property and Leasehold Improvements | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	3 years
Property and Leasehold Improvements | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	23 years
Construction in Progress
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 3,650	3,893
Auto / transportation equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 319	$ 312
Estimated Useful Life	3 years

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 4,627	$ 4,627	$ 13,845	$ 13,595
Operating Expense [Member]
Property Plant And Equipment [Line Items]
Depreciation and amortization	306	307	884	581
Cost of Revenue [Member]
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 1,407	$ 1,492	$ 4,303	$ 4,283

Intangible Assets, Net - Schedu

Intangible Assets, Net - Schedule of Intangible Assets, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Finite Lived Intangible Assets [Line Items]
Gross	$ 270,000	$ 270,000
Accumulated Amortization	(32,193)	(18,588)
Net	237,807	251,412
Trade Name [Member]
Finite Lived Intangible Assets [Line Items]
Gross	70,000	70,000
Accumulated Amortization	(8,282)	(4,782)
Net	$ 61,718	$ 65,218
Useful Life (in years)	15 years	15 years
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross	$ 180,000	$ 180,000
Accumulated Amortization	(16,813)	(9,707)
Net	$ 163,187	$ 170,293
Useful Life (in years)	19 years	19 years
Developed Software [Member]
Finite Lived Intangible Assets [Line Items]
Gross	$ 4,300	$ 4,300
Accumulated Amortization	(1,526)	(881)
Net	$ 2,774	$ 3,419
Useful Life (in years)	5 years	5 years
Developed Technology [Member]
Finite Lived Intangible Assets [Line Items]
Gross	$ 15,700	$ 15,700
Accumulated Amortization	(5,572)	(3,218)
Net	$ 10,128	$ 12,482
Useful Life (in years)	5 years	5 years

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 4,535,000	$ 4,535,000	$ 13,605,000	$ 13,675,000
Intangible assets with indefinite useful lives	$ 0		$ 0

Intangible Assets, Net - Sche_2

Intangible Assets, Net - Schedule of Estimated Aggregate Amortization Expense (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Remaining 2023	$ 4,535
2024	18,140
2025	18,140
2026	18,041
2027	14,140
Thereafter	164,811
Total	$ 237,807	$ 251,412

Reorganization - Additional Inf

Reorganization - Additional Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 07, 2022 Acquisition	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Feb. 17, 2023
Restructuring Cost and Reserve [Line Items]
Number of acquisitions since 2019 | Acquisition	13
Planned restructuring activities, Description				Pursuant to the Reorganization, the Company intended to:
Reorganization, Percentage of expected net workforce reduction	6%
Restructuring		$ 718	$ 996	$ 2,774	$ 996
Additional workforce percentage						14%
Incurred costs associated with the reorganization		718		2,774
Inventory write-off		$ 111	$ 996	1,302	$ 996
Employee termination costs				$ 135

Reorganization - Summary of Lia

Reorganization - Summary of Liability Related to Company's Reorganization (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Restructuring Reserve [Roll Forward]
Liability balance at December 31, 2022	$ 412
Charges	668
Payments	(945)
Liability balance at june 30, 2023	$ 135

Warrant Liability - Additional

Warrant Liability - Additional Information (Details) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($) $ / shares shares	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) Warrant $ / shares shares	Sep. 30, 2022 USD ($)	Sep. 29, 2023 $ / shares	Sep. 28, 2023 $ / shares	Dec. 31, 2022 $ / shares shares
Class Of Warrant Or Right [Line Items]
Fair value price per warrant					$ 230	$ 11.5
Change in fair value of Warrants | $	$ 409	$ 7,400	$ 2,589	$ 28,000
Class A Common Stock [Member]
Class Of Warrant Or Right [Line Items]
Par value per share	$ 0.0001		$ 0.0001				$ 0.0001
Public Warrants
Class Of Warrant Or Right [Line Items]
Class of warrants or rights outstanding (in shares) | shares	431,216		431,216				431,216
Fair value price per warrant	$ 0		$ 0
Private Placement Warrants
Class Of Warrant Or Right [Line Items]
Class of warrants or rights outstanding (in shares) | shares	495,000		495,000				495,000
Fair value price per warrant	$ 0.39		$ 0.39
Warrant Liability | Class A Common Stock [Member]
Class Of Warrant Or Right [Line Items]
Par value per share	$ 0.0001		$ 0.0001
Fair value measurements	11.5		11.5
Number of shares exercisable to purchase | Warrant			1

Warrant Liability - Summary of

Warrant Liability - Summary of Number of Outstanding Warrants and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Class of Warrant or Right [Line Items]
Fair value of warrants	$ 191	$ 2,780
Public Warrants
Class of Warrant or Right [Line Items]
Number of outstanding warrants	431,216	431,216
Fair value of warrants		$ 720
Private Placement Warrants
Class of Warrant or Right [Line Items]
Number of outstanding warrants	495,000	495,000
Fair value of warrants	$ 191	$ 2,060

Debt - Additional Information (

Debt - Additional Information (Details) $ in Thousands		1 Months Ended	3 Months Ended													6 Months Ended	9 Months Ended
	Nov. 13, 2023	Dec. 31, 2022 USD ($)	Sep. 30, 2026	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024 USD ($)	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2025	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Nov. 30, 2023 USD ($)	Oct. 31, 2023 USD ($)	Dec. 23, 2021 USD ($)
Debt Instrument [Line Items]
Long term debt date of maturity																						Dec. 31, 2026
Interest on debt increments period																		90 days
Debt issuance costs gross														$ 0				$ 524
Interest and debt expense														3,828	$ 2,337			11,076	$ 5,253
Amortization of debt issuance costs														165	$ 69			461	$ 299
Financing agreement maturity period		10 months
Financing payments		$ 1,265
Financing fee		$ 35
Financing annual rate		6.13%
SG&A Expenses [Member]
Debt Instrument [Line Items]
Insurance expense														404				1,211
Prepaid Assets [Member]
Debt Instrument [Line Items]
Financing payments recognized in assets														403				403
Other Current Liabilities [Member]
Debt Instrument [Line Items]
Financing payments recognized in liabilities														126				126
Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument face value																						$ 125,000
New Credit Agreement [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument face value														50,000				50,000
Third Amendment Credit Agreement [Member]
Debt Instrument [Line Items]
Debt instrument face value														50,000				$ 50,000
Net leverage ratio																		5
Debt instrument credit support amount														50,000				$ 50,000
Minimum EBITDA financial covenant														1,500
Customary arranger and lender consent fees														936				936
Increase decrease in term loan facility and revolving credit facility														100,000				$ 100,000
Debt instrument, basis spread on variable rate																		4.25%
Third Amendment Credit Agreement [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Interest coverage ratio	2.5
Net leverage ratio	3.5
Maximum net leverage ratio	4
Third Amendment Credit Agreement [Member] | Forecast [Member]
Debt Instrument [Line Items]
Interest coverage ratio			1.55	1.45	1.35											1.2	1.25
Net leverage ratio			4	4.5	5	5.5	5.75	6	6.25	6.5	6.75	7
Minimum EBITDA financial covenant													$ 2,700
Revolving Credit Facility [Member] | New Credit Agreement [Member]
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity																						$ 50,000
Borrowings from credit agreement		$ 37,000												42,000				$ 42,000
Revolving Credit Facility [Member] | Third Amendment Credit Agreement [Member]
Debt Instrument [Line Items]
Minimum unrestricted cash and cash equivalents														13,500				13,500
Revolving Credit Facility [Member] | Third Amendment Credit Agreement [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Minimum unrestricted cash and cash equivalents																					$ 13,500
Revolving Credit Facility [Member] | Third Amendment Credit Agreement [Member] | Forecast [Member]
Debt Instrument [Line Items]
Minimum unrestricted cash and cash equivalents										$ 10,000			$ 10,000			$ 10,000				$ 13,500
Letter of Credit [Member] | Revolving Credit Facility [Member] | Third Amendment Credit Agreement [Member]
Debt Instrument [Line Items]
Line of credit maximum borrowing capacity														$ 5,000				$ 5,000

Debt - Schedule of Amendment to

Debt - Schedule of Amendment to Credit Agreement (Details) - Third Amendment Credit Agreement [Member] $ in Thousands	3 Months Ended												6 Months Ended	9 Months Ended
	Sep. 30, 2026	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2024	Dec. 31, 2025	Sep. 30, 2023
Debt Instrument [Line Items]
Debt Instruments Net Leverage Ratio															5
Minimum EBITDA Financial Covenant												$ 1,500
Forecast [Member]
Debt Instrument [Line Items]
Interest Coverage Ratio	1.55	1.45	1.35										1.2	1.25
Debt Instruments Net Leverage Ratio	4	4.5	5	5.5	5.75	6	6.25	6.5	6.75	7
Minimum EBITDA Financial Covenant											$ 2,700

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total principal long-term debt	$ 159,187	$ 158,875
Debt issuance costs	(1,866)	(1,804)
Total debt	157,321	157,071
Less: current portion of long-term debt	157,321	42,744
Long-term debt, net of current portion	$ 0	$ 114,327
Credit Agreement Revolver [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	9.47%	8.20%
Principal debt	$ 42,000	$ 37,000
Credit Agreement Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	9.34%	8.43%
Principal debt	$ 117,187	$ 121,875

Other (Income) Expense - Schedu

Other (Income) Expense - Schedule of Other (Income) Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Other Income and Expenses [Abstract]
Change in fair value of TRA	$ 392		$ 442	$ (200)
Other	43	$ 81	131	276
Other expense	435	81	573	276
Change in fair value of Earnout Shares	(613)	(18,080)	(6,558)	(59,980)
Change in fair value of Warrants	(409)	(7,400)	(2,589)	(28,000)
Other	(27)	(68)	(5)	(591)
Other income	$ (1,049)	$ (25,548)	$ (9,152)	$ (88,771)

Shared Based Compensation - Sum

Shared Based Compensation - Summary of Stock Option Activity (Details) - Stock Options [Member] - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Beginning balance	15,853
Number of Shares, Granted	95,369
Number of Shares, Forfeited	(864)
Number of Shares, Ending balance	110,358	15,853
Number of Shares, Exercisable at June 30,2023	4,996
Weighted Average Exercise Price per Share, Beginning balance	$ 174.13
Weighted Average Exercise Price per Share, Granted	11.67
Weighted Average Exercise Price per Share, Forfeited	177.8
Weighted Average Exercise Price per Share, Ending Balance	33.71	$ 174.13
Weighted Average Exercise Price per Share, Exercisable at June 30, 2023	$ 173.92
Average Remaining Contractual Term	6 years 5 months 19 days	6 years 2 months 1 day
Average Remaining Contractual Term, Exercisable at June 30, 2023	5 years 5 months 1 day

Shared Based Compensation - Add

Shared Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	$ 1,139	$ 1,762	$ 3,471	$ 5,687
Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Average exercise price			$ 11.67
2021 Omnibus Plan [Member] | Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation cost	1,460		$ 1,460
Cost expected to be recognized, weighted average period			1 year 10 months 20 days
2021 Omnibus Plan [Member] | Restricted Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation cost	$ 6,696		$ 6,696
Cost expected to be recognized, weighted average period			1 year 9 months 3 days
Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Maximum percentage of employee eligible compensation to periodic payment of purchase price	15%		15%
Percentage of proceeds attributable to common units			85%
Common stock purchased by employees under the plan			12,482
Average exercise price			$ 6.9
Shares available for future issuance under the ESPP	48,345		48,345

Shared Based Compensation - Sch

Shared Based Compensation - Schedule of Non-vested Restricted Stock Unit Activity - (Details) - Restricted Stock Units [Member]	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Nonvested, Shares | shares	308,862
Granted, Shares | shares	174,431
Vested, Shares | shares	(17,941)
Forfeited, Shares | shares	(26,881)
Nonvested, Shares | shares	438,471
Nonvested | $ / shares	$ 185.63
Granted | $ / shares	208
Vested | $ / shares	168.1
Forfeited | $ / shares	140.22
Nonvested | $ / shares	$ 117.2

Shared Based Compensation - S_2

Shared Based Compensation - Schedule of Employee Stock Purchase Plan Valuation Assumptions (Details) - Employee Stock Purchase Plan [Member]	9 Months Ended
	Sep. 30, 2023 $ / shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	77.50%
Expected dividend yield	0%
Risk-free interest rate	4.10%
Fair value of share	$ 26.4
Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (years)	1 year 6 months
Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (years)	6 months

Earnings Per Share - Scheduled

Earnings Per Share - Scheduled Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Numerator
Net income (loss)	$ (4,362)	$ (3,125)	$ 2,115	$ (482,943)	$ 34,726	$ 24,258	$ (5,372)	$ (423,965)
Class A Common Units [Member]
Numerator
Net income (loss)	(8,568)			(1,038,970)			(17,164)	(985,693)
Less: Net loss attributable to non-controlling interests	(4,206)			(556,027)			(11,792)	(561,728)
Net (loss) income attributable to Class A common stock	$ (4,362)			$ (482,943)			$ (5,372)	$ (423,965)
Denominator
Basic	3,504,859			3,140,809			3,448,030	2,767,401
Diluted - weighted-average shares outstanding:	3,504,859			3,140,809			3,448,030	2,767,401
Basic	$ (1.24)			$ (153.76)			$ (1.56)	$ (153.2)
Diluted	$ (1.24)			$ (153.76)			$ (1.56)	$ (153.2)

Shareholders' Equity and Nonc_3

Shareholders' Equity and Noncontrolling Interest - Additional Information (Details) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Common stock, shares authorized (in shares)	25,000,000
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred Stock, Shares Outstanding	0	0
Class A Common Units [Member]
Class Of Stock [Line Items]
Common stock, shares authorized (in shares)	15,000,000
Common stock, par value (in dollars per share)	$ 0.0001
Common stock, shares outstanding	3,507,084
Class B Common Units [Member]
Class Of Stock [Line Items]
Common stock, shares authorized (in shares)	9,000,000
Common stock, par value (in dollars per share)	$ 0.0001
Common stock, shares outstanding	3,327,379
Class C Common Units [Member]
Class Of Stock [Line Items]
Common stock, shares authorized (in shares)	500,000
Common stock, par value (in dollars per share)	$ 0.0001
Common stock, shares outstanding	0

Shareholders' Equity and Nonc_4

Shareholders' Equity and Noncontrolling Interest - Schedule Of Calculation Of Comprehensive Loss Attributable To Non-controlling Interest Holders (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Noncontrolling Interest [Line Items]
Fathom OpCo comprehensive loss	$ (4,362)	$ (482,943)	$ (5,372)	$ (424,072)
Comprehensive loss attributable to noncontrolling interest	(4,206)	(556,027)	(11,792)	(561,728)
Fathom OpCo [Member]
Noncontrolling Interest [Line Items]
Fathom OpCo comprehensive loss	$ (8,659)	$ (1,070,703)	$ (25,278)	$ (1,079,745)
Non-controlling interest percentage	48.70%	51.90%	48.70%	51.90%
Comprehensive loss attributable to noncontrolling interest	$ (4,206)	$ (556,027)	$ (11,792)	$ (561,728)

Leases - Additional Information

Leases - Additional Information (Details)	Sep. 30, 2023
Lessee, Lease, Description [Line Items]
Lease terms	12 months
Minimum
Lessee, Lease, Description [Line Items]
Lease terms	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lease terms	10 years

Leases - Schedule of Balance Sh

Leases - Schedule of Balance Sheet Disclosure of Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets
Financing	$ 2,110	$ 2,253
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Operating And Finance Lease Right Of Use Asset
Total lease assets	$ 11,595	12,708
Current
Operating	$ 1,919	2,174
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Operating And Finance Lease Liability Current
Financing	$ 224	200
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Operating And Finance Lease Liability Current
Non-Current
Operating	$ 7,731	8,958
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Operating And Finance Lease Liability Noncurrent
Financing	$ 1,978	2,125
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Operating And Finance Lease Liability Noncurrent
Total lease liabilities	$ 11,852	13,457
Prepaid Expenses and Other Current Assets [Member]
Assets
Operating	126	143
Right-of-use Lease Assets, Net [Member]
Assets
Operating	$ 9,359	$ 10,312

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs Included in Unaudited Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Lease, Cost [Abstract]
Operating lease cost	$ 645	$ 837	$ 2,140	$ 2,457
Short-term lease cost		1		9
Finance lease cost
Amortization of ROU assets	60	55	191	162
Interest on lease liabilities	31	34	105	103
Sublease income		(34)	(68)	(102)
Total lease costs	$ 736	$ 893	$ 2,368	$ 2,629
Weighted-average remaining lease term (years), Operating	6 years 1 month 6 days	6 years 8 months 12 days	6 years 1 month 6 days	6 years 8 months 12 days
Weighted-average remaining lease term (years), Financing	7 years 4 months 24 days	8 years 4 months 24 days	7 years 4 months 24 days	8 years 4 months 24 days
Weighted-average discount rate, Operating	5.70%	5.90%	5.70%	5.90%
Weighted-average discount rate, Financing	5.70%	5.60%	5.70%	5.60%

Leases - Summary of Maturities

Leases - Summary of Maturities of Leases (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Operating Leases
Remaining 2023	$ 650
2024	2,417
2025	2,060
2026	1,634
2027	1,428
Thereafter	3,806
Lessee, Operating Lease, Liability, to be Paid, Total	11,995
Less: Discount	2,345
Present value of lease liability	9,650
Financing Leases
Remaining 2023	90
2024	345
2025	355
2026	358
2027	366
Thereafter	1,200
Finance Lease, Liability, Payment, Due, Total	2,714
Less: Discount	512
Present value of lease liability	2,202
Total
Remaining 2023	740
2024	2,762
2025	2,415
2026	1,992
2027	1,794
Thereafter	5,006
Lease Liability Payments Due, Total	14,709
Less: Discount	2,857
Present value of lease liability	$ 11,852

Fair Value Measurement - Schedu

Fair Value Measurement - Schedule of Fair Value Measurement of Assets and Liabilities Based on Hierarchy (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	$ 5,120	$ 14,370
Tax Receivable Agreement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	4,416	4,000
Fathom OpCo Acquisitions Contingent Consideration
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	181	700
Sponsor Earnout Shares Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	49	930
Fathom Earnout Shares Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	283	5,960
Warrant liability - Public Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities		720
Warrant liability - Private Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	191	2,060
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities		720
Level 1 | Warrant liability - Public Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities		720
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	5,120	13,650
Level 3 | Tax Receivable Agreement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	4,416	4,000
Level 3 | Fathom OpCo Acquisitions Contingent Consideration
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	181	700
Level 3 | Sponsor Earnout Shares Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	49	930
Level 3 | Fathom Earnout Shares Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	283	5,960
Level 3 | Warrant liability - Private Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities	$ 191	$ 2,060

Fair Value Measurement - Reconc

Fair Value Measurement - Reconciliation of Beginning and Ending Balances of Recurring Level 3 Fair Value Measurements (Details) - Level 3 $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	$ 14,370
Payments	(502)
Net (gain) loss	$ (8,748)	[1]
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Expense
Fair value, Ending Balance	$ 5,120
Tax Receivable Agreement Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	4,000
Net (gain) loss	416	[1]
Fair value, Ending Balance	4,416
Fathom OpCo Acquisitions Contingent Consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	700
Payments	(502)
Net (gain) loss	(17)	[1]
Fair value, Ending Balance	181
Sponsor Earnout Shares Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	930
Net (gain) loss	(881)	[1]
Fair value, Ending Balance	49
Fathom Earnout Shares Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	5,960
Net (gain) loss	(5,677)	[1]
Fair value, Ending Balance	283
Warrant liability - Public Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	720
Net (gain) loss	(720)	[1]
Warrant liability - Private Placement Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	2,060
Net (gain) loss	(1,869)	[1]
Fair value, Ending Balance	$ 191
[1] Net gains on changes in recurring Level 3 fair value measurements are recognized in Other expense or Other income in our unaudited condensed consolidated statement of comprehensive loss.

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2023 yr $ / shares	Mar. 31, 2023 USD ($)	Sep. 30, 2022	Sep. 30, 2023 USD ($) yr Warrant $ / shares	Sep. 30, 2022	Dec. 31, 2022 $ / shares
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Corporate tax rate	(0.08%)		0.64%	(0.67%)	0.82%
Class A Common Stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Par value per share	$ 0.0001			$ 0.0001		$ 0.0001
Class A Common Stock [Member] | Warrant Liability
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Par value per share	$ 0.0001			$ 0.0001
Fair value measurements	11.5			11.5
Number of shares exercisable to purchase | Warrant				1
Tax Receivable Agreement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Corporate tax rate				24.80%
Non-controlling interest percentage				48.70%
Initial amortization deductions | $				$ 46,070
Taxable income forecast | $		$ 67,762
Tax Receivable Agreement [Member] | Class A Common Stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Business combination contingent consideration liability measurement input	78			78
Stock price, per share	$ 5.75			$ 5.75
Sale of stock price percentage				25%
Cost of debt percentage				13.28%
Earnout Shares [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected term				3 years 2 months 23 days
Risk-free interest rate				4.71%
Strike Price [Member] | Private Placement Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value measurements	230			230
Expected Term [Member] | Private Placement Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value measurements | yr	0.0323			0.0323
Volatility [Member] | Private Placement Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value measurements	0.99			0.99
Operating Asset Volatility [Member] | Earnout Shares [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Volatility				62.20%
Equity Volatility [Member] | Earnout Shares [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Volatility				91.50%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Provision (benefit )for income taxes	$ (9)	$ (7,050)	$ 110	$ (8,435)
Effective tax rate	(0.08%)	0.64%	(0.67%)	0.82%

Variable Interest Entity - Summ

Variable Interest Entity - Summary of Total Assets, Liabilities, and Equity of the Company's Consolidated VEI (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Variable Interest Entity [Line Items]
Total assets	$ 345,625	$ 370,515
Total liabilities	215,259	226,544
Total equity	54,222	51,764	$ 105,708
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Total assets	345,355	370,245
Total liabilities	188,937	191,514
Total equity	$ 156,418	$ 178,731