Fathom Digital Manufacturing Corporation - Ordinary Shares (FATH) S-1 14 Jan 22 IPO registration Financial data

Cover Page

Cover Page	9 Months Ended
	Sep. 30, 2021
Document Information [Line Items]
Document Type	S-1
Entity Registrant Name	Fathom Digital Manufacturing Corp
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Central Index Key	0001836176
Amendment Flag	false

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($)	Sep. 30, 2021		Dec. 31, 2020		Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 10,531,000		$ 8,188,000		$ 1,026,000
Accounts receivable, net	24,512,000		15,563,000		9,065,000
Inventory	9,173,000		6,325,000		1,697,000
Prepaid expenses and other current assets	3,267,000		2,598,000
Prepaid expenses			1,853,000		538,000
Other current assets			745,000		0
Total current assets	47,483,000		32,674,000		12,326,000
Property and equipment, net	41,031,000		26,386,000		10,809,000
Intangible assets, net	111,573,000		83,466,000		36,095,000
Goodwill	83,113,000		63,215,000		33,007,000
Other non-current assets	145,000		1,038,000		0
TOTAL ASSETS	283,345,000		206,779,000		92,237,000
Current liabilities
Accrued expenses	5,821,000		4,181,000
Accrued offering costs			4,181,000		2,054,000
Accounts payable	7,475,000	[1]	4,404,000	[1],[2]	5,058,000	[2]
Other current liabilities	4,497,000		2,778,000		425,000
Contingent consideration	6,330,000		4,066,000		0
Current portion of debt	170,257,000		2,853,000		309,000
Total current liabilities	194,380,000		18,282,000		7,846,000
Long-term debt, net	0		90,486,000		29,597,000
Long-term contingent consideration	2,300,000		7,373,000		0
Deferred tax liabilities, net	3,009,000		0
Other non-current liabilities	1,463,000		514,000		59,000
Total liabilities	201,152,000		116,655,000		37,502,000
Contingently Redeemable Preferred Equity
Class A Ordinary Shares subject to possible redemption — 34,500,000 and no shares at $10.00 per share redemption value as of September 30, 2021 and December 31, 2020, respectively	54,105,000		54,105,000
Shareholders' Equity
Common unit			50,319,000		29,168,000
Accumulated other comprehensive loss	28,000		(68,000)		0
Accumulated surplus (deficit)	(22,290,000)		(14,232,000)		(6,269,000)
Total members' equity	28,088,000		36,019,000		22,899,000
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	283,345,000		206,779,000		92,237,000
ALTIMAR ACQUISITION CORP. II [Member]
Current assets
Cash	331,112,000		0
Prepaid expenses	744,813		0
Total current assets	1,075,925		0
Deferred offering costs	0		75,000
Investments held in the Trust Account	345,011,697		0
TOTAL ASSETS	346,087,622		75,000
Current liabilities
Accrued expenses	259,896		0
Accrued offering costs	3,607		50,000
Promissory Note — related party	0		5,000
Total current liabilities	263,503		55,000
Warrant liability	19,642,970		0
Deferred underwriting fee payable	12,075,000		0
Total liabilities	31,981,473		55,000
Commitments and Contingencies
Contingently Redeemable Preferred Equity
Class A Ordinary Shares subject to possible redemption — 34,500,000 and no shares at $10.00 per share redemption value as of September 30, 2021 and December 31, 2020, respectively	345,000,000
Shareholders' Equity
Preference shares, $0.0001 par value; 5,000,000 shares authorized; none issued or outstanding	0		0
Additional paid-in capital	0		24,137
Accumulated surplus (deficit)	(30,894,714)		(5,000)
Total shareholders' equity (deficit)	(30,893,851)		20,000
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	346,087,622		75,000
Class A common stock | ALTIMAR ACQUISITION CORP. II [Member]
Contingently Redeemable Preferred Equity
Class A Ordinary Shares subject to possible redemption — 34,500,000 and no shares at $10.00 per share redemption value as of September 30, 2021 and December 31, 2020, respectively	345,000,000		0
Shareholders' Equity
Common stock issued	0		0
Total shareholders' equity (deficit)	0		0
Class B common stock | ALTIMAR ACQUISITION CORP. II [Member]
Shareholders' Equity
Common stock issued	863		863	[3]
Total shareholders' equity (deficit)	863		863
Class A Contingently Redeemable Preferred Units
Contingently Redeemable Preferred Equity
Class A Ordinary Shares subject to possible redemption — 34,500,000 and no shares at $10.00 per share redemption value as of September 30, 2021 and December 31, 2020, respectively			54,105,000		31,836,000
Class A Common Units
Shareholders' Equity
Common unit	35,869,000		35,869,000		18,701,000
Class B Common Units
Shareholders' Equity
Common unit	$ 14,481,000		$ 14,450,000		$ 10,467,000
[1]	Inclusive of accounts payable to related parties of $1,332 and $541 as of September 30, 2021 and December 31, 2020, respectively.
[2]	Inclusive of accounts payable to related parties of $541 and $359 for 2020 and 2019, respectively.
[3]	Excludes an aggregate of up to 1,125,000 shares of Class B ordinary shares subject to forfeiture if the over-allotment option is not exercised in full or in part by the underwriters (see Note 5).

CONDENSED BALANCE SHEETS (Paren

CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts payable, Related parties, Current	$ 1,332	$ 541	$ 359
ALTIMAR ACQUISITION CORP. II [Member]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A common stock | ALTIMAR ACQUISITION CORP. II [Member]
Temporary equity, par value (in dollars per share)	$ 10	$ 10
Temporary equity, shares outstanding	34,500,000	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)		0
Common stock, shares outstanding (in shares)		0
Class B common stock | ALTIMAR ACQUISITION CORP. II [Member]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	8,625,000	8,625,000
Common stock, shares outstanding (in shares)	8,625,000	8,625,000
Common stock shares subject to forfeiture		1,125,000
Class A Contingently Redeemable Preferred Units [Member]
Temporary equity, par value (in dollars per share)	$ 100	$ 100	$ 100
Temporary equity, shares authorized	1,167,418	1,167,418	1,167,418
Temporary equity, Shares issued	1,167,418	1,167,418	702,493
Temporary equity, shares outstanding	1,167,418	1,167,418	702,493
Class A Common Units [Member]
Common units, Par or stated value per unit	$ 100	$ 100	$ 100
Common unit, Authorized	5,480,611	5,480,611	5,480,611
Common unit, Issued	5,480,611	5,480,611	2,883,452
Common unit, Outstanding	5,480,611	5,480,611	2,883,452
Class B Common Units [Member]
Common units, Par or stated value per unit	$ 100	$ 100	$ 100
Common unit, Authorized	2,242,981	2,242,981	2,242,981
Common unit, Issued	2,242,981	2,242,981	1,567,546
Common unit, Outstanding	2,242,981	2,242,981	1,567,546

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS - USD ($)		1 Months Ended	3 Months Ended	9 Months Ended
		Dec. 31, 2020	Sep. 30, 2021	Sep. 30, 2021
Operating (income) costs				$ 38,797,000
(Income) loss from operations				(7,341,000)
Other income (expense)
Other income (expense), net				14,592,000
Net income (loss)				(8,058,000)
ALTIMAR ACQUISITION CORP. II [Member]
Formation and operating costs		$ 5,000
Operating (income) costs			$ 1,121,132	1,691,620
(Income) loss from operations			1,121,132	1,691,620
Other income (expense)
Interest earned on investments held in the Trust Account			5,301	11,697
Transaction costs allocated to the Warrants			0	(755,071)
Change in fair value of Warrant liability			3,718,348	3,190,546
Other income (expense), net			3,723,649	2,447,172
Net income (loss)		$ (5,000)	$ 2,602,517	$ 755,552
Weighted average shares outstanding, basic and diluted	[1]	7,500,000
Basic and diluted net income (loss) per ordinary shares		$ 0
Redeemable Class A Ordinary Shares | ALTIMAR ACQUISITION CORP. II [Member]
Other income (expense)
Weighted average shares outstanding, basic and diluted			34,500,000	29,571,429
Basic and diluted net income (loss) per ordinary shares			$ 0.06	$ 0.02
Non Redeemable Class B Ordinary Shares | ALTIMAR ACQUISITION CORP. II [Member]
Other income (expense)
Weighted average shares outstanding, basic and diluted			8,625,000	8,460,165
Basic and diluted net income (loss) per ordinary shares			$ 0.06	$ 0.02
[1]	Includes an aggregate of up to 1,125,000 shares of Class B ordinary shares subject to forfeiture if the over-allotment option is not exercised in full or in part by the underwriters (see Note 5).

CONDENSED STATEMENT OF OPERATIO

CONDENSED STATEMENT OF OPERATIONS (Parenthetical)	Dec. 31, 2020shares
Class B common stock | ALTIMAR ACQUISITION CORP. II [Member]
Common stock shares subject to forfeiture	1,125,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	9 Months Ended				12 Months Ended
	Sep. 30, 2021		Sep. 30, 2020		Dec. 31, 2020		Dec. 31, 2019
Revenue	$ 107,887		$ 42,249		$ 61,289		$ 20,618
Cost of revenue	61,749	[1],[2]	22,637	[1],[2]	32,815	[3],[4]	10,696	[3],[4]
Gross profit	46,138		19,612		28,474		9,922
Operating expenses
Selling, general, and administrative	29,470	[5]	13,484	[5]	22,197	[6]	8,474	[6]
Depreciation and amortization	9,327		2,797		4,825		1,605
Total operating expenses	38,797		16,281		27,022		10,079
Operating income (loss)	7,341		3,331		1,452		(157)
Interest expense and other expense (income)
Interest expense	8,800		2,335		3,665		1,616
Other expense	9,007		2,524		6,335		3,187
Other income	(3,215)		(423)		(585)		(189)
Other income (expense), net	14,592		4,436		9,415		4,614
Net loss before income taxes	(7,251)		(1,105)
Provision for income taxes	807		0
Net income (loss)	(8,058)		(1,105)		(7,963)		(4,771)
Other comprehensive loss, net of tax
Foreign currency translation adjustments	96		6		(68)		0
Comprehensive loss	$ (7,962)		$ (1,099)		$ (8,031)		$ (4,771)
Net loss per unit attributable to Class A and Class B common unitholders:
Basic	$ (2.63)	[7]	$ (1.09)	[7]	$ (2.68)	[8]	$ (3.14)	[8]
Diluted	$ (2.63)	[7]	$ (1.09)	[7]	$ (2.68)	[8]	$ (3.14)	[8]
Weighted average units outstanding:
Basic	7,723,592		4,858,808		5,227,816		2,352,664
Diluted	7,723,592		4,858,808		5,227,816		2,352,664
[1]	Inclusive of $2,679 and $2,196 of depreciation and amortization for the nine months ended September 30, 2021 and September 30, 2020, respectively.
[2]	Inclusive of $6,200 and $4,434 of cost of revenue related to inventory purchases from a related party in the nine months ended September 30, 2021 and September 30, 2020, respectively. See Note 3 and Note 11.
[3]	Inclusive of $2,567 and $1,054 of depreciation and amortization in 2020 and 2019, respectively
[4]	Inclusive of $6,318 and $1,255 of cost of revenue related to inventory purchases from a related party in 2020 and 2019, respectively. See Note 3 and Note 15.
[5]	Inclusive of $1,431 and $355 of management fees incurred to a related party for the nine months ended September 30, 2021 and September 30, 2020, respectively. See Note 11.
[6]	Inclusive of $742 and $308 of management fees incurred to a related party in 2020 and 2019, respectively. See Note 15.
[7]	Basic and diluted net loss per unit amounts are the same for both Class A and Class B common units, see Note 10.
[8]	Basic and diluted net loss per unit amounts are the same for each class of common units, see Note 14.

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parentheticals) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Cost, Depreciation and Amortization	$ 2,679	$ 2,196	$ 2,567	$ 1,054
Management Services Agreement [Member]
Related party transactions, expenses	1,431	355	742	308
Related Party [Member]
Related Party Transaction, Purchases from Related Party	6,200	4,434	6,318	1,255
Related Party [Member] | Management Services Agreement [Member]
Related party transactions, expenses	$ 1,431	$ 355	$ 742	$ 308

CONDENSED STATEMENTS OF CHANGES

CONDENSED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($)		Total	ALTIMAR ACQUISITION CORP. II [Member]	Restated [Member]ALTIMAR ACQUISITION CORP. II [Member]	Additional Paid-in CapitalALTIMAR ACQUISITION CORP. II [Member]	Additional Paid-in CapitalRestated [Member]ALTIMAR ACQUISITION CORP. II [Member]	Accumulated Deficit	Accumulated DeficitALTIMAR ACQUISITION CORP. II [Member]	Accumulated DeficitRestated [Member]ALTIMAR ACQUISITION CORP. II [Member]	Accumulated Other Comprehensive Loss	Class A common stockALTIMAR ACQUISITION CORP. II [Member]	Class A common stockRestated [Member]ALTIMAR ACQUISITION CORP. II [Member]	Class B common stockALTIMAR ACQUISITION CORP. II [Member]	Class B common stockRestated [Member]ALTIMAR ACQUISITION CORP. II [Member]	Class A Contingently Redeemable Preferred UnitsCommon Stock [Member]	Class A Common UnitsCommon Stock [Member]	Class B Common UnitsCommon Stock [Member]
Opening Balance, Shares, Contingently Redeemable Preferred Units at Dec. 31, 2018															260,196
Opening Balance, Value, Contingently Redeemable Preferred Units at Dec. 31, 2018															$ 9,175,000
Opening Balance, Shares at Dec. 31, 2018																1,112,807	535,796
Opening Balance, Value at Dec. 31, 2018		$ 12,246,000					$ (1,498,000)									$ 8,995,000	$ 4,749,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Members' contributions, Value, Contingently Redeemable Preferred Units															$ 19,017,000
Members' contributions, Shares, Contingently Redeemable Preferred Units															375,267
Units issued for acquisitions, Value, Contingently Redeemable Preferred Units															$ 3,644,000
Units issued for acquisitions, Shares, Contingently Redeemable Preferred Units															67,030
Members' contributions, Value		13,033,000														$ 9,706,000	$ 3,327,000
Members' contributions, Shares																1,770,645	607,051
Units issued for acquisitions, Value		2,498,000															$ 2,498,000
Units issued for acquisitions, Shares																	424,699
Share based compensation, Values		21,000															$ 21,000
Distributions to members		(128,000)															(128,000)
Net income (loss)		(4,771,000)					(4,771,000)
Foreign currency translation adjustment		0
Ending Balance, Shares, Contingently Redeemable Preferred Units at Dec. 31, 2019															702,493
Ending Balance, Value, Contingently Redeemable Preferred Units at Dec. 31, 2019															$ 31,836,000
Ending Balance, Value at Dec. 31, 2019		22,899,000					(6,269,000)									$ 18,701,000	$ 10,467,000
Ending Balance, Shares at Dec. 31, 2019																2,883,452	1,567,546
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Members' contributions, Value, Contingently Redeemable Preferred Units															$ 10,522,000
Members' contributions, Shares, Contingently Redeemable Preferred Units															214,444
Units issued for acquisitions, Value, Contingently Redeemable Preferred Units															$ 566,000
Units issued for acquisitions, Shares, Contingently Redeemable Preferred Units															15,691
Members' contributions, Value		9,978,000														$ 9,005,000	$ 973,000
Members' contributions, Shares																1,362,200	147,265
Units issued for acquisitions, Value		537,000															$ 537,000
Units issued for acquisitions, Shares																	110,449
Share based compensation, Values		22,000															$ 22,000
Net income (loss)		(1,105,000)					(1,105,000)
Foreign currency translation adjustment		6,000								$ 6,000
Ending Balance, Shares, Contingently Redeemable Preferred Units at Sep. 30, 2020															932,628
Ending Balance, Value, Contingently Redeemable Preferred Units at Sep. 30, 2020															$ 42,924,000
Ending Balance, Value at Sep. 30, 2020		32,337,000					(7,374,000)			6,000						$ 27,706,000	$ 11,999,000
Ending Balance, Shares at Sep. 30, 2020																4,245,652	1,825,259
Opening Balance, Shares, Contingently Redeemable Preferred Units at Dec. 31, 2019															702,493
Opening Balance, Value, Contingently Redeemable Preferred Units at Dec. 31, 2019															$ 31,836,000
Opening Balance, Shares at Dec. 31, 2019																2,883,452	1,567,546
Opening Balance, Value at Dec. 31, 2019		22,899,000					(6,269,000)									$ 18,701,000	$ 10,467,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Members' contributions, Value, Contingently Redeemable Preferred Units															$ 20,759,000
Members' contributions, Shares, Contingently Redeemable Preferred Units															423,083
Units issued for acquisitions, Value, Contingently Redeemable Preferred Units															$ 1,510,000
Units issued for acquisitions, Shares, Contingently Redeemable Preferred Units															41,842
Members' contributions, Value		19,686,000														$ 17,168,000	$ 2,518,000
Members' contributions, Shares																2,597,159	380,906
Units issued for acquisitions, Value		1,431,000															$ 1,431,000
Units issued for acquisitions, Shares																	294,529
Share based compensation, Values		34,000															$ 34,000
Net income (loss)		(7,963,000)					(7,963,000)
Foreign currency translation adjustment		(68,000)								(68,000)
Shareholders' equity ending balance (in shares) at Dec. 31, 2020											0		8,625,000
Shareholders' equity ending balance at Dec. 31, 2020			$ 20,000		$ 24,137			$ (5,000)			$ 0		$ 863
Ending Balance, Shares, Contingently Redeemable Preferred Units at Dec. 31, 2020											0				1,167,418
Ending Balance, Value, Contingently Redeemable Preferred Units at Dec. 31, 2020		54,105,000									$ 0				$ 54,105,000
Ending Balance, Value at Dec. 31, 2020		36,019,000					(14,232,000)			(68,000)						$ 35,869,000	$ 14,450,000
Ending Balance, Shares at Dec. 31, 2020																5,480,611	2,242,981
Shareholders' equity beginning balance (in shares) at Dec. 06, 2020													0
Shareholders' equity beginning balance at Dec. 06, 2020			0		0			0					$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class B ordinary shares to Sponsor	[1]		25,000		24,137								$ 863
Issuance of Class B ordinary shares to Sponsor , Shares	[1]												8,625,000
Net income (loss)			(5,000)		0			(5,000)					$ 0
Shareholders' equity ending balance (in shares) at Dec. 31, 2020											0		8,625,000
Shareholders' equity ending balance at Dec. 31, 2020			20,000		24,137			(5,000)			$ 0		$ 863
Ending Balance, Shares, Contingently Redeemable Preferred Units at Dec. 31, 2020											0				1,167,418
Ending Balance, Value, Contingently Redeemable Preferred Units at Dec. 31, 2020		54,105,000									$ 0				$ 54,105,000
Ending Balance, Value at Dec. 31, 2020		36,019,000					(14,232,000)			(68,000)						$ 35,869,000	$ 14,450,000
Ending Balance, Shares at Dec. 31, 2020																5,480,611	2,242,981
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion Of Temporary Equity To Redmeption Value			(31,669,403)		(24,137)			(31,645,266)
Net income (loss)			(15,725,653)					(15,725,653)
Shareholders' equity ending balance (in shares) at Mar. 31, 2021												0		8,625,000
Shareholders' equity ending balance at Mar. 31, 2021			(47,375,056)	$ (47,375,056)					$ (47,375,919)			$ 0		$ 863
Ending Balance, Value, Contingently Redeemable Preferred Units at Mar. 31, 2021			345,000,000
Shareholders' equity beginning balance (in shares) at Dec. 31, 2020											0		8,625,000
Shareholders' equity beginning balance at Dec. 31, 2020			20,000		24,137			(5,000)			$ 0		$ 863
Opening Balance, Shares, Contingently Redeemable Preferred Units at Dec. 31, 2020											0				1,167,418
Opening Balance, Value, Contingently Redeemable Preferred Units at Dec. 31, 2020		54,105,000									$ 0				$ 54,105,000
Opening Balance, Shares at Dec. 31, 2020																5,480,611	2,242,981
Opening Balance, Value at Dec. 31, 2020		36,019,000					(14,232,000)			(68,000)						$ 35,869,000	$ 14,450,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation, Values		31,000															31,000
Net income (loss)		(8,058,000)	755,552				(8,058,000)
Foreign currency translation adjustment		96,000								96,000
Shareholders' equity ending balance (in shares) at Sep. 30, 2021											0		8,625,000
Shareholders' equity ending balance at Sep. 30, 2021			(30,893,851)		0			(30,894,714)			$ 0		$ 863
Ending Balance, Shares, Contingently Redeemable Preferred Units at Sep. 30, 2021											34,500,000				1,167,418
Ending Balance, Value, Contingently Redeemable Preferred Units at Sep. 30, 2021		54,105,000	345,000,000								$ 345,000,000				$ 54,105,000
Ending Balance, Value at Sep. 30, 2021		28,088,000					(22,290,000)			28,000						$ 35,869,000	$ 14,481,000
Ending Balance, Shares at Sep. 30, 2021																5,480,611	2,242,981
Shareholders' equity beginning balance (in shares) at Mar. 31, 2021												0		8,625,000
Shareholders' equity beginning balance at Mar. 31, 2021			(47,375,056)	(47,375,056)					(47,375,919)			$ 0		$ 863
Opening Balance, Value, Contingently Redeemable Preferred Units at Mar. 31, 2021			345,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			13,878,688					13,878,688
Shareholders' equity ending balance (in shares) at Jun. 30, 2021												0		8,625,000
Shareholders' equity ending balance at Jun. 30, 2021			(33,496,368)	$ (33,496,368)		$ 0			$ (33,497,231)			$ 0		$ 863
Ending Balance, Value, Contingently Redeemable Preferred Units at Jun. 30, 2021			345,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)			2,602,517					2,602,517
Shareholders' equity ending balance (in shares) at Sep. 30, 2021											0		8,625,000
Shareholders' equity ending balance at Sep. 30, 2021			(30,893,851)		$ 0			$ (30,894,714)			$ 0		$ 863
Ending Balance, Shares, Contingently Redeemable Preferred Units at Sep. 30, 2021											34,500,000				1,167,418
Ending Balance, Value, Contingently Redeemable Preferred Units at Sep. 30, 2021		54,105,000	$ 345,000,000								$ 345,000,000				$ 54,105,000
Ending Balance, Value at Sep. 30, 2021		$ 28,088,000					$ (22,290,000)			$ 28,000						$ 35,869,000	$ 14,481,000
Ending Balance, Shares at Sep. 30, 2021																5,480,611	2,242,981
[1]	Includes an aggregate of up to 1,125,000 shares of Class B ordinary shares subject to forfeiture if the over-allotment option is not exercised in full or in part by the underwriters (see Note 5).

CONDENSED STATEMENTS OF CHANG_2

CONDENSED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical)	Dec. 31, 2020shares
Class B common stock | ALTIMAR ACQUISITION CORP. II [Member]
Common stock shares subject to forfeiture	1,125,000

CONDENSED STATEMENT OF CASH FLO

CONDENSED STATEMENT OF CASH FLOWS - USD ($)	1 Months Ended	9 Months Ended		12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net income (loss)		$ (8,058,000)	$ (1,105,000)	$ (7,963,000)	$ (4,771,000)
Adjustments to reconcile net income (loss) to net cash used in operating activities
Depreciation included in operating expenses		2,110,000	105,000	598,000	135,000
Depreciation and amortization included in cost of revenue		2,679,000	2,196,000	2,567,000	1,054,000
Amortization of intangible assets		7,217,000	2,692,000	4,227,000	1,470,000
Loss (gain) on disposal of property and equipment		84,000	(393,000)	214,000	0
Loss on extinguishment of debt		2,031,000	0
Gain on PPP forgiveness		(1,624,000)	0
Foreign currency translation adjustment		96,000	6,000	(68,000)	0
Bad debt expense		239,000	49,000	223,000	48,000
Share-based compensation		31,000	22,000	34,000	21,000
Change in fair value of contingent consideration		(1,120,000)	0	1,055,000	1,181,000
Amortization of debt financing costs		1,342,000	153,000	205,000	56,000
Changes in operating assets and liabilities
Accounts receivable		(4,772,000)	852,000	1,063,000	(4,061,000)
Inventory		(551,000)	(172,000)	(356,000)	216,000
Prepaid expenses and other assets		(26,000)	(341,000)	(653,000)	1,409,000
Accounts payable		866,000	(1,716,000)	442,000	1,886,000
Accrued liabilities and other		1,193,000	441,000	282,000	765,000
Net cash used in operating activities		1,737,000	2,789,000	1,870,000	(591,000)
Cash flows from investing activities
Purchase of property and equipment		(6,648,000)	(701,000)	(1,626,000)	(729,000)
Cash used for acquisitions, net of cash acquired		(67,428,000)	(40,992,000)	(94,412,000)	(43,639,000)
Net cash used in investing activities		(74,076,000)	(41,693,000)	(96,038,000)	(44,368,000)
Cash flows from financing activities
Proceeds from debt		183,500,000	22,732,000	65,124,000	16,000,000
Payments on debt		(104,091,000)	0	(1,679,000)	(195,000)
Distributions to unitholders				0	(128,000)
Payment of debt issuance costs		(1,743,000)	0	(1,207,000)	(461,000)
Proceeds from issuance of members' units		0	21,603,000	40,445,000	32,050,000
Cash paid for contingent consideration		(2,984,000)	0	(1,353,000)	(3,500,000)
Net cash provided by financing activities		74,682,000	44,335,000	101,330,000	43,766,000
Net change in cash		2,343,000	5,431,000	7,162,000	(1,193,000)
Cash — beginning of period		8,188,000	1,026,000	1,026,000	2,219,000
Cash — end of period	$ 8,188,000	10,531,000	6,457,000	8,188,000	1,026,000
Supplemental Cash Flows Information:
Cash paid for interest		5,154,000	2,008,000	3,491,000	1,441,000
Cash paid for taxes		62,000	0	11,000	40,000
Cash paid to related parties		8,254,000	5,165,000	6,879,000	1,419,000
Property and equipment noncash transactions		911,000	0
Significant noncash transactions:
Initial recognition of contingent consideration for acquisitions		1,295,000	8,696,000	11,737,000	0
Issuance of member interests for acquisitions		0	$ 21,603,000	2,941,000	$ 6,142,000
ALTIMAR ACQUISITION CORP. II [Member]
Cash flows from operating activities
Net income (loss)	(5,000)	755,552
Adjustments to reconcile net income (loss) to net cash used in operating activities
Payment of formation and operating costs through issuance of Class B ordinary shares	5,000
Interest income on investments held in the Trust Account		(11,697)
Transaction costs allocated to the Warrants		755,071
Change in fair value of Warrant liability		(3,190,546)
Changes in operating assets and liabilities
Prepaid expenses		(744,813)
Accrued expenses		259,896
Net cash used in operating activities	0	(2,176,537)
Cash flows from investing activities
Investment of cash in the Trust Account		(345,000,000)
Net cash used in investing activities		(345,000,000)
Cash flows from financing activities
Proceeds from sale of the Units, net of underwriting discounts paid		338,100,000
Proceeds from sale of the Private Placement Warrants		9,900,000
Repayment of the Promissory Note — related party		(94,890)
Payment of offering costs		(397,461)
Net cash provided by financing activities		347,507,649
Net change in cash	0	331,112
Cash — beginning of period	0	0
Cash — end of period	0	331,112		0
Non-cash investing and financing activities
Offering costs included in accrued offering costs	50,000	3,607
Offering costs paid through the Promissory Note	5,000	89,890
Deferred underwriting fee payable	0	$ 12,075,000		$ 0
Deferred offering costs paid by Sponsor in exchange for the issuance of Class B ordinary shares	$ 20,000

Nature of Business

Nature of Business	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
Nature of Business		Note 1 — Nature of Business Fathom Holdco, LLC (the “Company”) was formed on April 16, 2021 as a limited liability company in accordance with the provisions of the Delaware Limited Liability Company Act, as amended (the “Delaware 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”). For purposes of this report, “Fathom Holdco,” the “Company,” “we,” “our,” “us,” or similar references mean Fathom Holdco, LLC and our consolidated subsidiaries unless the context requires otherwise. On April 30, 2021, the Company completed a common control reorganization (the “Reorganization”) whereby the interests in both MCT Holdings and Incodema Holdings were contributed to the Company. Prior to and subsequent to the Reorganization, MCT Holdings, Incodema Holdings, and the Company were each, directly or indirectly, under the common control of CORE Industrial Partners Fund I, L.P. (“CORE”) As such, after the completion of the Reorganization, the historical financial statements of the Company were retrospectively updated in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) guidance for common control transactions. The Company and its subsidiaries offer prototyping and low-volume in-house mid-volume Going Concern In accordance with U.S. GAAP, the Company is required to evaluate whether there are conditions or events that exist as of the date of issuance of these Unaudited Condensed Consolidated Financial Statements that raise doubt as to the Company’s ability to continue as a going concern within the twelve months following issuance. On April 30, 2021, the Company completed a financing transaction whereby it issued a $172,000 term loan due April 2022 (the “2021 Term Loan”) in order to finance the acquisitions of Centex Machine and Welding, Inc. (“Centex”), Laser Manufacturing, Inc. (“Laser”), Sureshot Precision, LLC d/b/a Micropulse West (“Micropulse West”), and Precision Process Corporation (“PPC”), as well as to refinance the Company’s existing debt, as described in Note 8. As the Company does not have sufficient cash on hand and cash flow from operations to repay the 2021 Term Loan, the maturity of the 2021 Term Loan raises substantial doubt about our ability to continue as a going concern within the next twelve months. If we are unable to repay, refinance or restructure our 2021 Term Loan, our assets may not be sufficient to repay in full the amounts owed. To address the upcoming maturity of the 2021 Term Loan, the Company has entered into a new credit facility with its existing creditors (the “New Credit Agreement”). The New Credit Agreement includes a $50,000 revolving credit facility and $125,000 term loan and matures in 2026. The proceeds from these loans will be used to repay the April 2021 Term Loan. The funding of the New Credit Agreement is contingent on the Company closing a definitive business combination with a publicly traded Special Purpose Acquisition Company (“SPAC”) before April 9, 2022 (the “SPAC Transaction”). In addition, the cash proceeds of such SPAC Transaction must be in excess of $313,000, or a lesser amount if mutually agreed by the Company and the SPAC. The Company intends to use the proceeds from the New Credit Agreement to repay the April 2021 Term Loan. If the SPAC Transaction is not completed prior to April 9, 2022, the Company will not receive any funds nor incur any indebtedness from the New Credit Agreement. Given the SPAC Transaction will be subject to regulatory and market conditions, approval by a SPAC’s shareholders, and the SPAC securing adequate financing, it is not within the Company’s control and therefore cannot be deemed probable as of the issuance of these unaudited condensed consolidated financial statements. As a result, the Company has concluded that management’s plans described above do not alleviate substantial doubt about the Company’s ability to continue as a going concern for the next twelve months. The accompanying unaudited condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business. Announcement of the SPAC Transaction On July 16, 2021, the Company and Altimar Acquisition Corp. II (NYSE:ATMR)(“Altimar”), a special purpose acquisition company, announced that they have entered into a definitive business combination agreement (the “Business Combination Agreement”) pursuant to which the Company and Altimar will combine, and after which the combined company will become a publicly-traded company. Upon completion of the transaction, the combined company expects to be listed on the New York Stock Exchange. As discussed further in Note 15, on November 16, 2021, Altimar and the Company executed amendment No. 1 to the Business Combination Agreement (the “Amendment No. 1 to the Business Combination Agreement”) that amended certain terms of the business combination agreement executed on July 16, 2021. Amendment No.1 to the Business Combination Agreement does not alter the fact that, upon closing of the transaction, the combined company, to be name Fathom Digital Manufacturing Company, will become a publicly traded company that is listed on the New York Stock Exchange. New Credit Agreement On July 9, 2021, the Company entered into a financing transaction, which included a $50,000 revolving credit facility and $125,000 term loan, which will be funded at a later date assuming certain subsequent conditions are met including the closing of the SPAC Transaction noted above. See Going concern section of Note 1 and Note 15 for additional information.	Note 1 — Nature of Business Fathom Holdco, LLC (the “Company”) was formed on April 16, 2021 as a limited liability company in accordance with the provisions of the Delaware Limited Liability Company Act, as amended (the “Delaware 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”). As of December 31, 2020, both MCT Holdings and Incodema Holdings were under the common control of CORE Industrial Partners Fund I, L.P. (“CORE”). MCT Holdings was formed on August 27, 2018 as a limited liability company in accordance with the Delaware Act for the purpose of holding 100 percent of the equity interest in Midwest Composite Technologies, LLC, acquired on August 31, 2018, acquiring 100 percent of the equity interest in Kemeera, LLC d/b/a FATHOM (“FATHOM”) on September 23, 2019, and acquiring 100 percent of the equity interest in ICO Mold, LLC on December 2, 2019, as further described in Note 3. Incodema Holdings was formed on July 15, 2020 as a limited liability company in accordance with the Delaware Act for the purpose of acquiring 100 percent of the equity interest in Incodema, LLC and Newchem, LLC on July 27, 2020, acquiring Dahlquist Machine, LLC on December 15, 2020, acquiring Majestic Metals, LLC on December 17, 2020 and acquiring Mark Two Engineering, LLC on December 18, 2020, as further described in Note 3. On April 30, 2021, CORE completed a reorganization whereby the interests in both MCT Holdings and Incodema Holdings were contributed to the Company. As such, the Company determined that the financial statements being presented should be the consolidated financial statements of the Company, inclusive of its wholly owned subsidiaries MCT Holdings and Incodema Holdings, with Incodema Holdings being reflected in the consolidated financial statements effective as of July 27, 2020, or the date it came under common control with MCT Holdings. Accordingly, the contingently redeemable Series A Preferred Units, members’ equity, and earnings per unit of the Company is retrospectively presented on a consolidated basis in these consolidated financial statements The Company and its subsidiaries offer prototyping and low-volume in-house mid-volume Going Concern In accordance with U.S. GAAP, the Company is required to evaluate whether there are conditions or events that exist as of the date of issuance of these consolidated financial statements that raise doubt as to the Company’s ability to continue as a going concern within the twelve months following issuance. On April 30, 2021, the Company completed a financing transaction whereby it issued a $172,000 term loan due April 2022 (the “2021 Term Loan”) in order to finance the acquisitions of Centex Machine and Welding, Inc. (“Centex”), Laser Manufacturing, Inc. (“Laser”), Sureshot Precision, LLC d/b/a Micropulse West (“Micropule West”), and Precision Process Corporation (“PPC”), as well as to refinance the Company’s existing debt, as described in Note 8. As the Company does not have sufficient cash on hand and cash flow from operations to repay the 2021 Term Loan, the maturity of the 2021 Term Loan raises substantial doubt about our ability to continue as a going concern within the next twelve months. If we are unable to repay, refinance or restructure our 2021 Term Loan, our assets may not be sufficient to repay in full the amounts owed. To address the upcoming maturity of the 2021 Term Loan, the Company has entered into a new credit facility with its existing creditors (the “New Credit Agreement”). The New Credit Agreement includes a $50,000 revolving credit facility and $125,000 term loan and matures in 2026. The proceeds from these loans will be used to repay the 2021 Term Loan. The funding of the New Credit Agreement is contingent on the Company closing a definitive business combination with a publicly traded Special Purpose Acquisition Company (“SPAC”) before April 9, 2022 (the “SPAC Transaction”). In addition, the cash proceeds of such SPAC Transaction must be in excess of $313,000, or a lesser amount if mutually agreed by the Company and the SPAC. The Company intends to use the proceeds from the New Credit Agreement to repay the 2021 Term Loan. If the SPAC Transaction is not completed prior to April 9, 2022, the Company will not receive any funds nor incur any indebtedness from the New Credit Agreement. Given the SPAC Transaction will be subject to regulatory and market conditions, approval by a SPAC’s shareholders, and the SPAC securing adequate financing, it is not within the Company’s control and therefore cannot be deemed probable as of the issuance of these consolidated financial statements. As a result, the Company has concluded that management’s plans described above do not alleviate substantial doubt about the Company’s ability to continue as a going concern for the next twelve months. The accompanying financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.
ALTIMAR ACQUISITION CORP. II [Member]
Nature of Business	Note 1 — Organization and Plan of Business Operations Altimar Acquisition Corp. II (the “Company”) is a blank check company incorporated as a Cayman Islands exempted company on December 7, 2020. The Company was incorporated for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses or entities (a “Business Combination”). The Company is not limited to a particular industry or sector for purposes of consummating a Business Combination. The Company is an early stage and emerging growth company and, as such, the Company is subject to all of the risks associated with early stage and emerging growth companies. As of December 31, 2020, the Company had not commenced any operations. All activity for the period from December 7, 2020 (inception) through December 31, 2020 relates to the Company’s formation and the proposed initial public offering (“Proposed Public Offering”), which is described below. The Company will not generate any operating revenues until after the completion of a Business Combination, at the earliest. The Company will generate non-operating The Company’s ability to commence operations is contingent upon obtaining adequate financial resources through a Proposed Public Offering of 30,000,000 units (the “Units” and, with respect to the Class A ordinary shares included in the Units being offered, the “Public Shares”) at $10.00 per Unit (or 34,500,000 Units if the underwriters’ over-allotment option is exercised in full), which is discussed in Note 3, and the sale of 9,000,000 Warrants Warrants The Company’s management has broad discretion with respect to the specific application of the net proceeds of the Proposed Public Offering and the sale of the Private Placement Warrants, although substantially all of the net proceeds are intended to be applied generally toward consummating a Business Combination. The stock exchange listing rules require that the Business Combination must be with one or more operating businesses or assets with a fair market value equal to at least 80% of the assets held in the Trust Account (as defined below) (excluding the amount of deferred underwriting commissions and taxes payable on the income earned on the Trust Account). The Company will only complete a Business Combination if the post-Business Combination company owns or acquires 50% or more of the issued and outstanding voting securities of the target or otherwise acquires a controlling interest in the target business sufficient for it not to be required to register as an investment company under the Investment Company Act of 1940, as amended (the “Investment Company Act”). There is no assurance that the Company will be able to successfully effect a Business Combination. Upon the closing of the Proposed Public Offering, management has agreed that $10.00 per Unit sold in the Proposed Public Offering, including proceeds of the sale of the Private Placement Warrants, will be held in a trust account (the “Trust Account”) and invested in U.S. government securities, within the meaning set forth in Section 2(a)(16) of the Investment Company Act, with a maturity of 185 days or less, or in any open-ended investment company that holds itself out as a money market fund investing solely in U.S. Treasuries and meeting certain conditions under Rule 2a-7 The Company will provide the Selling Stockholders of the public shares (the “Public Shareholders”) with the opportunity to redeem all or a portion of their public shares either (i) in connection with a general meeting called to approve the Business Combination or (ii) by means of a tender offer. The decision as to whether the Company will seek shareholder approval of a Business Combination or conduct a tender offer will be made by the Company, solely in its discretion. The Public Shareholders will be entitled to redeem their Public Shares, equal to the aggregate amount then on deposit in the Trust Account, calculated as of two business days prior to the consummation of the Business Combination (initially anticipated to be $10.00 per Public Share), including interest (which interest shall be net of taxes payable), divided by the number of then issued and outstanding public shares, subject to certain limitations as described in the prospectus. The per-shar e The Company will not redeem Public Shares in an amount that would cause its net tangible assets to be less than $5,000,001 (so that it does not then become subject to the SEC’s “penny stock” rules) or any greater net tangible asset or cash requirement that may be contained in the agreement relating to the Business Combination. If the Company seeks shareholder approval of the Business Combination, the Company will proceed with a Business Combination only if the Company receives an ordinary resolution under Cayman Islands law approving a Business Combination, which requires the affirmative vote of a majority of the shareholders who attend and vote at a general meeting of the Company, or such other vote as required by law or stock exchange rule. If a shareholder vote is not required and the Company does not decide to hold a shareholder vote for business or other legal reasons, the Company will, pursuant to its Amended and Restated Memorandum and Articles of Association, conduct the redemptions pursuant to the tender offer rules of the Securities and Exchange Commission (the “SEC”), and file tender offer documents containing substantially the same information as would be included in a proxy statement with the SEC prior to completing a Business Combination. If the Company seeks shareholder approval in connection with a Business Combination, the Sponsor has agreed to vote its Founder Shares (as defined in Note 5) and any Public Shares purchased during or after the Proposed Public Offering in favor of approving a Business Combination. Additionally, each Public Shareholder may elect to redeem their Public Shares, without voting, and if they do vote, irrespective of whether they vote for or against a proposed Business Combination. Notwithstanding the foregoing, if the Company seeks shareholder approval of the Business Combination and the Company does not conduct redemptions pursuant to the tender offer rules, a Public Shareholder, together with any affiliate of such shareholder or any other person with whom such shareholder is acting in concert or as a “group” (as defined under Section 13 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), will be restricted from redeeming its shares with respect to more than an aggregate of 15% of the Public Shares without the Company’s prior written consent. The Sponsor has agreed (a) to waive its redemption rights with respect to any Founder Shares and Public Shares held by it in connection with the completion of a Business Combination and (b) not to propose an amendment to the Amended and Restated Memorandum and Articles of Association (i) to modify the substance or timing of the Company’s obligation to allow redemption in connection with the Company’s initial Business Combination or to redeem 100% of the Public Shares if the Company does not complete a Business Combination within the Combination Period (as defined below) or (ii) with respect to any other provision relating to shareholders’ rights or pre-initial per-share The Company will have until 24 months from the closing of the Proposed Public Offering to consummate a Business Combination (the “Combination Period”). However, if the Company has not completed a Business Combination within the Combination Period, the Company will (i) cease all operations except for the purpose of winding up, (ii) as promptly as reasonably possible but not more than ten business days thereafter, redeem 100% of the Public Shares, at a per-share Warrants The Sponsor has agreed to waive its rights to liquidating distributions from the Trust Account with respect to the Founder Shares it will receive if the Company fails to complete a Business Combination within the Combination Period. However, if the Sponsor or any of its respective affiliates acquire Public Shares, such Public Shares will be entitled to liquidating distributions from the Trust Account if the Company fails to complete a Business Combination within the Combination Period. The underwriters have agreed to waive their rights to their deferred underwriting commission (see Note 6) held in the Trust Account in the event the Company does not complete a Business Combination within the Combination Period, and in such event, such amounts will be included with the other funds held in the Trust Account that will be available to fund the redemption of the Public Shares. In the event of such distribution, it is possible that the per share value of the assets remaining available for distribution will be less than the Proposed Public Offering price per Unit ($10.00). In order to protect the amounts held in the Trust Account, the Sponsor has agreed that it will be liable to the Company if and to the extent any claims by a third party (other than the Company’s independent registered public accounting firm) for services rendered or products sold to the Company, or a prospective target business with which the Company has discussed entering into a transaction agreement, reduce the amount of funds in the Trust Account to below the lesser of (1) $10.00 per Public Share and (2) the actual amount per Public Share held in the Trust Account as of the date of the liquidation of the Trust Account, if less than $10.00 per Public Share, due to reductions in the value of trust assets, in each case net of the interest that may be withdrawn to pay taxes. This liability will not apply to any claims by a third party who executed a waiver of any and all rights to seek access to the Trust Account and as to any claims under the Company’s indemnity of the underwriters of the Proposed Public Offering against certain liabilities, including liabilities under the Securities Act of 1933, as amended (the “Securities Act”). In the event that an executed waiver is deemed to be unenforceable against a third party, the Sponsor will not be responsible to the extent of any liability for such third-party claims. The Company will seek to reduce the possibility that the Sponsor will have to indemnify the Trust Account due to claims of creditors by endeavoring to have all vendors, service providers (other than the Company’s independent registered public accounting firm), prospective target businesses or other entities with which the Company does business, execute agreements with the Company waiving any right, title, interest or claim of any kind in or to monies held in the Trust Account.	NOTE 1. DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS Altimar Acquisition Corp. II (the “ Company Business Combination As of September 30, 2021, the Company had not commenced any operations. All activity for the period from December 7, 2020 (inception) through September 30, 2021 relates to the Company’s formation, the Company’s initial public offering (the “ Initial Public Offering non-operating The Registration Statement on Form S-1 No. 333-252260) Registration Statement Units Warrants Public Shares Public Warrants Simultaneously with the closing of the Initial Public Offering, the Company consummated the sale of 9,900,000 Warrants Private Placement Warrants Warrants Sponsor Transaction costs amounted to $19,490,958, consisting of $6,900,000 of underwriting fees, $12,075,000 of deferred underwriting fees (see Note 6) and $515,958 of other offering costs. $755,071 of the transaction costs was expensed through the condensed statement of operation on the date of the Initial Public Offering. The remaining transaction costs were charged to equity. Following the closing of the Initial Public Offering on February 9, 2021, an amount of $345,000,000 ($10.00 per Unit) from the net proceeds of the sale of the Units in the Initial Public Offering and the sale of the Private Placement Warrants was placed in a trust account (the “ Trust Account Investment Company Act Rule 2a-7 The Company’s management has broad discretion with respect to the specific application of the net proceeds of the Initial Public Offering and the sale of the Private Placement Warrants, although substantially all of the net proceeds are intended to be applied generally toward consummating a Business Combination. The New York Stock Exchange listing rules require that the Business Combination must be with one or more operating businesses or assets with a fair market value equal to at least The Company will provide the Selling Stockholders of the Public Shares Public Shareholders per-Public The Company will not redeem Public Shares in an amount that would cause its net tangible assets to be less than $5,000,001 (so that it does not then become subject to the U.S. Securities and Exchange Commission’s (the “ SEC Amended and Restated Memorandum and Articles of Association Notwithstanding the foregoing, if the Company seeks shareholder approval of the Business Combination and the Company does not conduct redemptions pursuant to the tender offer rules, a Public Shareholder, together with any affiliate of such Public Shareholder or any other person with whom such Public Shareholder is acting in concert or as a “group” (as defined under Section 13 of the Securities Exchange Act of 1934, as amended (the “ Exchange Act % of the Public Shares without the Company’s prior written consent. Each of the Sponsor and the Company’s executive officers and directors have agreed (a) to waive its redemption rights with respect to any Founder Shares and Public Shares held by it in connection with a Business Combination and (b) not to propose an amendment to the Amended and Restated Memorandum and Articles of Association (i) to modify the substance or timing of the Company’s obligation to allow redemption in connection with an initial Business Combination or to redeem 100% of the Public Shares if the Company does not complete a Business Combination prior to February 9, 2023 (the “ Combination Period pre-initial per-Public The Company will have until February 9, 2023 to consummate a Business Combination. However, if the Company has not completed a Business Combination within the Combination Period, the Company will (i) cease all operations except for the purpose of winding up, (ii) as promptly as reasonably possible but not more than ten per-share The Sponsor has agreed to waive its rights to liquidating distributions from the Trust Account with respect to the Founder Shares held by the Sponsor if the Company fails to complete a Business Combination within the Combination Period. However, if the Sponsor or any of its affiliates acquires Public Shares, such Public Shares will be entitled to liquidating distributions from the Trust Account if the Company fails to complete a Business Combination within the Combination Period. The underwriters have agreed to waive their rights to their deferred underwriting commission (see Note 6) held in the Trust Account in the event the Company fails to complete a Business Combination within the Combination Period and, in such event, such amounts will be included with the other funds held in the Trust Account that will be available to fund the redemption of the Public Shares. In the event of such distribution, it is possible that the per share value of the assets remaining available for distribution will be less than the offering price per Unit ($10.00). In order to protect the amounts held in the Trust Account, the Sponsor has agreed that it will be liable to the Company if and to the extent any claims by a third party (other than the Company’s independent registered public accounting firm) for services rendered or products sold to the Company, or a prospective target business with which the Company has discussed entering into a transaction agreement, reduce the amount of funds in the Trust Account to below the lesser of (1) $10.00 per Public Share and (2) the actual amount per Public Share held in the Trust Account as of the date of the liquidation of the Trust Account, if less than $10.00 per Public Share, due to reductions in the value of trust assets, in each case, net of the interest that may be withdrawn to pay taxes. This liability will not apply to any claims by a third party that executed a waiver of any and all rights to seek access to the Trust Account and as to any claims under the Company’s indemnity of the underwriters in the Initial Public Offering against certain liabilities, including liabilities under the Securities Act of 1933, as amended (the “ Securities Act

Restatement of Previously Issue

Restatement of Previously Issued Financial Statements	9 Months Ended
	Sep. 30, 2021
ALTIMAR ACQUISITION CORP. II [Member]
RESTATEMENT OF PREVIOUSLY ISSUED FINANCIAL STATEMENTS	NOTE 1A. RESTATEMENT OF PREVIOUSLY ISSUED FINANCIAL STATEMENTS In connection with the preparation of the Company’s unaudited interim condensed financial statements as of September 30, 2021, management determined it should restate its previously reported unaudited interim condensed financial statements. The Company had previously determined the Class A Ordinary Shares subject to possible redemption to be equal to the redemption value of per Class A Ordinary Shares while also taking into consideration a redemption cannot result in net tangible assets being less than Management has also determined that the Class A Ordinary Shares issued in connection with the Initial Public Offering can be redeemed or become redeemable subject to the occurrence of future events considered outside the Company’s control. Therefore, management has concluded that the redemption value should include all the Class A Ordinary Shares subject to possible redemption, resulting in the Class A Ordinary Shares subject to possible redemption being equal to their redemption value. In connection with the change in presentation for the Class A Ordinary Shares subject to possible redemption, the Company also restated its earnings per share calculation to allocate net income (loss) pro rata to Class A and Class B Ordinary Shares. The presentation contemplates a Business Combination as the most likely outcome, in which case, both the Class A Ordinary Shares and the Class B Ordinary Shares share pro rata in the income (loss) of the Company. In accordance with SEC Staff Accounting Bulletin No. 99, “Materiality,” and SEC Staff Accounting Bulletin No. 108, “Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements,” the Company evaluated the changes and has determined that the related impact was material to the previously filed financial statements that contained the error, reported in the Company’s Form 10-Qs 8-K There has been no change in the Company’s total assets, liabilities or operating results. The impact of the restatement on the Company’s previously issued financial statements is reflected in the following tables . The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported audited balance sheet as of February 9, 2021: As Previously Adjustment As Revised Balance Sheet as of February 9, 2021 (audited) Class A Ordinary Shares subject to possible redemption $ 300,351,190 $ 44,648,810 $ 345,000,000 Class A Ordinary Shares 446 (446 ) — Additional paid-in 13,003,096 (13,003,096 ) — Accumulated deficit (8,004,403 ) (31,645,268 ) (39,649,671 ) Total shareholders’ equity (deficit) 5,000,002 (44,648,810 ) (39,648,808 ) The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported unaudited balance sheet as of March 31, 2021: As Previously Adjustment As Revised Balance Sheet as of March 31, 2021 (unaudited) Class A Ordinary Shares subject to possible redemption $ 292,624,940 $ 52,375,060 $ 345,000,000 Class A Ordinary Shares 524 (524 ) — Additional paid-in 20,729,270 (20,729,270 ) — Accumulated deficit (15,730,653 ) (31,645,266 ) (47,375,919 ) Total shareholders’ equity (deficit) 5,000,004 (52,375,060 ) (47,375,056 ) The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported unaudited statement of cash flows for the three months ended March 31, 2021: As Previously Reported Adjustment As Revised Three Months ended March 31, 2021 (unaudited) Non-cash Initial classification of Class A Ordinary Shares subject to possible redemption 300,351,190 (300,351,190 ) — Change in value of Class A Ordinary Shares subject to possible redemption (7,726,250 ) 7,726,250 — The table below presents the eff e As Previously Adjustment As Revised Balance Sheet as of June 30, 2021 (unaudited) Class A Ordinary Shares subject to possible redemption $ 306,503,630 $ 38,496,370 $ 345,000,000 Class A Ordinary Shares 385 (385 ) — Additional paid-in 6,850,719 (6,850,719 ) — Accumulated deficit (1,851,965 ) (31,645,266 ) (33,497,231 ) Total shareholders’ equity (deficit) 5,000,002 (38,496,370 ) (33,496,368 ) The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported unaudited statement of cash flows for the six months ended June 30, 2021: As Previously Adjustment As Revised Six Months ended June 30, 2021 (unaudited) Non-cash Initial classification of Class A Ordinary Shares subject to possible redemption 300,351,192 (300,351,192 ) — Change in value of Class A Ordinary Shares subject to possible redemption 6,152,436 (6,152,436 ) — The impact to the reported amounts of w e Net Income (Loss) Per Share As Previously Adjustment As Revised Three Months Ended March 31, 2021 (unaudited) Weighted average shares outstanding — Class A Ordinary Shares 34,500,000 (14,950,000 ) 19,550,000 Basic and diluted net income (loss) per share — Class A Ordinary Shares $ — $ (0.57 ) $ (0.57 ) Weighted average shares outstanding — Class B Ordinary Shares 8,125,000 — 8,125,000 Basic and diluted net income (loss) per share — Class B Ordinary Shares $ (1.94 ) $ 1.37 $ (0.57 ) Net Income (Loss) Per Share As Previously Adjustment As Revised Three Months Ended June 30, 2021 (unaudited) Weighted average shares outstanding — Class A Ordinary Shares 34,500,000 — 34,500,000 Basic and diluted net income (loss) per share — Class A Ordinary Shares $ — $ 0.32 $ 0.32 Weighted average shares outstanding — Class B Ordinary Shares 8,625,000 — 8,625,000 Basic and diluted net income (loss) per share — Class B Ordinary Shares $ 1.61 $ (1.29 ) $ 0.32 Net Income (Loss) Per Share As Previously Adjustment As Revised Six Months Ended June 30, 2021 (unaudited) Weighted average shares outstanding — Class A Ordinary Shares 34,500,000 (7,433,702 ) 27,066,298 Basic and diluted net income (loss) per share — Class A Ordinary Shares $ — $ (0.05 ) $ (0.05 ) Weighted average shares outstanding — Class B Ordinary Shares 8,376,381 — 8,376,381 Basic and diluted net income (loss) per share — Class B Ordinary Shares $ (0.22 ) $ 0.17 $ (0.05 )

Summary of Significant Accounti

Summary of Significant Accounting Policies	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES		Note 2 — Significant Accounting Policies Basis of Presentation These Unaudited Condensed Consolidated Financial Statements of the Company are comprised of the Company’s subsidiaries from the date on which they were acquired. Each subsidiary is wholly owned by either MCT Holdings or Incodema Holdings, both of which are wholly owned by the Company. The Unaudited Condensed Consolidated Financial Statements have been prepared in conformity with U.S. GAAP pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. In the opinion of the Company, these Unaudited Condensed Consolidated Financial Statements contain all adjustments, consisting of only recurring adjustments, necessary for a fair representation of the Company’s financial position as of September 30, 2021, its results of operations for the nine months ended September 30, 2021 and September 30, 2020, and its cash flows for the nine months ended September 30, 2021 and September 30, 2020. The Unaudited Condensed Consolidated Balance Sheet as of December 31, 2020, included herein for comparative purposes, was derived from the Company’s audited consolidated balance sheet for the year ended December 31, 2020. These Unaudited Condensed Consolidated Financial Statements do not contain certain footnote disclosures that were included as part of the Company’s audited annual financial statements. As such, these Unaudited Condensed Consolidated Financial Statements should be read in conjunction with the Company’s audited annual financial statements for the years ended December 31, 2020 and 2019, which describes the Company’s significant accounting policies and includes all disclosures required by U.S. GAAP for annual reporting periods. Income Taxes The Company wholly owns Summit Tooling, Inc. (“Summit Tooling”), Centex, and Laser, which are treated as taxpaying C corporations in the U.S. Each of the Company’s taxpaying subsidiaries were acquired in 2021. Accordingly, the Company provides current and deferred taxes for these entities. The Company and its other subsidiaries are treated as flow-through entities for federal and state income tax purposes and are not subject to income tax as the LLC members are responsible for the tax consequences of each member’s proportionate share of the flow-through income or loss of the remaining Company operations. The Company’s flow-through operations are subject to certain state and local income and franchise taxes, which are included in the Consolidated Statements of Comprehensive Loss as other income, net. In addition, MCT Holdings’ wholly owned subsidiary, ICO Mold (Shenzhen), LLC, is subject to income tax within the jurisdiction of the People’s Republic of China. Foreign income tax expense was insignificant during both the nine months ended September 30, 2021 and September 30, 2020. As such, the Company’s tax provision pertains solely to the taxpaying C corporation subsidiaries. The Company’s taxable subsidiaries account for income taxes using the asset and liability method, under which deferred tax assets and liabilities are recognized for the future tax consequences of temporary differences between the book carrying values and the tax basis of the assets, liabilities, and tax attributes (e.g., NOLs) of the taxable subsidiaries. The Company is in a net deferred tax liability position which is classified as noncurrent on the Unaudited Condensed Consolidated Balance Sheet. The Company establishes a valuation allowance when necessary to reduce deferred tax assets to the amount that are more likely than not to be realized. The Company has evaluated the need for a valuation allowance and has determined that deferred tax assets are more likely than not to be realized. The Company evaluates tax positions taken or expected to be taken in a tax return for financial statement recognition. A tax position is recognized when it is more likely than not that the tax position will be sustained upon examination, including the resolution of appeals or litigation. The Company records the amount of benefits from tax positions taken that have a greater than 50% likelihood of being realized upon settlement with taxing authorities. Interest and penalties related to unrecognized tax benefits are recognized in the income tax benefits in the accompanying Unaudited Condensed Consolidated Statements of Comprehensive Loss. No interest and penalties were recognized for the periods presented. COVID-19 On March 11, 2020, the World Health Organization declared the outbreak of a respiratory disease caused by a new coronavirus as a “pandemic”. First identified in late 2019 and now known as COVID-19, year-end recent quarter-end; however, due to uncertainty surrounding the situation, and specifically as it pertains to	Note 2 — Significant Accounting Policies Basis of Presentation of the Consolidated Financial Statements The consolidated financial statements of the Company are comprised of the Company’s subsidiaries from the date on which they were acquired. Each subsidiary is wholly owned by either MCT Holdings or Incodema Holdings, both of which are wholly owned by the Company. The Company’s subsidiaries include: Midwest Composite Technologies, LLC (a Wisconsin Limited Liability Company); Kemeera LLC (a California Limited Liability Company); ICO Mold, LLC (a Delaware Limited Liability Company), Incodema, LLC (a New York Limited Liability Company); Newchem, LLC (a New York Limited Liability Company); Dahlquist Machine, LLC (a Minnesota Limited Liability Company); Majestic Metals, LLC (a Colorado Limited Liability Company); and Mark Two Engineering, LLC (a Florida Limited Liability Company). The Consolidated Financial Statements as of December 31, 2020 and 2019 have been prepared in accordance with accounting principles generally accepted in the United States of America. All material intercompany accounts and transactions have been eliminated in consolidation. COVID-19 On March 11, 2020, the World Health Organization declared the outbreak of a respiratory disease caused by a new coronavirus as a “pandemic”. First identified in late 2019 and now known as COVID-19, year-end; Correction of an Immaterial Error The Consolidated Balance Sheet as of December 31, 2020 includes the correction of an immaterial error related to contingent consideration. The correction relates to a reclassification of certain amounts between assets and liabilities comprised of a decrease in (short-term) contingent consideration of $8,726, a decrease to accounts receivable of $101, and decrease to other current assets of $144, a decrease to property and equipment, net of $418, a decrease to other non-current assets of $48, an increase to accounts payable of $253, an increase of $389 to other non-current liabilities, and an increase to long-term contingent consideration of $7,373. Cash and Cash Equivalents Cash and cash equivalents include cash and other short-term investments with original maturities of three months or less at the date of purchase. The Company maintains cash in bank deposit accounts which at times may exceed federally insured deposit limits. The Company has not experienced any losses on such accounts and considers such associated credit risk to be immaterial to the Company’s financial statements. Credit Risk, Major Customers, and Suppliers The Company extends trade credit to its customers on terms that are generally practiced in the industry. During the years ended December 31, 2020 and 2019, the Company did not have any customers that accounted for more than 10% of revenue. During the years ended December 31, 2020 and 2019, approximately 19% and 12%, respectively, of inventory purchases were from a single related party supplier, Fathom Precision International Ltd. See Note 15. Trade Accounts Receivable, Unbilled Revenue and Allowance for Doubtful Accounts Accounts receivable are stated at net invoice amounts. Unbilled revenue represents receivables due from customers as either the performance obligation has been completed for revenue recognized over time or the product has shipped and the customer invoice has yet to be generated. The balance in unbilled revenue, included in accounts receivable, was $173 and $634 as of December 31, 2020 and 2019, respectively. An allowance for doubtful accounts is established based on a specific assessment of all invoices that remain unpaid following normal customer payment periods. In addition, a general valuation allowance is established for the remaining accounts receivable that have not been specifically assessed based on historical loss experience as well as geographic and general economic conditions. All amounts deemed to be uncollectible are charged against the allowance for doubtful accounts in the period that determination is made. The allowance for doubtful accounts on accounts receivable balances was $649 as of December 31, 2020 and $386 as of December 31, 2019. Inventory Inventory is stated at the lower of cost or net realizable value (“NRV”), with NRV based on selling prices in first-in, first-out Property and Equipment Property and equipment are recorded at cost or fair value, if acquired in the business combinations, as described in Note 3. The straight-line method is used for computing depreciation and amortization. Assets are depreciated over their estimated useful lives. The cost of leasehold improvements are amortized over the lesser of the length of the related leases or the estimated useful lives of the assets. Costs of maintenance and repairs are charged to expense when incurred.​​​​​​​ Asset Useful Lives Property and leasehold Improvements 4-20 Machinery & equipment 1-6 Furniture & fixtures 1-7 Vehicles and equipment 1-4 Capitalized software 1-2 Goodwill The Company recognizes goodwill in accordance with ASC 350, Intangibles—Goodwill and Other. Intangible Assets Acquired intangible assets subject to amortization are stated at cost and are amortized using the straight-line method over the estimated useful lives of the assets. Intangible assets that are subject to amortization are reviewed for potential impairment whenever events or circumstances indicate that carrying amounts may not be recoverable. During 2019 and 2020 there were no impairments of intangible assets. Foreign Currency Exchange and Translation The expression of assets and liabilities in a foreign currency amount gives rise to exchange gains and losses when such obligations are paid in United States dollars. Foreign currency exchange rate adjustment (i.e., differences between amounts recorded and actual amounts owed or paid) are reported in the Consolidated Statements of Comprehensive Loss as foreign currency fluctuations occur. Foreign currency exchange rate adjustments are reported in the Consolidated Statements of Cash Flows using the exchange rates in effect at the time of the cash flows. Adjustments for the years ended December 31, 2020 and 2019 were immaterial. Assets and liabilities of the Company’s operations in China are translated into U.S. dollars at the rate of exchange in effect at the close of the period. Income and expenses are translated at an average rate of exchange for the period. The aggregate effect of translating the financial statements is included in other comprehensive loss. Fair Value Measurements Accounting standards require certain assets and liabilities be reported at fair value in the financial statements and provide a framework for establishing that fair value. The framework for determining fair value is based on a hierarchy that prioritizes the inputs and valuation techniques used to measure fair value. There are three levels of inputs that may be used to measure fair value: Fair values determined by Level 1 inputs use quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. Fair values determined by Level 2 inputs use other inputs that are observable, either directly or indirectly. These Level 2 inputs include quoted prices for similar assets and liabilities in active markets and other inputs such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs, including inputs that are available in situations where there is little, if any, market activity for the related asset. These Level 3 fair value measurements are based primarily on management’s own estimates using pricing models, discounted cash flow methodologies, or similar techniques considering the characteristics of the asset. 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. Debt Issuance Costs Debt issuance costs were incurred by the Company in connection with obtaining the debt to finance the acquisitions disclosed in Note 3. If such financing is settled or replaced prior to maturity with debt instruments that have substantially different terms, the settlement is treated as an extinguishment and the unamortized costs are charged to gain or loss on extinguishment of debt. If such financing is settled or replaced with debt instruments from the same lender that do not have substantially different terms, the new debt agreement is accounted for as a modification of the prior debt agreement and the unamortized costs remain capitalized, the new original issuance discount costs are capitalized, and any new third-party costs are charged to expense. These costs are recorded as a reduction in the recorded balance of the outstanding debt. The costs are amortized over the term of the related debt and reported as a component of interest expense by using the straight-line method which is not materially different than the effective interest method. Revenue Recognition On January 1, 2019, the Company adopted ASC 606, Revenue from Contracts with Customers point-in-time point-in-time Income Taxes As a limited liability company, the Company has elected to report as a partnership for federal and state income tax purposes at a consolidated level. Consequently, federal income taxes are not payable or provided for by the Company. Members are taxed individually on their pro-rata Other Comprehensive Loss Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income. Certain changes in assets and liabilities, however, such as foreign currency translation adjustments, are reported as a direct adjustment to the equity section of the Consolidated Balance Sheets. Such items, along with net income, are considered components of comprehensive loss. Use of Estimates The preparation of Consolidated Financial Statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Recent Accounting Pronouncements The Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases right-to-use right-to The FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326) 2016-13 The FASB issued ASU 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract, internal-use 350-40 2018-15 2018-15 The FASB issued ASU 2019-12, Income Taxes (Topic 740 ): Simplifying the Accounting for Income Taxes 2019-12 2019-12 step-up 2019-12 December 15, 2020, The FASB issued ASU 2020-04, Facilitating the effects of Reference Rate , which provide optional expedients and exceptions for applying generally accepted accounting principles (“GAAP”) to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this Update apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships entered into or evaluated after December , , except for hedging relationships existing as of December , , that an entity has elected certain optional expedients for and that are retained through the end of the hedging relationship. The amendments in this Update are effective for all entities as of March , through December , . The Company continues to evaluate the impact of the adoption of ASU 2020-04 will have on its Consolidated Financial Statements.
ALTIMAR ACQUISITION CORP. II [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Note 2 — Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the SEC. The Company does not have sufficient liquidity to meet its anticipated obligations over the next year from the date of issuance of these financial statements. In connection with the Company’s assessment of going concern considerations in accordance with Accounting Standards Update (“ASU”) 2014-15, Emerging Growth Company The Company is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), and it may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies including, but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended, reduced disclosure obligations regarding executive compensation in its periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and shareholder approval of any golden parachute payments not previously approved. Further, Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that a company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Making estimates requires management to exercise significant judgment. It is at least reasonably possible that the estimate of the effect of a condition, situation or set of circumstances that existed at the date of the financial statements, which management considered in formulating its estimate, could change in the near term due to one or more future confirming events. Accordingly, the actual results could differ significantly from those estimates. Deferred Offering Costs Deferred offering costs consist of legal, accounting and other expenses incurred through the balance sheet date that are directly related to the Proposed Public Offering and that will be charged to shareholder’s equity upon the completion of the Proposed Public Offering. Should the Proposed Public Offering prove to be unsuccessful, these deferred costs, as well as additional expenses incurred, will be charged to operations. Income Taxes ASC Topic 740 prescribes a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. The Company’s management determined that the Cayman Islands is the Company’s major tax jurisdiction. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. As of December 31, 2020, there were no unrecognized tax benefits and no amounts accrued for interest and penalties. The Company is currently not aware of any issues under review that could result in significant payments, accruals or material deviation from its position. The Company is considered to be an exempted Cayman Islands company with no connection to any other taxable jurisdiction and is presently not subject to income taxes or income tax filing requirements in the Cayman Islands or the United States. As such, the Company’s tax provision was zero for the period presented. Net Loss Per Ordinary Share Net loss per ordinary share is computed by dividing net loss by the weighted average number of ordinary shares issued and outstanding during the period, excluding ordinary shares subject to forfeiture. Weighted average shares were reduced for the effect of an aggregate of 1,125,000 Class B ordinary shares that are subject to forfeiture depending on the extent to which the underwriters’ over-allotment option is exercised (see Note 5). At December 31, 2020, the Company did not have any dilutive securities and other contracts that could, potentially, be exercised or converted into ordinary shares and then share in the earnings of the Company. As a result, diluted loss per ordinary share is the same as basic loss per ordinary share for the period presented. Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of a cash account in a financial institution, which, at times may exceed the Federal Depository Insurance Coverage of $250,000. The Company has not experienced losses on this account and management believes the Company is not exposed to significant risks on such accounts. Fair Value of Financial Instruments The fair value of the Company’s assets and liabilities, which qualify as financial instruments under FASB ASC Topic 820, “Fair Value Measurement,” approximates the carrying amounts represented in the accompanying balance sheet, primarily due to their short-term nature. Recent Accounting Standards Management does not believe that any recently issued, but not yet effective, accounting standards, if currently adopted, would have a material effect on the Company’s financial statements.	NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIE S Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“ GAAP 10-Q S-X e The interim results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021 or for any future periods. Emerging Growth Company The Company is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012, as amended (the “ JOBS Act Further, Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a registration statement under the Securities Act declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that a company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging irrevocable. The Company has elected not to opt out of such extended transition period which means that, when a standard is issued or revised and it has different application dates for public or private companies, the Company, as an emerging growth company, can adopt the new or revised standard at the time private companies adopt the new or revised standard. This may make comparison of the Company’s financial statement with another public company which is neither an emerging growth company nor an emerging growth company which has opted out of using the extended transition period difficult or impossible because of the potential differences in accounting standards used. Use of Estimates The preparation of the condensed financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of revenues and expenses during the reporting period. Making estimates requires the Company’s management to exercise significant judgment. It is at least reasonably possible that the estimate of the effect of a condition, situation or set of circumstances that existed at the date of the condensed financial statements, which the Company’s management considered in formulating its estimate, could change in the near term due to one or more future confirming events. Accordingly, the actual results could differ significantly from those estimates. One of the more significant accounting estimates included in these condensed financial statements is the determination of the fair value of the Warrant liability. Such estimates may be subject to change as more current information becomes available and accordingly the actual results could differ significantly from those estimates. Cash and Cash Equivalents The Company considers all short-term investments with an original maturity of three months or less when purchased to be cash equivalents. As of September 30, 2021 the Company held $345,011,697 in a money market fund in the Trust Account. The Company did not have any cash equivalents as of December 31, 2020. Offering Costs Offering costs consist of legal, accounting and underwriting fees and other costs incurred through the balance sheet date that are directly related to the Initial Public Offering. Offering costs amounted to $19,490,958, of which $18,735,887 were charged to Class A Ordinary Shares subject to possible redemption upon the completion of the Initial Public Offering and Class A Ordinary Shares Subject to Possible Redemption The Company accounts for the Class A Ordinary Shares subject to possible redemption in accordance with the guidance in Accounting Standards Codification (“ ASC Distinguishing Liabilities from Equity 34,500,000 and zero, respectively, Class A Ordinary Shares subject to possible redemption are presented at redemption value as temporary equity, outside of the shareholders’ equity section of the Company’s condensed balance sheets. The Company recognizes changes in redemption value immediately as they occur and adjusts carrying value of redeemable Ordinary Shares to equal the redemption value at the end of the reporting period. Immediately upon the closing of the Initial Public Offering, the Company recognized the accretion from initial book value to redemption amount value. The change in the carrying value of the redeemable Class A Ordinary Shares resulted in charges against additional paid-in At September 30, 2021 the Class A Ordinary Shares reflected in the condensed balance sheet are reconciled in the following table: Gross proceeds $ 345,000,000 Plus / (less) adjustments to carrying value: Proceeds allocated to the Public Warrants (12,933,516 ) Class A Ordinary Shares issuance costs (18,735,887 ) Plus: Accretion of carrying value to redemption value 31,669,403 Class A Ordinary Shares subject to possible redemption $ 345,000,000 Warrant Liability The Company accounts for the Warrants as either equity-classified or liability-classified instruments based on an assessment of the Warrants’ specific terms and applicable authoritative guidance in the Financial Accounting Standards Board (the “ FASB Distinguishing Liabilities from Equity Derivatives and Hedging For issued or modified Warrants that meet all of the criteria for equity classification, the Warrants are required to be recorded as a component of additional paid-in non-cash Income Taxes The Company accounts for income taxes under ASC Topic 740, “ Income Taxes positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. The Company’s management determined that the Cayman Islands is the Company’s major tax jurisdiction. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. As of September 30, 2021 and December 31, 2020, there were The Company is considered to be an exempted Cayman Islands company with no connection to any other taxable jurisdiction and is presently not subject to income taxes or income tax filing requirements in the Cayman Islands or the United States. As such, the Company’s tax provision was zero for the period presented. Net Income (Loss) per Ordinary Share The Company complies with accounting and disclosure requirements of ASC Topic 260, “ Earnings Per Share Net income (loss) per ordinary share is computed by dividing net income (loss) by the weighted average number of ordinary shares outstanding for the period. The calculation of diluted income (loss) per share does not consider the effect of the Public Warrants issued in connection with the Initial Public Offering and the sale of the Private Placement Warrants, because the exercise of the Warrants is contingent upon the occurrence of future events. Accretion associated with the redeemable shares of the Class A Ordinary Shares is excluded from earnings per share as the redemption value approximates fair value. The following table reflects the calculation of basic and diluted net income (loss) per ordinary share (in dollars, except per share amounts): Three Months September 30, 2021 Nine Months September 30, 2021 Redeemable Class A Ordinary Shares Numerator: Allocation of net income (loss) $ 2,082,014 $ 587,479 Denominator: Basic and diluted weighted average shares outstanding 34,500,000 29,571,429 Basic and diluted net income (loss) per share $ 0.06 $ 0.02 Class B Ordinary Shares Numerator: Allocation of net income (loss) $ 520,503 $ 168,073 Denominator: Basic and diluted weighted average shares outstanding 8,625,000 8,460,165 Basic and diluted net income (loss) per share $ 0.06 $ 0.02 For the three and nine months ended September 30, 2021, basic and diluted shares are the same as there are no redeemable and non-redeemable Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash accounts in a financial institution, which at times may exceed the Federal Depository Insurance Corporation coverage limit of $250,000. The Company has not experienced losses on these accounts and the Company’s management believes the Company is not exposed to significant risks on such account. Fair Value of Financial Instruments The fair value of the Company’s assets and liabilities, which qualify as financial instruments under ASC Topic 820, “ Fair Value Measurement Recent Accounting Standards In August 2020, the FASB issued Accounting Standards Update No. 2020-06, ”Debt 470-20)” Derivatives and Hedging — Contracts in Entity’s Own Equity (Subtopic 815-40): ASU 2020-06 2020-06 2020-06 2020-06 2020-06 The Company’s management does not believe that any other recently issued, but not yet effective, accounting standards, if currently adopted, would have a material effect on the Company’s condensed financial statements.

Business Combination

Business Combination	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Business Combinations [Abstract]
Business Combination	Note 3 — Business Combinations The transactions below met the requirements to be considered a business combination under Accounting Standards Codification (“ASC”) 805. The accounts, affected for preliminary adjustments to reflect fair market values assigned to assets purchased and liabilities assumed, and results of operations, are included in the Company’s financial statements from the date of acquisition. The Company has allocated the purchase price to the tangible assets, identifiable intangible assets and liabilities based on their estimated fair market values at the acquisition date as required under ASC 805. The excess of the purchase price over the fair value of the net identifiable tangible assets, intangible assets and liabilities was recorded as goodwill. Acquisition of Summit Tooling and Summit Plastics MCT Holdings completed an acquisition of Summit Tooling and Summit Plastics LLC (“Summit Plastics”, collectively, “Summit”) on February 1, 2021 in which it acquired 100 percent of the equity interest of Summit. In conjunction with the equity purchase, the Company acquired the real estate in which Summit performs their operations. Summit Tooling designs and manufactures plastic injection molds and Summit Plastics provides molding of precision plastic components for a variety of industries. The primary reason for the acquisition was to expand the Company’s capabilities in manufacturing and expand its customer base of high-quality manufacturing and industrial technology companies in North America. The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands): Cash $ 10,875 Fair value of total consideration transferred $ 10,875 The consideration excludes $892 of buyer transaction expenses that are included in other expenses within the accompanying Unaudited Condensed Consolidated Statements of Comprehensive Loss. The Company paid a transaction fee of $225 to an affiliate of the majority member of the Company. The goodwill recognized as part of the acquisition primarily reflects the value of the assembled workforce acquired and the value of future growth prospects and expected business synergies realized as a result of combining and integrating the acquired business into the Company’s existing platform. The goodwill recognized is partially deductible for tax purposes. The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of Summit (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ 40 Accounts receivable 627 Inventory 339 Fixed assets 4,371 Intangible assets 5,000 Total assets acquired 10,377 Accounts payable 40 Deferred revenue 776 Other current liabilities 95 Other noncurrent liabilities 1,323 Total liabilities assumed 2,234 Total identifiable net assets 8,143 Goodwill $ 2,732 Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Estimated Life (Years) Trade name $ 400 5 Customer relationships 4,600 11 Total Intangible assets $ 5,000 The amounts of revenue and net loss of Summit since the acquisition date included in the Unaudited Condensed Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 4,496 Net loss (1,029 ) Acquisition of PPC Incodema Holdings completed an acquisition of PPC on April 30, 2021 in which it acquired 100 percent of the membership interest of PPC. In conjunction with the equity purchase, the Company acquired the real estate in which PPC performs their operations. PPC is a manufacturing company that offers integrated engineering-to- small-run for medical, high-tech, automotive and metal stamping industries. The primary reason for the acquisition was to both expand the Company’s capabilities into metal stamping with high-quality manufacturing and industrial technology companies in North America. The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands) Cash $ 25,721 Fair value of total consideration transferred $ 25,721 The consideration excludes $984 of buyer transaction expenses that are included in other expenses within the accompanying Unaudited Condensed Consolidated Statements of Comprehensive Loss. The Company paid a transaction fee of $264 to an affiliate of the majority member of the Company. The goodwill recognized as part of the acquisition primarily reflects the value of the assembled workforce acquired and the value of future growth prospects and expected business synergies realized as a result of combining and integrating the acquired business into the Company’s existing platform. The goodwill recognized is partially deductible for tax purposes. The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of PPC (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ 162 Accounts receivable 899 Inventory 480 Fixed assets 2,413 Intangible assets 14,200 Total assets acquired 18,154 Accounts payable 148 Accrued expenses 79 Total liabilities assumed 227 Total identifiable net assets 17,927 Goodwill $ 7,794 Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Estimated Life Trade name $ 1,100 5 Customer relationships 13,100 17 Total intangible assets $ 14,200 The amounts of revenue and net loss of PPC since the acquisition date included in the Unaudited Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 4,571 Net loss (262 ) Acquisition of Centex and Laser Incodema Holdings completed acquisitions of Centex and Laser on April 30, 2021 in which it acquired 100 percent of the equity interests of Centex and Laser. Both entities are wholly owned entities of Incodema Holdings. Centex is a top tier medical device manufacturing supplier and Laser provides high precision manufacturing services, combining state of the art technology with expert craftsmanship to deliver superior products. The acquisition is consistent with the Company’s mission to expand its high-quality manufacturing and industrial technology capabilities in North America. The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands): Centex Laser Total Cash $ 11,774 $ 6,946 $ 18,720 Fair value of total consideration transferred $ 11,774 $ 6,946 $ 18,720 The consideration excludes $1,226 of buyer transaction expenses that are included in other expenses within the accompanying Unaudited Condensed Consolidated Statements of Comprehensive Loss. The Company paid a transaction fee of $190 to an affiliate of the majority member of the Company. The goodwill recognized as part of the acquisition primarily reflects the value of the assembled workforce acquired and the value of future growth prospects and expected business synergies realized as a result of combining and integrating the acquired businesses into the Company’s existing platform. The goodwill recognized is partially deductible for tax purposes. The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition of Centex and Laser (in thousands): Acquisition Date Fair Centex Laser Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ — $ 68 Accounts receivable 1,775 900 Inventory 524 622 Prepaid expenses 108 1 Fixed assets 1,787 760 Intangible assets 6,243 3,557 Other assets 1 2 Total assets acquired 10,438 5,910 Accounts payable 252 568 Paycheck Protection Program (PPP) loan 649 — Accrued expenses 271 27 Other current liabilities 23 44 Other noncurrent liabilities 1,234 703 Total liabilities assumed 2,429 1,342 Total identifiable net assets $ 8,009 $ 4,568 Goodwill 3,765 2,378 Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Life Trade name $ 510 5 Customer relationships 5,733 17 Total intangible assets $ 6,243 Acquisition Estimated Life Trade name $ 290 5 Customer relationships 3,267 17 Total intangible assets $ 3,557 The amounts of revenue and net loss of Centex since the acquisition date included in the Unaudited Condensed Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 3,049 Net loss (1,102 ) The amounts of revenue and net income of Laser since the acquisition date included in the Unaudited Condensed Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 2,707 Net income 425 Acquisition of Micropulse West Incodema Holdings completed an acquisition of Micropulse West on April 30, 2021 in which it acquired 100 percent of the membership interest of Micropulse West. Micropulse West is a full-service specialist offering a variety of services such as wire Electrical Discharge Machine (“EDM”), ram EDM, small hole EDM, CNC and manual machining/turning, surface grinding, and inspection. The acquisition is consistent with the Company’s mission to acquire high-quality manufacturing and industrial technology companies in North America. The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands): Cash $ 12,452 Contingent consideration 1,295 Fair value of total consideration transferred $ 13,747 The consideration excludes $869 of buyer transaction expenses that are included in other expenses within the accompanying Unaudited Condensed Consolidated Statements of Comprehensive Loss. The Company paid a transaction fee of $130 to an affiliate of the majority member of the Company. The goodwill recognized as part of the acquisition primarily reflects the value of the assembled workforce acquired and the value of future growth prospects and expected business synergies realized as a result of combining and integrating the acquired businesses into the Company’s existing platform. The goodwill recognized is partially deductible for tax purposes. The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition of Micropulse West (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ 70 Accounts receivable 866 Inventory 333 Other current assets 10 Fixed assets 2,490 Intangible assets 7,000 Total assets acquired 10,769 Accounts payable 139 Accrued expenses 13 Other current liabilities 99 Total liabilities assumed 251 Total identifiable net assets 10,518 Goodwill $ 3,229 Additional contingent consideration is due to the seller of Micropulse West. The earnout is based upon the Micropulse West’s reported earnings before interest, taxes, depreciation, and amortization for the trailing twelve- month period ending April 30, 2022. The maximum amount payable under the arrangement is $4,000. The Company expects that the aggregate undiscounted payments under the contingent consideration arrangement will range from $0 to $4,000. Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Estimated Life Trade name $ 600 5 Customer relationships 6,400 17 Total intangible assets $ 7,000 The amounts of revenue and net loss of Micropulse West since the acquisition date included in the Unaudited Condensed Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 3,022 Net loss (187 ) Supplemental and Unaudited Pro Forma Information The following unaudited supplemental pro forma information summarizes the combined results of operations for the above-described transactions as if the transactions had occurred on January 1, 2020 (in thousands). Nine months ended 2021 2020 Revenue $ 118,254 $ 111,945 Net income $ 2,261 $ (1,203 ) The supplemental and unaudited pro forma net income includes the following adjustments: • Adjustments to fair value write-up • Adjustments to property and equipment for the nine months ended September 30, 2021 and September 30, 2020 of $306 and $2,045, respectively. • Adjustments to intangible amortization for the nine months ended September 30, 2021 and September 30, 2020 of $773 and $5,349, respectively. • Adjustments to interest expense for the nine months ended September 30, 2021 and September 30, 2020 of $(8,902) and $4,129, respectively. The historical financial information has been adjusted by applying the Company’s accounting policies and giving effect to the pro forma adjustments, which consist of (i) amortization expense associated with identified intangible assets; (ii) depreciation of fixed asset step-up pre-acquisition step-up	Note 3 — Business Combination The transactions below met the requirements to be considered a business combination under ASC 805. The accounts, affected for preliminary adjustments to reflect fair market values assigned to assets purchased and liabilities assumed, and results of operations, are included in the Company’s Consolidated Financial Statements from the date of acquisition. The Company has allocated the purchase price to the tangible and identifiable intangible assets based on their estimated fair market values at the acquisition date as required under ASC 805. The excess of the purchase price over the fair value of the net identifiable tangible and intangible assets was recorded as goodwill. Acquisition of Kemeera, LLC. d/b/a FATHOM MCT Group Holdings, LLC completed an acquisition of Kemeera, LLC d/b/a FATHOM (“FATHOM”) on September 23, 2019 in which it acquired 100 percent of the membership interest of FATHOM. FATHOM provides a mix of prototype and production manufacturing services in addition to development and engineering services. FATHOM’s prototype services include 3D printing and additive manufacturing, CNC machining, urethane casting, tooling, injection molding, and part assembly and finishing. Additional services include industrial and engineering support and contract research and development projections. The primary reason for the acquisition was to expand the Company’s capabilities in 3-D The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 26,912 Equity instruments 2,923 Fair value of total consideration transferred $ 29,835 The consideration excludes $1,094 of buyer transaction expenses that are included in other expenses within the accompanying Consolidated Statements of Comprehensive Loss. The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of FATHOM (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ 125 Accounts receivable 2,298 Inventory 333 Prepaid expenses 351 Fixed assets 4,627 Intangible assets 14,100 Total assets acquired 21,834 Accounts payable 1,852 Accrued expenses 491 Other current liabilities 141 Taxes payable 158 Long-term debt 63 Total liabilities assumed 2,705 Total identifiable net assets 19,129 Goodwill $ 10,706 Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Fair Value Estimated Life Trade name $ 4,300 15 Customer relationships 5,300 10 Developed technology 4,500 5 Total Intangible assets $ 14,100 The amounts of revenue and net (loss) income of FATHOM since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 2019 Revenue $ 20,899 $ 6,569 Net income (loss) $ 370 $ (1,488 ) Acquisition of ICO Mold, LLC MCT Group Holdings, LLC completed an acquisition of ICO Mold, LLC and its subsidiary ICO Mold (Shenzhen), LLC (collectively, “ICO Mold”) on December 2, 2019 in which it acquired 100 percent of the membership interest of ICO Mold. ICO Mold is a custom plastic manufacturer servicing customers in a variety of industries that provides custom plastic injection molding, CNC machining of plastic and metal, and urethane casting. The primary reason for the acquisition was to both expand the Company’s capabilities into injection molding with high-quality manufacturing and industrial technology companies in North America and expand manufacturing capability in China. The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 15,998 Equity instruments 3,219 Fair value of total consideration transferred $ 19,217 The consideration excludes $965 of buyer transaction expenses that are included in other expenses within the accompanying Consolidated Statements of Comprehensive Loss. The Company paid a transaction fee of $230 to an affiliate of the majority member of the Company. The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of ICO Mold (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ 105 Accounts receivable 800 Inventory 88 Prepaid expenses 20 Fixed assets 62 Intangible assets 5,500 Total assets acquired 6,575 Accounts payable 678 Accrued expenses 194 Taxes payable 12 Total liabilities assumed 884 Total identifiable net assets 5,691 Goodwill $ 13,526 Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Trade name $ 700 5 Customer relationships 3,500 6 Developed software 1,300 5 Total intangible assets $ 5,500 The amounts of revenue and net (loss) income of ICO Mold since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 2019 Revenue $ 10,884 $ 672 Net income (loss) $ 641 $ (982 ) Acquisition of Incodema, LLC and Newchem, LLC Incodema Holdings, LLC completed acquisitions of Incodema, LLC (“Incodema”) and Newchem, LLC (“Newchem”) on July 27, 2020 in which it acquired 100 percent of the membership interests of Incodema and Newchem. Both entities are wholly owned entities of Incodema Holdings. Incodema is a prototype and short run sheet metal stamping provider which produces high quality items such as sheet metal stampings, intricate metal formings, short run production stamping, and laser cutting. Newchem is a photochemical milling company whose process involves coating material specified with a light sensitive polymer, imaging with a photo tool using UV light, developing and then chemically etching. The acquisition is consistent with the Company’s mission to expand its high-quality manufacturing and industrial technology capabilities in North America. The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Incodema Newchem Total Cash $ 30,948 $ 6,320 $ 37,268 Equity instruments $ 920 $ 183 $ 1,103 Contingent consideration $ 8,696 $ — $ 8,696 Fair value of total consideration transferred $ 40,564 $ 6,503 $ 47,067 The consideration transferred is subject to customary working capital settlements in the post-combination period. The consideration excludes $1,489 of buyer transaction expenses that are included in other expenses within the accompanying Consolidated Statements of Comprehensive Loss. The Company paid a transaction fee of $400 to an affiliate of the majority member of the Company. The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition of Incodema and Newchem (in thousands): Acquisition Date Fair Value Incodema Newchem Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ 63 $ 69 Accounts receivable 2,370 741 Inventory 735 487 Other current assets 3 1 Prepaid expenses 77 8 Fixed assets 2,277 1,949 Intangible assets 19,300 2,800 Total assets acquired 24,825 6,055 Accounts payable 324 223 Accrued expenses 110 35 Other current liabilities 286 61 Total liabilities assumed 720 319 Total identifiable net assets $ 24,105 $ 5,736 Goodwill 16,459 767 Additional contingent consideration is due to the seller of Incodema based upon the Gross Profit of a specified product sold by Incodema for the years ending December 31, 2020, 2021, and 2022. The Company expects that the aggregate undiscounted payments under the contingent consideration arrangement will be $3,260, $3,480 and $3,020 in the years ended December 31, 2021, 2022 and 2023, respectively. Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Trade name $ 2,700 15 Customer relationships 11,500 9 Developed software 5,100 5 Total intangible assets $ 19,300 Acquisition Estimated Trade name $ 300 5 Customer relationships 2,500 16 Total intangible assets $ 2,800 The amounts of revenue and net (loss) income of Incodema since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 Revenue $ 6,900 Net loss $ (1,085 ) The amounts of revenue and net income of Newchem since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 Revenue $ 2,369 Net income $ 184 Acquisition of Dahlquist Machine, LLC Incodema Holdings, LLC completed an acquisition of Dahlquist Machine, LLC (“Dahlquist”) on December 16, 2020 in which it acquired 100 percent of the membership interest of Dahlquist. In conjunction with the equity purchase, the Company acquired the real estate in which Dahlquist Machine, LLC performs their operations. Dahlquist is a precision machining company with state-of-the-art The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 16,098 Equity instruments 368 Contingent consideration 1,166 Fair value of total consideration transferred $ 17,632 fabricator and has evolved into one of the most progressive precision sheet metal products manufacturers in the nation. The acquisition is consistent with the Company’s mission to expand its high-quality manufacturing and industrial technology capabilities in North America. The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 33,557 Equity instruments 1,471 Fair value of total consideration transferred $ 35,028 The consideration transferred is subject to customary working capital settlements in the post-combination period. The consideration excludes $1,145 of buyer transaction expenses that are included in other expenses within the accompanying Consolidated Statements of Comprehensive Loss. The Company paid a transaction fee of $361 to an affiliate of the majority member of the Company. The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ — Accounts receivable 2,645 Inventory 1,184 Other current assets 30 Prepaid expenses 201 Fixed assets 4,229 Intangible assets 20,100 Total assets acquired 28,389 Accounts payable 244 Accrued expenses 231 Other current liabilities 644 Total liabilities assumed 1,119 Total identifiable net assets 27,270 Goodwill $ 7,758 Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Trade name $ 1,500 5 Customer relationships 18,600 16 Total intangible assets $ 20,100 The amounts of revenue and net (loss) income of Majestic since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 Revenue $ 911 Net loss $ (1,129 ) Other acquisitions Midwest Composite Technologies, LLC purchased substantially all assets and property, and agreed to assume certain liabilities of GPI Prototype & Manufacturing Services, LLC (“GPI”) on August 18, 2020 for a total consideration transferred of $2,441. The primary reason for the acquisition was to expand the Company’s capabilities in 3-D Incodema Buyer LLC completed an acquisition of Mark Two Engineering, LLC (“Mark Two”) on December 18, 2020 in which it acquired 100 percent of the membership interest of Mark Two for a total consideration transferred of $6,639. Mark Two is a contract manufacturing firm that specializes in rapid prototyping, complex high-precision component machining and manufacturing in the Medical Device and Aerospace industries. The acquisition is consistent with the Company’s mission to expand its high-quality manufacturing and industrial technology capabilities in North America. Supplemental and Unaudited Pro Forma Information The following unaudited supplemental pro forma information summarizes the combined results of operations for the above-described transactions as if the transactions had occurred on the following dates • January 1, 2018 for the FATHOM and ICO Mold transactions. • January 1, 2019 for the Incodema, Newchem, GPI, Dahlquist, Majestic, and Mark Two transactions. 2020 2019 Revenue $ 110,583 $ 97,020 Net income (loss) $ (7,441 ) $ (11,223 ) The supplemental and unaudited pro forma net income (loss) includes the following adjustments: • Adjustment to fair value write-up of inventory sold for the years ended December 31, 2020 and 2019 of $649 and $(649), respectively. • Adjustment to PPE depreciation for the years ended December 31, 2020 and 2019 of $2,282 and $2,139, respectively. • Adjustment to amortization of intangible assets for the years ended December 31, 2020 and 2019 of $3,821 and $7,223, respectively. • Adjustment to interest expense for the years ended December 31, 2020 and 2019 of $3,659 and $4,923, respectively. The historical financial information has been adjusted by applying the Company’s accounting policies and giving effect to the pro forma adjustments, which consist of (i) amortization expense associated with identified intangible assets; (ii) depreciation of fixed asset step-up pre-acquisition step-up

Revenue

Revenue	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue	Note 4 — Revenue The Company accounts for revenue in accordance with ASC 606, Revenue from Contracts with Customers Revenue by product line for the nine months ended September 30, 2021 and September 30, 2020 was as follows: Nine months ended (in thousands) 2021 2020 Revenue: Additive manufacturing $ 13,322 $ 12,755 Injection molding 20,941 12,999 CNC machining 30,063 8,093 Precision sheet metal 38,494 4,150 Other revenue 5,067 4,252 Total revenue $ 107,887 $ 42,249 The Company’s deferred revenue balance as of September 30, 2021 and December 31, 2020 is $1,679 and $1,210, respectively. Deferred revenue is the result of billings in excess of revenue being recognized and is recorded in other current liabilities on the Company’s Unaudited Condensed Consolidated Balance Sheet. Deferred revenue is recognized fully in the following period due to the short-term nature of the customer contracts.	Note 4 — Revenue The Company accounts for revenue in accordance with ASC 606, Revenue from Contracts with Customers 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 will not have a valid contract. The Company provides high quality, advanced rapid prototyping, precision manufacturing and finishing services in low-to-mid on-demand 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. The majority 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, we allocate revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling price based on the price charged to customers. Below is a listing of the Company’s major sales product lines and their recognition patterns: Additive Manufacturing Our Additive Manufacturing product line utilizes plastic and metal 3D printing technology to provide a wide-variety of high-quality, precision rapid prototyping solutions and low volume production. Performance obligations are dictated by the contractual shipping terms agreed upon by the Company and its customers. Revenue is recognized at a point in time based on shipping terms. Injection Molding Our Injection Molding product line uses our 3D CAD machining technology for the automated design and manufacture custom tooling and small to medium part production runs. Tooling and sampling production and part production runs are recognized at a point in time based on shipping terms. Computer Numerical Control (“CNC”) Machining Our CNC Machining product line delivers high-quality precision parts by way of modern machining methods to drive more outstanding results. Performance obligations are dictated by the contractual shipping terms agreed upon by the Company and its customers. Revenue is recognized at a point in time based on shipping terms. Precision Sheet Metal Our Precision Sheet Metal product line includes efficient quick-turn custom sheet metal parts from prototype to mid-volume Other Product Lines Urethane Casting Our Urethane Casting product line is most commonly used during prototyping, including finished looking parts for final tests and presentations, and low volume production. Performance obligations are dictated by the contractual shipping terms agreed upon by the Company and its customers. Revenue is recognized at a point in time based on shipping terms. The remaining other product lines include, but are not limited to, in-house Revenue by product line for the years ended December 31, 2020 and 2019 was as follows: Year ended December 31, (in thousands) 2020 2019 Revenue: Additive manufacturing $ 19,032 $ 11,461 Injection molding 17,093 2,056 CNC machining 9,173 3,833 Precision sheet metal 9,811 — Other revenue 6,180 3,268 Total revenue $ 61,289 $ 20,618 The Company generally expenses sales commissions when incurred because the amortization period would have been one year or less. These costs are recorded within selling, general, and administrative expenses. The Company’s deferred revenue balance as of December 31, 2020 and 2019 is $1,210 and $368, respectively. Deferred revenue is the result of billings in excess of revenue being recognized and is recorded in other current liabilities on the Company’s balance sheet. Deferred revenue is recognized fully in the following period due to the short-term nature of the customer contracts.

Inventory

Inventory	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventory	Note 5 — Inventory 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 The Company’s inventory consisted of the following as of September 30, 2021 and December 31, 2020, respectively (in thousands): September 30, December 31, Finished goods $ 3,338 $ 1,351 Raw materials 2,788 2,277 Work in process 2,684 2,359 Tooling 363 338 Total $ 9,173 $ 6,325	Note 5 — Inventory 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 The Company’s inventory consisted of the following at December 31, 2020 and 2019, respectively (in thousands): December 31, 2020 December 31, 2019 Finished goods $ 1,351 $ 352 Raw materials 2,277 1,272 Work in process 2,359 73 Tooling 338 — Total $ 6,325 $ 1,697

Initial Public Offering

Initial Public Offering	1 Months Ended	9 Months Ended
	Dec. 31, 2020	Sep. 30, 2021
ALTIMAR ACQUISITION CORP. II [Member]
INITIAL PUBLIC OFFERING	Note 3 — Proposed Public Offering Pursuant to the Proposed Public Offering, the Company will offer for sale up to 30,000,000 Units (or 34,500,000 Units if the underwriters’ over-allotment option is exercised in full) at a purchase price of $10.00 per Unit. Each Unit will consist of one Class A ordinary share and one-fourth Warrant Selling Stockholder	NOTE 3. INITIAL PUBLIC OFFERING The Company sold 34,500,000 Units in the Initial Public Offering, which includes a full exercise by the underwriters of their over-allotment option in the amount of 4,500,000 Units at a purchase price of $10.00 per Unit. Each Unit consists of one Class A Ordinary Share and one Each whole Public Warrant entitles the Selling Stockholder to purchase one Class A Ordinary

Private Placement

Private Placement	1 Months Ended	9 Months Ended
	Dec. 31, 2020	Sep. 30, 2021
ALTIMAR ACQUISITION CORP. II [Member]
Private Placement	Note 4 — Private Placement The Sponsor has committed to purchase an aggregate of 9,000,000 Private Placement Warrants (or 9,900,000 Private Placement Warrants if the underwriters’ over-allotment option is exercised in full) at a price of $1.00 per Private Placement Warrant, for an aggregate purchase price of $9,000,000 (or $9,900,000 if the underwriters’ over-allotment option is exercised in full), in a private placement that will occur simultaneously with the closing of the Proposed Public Offering. Each Private Placement Warrant is exercisable to purchase one Class A ordinary share at a price of $11.50 per share, subject to adjustment (see Note 7). A portion of the proceeds from the Private Placement Warrants will be added to the proceeds from the Proposed Public Offering to be held in the Trust Account. If the Company does not complete a Business Combination within the Combination Period, the proceeds from the sale of the Private Placement Warrants will be used to fund the redemption of the Public Shares (subject to the requirements of applicable law) and the Private Placement Warrants will expire worthless.	NOTE 4. PRIVATE PLACEMENT Simultaneously with the closing of the Initial Public Offering and the underwriters’ full exercise of their over-allotment option, the Sponsor purchased an aggregate of 9,900,000 Private Placement Warrants at a price of $1.00 per Private Placement Warrant, for an aggregate purchase price of $9,900,000 in a private placement transaction. Each Private Placement Warrant is exercisable to purchase one Class A Ordinary Share at a price of $11.50 per Class A Ordinary Share, subject to adjustment (see Note 8). A portion of the proceeds from the sale of the Private Placement Warrants was added to the proceeds from the Initial Public Offering held in the Trust Account. If the Company does not complete a Business Combination within the Combination Period, the proceeds from the sale of the Private Placement Warrants will be used to fund the redemption of the Public Shares, subject to the requirements of applicable law, and the Private Placement Warrants will expire worthless.

Property and Equipment

Property and Equipment	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	Note 6 — Property and Equipment Property and equipment consist of the following as of September 30, 2021 and December 31, 2020, respectively (in thousands): September 30, December 31, Machinery & equipment $ 37,695 $ 25,214 Furniture & fixtures 930 812 Property and leasehold Improvements 6,556 2,838 Construction in progress 2,656 576 47,837 29,440 Accumulated depreciation and amortization (6,806 ) (3,054 ) Total $ 41,031 $ 26,386 Depreciation and amortization expense related to property and equipment that is included in operating expenses for the nine months ended September 30, 2021 and September 30, 2020 was $2,110 and $105, respectively. Depreciation and amortization expense related to property and equipment included in cost of revenues for the nine months ended September 30, 2021 and September 30, 2020 was $2,679 and $2,196, respectively.	Note 6 — Property and Equipment Property and equipment consist of the following as of December 31, 2020 and 2019, respectively (in thousands): December 31, 2020 December 31, 2019 Machinery & equipment $ 25,214 $ 10,600 Furniture & fixtures 812 397 Property and leasehold Improvements 2,838 720 Construction in progress 576 256 $ 29,440 11,973 Accumulated depreciation and amortization (3,054 ) (1,164 ) Total $ 26,386 $ 10,809 Depreciation and amortization expense included in operating expenses for the years ended December 31, 2020 and 2019 was $598 and $135, respectively. Depreciation and amortization expense included in cost of revenues for the years ended December 31, 2020 and 2019 was $2,567 and $1,054, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Note 7 — Goodwill and Intangible Assets The carrying amount of goodwill as of September 30, 2021 and December 31, 2020 is as follows, respectively (in thousands): Dec. 31, 2020 Goodwill September 30, Goodwill $ 63,215 $ 19,898 $ 83,113 Intangible assets other than goodwill at September 30, 2021 and December 31, 2020 were as follows: September 30, 2021 December 31, 2020 Useful Weighted (in thousands) Gross Accumulated Net Gross Accumulated Net Trade name $ 15,100 $ 2,133 $ 12,967 $ 12,200 $ 919 $ 11,281 5-15 11.4 Customer relationships 100,700 9,492 91,208 67,600 4,448 63,152 5 - 14.3 Developed software 6,400 1,680 4,720 6,400 720 5,680 5 7.4 Developed technology 4,500 1,822 2,678 4,500 1,147 3,353 5 8.0 Total intangible assets $ 126,700 $ 15,127 $ 111,573 $ 90,700 $ 7,234 $ 83,466 Aggregate amortization expense was $7,892 and $3,368 for the nine months ended September 30, 2021 and September 30, 2020, respectively, of which $7,217 and $2,692 was included in operating expenses for the nine months ended September 30, 2021 and September 30, 2020, respectively. There are no intangible assets, other than goodwill, with indefinite useful lives. Estimated amortization expense for each of the next five years (in thousands): Remaining 2021 $ 2,887 2022 11,533 2023 11,533 2024 11,278 2025 9,706 Thereafter 64,637 Total $ 111,574	Note 7 — Goodwill and Intangible Assets The changes in the carrying amount of goodwill for the years ended December 31, 2020 and 2019 were as follows: (in thousands) Dec. 31, 2018 Goodwill Dec. 31, 2019 Goodwill Dec. 31, 2020 Goodwill $ 8,775 $ 24,232 $ 33,007 $ 30,208 $ 63,215 Intangible assets other than goodwill for the years ended December 31, 2020 and 2019 were as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 (in thousands) Gross Accumulated Net Gross Accumulated Net Useful Weighted Trade name $ 12,200 $ 919 $ 11,281 $ 6,800 $ 249 $ 6,551 5-15 12.7 Customer relationships 67,600 4,448 63,152 25,600 1,591 24,009 5-16 13.3 Developed software 6,400 720 5,680 1,300 21 1,279 5 4.5 Developed technology 4,500 1,147 3,353 4,500 244 4,256 5 3.7 Total intangible assets $ 90,700 $ 7,234 $ 83,466 $ 38,200 $ 2,105 $ 36,095 Aggregate amortization expense was $5,129 and $1,714 for the years ended December 31, 2020 and 2019, respectively. There are no intangible assets, other than goodwill, with indefinite useful lives. Estimated amortization expense for each of the next five years: 2021 $ 8,864 2022 $ 8,864 2023 $ 8,864 2024 $ 8,605 2025 $ 7,027 Thereafter $ 41,242 Total $ 83,466

Long-Term Debt

Long-Term Debt	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Note 8 — Debt 2018 and 2019 Credit Facilities During 2018, the Company entered a revolving credit agreement, a term loan and a delayed draw term loan (“DDTL”) credit agreement, which collectively make up the “2018 Credit Facilities”, to support its operations, cash requirements and acquisition growth strategy. During 2019, the Company entered into the second and third amendments to the 2018 Credit Facilities. Under the credit agreement, the Company is subject to various financial covenants, including quarterly fixed-charge coverage ratio; total leverage ratio; and minimum earnings before interest, taxes, depreciation, and amortization (“EBITDA”). The credit facility also includes a capital expenditure limit of $3,100 for the year ended December 31, 2020. As of December 31, 2020, the Company was in compliance with all covenant requirements. The 2018 DDTL had unused capacity of $510 December 31, 2020 and was fully repaid as of September 30, 2021. 2020 Credit Facilities On July 27, 2020, the Company entered into a $34,500 secured, unsubordinated credit facility with a financial institution, consisting of a $19,500 term loan and a $15,000 delayed draw term loan, with a maturity of July 27, 2026. At closing, $19,500 was funded and along with cash on the Company’s balance sheet, used to finance the acquisition of Incodema and Newchem. The term loan credit facility resulted in issuance costs of $520, which were capitalized. The loan is secured by pledged equity interests and the assets of the Company, including, but not limited to, cash and deposits, inventory, property, plant, and equipment, and intangible assets. Under the agreements, the Company is subject to various financial covenants, including a fixed charge coverage ratio and total net leverage ratio, and required to make quarterly principal installments commencing on September 30 March 31 On December 16, 2020, the Company entered into the first amendment to the 2020 Credit Facility. Pursuant to the amendment, the availability on the delayed draw term loan was increased to $40,500. The Company is charged a Commitment Fee of 0.5% for the initial six month period and 1.0% following the six month period on the unused portion of the delayed draw term loan. The amendment resulted in issuance costs of $692 of which $660 were capitalized and $32 were expensed. Borrowings on the delayed draw term loan amount were not drawn until acquisitions of Dahlquist, Mark Two, and Majestic Metals beginning mid-December. 2021 Term Loan On April 30, 2021, the Company completed a financing transaction whereby it issued a $172,000 term loan due April 2022 (the “2021 Term Loan”) in order to finance the acquisitions of Centex, Laser, Micropulse West, and PPC, as well as to refinance the Company’s existing debt. The 2021 Term Loan is due for repayment on April 29, 2022. As discussed further in Notes 1 and 15, on July 9, 2021 the Company entered into an agreement to refinance the 2021 Term Loan on a permanent basis, subject to certain conditions. As of September 30, 2021, the Company was in compliance with all 2021 Term Loan covenants. See Notes 1 and 15 for further information. Paycheck Protection Program Loan During the year ended December 31, 2020, the Company received a Paycheck Protection Program (“PPP”) loan in the amount of $1,624 through the Small Business Administration (“SBA”) under the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act. In April 2021, the Company’s PPP loan was forgiven in full by the SBA and the Company recorded a gain of $1,624 which was recorded to other income on the Company’s Unaudited Condensed Consolidated Statement of Comprehensive Loss for the nine months ended September 30, 2021. The Company’s debt as of September 30, 2021 and December 31, 2020 is as follows (in thousands): As of September 30, 2021 As of December 31, 2020 Debt Description Interest Rate Amount Interest Rate Amount 2018 Term Loan, as amended $ — 7.75% $ 29,700 2018 DDTL — 7.75% 2,990 2020 Term Loan — 3 month LIBOR 19,401 2020 DDTL — 3 month LIBOR 40,500 2021 Term Loan 3 month LIBOR + 172,000 — Total principal debt 172,000 92,591 Debt issuance costs (1,743 ) (1,867 ) PPP and other loans — 2,615 Total debt, net 170,257 93,339 Less: current portion of long-term debt — 2,853 Less: current 2021 Term Loan 172,000 — Less: current portion of debt issuance costs (1,743 ) — Long-term debt, net of current portion $ — $ 90,486 The balance of the above debt matures as follows: 2021 $ — 2022 172,000 Thereafter — Total $ 172,000 Interest on all debt is payable quarterly, with the unpaid amount due upon maturity. Interest expense associated with long-term debt for the nine months ended September 30, 2021 and September 30, 2020 was $8,800 and $2,335, respectively. Included in interest expense, net on the accompanying Unaudited Condensed Consolidated Statements of Comprehensive Loss is amortization of debt issuance costs of $1,342 and $153 that were expensed for the nine months ended September 30, 2021 and September 30, 2020, respectively. New Credit Agreement On July 9, 2021, the Company entered into a financing transaction, which included a $50,000 revolving credit facility and $125,000 term loan, which will be funded at a later date assuming certain subsequent conditions are met including the closing of the SPAC Transaction noted above. The loans made under the New Credit Agreement will mature in 2026. Funding of loans under the New Credit Agreement is conditioned upon completing the SPAC Transaction noted above before April 9, 2022. In addition, funding of the loans under the New Credit Agreement is further conditioned on the cash proceeds of the SPAC Transaction being in excess of $313 million, or a lesser amount if mutually agreed. The Company expects that the proceeds from the SPAC Transaction will be less than $313,000, however the Company and Altimar have mutually agreed that the New Credit Agreement will be funded despite the cash proceeds being less than $313,000. The revolving credit facility under the New Credit Agreement will be available for working capital and other general corporate purposes and will include a letter of credit sub-facility	Note 8 — Long-Term Debt 2018 and 2019 Credit Facilities On August 31, 2018, the Company entered into a revolving credit agreement with a bank permitting aggregate borrowings of up to $1,500 pursuant to a secured, unsubordinated revolving credit facility with a maturity date of August 31, 2023. The revolving credit facility supports our operations and cash requirements. Under the agreement, the Company is subject to certain covenants, as discussed below. A commitment fee of 0.5% per annum is charged on the unused commitments. Borrowings under the revolving credit facility are available in U.S. Dollars and bear interest at a variable interest rate based on LIBOR plus a senior net leverage-based margin, which were 7.75% and 8.30% per annum as of December 31, 2020 and 2019, respectively. As of December 31, 2020 and 2019, there were no outstanding borrowings on the revolving credit facility. On August 31, 2018, the Company entered into a $15,000 term loan and a $10,000 delayed draw term loan credit agreement with a bank that provided a secured, unsubordinated term loan credit facility with a maturity of August 23, 2023. The loan is secured by pledged equity interests and the assets of the Company, including, but not limited to, cash and deposits, inventory, property, plant, and equipment, and intangible assets. The term loans support our acquisition growth strategy. Under the agreements, the Company is subject to certain covenants, as discussed below, and required to make quarterly principal installments through the end of the term. A draw down fee of 1% is charged on the delayed draw term loan. Borrowing under the term loan facility is in U.S. Dollars and bears interest at a variable interest rate based on LIBOR plus a senior net leverage-based margin, which were 7.75% and 8.30% per annum as of December 31, 2020 and 2019, respectively. The term loan credit facility resulted in issuance costs of which $390 were capitalized. The term loan credit facility combined with the revolving credit facility make up the “2018 Credit Facilities.” On September 23, 2019, the Company entered into the second amendment to the 2018 Credit Facilities. Pursuant to the amendment, Fathom, acquired at the same time as the amendment, became a borrower under the credit agreement, and the total commitment on the delayed draw term loan was reduced from $10,000 to $8,500 On December 2, 2019, the Company entered into the third amendment to the 2018 Credit Facilities. Pursuant to the amendment, an additional $15,000 term loan was issued as part of financing for the ICOMold acquisition as described in Note 3. The amendment also established ICOMold as a borrower under the credit agreement, reduced the total commitment on the delayed draw term loan, reduced the original term loan principal, and resulted in additional issuance costs of $461 of which $344 was capitalized and $117 were expensed. On May 31, 2020, the total commitment on the Delayed Draw Term Loan (“DDTL”) was reduced to $3,500. As per the agreement, the total commitment amount was to be reduced by any remaining unused commitment in excess of $3,500 on this date. Availability of advances from the delayed draw term loan expired on February 26, 2021. On August 18, 2020, the Company drew $2,000 on the delayed draw term loan as part of financing for the GPI acquisition as described in Note 3. The credit agreement requires annual mandatory prepayments based on a percentage of the Company’s excess cash flow defined by the credit agreement. As of December 31, 2020 and 2019, no additional prepayment was required related to the excess cash flow. Under the credit agreement, the Company is subject to various financial covenants, including quarterly fixed-charge coverage ratio; total leverage ratio; and minimum earnings before interest, taxes, depreciation, and amortization (“EBITDA”). The credit facility also includes a capital expenditure limit of $3,100 and $2,750 for the years ended December 31, 2020 and 2019, respectively. As of December 31, 2020 and 2019, as well as interim periods, the Company is in compliance with all covenant requirements. The 2018 DDTL had unused capacity of $510 and $7,507 as of December 31, 2020 and 2019, respectively. The 2018 Credit Facilities mature on August 31, 2023. 2020 Credit Facilities On July 27, 2020, the Company entered into a $34,500 secured, unsubordinated credit facility with a financial institution, consisting of a $19,500 term loan and a $15,000 delayed draw term loan, with a maturity of July 27, 2026. At closing, $19,500 was funded and along with cash on the Company’s balance sheet, used to finance the acquisition of Incodema and Newchem as discussed in Note 3. The term loan credit facility resulted in issuance costs of $520, which were capitalized. The loan is secured by pledged equity interests and the assets of the Company, including, but not limited to, cash and deposits, inventory, property, plant, and equipment, and intangible assets. Under the agreements, the Company is subject to various financial covenants, including a fixed charge coverage ratio and total net leverage ratio, and required to make quarterly principal installments commencing on September March On December 16, 2020, the Company entered into the first amendment to the 2020 Credit Facility. Pursuant to the amendment, the availability on the delayed draw term loan was increased to $40,500. The Company is charged a Commitment Fee of 0.5% for the initial 6 month period and 1.0% following the six month period on the unused portion of the delayed draw term loan. The amendment resulted in issuance costs of $692 of which $660 were capitalized and $32 were expensed. Borrowings on the delayed draw term loan amount were not drawn until acquisitions of Dahlquist, Mark Two, and Majestic Metals beginning mid-December The 2020 Credit Facilities mature on July 27, 2026. Paycheck Protection Program Loan During the year ended December 31, 2020, the Company received a Paycheck Protection Program (“PPP”) loan in the amount of $1,624 through the Small Business Administration (“SBA”) under the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act. At the time of submission of the application and at the time the PPP Loan was funded, the Company satisfied and the Company continues to satisfy all of the applicable criteria for the PPP Loan set forth in the Small Business Act (15 U.S.C. 636(a)) and the CARES Act. Under the terms of this program, the loan may be fully or partially forgiven if the loan proceeds are spent on qualifying expenses and if staffing level and salary maintenance requirements are met. The Company was permitted to use the funds on qualifying expenses over a covered period of up to 24 weeks. At the conclusion of the covered period, any balance that is not forgiven by the SBA will be repaid within two years from issuance date with interest accruing at a rate of 1.0 percent, with monthly payments of principal and interest beginning ten months after the conclusion of the covered period. Additionally, the Company assumed additional PPP loans during the year ended December 31, 2020 in the amount of $991 through the acquisitions of Dahlquist and Mark Two as discussed in Note 3. For PPP loans assumed through these acquisitions (the “Assumed PPP Loans”), the applicable seller agreed to indemnify the Company of all losses which the Company may suffer, sustain or become subject to as a result of or related to any applicable Assumed PPP Loan. As such, an indemnification asset of $991 was recorded as of the acquisition of each company and the balance thereof is included in other assets. Any request for forgiveness is subject to review and approval by the lender and the SBA, including review of qualifying expenditures and staffing and salary levels. Subsequent to December 31, 2020, the Company has submitted requests for forgiveness. The Company expects to receive forgiveness for the entire loan balance in 2021. There can be no assurance that any portion of the PPP loans will be forgiven. (in thousands) As of December 31, 2020 As of December 31, 2019 Debt Description Interest Rate Amount Interest Amount 2018 Term Loan, as amended 7.75% $ 29,700 8.30 % $ 29,775 2018 DDTL 7.75% 2,990 8.30 % 993 2020 Term Loan 3 month LIBOR 19,401 — 2020 DDTL 3 month LIBOR 40,500 — Total principal long-term debt 92,591 30,768 Debt issuance costs (1,867 ) (862 ) PPP and other loans $ 2,615 — Total debt 93,339 29,906 Less: current portion of long-term debt 2,853 309 Long-term debt, net of current portion $ 90,486 $ 29,597 The balance of the above debt matures as follows: 2021 $ 2,853 2022 2,699 2023 31,614 2024 603 2025 603 Thereafter 56,834 Total 95,206 Interest on all debt is payable quarterly, with the unpaid amount due upon maturity. Interest expense associated with long-term debt for the years ended December 31, 2020 and 2019 was $3,665 and $1,616 respectively. Included in Interest expense, net on the accompanying Consolidated Statements of Comprehensive Loss is amortization of debt issuance costs of $205 and $56 that were expensed for the years ended December 31, 2020 and 2019, respectively.

Operating Leases

Operating Leases	12 Months Ended
	Dec. 31, 2020
Leases, Operating [Abstract]
Operating Leases	Note 9 — Operating Leases The Company accounts for leases in accordance with ASC 840, Leases. The Company enters into leases in the normal course of business primarily for office space, manufacturing facilities and certain company vehicles and equipment and finance leases for certain company equipment. The Company is obligated under non-cancellable The Company determines if an arrangement is a lease at inception. Operating leases are off balance sheet arrangements with rent expense included in Cost of revenue and Selling, general and administrative in the Consolidated Statements of Comprehensive Loss. Future noncancelable operating lease commitments are as follows (in thousands): Year ended Total 2021 $ 2,585 2022 2,179 2023 1,834 2024 1,030 2025 589 Thereafter 465 Total lease payments $ 8,682 Rental expense was approximately $1,536 and $795 for the years ended December 31, 2020 and 2019, respectively. As of December 31, 2020, and 2019, deferred rent amounted to approximately $48 and $35, respectively, and was included in Other noncurrent liabilities.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Retirement Plans	Note 10 — Retirement Plans The Company sponsors various 401(k) plans for substantially all domestic employees. The plans provide for the Company to make a discretionary matching contribution. Employer matching contributions to the plans totaled $330 and $96 for the years ended December 31, 2020 and 2019, respectively.

Other Income and Expense, Net

Other Income and Expense, Net	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Other Income and Expenses [Abstract]
Other Income and Expense, Net	Note 9 — Other Income and Expense, Net Other Income and expense, net is comprised of the following for the nine months ended September 30, 2021 and September 30, 2020: September 30, 2021 September 30, 2020 Acquisition expenses $ 4,045 $ 1,925 Loss on debt extinguishment 2,031 — Loan prepayment fees 1,463 — Other 1,384 599 Loss on sale of assets 84 — Other expense $ 9,007 $ 2,524 Gain on sale of assets $ — $ (393 ) Gain on PPP forgiveness (1,624 ) — Change in FV of contingent consideration (1,120 ) — Other (471 ) (30 ) Other (income) (3,215 ) (423 ) Other expense and (income), net $ 5,792 $ 2,101	Note 11 — Other income and expense, net Other Income and expense, net is comprised of the following for the years ended December 31, 2020 and 2019: December 31, December 31, Acquisition expenses $ 3,765 $ 2,006 Change in fair value of contingent consideration 1,055 1,181 Other 1,515 — Other expense 6,335 3,187 Gain on sale of assets (214 ) — Other income (371 ) (189 ) Other (income) and expense, net 5,750 2,998

Class A Contingently Redeemable

Class A Contingently Redeemable Preferred Units	12 Months Ended
	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
Class A Contingently Redeemable Preferred Units	Note 12 — Class A Contingently Redeemable Preferred Units The Company has the following contingently redeemable preferred units issued and outstanding at December 31, 2020 and December 31, 2019 (in thousands, except unit and per unit data): Shares Shares Original Carrying Accumulated Amount Class A Preferred Units 1,167,418 1,167,418 $ 46.35 $ 54,105 $ 9,253 $ 63,358 The Company has the following contingently redeemable preferred units issued and outstanding at December 31, 2019 (in thousands, except unit and per unit data): Shares Shares Original Carrying Accumulated Amount Class A Preferred Units 702,493 702,493 $ 45.32 $ 31,836 $ 3,209 $ 35,045 The rights and preferences of Selling Stockholders Dividends The Company’s Class A Contingently Redeemable Preferred Units (“Class A Preferred Units”) were issued at $100 par per unit and accumulate a preferred return at 8.0 percent, compounded on the first business day of each calendar quarter in respect of the prior calendar quarter. The Company does not record any changes in carrying value of the Class A Preferred Units due to cumulative unpaid dividends. Dividends are accrued at the time they are declared by the Company’s Board of Managers. No dividends were declared or paid on the Class A Preferred Units in the years ended December 31, 2020 and December 31, 2019. Voting Rights Class A Contingently Redeemable Preferred unitholders are not entitled to voting rights. Redemption The Company shall make a distribution to each of the Class A Preferred unitholders in an amount equal to the aggregate Class A Preferred unpaid yield and Class A Preferred unreturned capital, effective upon the occurrence of any of the following events (referred to as a “redemption event”): the sale, lease, license, transfer, conveyance or other disposition of a majority of the assets of the subsidiaries of the Company; the merger, consolidation, recapitalization, reorganization or sale of securities; any merger, consolidation, joint venture or other business combination pursuant to which the Company is combined with that of a special purpose acquisition company or other blank-check company which has a class of equity securities publicly listed on a national securities exchange; or a Public Offering with respect to Holdings LLC or any of its Subsidiaries, the reorganization of Holdings LLC or any of its Subsidiaries from a limited liability company to a corporation (whether or not in connection with a Public Offering) or an election by Holdings LLC to be treated as a corporation for U.S. federal income tax purposes. As a result, the Class A Preferred Units are recorded separately from members’ equity because they are redeemable upon the occurrence of redemption events that are considered not solely within the Company’s control. The Company expensed issuance costs related to the Class A Preferred Stock as incurred for the twelve months ended December 31, 2020 and December 31, 2020. The amounts expensed were immaterial to the Company’s financial statements.

Members' Equity

Members' Equity	12 Months Ended
	Dec. 31, 2020
Members' Equity [Abstract]
Members' Equity	Note 13 — Members’ Equity The Company’s equity consists of Class A Common Units and Class B Common Units. See Note 3 for member units issued as part of business combination transactions in 2020 and 2019. Unit Selling Stockholders Selling Stockholders Selling Stockholders The following table represents a summary of the Company’s Member’s Equity as of December 31, 2020 and December 31, 2019: December 31, December 31, Class A Common Units 5,480,611 2,883,452 Class B Common Units 2,242,981 1,567,546 December 31, December 31, Class A Common Units $ 35,869 $ 18,701 Class B Common Units 14,450 10,467 $ 50,319 $ 29,168

Earnings Per Unit

Earnings Per Unit	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Earnings Per Unit [Abstract]
Earnings Per Unit	Note 10 — Earnings Per Unit Basic and diluted earnings per common unit is presented in conformity with the two-class Selling Stockholders two-class Basic net loss per unit is computed based on the weighted average number of common units outstanding. Diluted net loss per unit is computed based on the weighted average number of common units outstanding, increased by the number of any additional units that would have been outstanding had any potentially dilutive common units been issued and reduced by the number of units the Company could have repurchased from the proceeds from issuance of the potentially dilutive units. The Company had no dilutive instruments outstanding as of September 30, 2021 and September 30, 2020. As a result, basic and diluted earnings per units are the same as of September 30, 2021 and September 30, 2020. The Company’s Class A and Class B common units participate equally in the Company’s undistributed earnings. As such, the Company’s undistributed earnings are allocated pro-rata September 30, 2021 September 30, 2020 (in thousands, except for unit and per unit amounts) Class A Class B Class A Class B Basic Earnings Per Unit: Numerator Net loss $ (5,718 ) $ (2,340 ) $ (734 ) $ (371 ) Less: annual dividends on redeemable preferred units (8,692 ) (3,557 ) (2,781 ) (1,405 ) Net loss attributable to common unitholders (14,410 ) (5,897 ) (3,515 ) (1,776 ) Denominator Weighted-average units used to compute basic earnings per unit 5,480,611 2,242,981 3,227,744 1,631,064 Basic and Diluted Earnings Per Unit $ (2.63 ) $ (2.63 ) $ (1.09) $ (1.09)	Note 14 — Earnings Per Unit Basic and diluted earnings per common unit is presented in conformity with the two-class Selling Stockholders two-class Basic net income (loss) per unit is computed based on the weighted average number of common units outstanding. Diluted net income (loss) per unit is computed based on the weighted average number of common units outstanding, increased by the number of any additional units that would have been outstanding had any potentially dilutive common units been issued and reduced by the number of units the Company could have repurchased from the proceeds from issuance of the potentially dilutive units. The Company had no dilutive instruments outstanding as of December 31, 2020 and December 31, 2019. As a result, basic and diluted earnings per units are the same as of December 31, 2020 and December 31, 2019. The Company’s Class A and Class B common units participate equally in the Company’s undistributed earnings. As such, the Company’s undistributed earnings are allocated pro-rata The computation of basic and diluted earnings per Class A common and Class B common unit for all periods disclosed was calculated using the shares issued to previous unitholders in connection with the Company’s reorganization on April 30 th December 31, 2020 December 31, 2019 (in thousands, except for unit and per unit amounts) Class A Class B Class A Class B Basic Earnings Per Unit: Numerator Net income (loss) $ (5,380 ) $ (2,584 ) $ (3,201 ) $ (1,571 ) Less: annual dividends on redeemable preferred units (4,083 ) (1,961 ) (1,753 ) (860 ) Net income (loss) attributable to common unitholders (9,463 ) (4,545 ) (4,954 ) (2,431 ) Denominator Weighted-average units used to compute basic earnings per unit 3,531,681 1,696,135 1,578,164 774,500 Basic Earnings Per Unit $ (2.68 ) $ (2.68 ) $ (3.14 ) $ (3.14 )

Related Party Transactions

Related Party Transactions	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
Related Party Transactions		Note 11 — Related Party Transactions Affiliate Purchases Certain employees of the Company had a non-controlling Management Fees MCT Holdings and Incodema Holdings entered into a management services agreement with an entity related through common ownership to the majority member in August 2018 and July 2020, respectively. For the nine months ended September 30, 2021 and September 30, 2020, the Company incurred expenses related to such management fees of $1,431 and $355, respectively. See Note 3 for additional disclosure of transaction fees paid to the same entity related through common ownership to the majority member.	Note 15 — Related Party Transactions Affiliate Purchases For the years ended December 31, 2020 and 2019, certain employees of the Company had a non-controlling Management Fees MCT Holdings and Incodema Holdings entered into a management services agreement with an entity related through common ownership to the majority member in August 2018 and July 2020, respectively. For the years ended December 31, 2020 and 2019, the Company incurred expenses related to such management fees of approximately $742 and $308, respectively. See Note 3 for additional disclosure of transaction fees paid to the same entity related through common ownership to the majority member.
ALTIMAR ACQUISITION CORP. II [Member]
Related Party Transactions	Note 5 — Related Party Transactions Founder Shares On December 15, 2020, the Sponsor paid $25,000 to cover certain offering and formation costs of the Company in consideration for 8,625,000 Class B ordinary shares (the “Founder Shares”). The Founder Shares include an aggregate of up to 1,125,000 shares that are subject to forfeiture depending on the extent to which the underwriters’ over-allotment option is exercised, so that the number of Founder Shares will equal, on an as-converted The Sponsor has agreed, subject to limited exceptions, not to transfer, assign or sell any of the Founder Shares until the earlier of (A) one year after the completion of a Business Combination and (B) subsequent to a Business Combination, (x) if the closing price of the Class A ordinary shares equals or exceeds $12.00 per share (as adjusted for share sub-divisions, 30-trading Administrative Services Agreement The Company will enter into an agreement, commencing on the date that the securities are first listed on the NYSE through the earlier of the Company’s consummation of a Business Combination and its liquidation, to pay an affiliate of the Sponsor a sum of $10,000 per month for office space and secretarial and administrative services. Promissory Note — Related Party On December 15, 2020, the Company issued an unsecured promissory note (the “Promissory Note”) to the Sponsor, pursuant to which the Company may borrow up to an aggregate principal amount of $300,000. The Promissory Note is non-interest Related Party Loans In order to finance transaction costs in connection with a Business Combination, the Sponsor or an affiliate of the Sponsor, or certain of the Company’s officers and directors may, but are not obligated to, loan the Company funds as may be required (“Working Capital Loans”). If the Company completes a Business Combination, the Company would repay the Working Capital Loans out of the proceeds of the Trust Account released to the Company. Otherwise, the Working Capital Loans would be repaid only out of funds held outside the Trust Account. In the event that a Business Combination does not close, the Company may use a portion of proceeds held outside the Trust Account to repay the Working Capital Loans, but no proceeds held in the Trust Account would be used to repay the Working Capital Loans. Except for the foregoing, the terms of such Working Capital Loans, if any, have not been determined and no written agreements exist with respect to such loans. The Working Capital Loans would either be repaid upon consummation of a Business Combination, without interest, or, at the lender’s discretion, up to $2,000,000 of such Working Capital Loans may be convertible into Warrants Warrant Warrants	NOTE 5. RELATED PARTY TRANSACTIONS Founder Shares On January 28, 2021, the Sponsor transferred 25,000 Founder Shares to certain of the Company’s directors, resulting in the Sponsor holding 8,450,000 Founder Shares. The Founder Shares included an aggregate of up to Founder Shares that were subject to forfeiture depending on the extent to which the underwriters’ over-allotment option was exercised, so that the number of the Founder Shares would equal, on an as-converted basis, approximately % of the Company’s issued and outstanding ordinary shares after the Initial Public Offering. As a result of the underwriters’ election to fully exercise their over-allotment option on February 9, 2021, the Founder Shares are no longer subject to forfeiture. The Sponsor has agreed, subject to limited exceptions, not to transfer, assign or sell any of the Founder Shares until the earlier of (A) one year after the completion of a Business Combination and (B) subsequent to a Business Combination, (x) if the closing price of the Class A Ordinary Shares equals or exceeds $12.00 per share (as adjusted for share sub-divisions, 30-trading Administrative Services Agreement The Company entered into an agreement, commencing on February 4, 2021, through the earlier of the Company’s consummation of a Business Combination and its liquidation, to pay an affiliate of the Sponsor a sum of $10,000 per month for office space and secretarial and administrative services. For the three and nine months ended September 30, 2021, the Company incurred is included in accrued expenses in the accompanying condensed balance sheet as of September 30, 2021. Promissory Note — Related Party On December 15, 2020, the Company issued an unsecured promissory note (the “ Promissory Note non-interest Related Party Loans In order to finance transaction costs in connection with a Business Combination, the Sponsor or an affiliate of the Sponsor, or certain of the Company’s executive officers and directors may, but are not obligated to, loan the Company funds as may be required (the “ Working Capital Loans Account would be used to repay the Working Capital Loans. Except for the foregoing, the terms of the Working Capital Loans, if any, have not been determined and no written agreements exist with respect to the Working Capital Loans. The Working Capital Loans would either be repaid upon consummation of a Business Combination, without interest, or, at the lender’s discretion, up to $ of the Working Capital Loans may be convertible into Warrants per Warrant Warrants

Share Based Compensation

Share Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Share Based Compensation	Note 16 — Share Based Compensation The Company has two share-based compensation plans as described below. Total compensation cost that has been charged against income for those plans was $34 and $21 for 2020 and 2019, respectively. MCT Holdings 2019 Phantom Equity Bonus Plan (the “MCT Plan”) and Incodema Holdings’ 2020 Phantom Equity Bonus Plan (the “Incodema Plan”), both of which are unitholder approved, permit the grant of phantom units to eligible employee recipients for up to 10,000 phantom units for each respective plan. The awards were established for the purpose of providing recipients with a financial incentive through the opportunity to earn bonus compensation tied to appreciation in the equity value of MCT Holdings and Incodema Holdings, respectively. The awards under both plans have two vesting components: (1) time vesting and; (2) performance vesting. A quarter (25%) of the awards vest ratably, in equal installments, on each of first four employment commencement date anniversaries or vest in full upon the consummation of the sale of the Company. The remaining three-quarters (75%) of the awards vest if the MCT Holdings and Incodema Holdings investors realize a Multiple on Invested Capital (“MOIC”) of at least 2x upon the consummation of such sale of each company. The award units are representative of a percentage of the proceeds from the sale, allowing for up to 10,000 units to be awarded and 10% of the value of the sale to be paid-out Awards will be settled in cash based on the percentage of proceeds they represent in accordance with the outlined calculations in the plans. However, the administrator, in its sole discretion, can determine if any or all proceeds payable are to be in a form other than cash or marketable securities. Awards shall be payable in the same mix of consideration received by all such Selling Stockholders The fair value of awards granted was determined using the Black-Scholes pricing model and the following weighted-average assumptions in the table below as of the grant date. Expected volatility is based on the historic volatility of our guideline companies, which we believe best represent our company. 2020 2019 Risk-free interest rate 0.28 % 2.24 % Expected Term 4.65 4.47 Expected Volatility 76.67 % 73.55 % Expected dividend yield 0.00 % 0.00 % The Company’s accounting policy is to record forfeitures as they occur, however there were no forfeitures in the years ended December 31, 2020 and 2019. A summary of the activity in the plan for 2020 follows: Shares Weighted-Average Grant-Date Fair Value Nonvested at January 1, 2020 3,814 $ 96.74 Granted 5,250 51.02 Vested 380 90.07 Forfeited — — Nonvested at December 31, 2020 8,684 $ 63.74 As of December 31, 2020, there was $554 of total unrecognized compensation cost related to the Phantom Units granted under the Plan. The cost is expected to be recognized over a weighted average period of 2.8 years. The total fair value of shares vested during the years ended December 31, 2020 was $34. No cash payments related to the Phantom Units were made during 2020. A summary of the activity in the plan for 2019 follows: Shares Weighted-Average Grant-Date Fair Value Nonvested at January 1, 2019 — $ — Granted 4,000 97.34 Vested 186 109.59 Forfeited — — Nonvested at December 31, 2019 3,814 $ 96.74 As of December 31, 2019, there was $368 of total unrecognized compensation cost related to the Phantom Units granted under the Plan. The cost is expected to be recognized over a weighted average period of 3.8 years. The total fair value of shares vested during the years ended December 31, 2019 was $21. No cash payments related to the Phantom Units were made during 2019.

Fair Value Measurements

Fair Value Measurements	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Fair Value Measurements	Note 12 — Fair Value Measurement Accounting standards require certain assets and liabilities be reported at fair value in the financial statements and provide a framework for establishing that fair value. The framework for determining fair value is based on a hierarchy that prioritizes the inputs and valuation techniques used to measure fair value. There are three levels of inputs that may be used to measure fair value: Fair values determined by Level 1 inputs use quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. Fair values determined by Level 2 inputs use other inputs that are observable, either directly or indirectly. These Level 2 inputs include quoted prices for similar assets and liabilities in active markets and other inputs such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs, including inputs that are available in situations where there is little, if any, market activity for the related asset. These Level 3 fair value measurements are based primarily on management’s own estimates using pricing models, discounted cash flow methodologies, or similar techniques considering the characteristics of the asset. 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. The Company used the following methods and significant assumptions to estimate fair value: Contingent Consideration: Assets and liabilities measured at fair value on a recurring basis, are summarized below: Fair Value Measurement at September 30, 2021 Using: Quoted Prices Significant Other Significant Total Contingent consideration $ — $ — $ 8,630 $ 8,630 Fair Value Measurement at December 31, 2020 Using: Quoted Prices Significant Other Significant Total Contingent consideration $ — $ — $ 11,439 $ 11,439 The table below presents a reconciliation of all liabilities measured at fair value on a recurring basis using significant on observable inputs (Level 3) as of and for the nine months ended September 30, 2021 and as of and for the twelve months ended December 31, 2020: Contingent Consideration September 30, December 31, Balance of recurring Level 3 liabilities at January 1 $ 11,439 $ — Total gains or losses for the period: Included in earnings (1,120 ) 1,055 Included in other comprehensive loss — — Issuances 1,295 11,737 Payments (2,984 ) (1,353 ) Transfers into Level 3 — — Transfers out of Level 3 — — Balance of recurring Level 3 liabilities at end of period $ 8,630 $ 11,439 The valuation techniques used to determine the fair value of the contingent consideration as of September 30, 2021 and December 31, 2020 included a combination of discounted cash flow, Black Scholes-Merton model, and Monte Carlo simulation. The significant unobservable inputs used in the calculation of fair value include the discount rate, volatility, and credit spreads. The discount rates range from 2.9% to 18.8%, the volatility ranges from 15.3% to 80.2%, and the credit spreads range from 5.2% to 6.6%. Debt:	Note 17 — Fair Value Measurement The Company used the following methods and significant assumptions to estimate fair value: Contingent Consideration: Assets and liabilities measured at fair value on a recurring basis, are summarized below: Fair Value Measurement at December 31, 2020 Using: Quoted Prices in (Level 1) Significant Other (Level 2) Significant (Level 3) Total Contingent consideration $ — $ — $ 11,439 $ 11,439 The table below presents a reconciliation of all liabilities measured at fair value on a recurring basis using significant on observable inputs (Level 3) for the year ended December 31: Contingent Consideration 2020 2019 Balance of recurring Level 3 liabilities at January 1 $ — $ 2,319 Total gains or losses for the period: Included in earnings 1,055 1,181 Included in other comprehensive loss — — Issuances 11,737 — Payments (1,353 ) (3,500 ) Transfers into Level 3 — — Transfers out of Level 3 — — Balance of recurring Level 3 liabilities at December 31 $ 11,439 $ — The following table presents quantitative information about recurring Level 3 fair value measurements at December 31, 2020: Fair December 31, 2020 Contingent consideration $ 11,439 The valuation techniques used to determine the fair value of the contingent consideration as of December 31, 2020 included a combination of discounted cash flow, Black-Scholes-Merton model, and Monte Carlo simulation. The significant unobservable inputs used in the calculation of fair value include the discount rate, volatility, and credit spreads. The discount rates range from 2.9% to 18.8%, the volatility ranges from 15.3% to 80.2%, and the credit spreads range from 5.2% to 6.6%.
ALTIMAR ACQUISITION CORP. II [Member]
Fair Value Measurements	NOTE 9. FAIR VALUE MEASUREMENTS The fair value of the Company’s financial assets and liabilities reflects the Company’s management’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. As of September 30, 2021, assets held in the Trust Account were comprised of The following table presents information about the Company’s assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2021 and indicates the fair value hierarchy of the valuation inputs the Company utilized to determine such fair value: Description Level September 30, Assets: Investments held in the Trust Account 1 345,011,697 Liabilities: Warrant liability — Public Warrants 1 $ 9,070,433 Warrant liability — Private Placement Warrants 3 $ 10,572,537 The Warrants were accounted for as liabilities in accordance with ASC 815-40 The following table provides quantitative information regarding Level 3 fair value meas ureme As of Stock price $ 9.85 Strike price $ 11.50 Term (in years) 5.0 Volatility 16.5 % Risk-free rate 1.00 % Dividend yield 0.0 % The following table presents the changes in the fair value of Level 3 Warrant Private Public Warrant Fair value as of February 9, 2021 $ 17,144,332 $ 12,933,516 $ 30,077,848 Change in valuation inputs or other assumptions (3,784,363 ) (2,932,167 ) (6,716,530 ) Fair value of Warrants transferred out of Level 3 — (10,001,349 ) (10,001,349 ) Fair value of Level 3 Warrant $ 13,359,969 $ — $ 13,359,969 Change in valuation inputs or other assumptions $ (2,787,432 ) $ — $ (2,787,432 ) Fair value of Level 3 Warrant Liabilities as of September 30, 2021 $ 10,572,537 $ — $ 10,572,537

Commitments and Contingencies

Commitments and Contingencies	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
Commitments and Contingencies		Note 13 — Commitments and Contingencies The Company is subject to various claims and lawsuits 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 consolidated financial position of the Company. In July 2021, the Company entered into a settlement agreement in a hybrid collective/class action complaint filed by one of its former employees for alleged violations of the Fair Labor Standards Act and Wisconsin wage and hour law. The settlement amount did not have a material effect on the consolidated financial position of the Company.	Note 18 — Commitments and Contingencies PPP Loan Forgiveness and Indemnification Assets As part of the Coronavirus Aid, Relief, and Economic Security Act of 2020 (“CARES Act”), certain companies were eligible to receive a Paycheck Protection Program (“PPP”) Loan, which is forgivable under the CARES Act as long as the loan proceeds are used for specific purposes. As disclosed in Note 3, the Company acquired certain businesses which had PPP Loan balances outstanding at the time of acquisition, and thus assumed the applicable PPP Loans. As part of these acquisitions, the Company agreed to take all actions reasonably required to pursue forgiveness of the loans in accordance with the CARES Act. In the event the Assumed PPP Loans are not approved for forgiveness by the U.S. Small Business Administration (“SBA”), the Company has the contractual right to require repayment from the former owners of the acquired businesses that received such loans. As of each acquisition date, an amount equal to the then outstanding principal balance of the Assumed PPP Loans was disbursed to an escrow account to be held until such time that the SBA determines whether the Assumed PPP Loans will be forgiven or not. In such case that the loan is forgiven by the SBA, the funds held in escrow will be distributed to the respective former owners of the applicable acquired business. In such case that the loan is not forgiven, the funds held in escrow will be distributed to the Company within 10 days of notice of the SBA’s decision not to forgive the Assumed PPP Loan. The term of the contractual guarantee from the sellers is from the date of acquisition until the date of the SBA’s forgiveness decision. The ultimate date of the SBA’s forgiveness decision is not known or knowable as of the date of the financial statements, but is reasonably expected to occur in fiscal 2021. As a result of this contractual right to reimbursement, the Company is indemnified for the principal balance of the Assumed PPP Loans, either through forgiveness from the SBA or through reimbursement from the sellers. As such, the Company has recorded an indemnification asset equal to the principal balance of the PPP Loans assumed. The total indemnification assets are recorded as other assets on the Company’s balance sheet as of December 31, 2020 in the amount of $991 as an offset to the Assumed PPP Loans acquired which are held at the following consolidated subsidiaries: ◾ Mark Two — $473 PPP Loan received on April 17, 2020. ◾ Dahlquist — $518 PPP loan received on April 21, 2020. Litigation The Company is subject to various claims and lawsuits 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 consolidated financial position of the Company.
ALTIMAR ACQUISITION CORP. II [Member]
Commitments and Contingencies	Note 6 — Commitments and Contingencies Risks and Uncertainties Management continues to evaluate the impact of the COVID-19 Registration and Shareholders Rights The Selling Stockholders of the Founder Shares, Private Placement Warrants and any Warrants that may be issued upon conversion of Working Capital Loans (and any Class A ordinary shares issuable upon the exercise of the Private Placement Warrants and Warrants that may be issued upon conversion of the Working Capital Loans) will be entitled to registration rights pursuant to a registration and shareholder rights agreement to be signed prior to or on the effective date of the Proposed Public Offering. The Selling Stockholders of these securities are entitled to make up to three demands, excluding short form demands, that the Company register such securities. In addition, the Selling Stockholders have certain “piggy-back” registration rights with respect to registration statements filed subsequent to the completion of a Business Combination. However, the registration and shareholder rights agreement provides that the Company will not permit any registration statement filed under the Securities Act to become effective until termination of the applicable lockup period. The registration rights agreement does not contain liquidating damages or other cash settlement provisions resulting from delays in registering the Company’s securities. The Company will bear the expenses incurred in connection with the filing of any such registration statements. Underwriting Agreement The Company will grant the underwriters a 45-day The underwriters will be entitled to a cash underwriting discount of $0.20 per Unit, or $6,000,000 in the aggregate (or $6,900,000 if the underwriters’ over-allotment option is exercised in full), payable upon the closing of the Proposed Public Offering. In addition, the underwriters will be entitled to a deferred fee of $0.35 per Unit, or $10,500,000 in the aggregate (or $12,075,000 in the aggregate if the underwriters’ over-allotment option is exercised in full). The deferred fee will become payable to the underwriters from the amounts held in the Trust Account solely in the event that the Company complet es a B	NOTE 6. COMMITMENTS AND CONTINGENCIES Risks and Uncertainties Management continues to evaluate the impact of the COVID-19 COVID-19 n Registration and Shareholder Rights Pursuant to a registration and shareholder rights agreement entered into on February 4, 2021, the Selling Stockholders of the Founder Shares, the Private Placement Warrants and any Warrants that may be issued upon conversion of the Working Capital Loans (and any Class A Ordinary Shares issuable upon the exercise of the Private Placement Warrants and Warrants that may be issued upon conversion of the Working Capital Loans) will be entitled to registration rights pursuant to a registration and shareholder rights agreement. The Selling Stockholders of these securities are entitled to make up to three demands, excluding short form demands, that the Company register such securities. In addition, the Selling Stockholders have certain “piggy-back” registration rights with respect to registration statements filed subsequent to the completion of a Business Combination. However, the registration and shareholder rights agreement provides that the Company will not permit any registration statement filed under the Securities Act to become effective until termination of the applicable lockup period. The registration rights agreement does not contain liquidating damages or other cash settlement provisions resulting from delays in registering the Company’s securities. The Company will bear the expenses incurred in connection with the filing of any such registration statements. Underwriting Agreement The underwriters are entitled to a deferred underwriting fee of $0.35 per Unit, or $12,075,000 in the aggregate. The deferred underwriting fee will become payable to the underwriters from the amounts held in the Trust Account solely in the event that the Company completes a Business Combination, subject to the terms of the underwriting agreement. Business Combination Agreement On July 15, 2021, the Company entered into a definitive business combination agreement (the “Business Combination Agreement”), by and among the Company and Fathom Holdco, LLC to form “Fathom Digital Manufacturing Corporation” (“Fathom”), a publicly-traded industrial technology company that provides digital manufacturing services focused on prototype development and low volume production for blue chip corporate clients. Pursuant to the transaction, the Company will combine with Fathom at an estimated $1.5 billion pro forma equity value. Cash proceeds in connection with the transaction will be funded through a combination of the Company’s cash in its Trust Account and a $80 million fully committed, common stock private investment in common equity at $10.00 per share. The transaction will be consummated subject to the deliverables and provisions as further described in the Business Combination Agreement.

Shareholders' Equity

Shareholders' Equity	1 Months Ended	9 Months Ended
	Dec. 31, 2020	Sep. 30, 2021
ALTIMAR ACQUISITION CORP. II [Member]
SHAREHOLDERS' EQUITY	Note 7 — Shareholder’s Equity Preference Shares Class A Ordinary Shares Class B Ordinary Shares Only Selling Stockholders The Class B ordinary shares will automatically convert into Class A ordinary shares at the time of a Business Combination or earlier at the option of the Selling Stockholders as-converted one-to-one. Warrants The Company will not be obligated to deliver any Class A ordinary shares pursuant to the exercise of a Warrant and will have no obligation to settle such Warrant exercise unless a registration statement under the Securities Act with respect to the Class A ordinary shares underlying the Warrants is then effective and a prospectus relating thereto is current, subject to the Company satisfying its obligations with respect to registration, or a valid exemption from registration is available. No Warrant will be exercisable and the Company will not be obligated to issue a Class A ordinary share upon exercise of a Warrant unless the Class A ordinary share issuable upon such Warrant exercise has been registered, qualified or deemed to be exempt under the securities laws of the state of residence of the registered Selling Stockholder of the Warrants. The Company has agreed that as soon as practicable, but in no event later than 20 business days, after the closing of a Business Combination, it will use its commercially reasonable efforts to file with the SEC a registration statement for the registration, under the Securities Act, of the Class A ordinary shares issuable upon exercise of the Warrants, and the Company will use its commercially reasonable efforts to cause the same to become effective Redemption of Warrants when the price per Class A ordinary share equals or exceeds $18.00 . Once the Warrants become exercisable, the Company may redeem the outstanding Warrants (except as described with respect to the Private Placement Warrants): • in whole and not in part; • at a price of $0.01 per Warrant; • upon a minimum of 30 days’ prior written notice of redemption to each Warrant Selling Stockholder • if, and only if, the closing price of the Class A ordinary shares equals or exceeds $18.00 per share (as adjusted) for any 20 trading days within a 30-trading three Warrant Selling Stockholders. If and when the Warrants become redeemable by the Company, the Company may exercise its redemption right even if it is unable to register or qualify the underlying securities for sale under all applicable state securities laws. Redemption of Warrants when the price per Class A ordinary share equals or exceeds $10.00 . Once the Warrants become exercisable, the Company may redeem the outstanding Warrants: • in whole and not in part; • at $0.10 per Warrant Selling Stockholders Warrants • if, and only if, the closing price of the Class A ordinary shares equal or exceeds $10.00 per public share (as adjusted) for any 20 trading days within the 30-trading three Warrant Selling Stockholders. If the Company calls the Public Warrants for redemption, as described above, its management will have the option to require any Selling Stockholder that wishes to exercise the Public Warrants to do so on a “cashless basis,” as described in the Warrant Agreement. The exercise price and number of ordinary shares issuable upon exercise of the Public Warrants may be adjusted in certain circumstances including in the event of a share dividend, extraordinary dividend or recapitalization, reorganization, merger or consolidation. However, except as described below, the Public Warrants will not be adjusted for issuances of ordinary shares at a price below its exercise price. Additionally, in no event will the Company be required to net cash settle the Public Warrants. If the Company is unable to complete a Business Combination within the Combination Period and the Company liquidates the funds held in the Trust Account, Selling Stockholders of Public Warrants will not receive any of such funds with respect to their Public Warrants, nor will they receive any distribution from the Company’s assets held outside of the Trust Account with respect to such Public Warrants. Accordingly, the Public Warrants may expire worthless. In addition, if (x) the Company issues additional Class A ordinary shares or equity-linked securities for capital raising purposes in connection with the closing of a Business Combination at an issue price or effective issue price of less than $9.20 per Class A ordinary share (with such issue price or effective issue price to be determined in good faith by the Company’s board of directors and, in the case of any such issuance to the Sponsor or Selling Stockholders Selling Stockholders W The Private Placement Warrants will be identical to the Public Warrants underlying the Units being sold in the Proposed Public Offering, except that the Private Placement Warrants and the Class A ordinary shares issuable upon the exercise of the Private Placement Warrants will not be transferable, assignable or salable until 30 days after the completion of a Business Combination, subject to certain limited exceptions. Additionally, the Private Placement Warrants will be exercisable on a cashless basis and be non-redeemable, Selling Stockholders	NOTE 7. SHAREHOLDERS’ EQUITY Preference Shares — per share, with such designations, voting and other rights and preferences as may be determined from time to time by the Company’s board of directors. As of September 30, 2021 and December 31, 2020, there were Class A Ordinary Shares The Company is authorized to issue Class A Ordinary Shares, with a par value of $ per share. Holders of the Class A Ordinary Shares are entitled to vote for each Class A Ordinary Share. As of September 30, 2021, there were none issued and outstanding, excluding 34,500,000 Class A Ordinary Shares subject to possible redemption. As of December 31, 2020, there were Class A Ordinary Shares issued or outstanding. Class B Ordinary Shares vote for each Class B Ordinary Shares. As of September 30, 2021 and December 31, 2020, there were Only Selling Stockholders The Class B Ordinary Shares will automatically convert into the Class A Ordinary Shares at the time of a Business Combination, or earlier at the option of the Selling Stockholders thereof, at a ratio such that the number of the Class A Ordinary Shares issuable upon conversion of all of the Founder Shares will equal, in the aggregate, on an as-converted one-to-one .

Warrant Liability

Warrant Liability	9 Months Ended
	Sep. 30, 2021
ALTIMAR ACQUISITION CORP. II [Member]
WARRANT LIABILITY	NOTE 8. WARRANT LIABILITY As of September 30, 2021, there were The Company will not be obligated to deliver any Class A Ordinary Shares pursuant to the exercise of a Public Warrant and will have no obligation to settle such exercise unless a registration statement under the Securities Act with respect to the Class A Ordinary Shares underlying the Public Warrant is then effective and a prospectus relating thereto is current, subject to the Company satisfying its obligations with respect to registration, or a valid exemption from registration is available. No Public Warrant will be exercisable and the Company will not be obligated to issue a Class A Ordinary Share upon exercise of a Public Warrant unless the Class A Ordinary Share issuable upon such exercise has been registered, qualified or deemed to be exempt under the securities laws of the state of residence of the registered Selling Stockholder of the Public Warrant. The Company has agreed that as soon as practicable, but in no event later than 20 business days, after the closing of a Business Combination, it will use its commercially reasonable efforts to file with the SEC a registration statement for the registration, under the Securities Act, of the Class A Ordinary Shares issuable upon exercise of the Public Warrants, and the Company will use its commercially reasonable efforts to cause the same to become effective within 60 business provided however Redemption of the Warrants when the price per Class A Ordinary Share equals or exceeds $18.00. • in whole and not in part; • at a price of $0.01 per Warrant; • upon a minimum of 30 days’ prior written notice of redemption to each Selling Stockholder of the Warrant; and • if, and only if, the closing price of the Class A Ordinary Shares equals or exceeds $18.00 per share (as adjusted) for any 20 trading days within a 30-trading three Selling Stockholders If and when the Warrants become redeemable by the Company, the Company may exercise its redemption right even if it is unable to register or qualify the underlying securities for sale under all applicable state securities laws. Redemption of the Warrants when the price per Class A Ordinary Share equals or exceeds $10.00 • in whole and not in part; • at a price of $0.10 per Warrant upon a minimum of 30 days’ prior written notice of redemption; provided, however Selling Stockholders • if, and only if, the closing price of the Class A Ordinary Shares equal or exceeds $10.00 per Class A Ordinary Share (as adjusted) for any 20 trading days within the 30-trading three Selling Stockholders If the Company calls the Public Warrants for redemption, as described above, the Company’s management will have the option to require any Selling Stockholder that wishes to exercise the Public Warrants to do so on a “cashless basis,” as described in the Warrant Agreement. The exercise price and number of the Class A Ordinary Shares issuable upon exercise of the Public Warrants may be adjusted in certain circumstances including in the event of a share dividend, extraordinary dividend or recapitalization, reorganization, merger or consolidation. However, except as described below, the Public Warrants will not be adjusted for issuances of the Class A Ordinary Shares at a price below its exercise price. Additionally, in no event will the Company be required to net cash settle the Public Warrants. If the Company is unable to complete a Business Combination within the Combination Period and the Company liquidates the funds held in the Trust Account, Selling Stockholders of the Public Warrants will not receive any of such funds with respect to their Public Warrants, nor will they receive any distribution from the Company’s assets held outside of the Trust Account with respect to their Public Warrants. Accordingly, the Public Warrants may expire worthless. In addition, if (x) the Company issues additional Class A Ordinary Shares or equity-linked securities for capital raising purposes in connection with the closing of a Business Combination at an issue price or effective issue price of less than $9.20 per Class A Ordinary Share (with such issue price or effective issue price to be determined in good faith by the Company’s board of directors and, in the case of any such issuance to the Sponsor or Selling Stockholders Selling Stockholders Newly Issued Price Market Value Warrants Price, and the $18.00 per share redemption trigger price will be adjusted (to the nearest cent) to be equal to 180% of the higher of the Market Value and the Newly Issued Price, and the $10.00 per share redemption trigger price will be adjusted (to the nearest cent) to be equal to the higher of the Market Value and the Newly Issued Price. As of September 30, 2021, there were g the Un non-redeemable, Selling Stockholders .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 14 — Income Taxes The Company and most of its subsidiaries are treated as flow-through entities for federal and state income tax purposes and are not subject to income tax as the LLC members are responsible for the tax consequences of each member’s proportionate share of the flow-through income or loss. As such, the Company’s tax provision pertains solely to its subsidiaries which are taxable C corporations for U.S. federal income tax purposes. The Company’s effective income tax rate was (11.1%) and 0.0% for the nine months ended September 30, 2021 and September 30, 2020, respectively. The change in the Company’s effective income tax rate for the nine months ended September 30, 2020 and compared to the nine months ended September 30, 2021 relates to the acquisitions of three taxable C corporations during 2021. The effective tax rate for the nine months ended September 30, 2021 differs from the statutory tax rate of 21% primarily as a result of operations held in flow-through entities, state taxes, and the impact of certain transaction costs which were capitalized for tax purposes, but are not expected to result in deduction is future tax periods. As of September 30, 2021, the Company did not recognize income tax expense or benefits associated with uncertain tax positions. Significant components of the Company’s tax expense for the nine months ended September 30, 2021 and September 30, 2020, are as follows (in thousands): Nine Months Ended September 30 2021 2020 Current expense State 14 — Federal 1,044 — Subtotal 1,058 — Deferred tax benefit State (18 ) — Federal (233 ) — Subtotal (251 ) — Total 807 — Significant components of the Company’s net deferred tax liability as of September 30, 2021 and December 31, 2020, are as follows (in thousands): September 30, 2021 December 31, 2020 Deferred tax assets Net operating losses 68 — Allowance for bad debts 17 — Inventory reserves 116 — Other accruals 8 — Interest expense limitation 38 — Total deferred tax assets 247 — Deferred tax liabilities Fixed assets (487 ) — Intangibles (2,647 ) — Cash-to-accrual (122 ) — Total deferred tax liabilities (3,256 ) — Total net deferred tax liabilities (3,009 ) —

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	Note 19—Segment Reporting Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing operating performance. In consideration of Accounting Standards Codification (ASC) 280, “ Segment Reporting

Subsequent Events

Subsequent Events	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
SUBSEQUENT EVENTS		Note 15 — Subsequent Events Amendment No. 1 to Business Combination Agreement On November 16, 2021, The Company and Altimar executed Amendment No. 1 to the Business Combination Agreement which amended the prior Business Combination Agreement that was executed on July 16, 2021. This amendment included the following principal changes to the prior Business Combination Agreement: • The minimum cash condition required to close the transaction was reduced from $313,000 to $90,000 • The amount of cash to be contributed to the Company’s balance sheet upon closing of the transactions was reduced from $25,000 to $10,000 • The minimum amount of Company debt to be paid down upon closing of the transaction was reduced from $22,000 to $20,000 • Provisions relating to the forfeiture of certain shares in the surviving company by Altimar’s founders based on the level of redemptions were amended and restated to provide for a forfeiture of by such founders of 2,587,500 shares • The equity consideration payable to the owners of the Company was increased by 1,293,750 shares • Provisions were added to reflect the backstop commitment by affiliates of the majority member of the Company to purchase up to 1,000 shares of Altimar at an aggregate price of up to $10,000 to the extent necessary to satisfy the revised minimum cash condition As a result of Amendment No. 1 to Business Combination Agreement, the Company continues to expect to combine with Altimar and the combined company, to be named Fathom Digital Manufacturing Corporation, will be publicly traded and listed on the New York Stock Exchange.	Note 20 — Subsequent Events Acquisition of Summit Tooling, Inc. and Summit Plastics LLC On February 1, 2021, the Company acquired 100 percent of the equity interest of Summit Tooling, Inc. and Summit Plastics LLC for approximately $10,990 subject to an adjustment for working capital and escrow provisions. Summit Tooling designs and manufactures plastic injection molds and Summit Plastics provides molding of precision plastic components for a variety of industries. In conjunction with this acquisition, the Company drew upon its delayed draw term loan facility in the amount of $5,500. Acquisition of Centex Machine and Welding Inc. and Laser Manufacturing, Inc. On April 30, 2021, the Company acquired 100 percent of the equity interest of Centex Machine and Welding Inc. and Laser Manufacturing, Inc. for approximately $18,839 subject to an adjustment for working capital and escrow provisions. Centex is a top tier medical device manufacturing supplier and Laser provides high-precision manufacturing services, combining state of the art technology with expert craftsmanship to deliver superior products. Acquisition of Sureshot Precision, LLC (d/b/a Micropulse West) On April 30, 2021, the Company acquired 100 percent of the membership interest of Sureshot Precision, LLC (d/b/a Micropulse West) for approximately $12,542 subject to an adjustment for working capital and escrow provisions. Micropulse West is a full service specialist offering a variety of services such as wire Electrical Discharge Machine (“EDM”), ram EDM, small hole EDM, CNC and manual machining/turning, surface grinding, and inspection. Acquisition of Precision Process Corporation On April 30, 2021, the Company acquired 100 percent of the equity interest of Precision Process Corporation for approximately $24,135 subject to an adjustment for working capital and escrow provisions. PPC is a manufacturing company that offers integrated engineering-to-production small-run Company Reorganization On April 30, 2021, a reorganization was completed to combine MCT Holdings and Incodema Holdings, both of which were under common control. As part of the reorganization a new holding company with no other substantive operations was created as Fathom Holdco, LLC for the purposes of owning the interests in MCT Holdings and Incodema Holdings. As such, these Consolidated Financial Statements have been prepared using the new parent Company. See also Note 2, Basis of Presentation, 2021 Term Loan On April 30, 2021, the Company entered into a financing transaction whereby it borrowed $172,000 for purposes of financing acquisitions and paying down existing debt under the 2018, 2019 and 2020 credit facilities. Refer to Going Concern New Credit Agreement On July 9, 2021, the Company entered into a financing transaction whereby it entered into a $50,000 revolving credit facility and $125,000 term loan, assuming certain subsequent conditions are met. Refer to Going Concern Subsequent events have been evaluated and disclosed through August 3, 2021, the date of issuance of these Consolidated Financial Statements.
ALTIMAR ACQUISITION CORP. II [Member]
SUBSEQUENT EVENTS	Note 8 — Subsequent Events The Company evaluated subsequent events and transactions that occurred after the balance sheet date up to January 20, 2021, the date that the financial statements were available to be issued. Based upon this review, the Company did not identify any subsequent events that would have required adjustment or disclosure in the financial statements.	NOTE 10. SUBSEQUENT EVENTS The Company evaluated subsequent events and transactions that occurred after the balance sheet date up to the date that the condensed financial statements were issued. Based upon this review, the Company did not identify any subsequent events that would have required adjustment or disclosure in the condensed financial statements.

Summary Of Significant Accoun_2

Summary Of Significant Accounting Policies (Policies)	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
Basis of Presentation		Basis of Presentation These Unaudited Condensed Consolidated Financial Statements of the Company are comprised of the Company’s subsidiaries from the date on which they were acquired. Each subsidiary is wholly owned by either MCT Holdings or Incodema Holdings, both of which are wholly owned by the Company. The Unaudited Condensed Consolidated Financial Statements have been prepared in conformity with U.S. GAAP pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. In the opinion of the Company, these Unaudited Condensed Consolidated Financial Statements contain all adjustments, consisting of only recurring adjustments, necessary for a fair representation of the Company’s financial position as of September 30, 2021, its results of operations for the nine months ended September 30, 2021 and September 30, 2020, and its cash flows for the nine months ended September 30, 2021 and September 30, 2020. The Unaudited Condensed Consolidated Balance Sheet as of December 31, 2020, included herein for comparative purposes, was derived from the Company’s audited consolidated balance sheet for the year ended December 31, 2020. These Unaudited Condensed Consolidated Financial Statements do not contain certain footnote disclosures that were included as part of the Company’s audited annual financial statements. As such, these Unaudited Condensed Consolidated Financial Statements should be read in conjunction with the Company’s audited annual financial statements for the years ended December 31, 2020 and 2019, which describes the Company’s significant accounting policies and includes all disclosures required by U.S. GAAP for annual reporting periods.	Basis of Presentation of the Consolidated Financial Statements The consolidated financial statements of the Company are comprised of the Company’s subsidiaries from the date on which they were acquired. Each subsidiary is wholly owned by either MCT Holdings or Incodema Holdings, both of which are wholly owned by the Company. The Company’s subsidiaries include: Midwest Composite Technologies, LLC (a Wisconsin Limited Liability Company); Kemeera LLC (a California Limited Liability Company); ICO Mold, LLC (a Delaware Limited Liability Company), Incodema, LLC (a New York Limited Liability Company); Newchem, LLC (a New York Limited Liability Company); Dahlquist Machine, LLC (a Minnesota Limited Liability Company); Majestic Metals, LLC (a Colorado Limited Liability Company); and Mark Two Engineering, LLC (a Florida Limited Liability Company). The Consolidated Financial Statements as of December 31, 2020 and 2019 have been prepared in accordance with accounting principles generally accepted in the United States of America. All material intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates			Use of Estimates The preparation of Consolidated Financial Statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Cash and Cash Equivalents			Cash and Cash Equivalents Cash and cash equivalents include cash and other short-term investments with original maturities of three months or less at the date of purchase. The Company maintains cash in bank deposit accounts which at times may exceed federally insured deposit limits. The Company has not experienced any losses on such accounts and considers such associated credit risk to be immaterial to the Company’s financial statements.
Income Taxes		Income Taxes The Company wholly owns Summit Tooling, Inc. (“Summit Tooling”), Centex, and Laser, which are treated as taxpaying C corporations in the U.S. Each of the Company’s taxpaying subsidiaries were acquired in 2021. Accordingly, the Company provides current and deferred taxes for these entities. The Company and its other subsidiaries are treated as flow-through entities for federal and state income tax purposes and are not subject to income tax as the LLC members are responsible for the tax consequences of each member’s proportionate share of the flow-through income or loss of the remaining Company operations. The Company’s flow-through operations are subject to certain state and local income and franchise taxes, which are included in the Consolidated Statements of Comprehensive Loss as other income, net. In addition, MCT Holdings’ wholly owned subsidiary, ICO Mold (Shenzhen), LLC, is subject to income tax within the jurisdiction of the People’s Republic of China. Foreign income tax expense was insignificant during both the nine months ended September 30, 2021 and September 30, 2020. As such, the Company’s tax provision pertains solely to the taxpaying C corporation subsidiaries. The Company’s taxable subsidiaries account for income taxes using the asset and liability method, under which deferred tax assets and liabilities are recognized for the future tax consequences of temporary differences between the book carrying values and the tax basis of the assets, liabilities, and tax attributes (e.g., NOLs) of the taxable subsidiaries. The Company is in a net deferred tax liability position which is classified as noncurrent on the Unaudited Condensed Consolidated Balance Sheet. The Company establishes a valuation allowance when necessary to reduce deferred tax assets to the amount that are more likely than not to be realized. The Company has evaluated the need for a valuation allowance and has determined that deferred tax assets are more likely than not to be realized. The Company evaluates tax positions taken or expected to be taken in a tax return for financial statement recognition. A tax position is recognized when it is more likely than not that the tax position will be sustained upon examination, including the resolution of appeals or litigation. The Company records the amount of benefits from tax positions taken that have a greater than 50% likelihood of being realized upon settlement with taxing authorities. Interest and penalties related to unrecognized tax benefits are recognized in the income tax benefits in the accompanying Unaudited Condensed Consolidated Statements of Comprehensive Loss. No interest and penalties were recognized for the periods presented.	Income Taxes As a limited liability company, the Company has elected to report as a partnership for federal and state income tax purposes at a consolidated level. Consequently, federal income taxes are not payable or provided for by the Company. Members are taxed individually on their pro-rata
Concentration of Credit Risk			Credit Risk, Major Customers, and Suppliers The Company extends trade credit to its customers on terms that are generally practiced in the industry. During the years ended December 31, 2020 and 2019, the Company did not have any customers that accounted for more than 10% of revenue. During the years ended December 31, 2020 and 2019, approximately 19% and 12%, respectively, of inventory purchases were from a single related party supplier, Fathom Precision International Ltd. See Note 15.
Fair Value Measurements			Fair Value Measurements Accounting standards require certain assets and liabilities be reported at fair value in the financial statements and provide a framework for establishing that fair value. The framework for determining fair value is based on a hierarchy that prioritizes the inputs and valuation techniques used to measure fair value. There are three levels of inputs that may be used to measure fair value: Fair values determined by Level 1 inputs use quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. Fair values determined by Level 2 inputs use other inputs that are observable, either directly or indirectly. These Level 2 inputs include quoted prices for similar assets and liabilities in active markets and other inputs such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs, including inputs that are available in situations where there is little, if any, market activity for the related asset. These Level 3 fair value measurements are based primarily on management’s own estimates using pricing models, discounted cash flow methodologies, or similar techniques considering the characteristics of the asset. 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.
COVID-19		COVID-19 On March 11, 2020, the World Health Organization declared the outbreak of a respiratory disease caused by a new coronavirus as a “pandemic”. First identified in late 2019 and now known as COVID-19, year-end recent quarter-end; however, due to uncertainty surrounding the situation, and specifically as it pertains to	COVID-19 On March 11, 2020, the World Health Organization declared the outbreak of a respiratory disease caused by a new coronavirus as a “pandemic”. First identified in late 2019 and now known as COVID-19, year-end;
Recent Accounting Standards		Recent Accounting Pronouncements The Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases right-to-use right-to The FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326) 2016-13	Recent Accounting Pronouncements The Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases right-to-use right-to The FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326) 2016-13 The FASB issued ASU 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract, internal-use 350-40 2018-15 2018-15 The FASB issued ASU 2019-12, Income Taxes (Topic 740 ): Simplifying the Accounting for Income Taxes 2019-12 2019-12 step-up 2019-12 December 15, 2020, The FASB issued ASU 2020-04, Facilitating the effects of Reference Rate , which provide optional expedients and exceptions for applying generally accepted accounting principles (“GAAP”) to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this Update apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships entered into or evaluated after December , , except for hedging relationships existing as of December , , that an entity has elected certain optional expedients for and that are retained through the end of the hedging relationship. The amendments in this Update are effective for all entities as of March , through December , . The Company continues to evaluate the impact of the adoption of ASU 2020-04 will have on its Consolidated Financial Statements.
Correction of an Immaterial Error			Correction of an Immaterial Error The Consolidated Balance Sheet as of December 31, 2020 includes the correction of an immaterial error related to contingent consideration. The correction relates to a reclassification of certain amounts between assets and liabilities comprised of a decrease in (short-term) contingent consideration of $8,726, a decrease to accounts receivable of $101, and decrease to other current assets of $144, a decrease to property and equipment, net of $418, a decrease to other non-current assets of $48, an increase to accounts payable of $253, an increase of $389 to other non-current liabilities, and an increase to long-term contingent consideration of $7,373.
Trade Accounts Receivable, Unbilled Revenue and Allowance for Doubtful Accounts			Trade Accounts Receivable, Unbilled Revenue and Allowance for Doubtful Accounts Accounts receivable are stated at net invoice amounts. Unbilled revenue represents receivables due from customers as either the performance obligation has been completed for revenue recognized over time or the product has shipped and the customer invoice has yet to be generated. The balance in unbilled revenue, included in accounts receivable, was $173 and $634 as of December 31, 2020 and 2019, respectively. An allowance for doubtful accounts is established based on a specific assessment of all invoices that remain unpaid following normal customer payment periods. In addition, a general valuation allowance is established for the remaining accounts receivable that have not been specifically assessed based on historical loss experience as well as geographic and general economic conditions. All amounts deemed to be uncollectible are charged against the allowance for doubtful accounts in the period that determination is made. The allowance for doubtful accounts on accounts receivable balances was $649 as of December 31, 2020 and $386 as of December 31, 2019.
Inventory			Inventory Inventory is stated at the lower of cost or net realizable value (“NRV”), with NRV based on selling prices in first-in, first-out
Property and Equipment			Property and Equipment Property and equipment are recorded at cost or fair value, if acquired in the business combinations, as described in Note 3. The straight-line method is used for computing depreciation and amortization. Assets are depreciated over their estimated useful lives. The cost of leasehold improvements are amortized over the lesser of the length of the related leases or the estimated useful lives of the assets. Costs of maintenance and repairs are charged to expense when incurred.​​​​​​​ Asset Useful Lives Property and leasehold Improvements 4-20 Machinery & equipment 1-6 Furniture & fixtures 1-7 Vehicles and equipment 1-4 Capitalized software 1-2
Goodwill			Goodwill The Company recognizes goodwill in accordance with ASC 350, Intangibles—Goodwill and Other.
Intangible Assets			Intangible Assets Acquired intangible assets subject to amortization are stated at cost and are amortized using the straight-line method over the estimated useful lives of the assets. Intangible assets that are subject to amortization are reviewed for potential impairment whenever events or circumstances indicate that carrying amounts may not be recoverable. During 2019 and 2020 there were no impairments of intangible assets.
Foreign Currency Exchange and Translation			Foreign Currency Exchange and Translation The expression of assets and liabilities in a foreign currency amount gives rise to exchange gains and losses when such obligations are paid in United States dollars. Foreign currency exchange rate adjustment (i.e., differences between amounts recorded and actual amounts owed or paid) are reported in the Consolidated Statements of Comprehensive Loss as foreign currency fluctuations occur. Foreign currency exchange rate adjustments are reported in the Consolidated Statements of Cash Flows using the exchange rates in effect at the time of the cash flows. Adjustments for the years ended December 31, 2020 and 2019 were immaterial. Assets and liabilities of the Company’s operations in China are translated into U.S. dollars at the rate of exchange in effect at the close of the period. Income and expenses are translated at an average rate of exchange for the period. The aggregate effect of translating the financial statements is included in other comprehensive loss.
Debt Issuance Costs			Debt Issuance Costs Debt issuance costs were incurred by the Company in connection with obtaining the debt to finance the acquisitions disclosed in Note 3. If such financing is settled or replaced prior to maturity with debt instruments that have substantially different terms, the settlement is treated as an extinguishment and the unamortized costs are charged to gain or loss on extinguishment of debt. If such financing is settled or replaced with debt instruments from the same lender that do not have substantially different terms, the new debt agreement is accounted for as a modification of the prior debt agreement and the unamortized costs remain capitalized, the new original issuance discount costs are capitalized, and any new third-party costs are charged to expense. These costs are recorded as a reduction in the recorded balance of the outstanding debt. The costs are amortized over the term of the related debt and reported as a component of interest expense by using the straight-line method which is not materially different than the effective interest method.
Revenue Recognition			Revenue Recognition On January 1, 2019, the Company adopted ASC 606, Revenue from Contracts with Customers point-in-time point-in-time
Other Comprehensive Loss			Other Comprehensive Loss Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income. Certain changes in assets and liabilities, however, such as foreign currency translation adjustments, are reported as a direct adjustment to the equity section of the Consolidated Balance Sheets. Such items, along with net income, are considered components of comprehensive loss.
ALTIMAR ACQUISITION CORP. II [Member]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the SEC. The Company does not have sufficient liquidity to meet its anticipated obligations over the next year from the date of issuance of these financial statements. In connection with the Company’s assessment of going concern considerations in accordance with Accounting Standards Update (“ASU”) 2014-15,	Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“ GAAP 10-Q S-X e The interim results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021 or for any future periods.
Emerging Growth Company	Emerging Growth Company The Company is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), and it may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies including, but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended, reduced disclosure obligations regarding executive compensation in its periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and shareholder approval of any golden parachute payments not previously approved. Further, Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that a company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging	Emerging Growth Company The Company is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012, as amended (the “ JOBS Act Further, Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a registration statement under the Securities Act declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that a company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging irrevocable. The Company has elected not to opt out of such extended transition period which means that, when a standard is issued or revised and it has different application dates for public or private companies, the Company, as an emerging growth company, can adopt the new or revised standard at the time private companies adopt the new or revised standard. This may make comparison of the Company’s financial statement with another public company which is neither an emerging growth company nor an emerging growth company which has opted out of using the extended transition period difficult or impossible because of the potential differences in accounting standards used.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Making estimates requires management to exercise significant judgment. It is at least reasonably possible that the estimate of the effect of a condition, situation or set of circumstances that existed at the date of the financial statements, which management considered in formulating its estimate, could change in the near term due to one or more future confirming events. Accordingly, the actual results could differ significantly from those estimates.	Use of Estimates The preparation of the condensed financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of revenues and expenses during the reporting period. Making estimates requires the Company’s management to exercise significant judgment. It is at least reasonably possible that the estimate of the effect of a condition, situation or set of circumstances that existed at the date of the condensed financial statements, which the Company’s management considered in formulating its estimate, could change in the near term due to one or more future confirming events. Accordingly, the actual results could differ significantly from those estimates. One of the more significant accounting estimates included in these condensed financial statements is the determination of the fair value of the Warrant liability. Such estimates may be subject to change as more current information becomes available and accordingly the actual results could differ significantly from those estimates.
Cash and Cash Equivalents		Cash and Cash Equivalents The Company considers all short-term investments with an original maturity of three months or less when purchased to be cash equivalents. As of September 30, 2021 the Company held $345,011,697 in a money market fund in the Trust Account. The Company did not have any cash equivalents as of December 31, 2020.
Offering Costs	Deferred Offering Costs Deferred offering costs consist of legal, accounting and other expenses incurred through the balance sheet date that are directly related to the Proposed Public Offering and that will be charged to shareholder’s equity upon the completion of the Proposed Public Offering. Should the Proposed Public Offering prove to be unsuccessful, these deferred costs, as well as additional expenses incurred, will be charged to operations.	Offering Costs Offering costs consist of legal, accounting and underwriting fees and other costs incurred through the balance sheet date that are directly related to the Initial Public Offering. Offering costs amounted to $19,490,958, of which $18,735,887 were charged to Class A Ordinary Shares subject to possible redemption upon the completion of the Initial Public Offering and
Class A Ordinary Shares Subject to Possible Redemption		Class A Ordinary Shares Subject to Possible Redemption The Company accounts for the Class A Ordinary Shares subject to possible redemption in accordance with the guidance in Accounting Standards Codification (“ ASC Distinguishing Liabilities from Equity 34,500,000 and zero, respectively, Class A Ordinary Shares subject to possible redemption are presented at redemption value as temporary equity, outside of the shareholders’ equity section of the Company’s condensed balance sheets. The Company recognizes changes in redemption value immediately as they occur and adjusts carrying value of redeemable Ordinary Shares to equal the redemption value at the end of the reporting period. Immediately upon the closing of the Initial Public Offering, the Company recognized the accretion from initial book value to redemption amount value. The change in the carrying value of the redeemable Class A Ordinary Shares resulted in charges against additional paid-in At September 30, 2021 the Class A Ordinary Shares reflected in the condensed balance sheet are reconciled in the following table: Gross proceeds $ 345,000,000 Plus / (less) adjustments to carrying value: Proceeds allocated to the Public Warrants (12,933,516 ) Class A Ordinary Shares issuance costs (18,735,887 ) Plus: Accretion of carrying value to redemption value 31,669,403 Class A Ordinary Shares subject to possible redemption $ 345,000,000
Warrant Liability		Warrant Liability The Company accounts for the Warrants as either equity-classified or liability-classified instruments based on an assessment of the Warrants’ specific terms and applicable authoritative guidance in the Financial Accounting Standards Board (the “ FASB Distinguishing Liabilities from Equity Derivatives and Hedging For issued or modified Warrants that meet all of the criteria for equity classification, the Warrants are required to be recorded as a component of additional paid-in non-cash
Income Taxes	Income Taxes ASC Topic 740 prescribes a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. The Company’s management determined that the Cayman Islands is the Company’s major tax jurisdiction. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. As of December 31, 2020, there were no unrecognized tax benefits and no amounts accrued for interest and penalties. The Company is currently not aware of any issues under review that could result in significant payments, accruals or material deviation from its position. The Company is considered to be an exempted Cayman Islands company with no connection to any other taxable jurisdiction and is presently not subject to income taxes or income tax filing requirements in the Cayman Islands or the United States. As such, the Company’s tax provision was zero for the period presented.	Income Taxes The Company accounts for income taxes under ASC Topic 740, “ Income Taxes positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. The Company’s management determined that the Cayman Islands is the Company’s major tax jurisdiction. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. As of September 30, 2021 and December 31, 2020, there were The Company is considered to be an exempted Cayman Islands company with no connection to any other taxable jurisdiction and is presently not subject to income taxes or income tax filing requirements in the Cayman Islands or the United States. As such, the Company’s tax provision was zero for the period presented.
Net Income (Loss) per Ordinary Share	Net Loss Per Ordinary Share Net loss per ordinary share is computed by dividing net loss by the weighted average number of ordinary shares issued and outstanding during the period, excluding ordinary shares subject to forfeiture. Weighted average shares were reduced for the effect of an aggregate of 1,125,000 Class B ordinary shares that are subject to forfeiture depending on the extent to which the underwriters’ over-allotment option is exercised (see Note 5). At December 31, 2020, the Company did not have any dilutive securities and other contracts that could, potentially, be exercised or converted into ordinary shares and then share in the earnings of the Company. As a result, diluted loss per ordinary share is the same as basic loss per ordinary share for the period presented.	Net Income (Loss) per Ordinary Share The Company complies with accounting and disclosure requirements of ASC Topic 260, “ Earnings Per Share Net income (loss) per ordinary share is computed by dividing net income (loss) by the weighted average number of ordinary shares outstanding for the period. The calculation of diluted income (loss) per share does not consider the effect of the Public Warrants issued in connection with the Initial Public Offering and the sale of the Private Placement Warrants, because the exercise of the Warrants is contingent upon the occurrence of future events. Accretion associated with the redeemable shares of the Class A Ordinary Shares is excluded from earnings per share as the redemption value approximates fair value. The following table reflects the calculation of basic and diluted net income (loss) per ordinary share (in dollars, except per share amounts): Three Months September 30, 2021 Nine Months September 30, 2021 Redeemable Class A Ordinary Shares Numerator: Allocation of net income (loss) $ 2,082,014 $ 587,479 Denominator: Basic and diluted weighted average shares outstanding 34,500,000 29,571,429 Basic and diluted net income (loss) per share $ 0.06 $ 0.02 Class B Ordinary Shares Numerator: Allocation of net income (loss) $ 520,503 $ 168,073 Denominator: Basic and diluted weighted average shares outstanding 8,625,000 8,460,165 Basic and diluted net income (loss) per share $ 0.06 $ 0.02 For the three and nine months ended September 30, 2021, basic and diluted shares are the same as there are no redeemable and non-redeemable
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of a cash account in a financial institution, which, at times may exceed the Federal Depository Insurance Coverage of $250,000. The Company has not experienced losses on this account and management believes the Company is not exposed to significant risks on such accounts.	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash accounts in a financial institution, which at times may exceed the Federal Depository Insurance Corporation coverage limit of $250,000. The Company has not experienced losses on these accounts and the Company’s management believes the Company is not exposed to significant risks on such account.
Fair Value Measurements	Fair Value of Financial Instruments The fair value of the Company’s assets and liabilities, which qualify as financial instruments under FASB ASC Topic 820, “Fair Value Measurement,” approximates the carrying amounts represented in the accompanying balance sheet, primarily due to their short-term nature.	Fair Value of Financial Instruments The fair value of the Company’s assets and liabilities, which qualify as financial instruments under ASC Topic 820, “ Fair Value Measurement
Recent Accounting Standards	Recent Accounting Standards Management does not believe that any recently issued, but not yet effective, accounting standards, if currently adopted, would have a material effect on the Company’s financial statements.	Recent Accounting Standards In August 2020, the FASB issued Accounting Standards Update No. 2020-06, ”Debt 470-20)” Derivatives and Hedging — Contracts in Entity’s Own Equity (Subtopic 815-40): ASU 2020-06 2020-06 2020-06 2020-06 2020-06 The Company’s management does not believe that any other recently issued, but not yet effective, accounting standards, if currently adopted, would have a material effect on the Company’s condensed financial statements.

Restatement of Previously Iss_2

Restatement of Previously Issued Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2021
ALTIMAR ACQUISITION CORP. II [Member]
Schedule of Error Corrections and Prior Period Adjustments	The impact of the restatement on the Company’s previously issued financial statements is reflected in the following tables . The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported audited balance sheet as of February 9, 2021: As Previously Adjustment As Revised Balance Sheet as of February 9, 2021 (audited) Class A Ordinary Shares subject to possible redemption $ 300,351,190 $ 44,648,810 $ 345,000,000 Class A Ordinary Shares 446 (446 ) — Additional paid-in 13,003,096 (13,003,096 ) — Accumulated deficit (8,004,403 ) (31,645,268 ) (39,649,671 ) Total shareholders’ equity (deficit) 5,000,002 (44,648,810 ) (39,648,808 ) The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported unaudited balance sheet as of March 31, 2021: As Previously Adjustment As Revised Balance Sheet as of March 31, 2021 (unaudited) Class A Ordinary Shares subject to possible redemption $ 292,624,940 $ 52,375,060 $ 345,000,000 Class A Ordinary Shares 524 (524 ) — Additional paid-in 20,729,270 (20,729,270 ) — Accumulated deficit (15,730,653 ) (31,645,266 ) (47,375,919 ) Total shareholders’ equity (deficit) 5,000,004 (52,375,060 ) (47,375,056 ) The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported unaudited statement of cash flows for the three months ended March 31, 2021: As Previously Reported Adjustment As Revised Three Months ended March 31, 2021 (unaudited) Non-cash Initial classification of Class A Ordinary Shares subject to possible redemption 300,351,190 (300,351,190 ) — Change in value of Class A Ordinary Shares subject to possible redemption (7,726,250 ) 7,726,250 — The table below presents the eff e As Previously Adjustment As Revised Balance Sheet as of June 30, 2021 (unaudited) Class A Ordinary Shares subject to possible redemption $ 306,503,630 $ 38,496,370 $ 345,000,000 Class A Ordinary Shares 385 (385 ) — Additional paid-in 6,850,719 (6,850,719 ) — Accumulated deficit (1,851,965 ) (31,645,266 ) (33,497,231 ) Total shareholders’ equity (deficit) 5,000,002 (38,496,370 ) (33,496,368 ) The table below presents the effect of the financial statement adjustments related to the restatement discussed above of the Company’s previously reported unaudited statement of cash flows for the six months ended June 30, 2021: As Previously Adjustment As Revised Six Months ended June 30, 2021 (unaudited) Non-cash Initial classification of Class A Ordinary Shares subject to possible redemption 300,351,192 (300,351,192 ) — Change in value of Class A Ordinary Shares subject to possible redemption 6,152,436 (6,152,436 ) — The impact to the reported amounts of w e Net Income (Loss) Per Share As Previously Adjustment As Revised Three Months Ended March 31, 2021 (unaudited) Weighted average shares outstanding — Class A Ordinary Shares 34,500,000 (14,950,000 ) 19,550,000 Basic and diluted net income (loss) per share — Class A Ordinary Shares $ — $ (0.57 ) $ (0.57 ) Weighted average shares outstanding — Class B Ordinary Shares 8,125,000 — 8,125,000 Basic and diluted net income (loss) per share — Class B Ordinary Shares $ (1.94 ) $ 1.37 $ (0.57 ) Net Income (Loss) Per Share As Previously Adjustment As Revised Three Months Ended June 30, 2021 (unaudited) Weighted average shares outstanding — Class A Ordinary Shares 34,500,000 — 34,500,000 Basic and diluted net income (loss) per share — Class A Ordinary Shares $ — $ 0.32 $ 0.32 Weighted average shares outstanding — Class B Ordinary Shares 8,625,000 — 8,625,000 Basic and diluted net income (loss) per share — Class B Ordinary Shares $ 1.61 $ (1.29 ) $ 0.32 Net Income (Loss) Per Share As Previously Adjustment As Revised Six Months Ended June 30, 2021 (unaudited) Weighted average shares outstanding — Class A Ordinary Shares 34,500,000 (7,433,702 ) 27,066,298 Basic and diluted net income (loss) per share — Class A Ordinary Shares $ — $ (0.05 ) $ (0.05 ) Weighted average shares outstanding — Class B Ordinary Shares 8,376,381 — 8,376,381 Basic and diluted net income (loss) per share — Class B Ordinary Shares $ (0.22 ) $ 0.17 $ (0.05 )

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Schedule Of Earnings Per Share, Basic and Diluted	September 30, 2021 September 30, 2020 (in thousands, except for unit and per unit amounts) Class A Class B Class A Class B Basic Earnings Per Unit: Numerator Net loss $ (5,718 ) $ (2,340 ) $ (734 ) $ (371 ) Less: annual dividends on redeemable preferred units (8,692 ) (3,557 ) (2,781 ) (1,405 ) Net loss attributable to common unitholders (14,410 ) (5,897 ) (3,515 ) (1,776 ) Denominator Weighted-average units used to compute basic earnings per unit 5,480,611 2,242,981 3,227,744 1,631,064 Basic and Diluted Earnings Per Unit $ (2.63 ) $ (2.63 ) $ (1.09) $ (1.09)	December 31, 2020 December 31, 2019 (in thousands, except for unit and per unit amounts) Class A Class B Class A Class B Basic Earnings Per Unit: Numerator Net income (loss) $ (5,380 ) $ (2,584 ) $ (3,201 ) $ (1,571 ) Less: annual dividends on redeemable preferred units (4,083 ) (1,961 ) (1,753 ) (860 ) Net income (loss) attributable to common unitholders (9,463 ) (4,545 ) (4,954 ) (2,431 ) Denominator Weighted-average units used to compute basic earnings per unit 3,531,681 1,696,135 1,578,164 774,500 Basic Earnings Per Unit $ (2.68 ) $ (2.68 ) $ (3.14 ) $ (3.14 )
Schedule of Property, Plant and Equipment, Estimated Useful Lives [Table Text Block]		Costs of maintenance and repairs are charged to expense when incurred. Asset Useful Lives Property and leasehold Improvements 4-20 Machinery & equipment 1-6 Furniture & fixtures 1-7 Vehicles and equipment 1-4 Capitalized software 1-2
ALTIMAR ACQUISITION CORP. II [Member]
Schedule Of Earnings Per Share, Basic and Diluted	The following table reflects the calculation of basic and diluted net income (loss) per ordinary share (in dollars, except per share amounts): Three Months September 30, 2021 Nine Months September 30, 2021 Redeemable Class A Ordinary Shares Numerator: Allocation of net income (loss) $ 2,082,014 $ 587,479 Denominator: Basic and diluted weighted average shares outstanding 34,500,000 29,571,429 Basic and diluted net income (loss) per share $ 0.06 $ 0.02 Class B Ordinary Shares Numerator: Allocation of net income (loss) $ 520,503 $ 168,073 Denominator: Basic and diluted weighted average shares outstanding 8,625,000 8,460,165 Basic and diluted net income (loss) per share $ 0.06 $ 0.02
Summary of Temporary Equity Reconciliation Of Cash Flows To Outstanding Value	At September 30, 2021 the Class A Ordinary Shares reflected in the condensed balance sheet are reconciled in the following table: Gross proceeds $ 345,000,000 Plus / (less) adjustments to carrying value: Proceeds allocated to the Public Warrants (12,933,516 ) Class A Ordinary Shares issuance costs (18,735,887 ) Plus: Accretion of carrying value to redemption value 31,669,403 Class A Ordinary Shares subject to possible redemption $ 345,000,000

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Schedule of supplemental and unaudited pro forma information	The following unaudited supplemental pro forma information summarizes the combined results of operations for the above-described transactions as if the transactions had occurred on January 1, 2020 (in thousands). Nine months ended 2021 2020 Revenue $ 118,254 $ 111,945 Net income $ 2,261 $ (1,203 )	The following unaudited supplemental pro forma information summarizes the combined results of operations for the above-described transactions as if the transactions had occurred on the following dates • January 1, 2018 for the FATHOM and ICO Mold transactions. • January 1, 2019 for the Incodema, Newchem, GPI, Dahlquist, Majestic, and Mark Two transactions. 2020 2019 Revenue $ 110,583 $ 97,020 Net income (loss) $ (7,441 ) $ (11,223 )
Incodema Holdings LLC
Business Acquisition [Line Items]
Schedule of fair values of the assets acquired and liabilities		The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition of Dahlquist (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ 357 Accounts receivable 1,215 Inventory 1,597 Indemnification asset - PPP Loan 518 Prepaid expenses 8 Fixed assets 3,753 Intangible assets 8,300 Total assets acquired 15,748 Accounts payable 68 Paycheck Protection Program (PPP) loan 518 Accrued expenses 475 Total liabilities assumed 1,061 Total identifiable net assets 14,687 Goodwill $ 2,945
Fathom LLC
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred		The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 26,912 Equity instruments 2,923 Fair value of total consideration transferred $ 29,835
Schedule of fair values of the assets acquired and liabilities		The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of FATHOM (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ 125 Accounts receivable 2,298 Inventory 333 Prepaid expenses 351 Fixed assets 4,627 Intangible assets 14,100 Total assets acquired 21,834 Accounts payable 1,852 Accrued expenses 491 Other current liabilities 141 Taxes payable 158 Long-term debt 63 Total liabilities assumed 2,705 Total identifiable net assets 19,129 Goodwill $ 10,706
Summary of the intangible assets acquired in the acquisition		Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Fair Value Estimated Life Trade name $ 4,300 15 Customer relationships 5,300 10 Developed technology 4,500 5 Total Intangible assets $ 14,100
Schedule of amounts of revenue and net (loss)		The amounts of revenue and net (loss) income of FATHOM since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 2019 Revenue $ 20,899 $ 6,569 Net income (loss) $ 370 $ (1,488 )
ICO Mold
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred		The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 15,998 Equity instruments 3,219 Fair value of total consideration transferred $ 19,217
Schedule of fair values of the assets acquired and liabilities		The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of ICO Mold (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ 105 Accounts receivable 800 Inventory 88 Prepaid expenses 20 Fixed assets 62 Intangible assets 5,500 Total assets acquired 6,575 Accounts payable 678 Accrued expenses 194 Taxes payable 12 Total liabilities assumed 884 Total identifiable net assets 5,691 Goodwill $ 13,526
Summary of the intangible assets acquired in the acquisition		Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Trade name $ 700 5 Customer relationships 3,500 6 Developed software 1,300 5 Total intangible assets $ 5,500
Schedule of amounts of revenue and net (loss)		The amounts of revenue and net (loss) income of ICO Mold since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 2019 Revenue $ 10,884 $ 672 Net income (loss) $ 641 $ (982 )
Incodema And Newchem LLC | Incodema LLC
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred		The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Incodema Newchem Total Cash $ 30,948 $ 6,320 $ 37,268 Equity instruments $ 920 $ 183 $ 1,103 Contingent consideration $ 8,696 $ — $ 8,696 Fair value of total consideration transferred $ 40,564 $ 6,503 $ 47,067
Schedule of fair values of the assets acquired and liabilities		The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition of Incodema and Newchem (in thousands): Acquisition Date Fair Value Incodema Newchem Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ 63 $ 69 Accounts receivable 2,370 741 Inventory 735 487 Other current assets 3 1 Prepaid expenses 77 8 Fixed assets 2,277 1,949 Intangible assets 19,300 2,800 Total assets acquired 24,825 6,055 Accounts payable 324 223 Accrued expenses 110 35 Other current liabilities 286 61 Total liabilities assumed 720 319 Total identifiable net assets $ 24,105 $ 5,736 Goodwill 16,459 767
Summary of the intangible assets acquired in the acquisition		Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Trade name $ 2,700 15 Customer relationships 11,500 9 Developed software 5,100 5 Total intangible assets $ 19,300 Acquisition Estimated Trade name $ 300 5 Customer relationships 2,500 16 Total intangible assets $ 2,800
Schedule of amounts of revenue and net (loss)		The amounts of revenue and net (loss) income of Incodema since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 Revenue $ 6,900 Net loss $ (1,085 ) The amounts of revenue and net income of Newchem since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 Revenue $ 2,369 Net income $ 184
Daholquist Machine
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred		The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 16,098 Equity instruments 368 Contingent consideration 1,166 Fair value of total consideration transferred $ 17,632
Summary of the intangible assets acquired in the acquisition		Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Trade name $ 500 5 Customer relationships 7,800 14 Total intangible assets $ 8,300
Schedule of amounts of revenue and net (loss)		The amounts of revenue and net (loss) income of Dahlquist since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 Revenue $ 310 Net loss $ (940 )
Daholquist Machine | Incodema Holdings LLC
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred		The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following: Consideration (in thousands) Cash $ 33,557 Equity instruments 1,471 Fair value of total consideration transferred $ 35,028
Schedule of fair values of the assets acquired and liabilities		The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash and cash equivalents $ — Accounts receivable 2,645 Inventory 1,184 Other current assets 30 Prepaid expenses 201 Fixed assets 4,229 Intangible assets 20,100 Total assets acquired 28,389 Accounts payable 244 Accrued expenses 231 Other current liabilities 644 Total liabilities assumed 1,119 Total identifiable net assets 27,270 Goodwill $ 7,758
Summary of the intangible assets acquired in the acquisition		Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Trade name $ 1,500 5 Customer relationships 18,600 16 Total intangible assets $ 20,100
Schedule of amounts of revenue and net (loss)		The amounts of revenue and net (loss) income of Majestic since the acquisition date included in the Consolidated Statements of Comprehensive Loss for the reporting periods are as follows: (in thousands) 2020 Revenue $ 911 Net loss $ (1,129 )
Centex And Laser | Incodema LLC
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred	The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands): Centex Laser Total Cash $ 11,774 $ 6,946 $ 18,720 Fair value of total consideration transferred $ 11,774 $ 6,946 $ 18,720
Schedule of fair values of the assets acquired and liabilities	The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition of Centex and Laser (in thousands): Acquisition Date Fair Centex Laser Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ — $ 68 Accounts receivable 1,775 900 Inventory 524 622 Prepaid expenses 108 1 Fixed assets 1,787 760 Intangible assets 6,243 3,557 Other assets 1 2 Total assets acquired 10,438 5,910 Accounts payable 252 568 Paycheck Protection Program (PPP) loan 649 — Accrued expenses 271 27 Other current liabilities 23 44 Other noncurrent liabilities 1,234 703 Total liabilities assumed 2,429 1,342 Total identifiable net assets $ 8,009 $ 4,568 Goodwill 3,765 2,378
Summary of the intangible assets acquired in the acquisition	Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Estimated Life Trade name $ 510 5 Customer relationships 5,733 17 Total intangible assets $ 6,243 Acquisition Estimated Life Trade name $ 290 5 Customer relationships 3,267 17 Total intangible assets $ 3,557
Schedule of amounts of revenue and net (loss)	The amounts of revenue and net loss of Centex since the acquisition date included in the Unaudited Condensed Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 3,049 Net loss (1,102 )
Micropulse West | Incodema Holdings LLC
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred	The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands): Cash $ 12,452 Contingent consideration 1,295 Fair value of total consideration transferred $ 13,747
Schedule of fair values of the assets acquired and liabilities	The following table sets forth the preliminary fair values of the assets acquired and liabilities assumed in connection with the acquisition of Micropulse West (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ 70 Accounts receivable 866 Inventory 333 Other current assets 10 Fixed assets 2,490 Intangible assets 7,000 Total assets acquired 10,769 Accounts payable 139 Accrued expenses 13 Other current liabilities 99 Total liabilities assumed 251 Total identifiable net assets 10,518 Goodwill $ 3,229
Summary of the intangible assets acquired in the acquisition	Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Estimated Life Trade name $ 600 5 Customer relationships 6,400 17 Total intangible assets $ 7,000
Schedule of amounts of revenue and net (loss)	The amounts of revenue and net loss of Micropulse West since the acquisition date included in the Unaudited Condensed Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 3,022 Net loss (187 )
Summit Tooling And Summit Plastics
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred	The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands): Cash $ 10,875 Fair value of total consideration transferred $ 10,875
Schedule of fair values of the assets acquired and liabilities	The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of Summit (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ 40 Accounts receivable 627 Inventory 339 Fixed assets 4,371 Intangible assets 5,000 Total assets acquired 10,377 Accounts payable 40 Deferred revenue 776 Other current liabilities 95 Other noncurrent liabilities 1,323 Total liabilities assumed 2,234 Total identifiable net assets 8,143 Goodwill $ 2,732
Summary of the intangible assets acquired in the acquisition	Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Estimated Life (Years) Trade name $ 400 5 Customer relationships 4,600 11 Total Intangible assets $ 5,000
Schedule of amounts of revenue and net (loss)	The amounts of revenue and net loss of Summit since the acquisition date included in the Unaudited Condensed Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 4,496 Net loss (1,029 )
PPP
Business Acquisition [Line Items]
Schedule of fair value of the total purchase consideration transferred	The transaction was accounted for using the acquisition method of accounting and the fair value of the total purchase consideration transferred consisted of the following (in thousands) Cash $ 25,721 Fair value of total consideration transferred $ 25,721
Schedule of fair values of the assets acquired and liabilities	The following table sets forth the fair values of the assets acquired and liabilities assumed in connection with the acquisition of PPC (in thousands): Recognized amounts of identifiable assets acquired and liabilities assumed Cash $ 162 Accounts receivable 899 Inventory 480 Fixed assets 2,413 Intangible assets 14,200 Total assets acquired 18,154 Accounts payable 148 Accrued expenses 79 Total liabilities assumed 227 Total identifiable net assets 17,927 Goodwill $ 7,794
Summary of the intangible assets acquired in the acquisition	Below is a summary of the intangible assets acquired in the acquisition (in thousands): Acquisition Date Estimated Life Trade name $ 1,100 5 Customer relationships 13,100 17 Total intangible assets $ 14,200
Schedule of amounts of revenue and net (loss)	The amounts of revenue and net loss of PPC since the acquisition date included in the Unaudited Consolidated Statements of Comprehensive Loss for the nine months ended September 30, 2021 are as follows (in thousands): Revenue $ 4,571 Net loss (262 )

Revenue (Tables)

Revenue (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Disaggregation of Revenue [Abstract]
Schedule of Revenue by Product Line	Revenue by product line for the nine months ended September 30, 2021 and September 30, 2020 was as follows: Nine months ended (in thousands) 2021 2020 Revenue: Additive manufacturing $ 13,322 $ 12,755 Injection molding 20,941 12,999 CNC machining 30,063 8,093 Precision sheet metal 38,494 4,150 Other revenue 5,067 4,252 Total revenue $ 107,887 $ 42,249	Revenue by product line for the years ended December 31, 2020 and 2019 was as follows: Year ended December 31, (in thousands) 2020 2019 Revenue: Additive manufacturing $ 19,032 $ 11,461 Injection molding 17,093 2,056 CNC machining 9,173 3,833 Precision sheet metal 9,811 — Other revenue 6,180 3,268 Total revenue $ 61,289 $ 20,618

Inventory (Tables)

Inventory (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Summary of Inventory	The Company’s inventory consisted of the following as of September 30, 2021 and December 31, 2020, respectively (in thousands): September 30, December 31, Finished goods $ 3,338 $ 1,351 Raw materials 2,788 2,277 Work in process 2,684 2,359 Tooling 363 338 Total $ 9,173 $ 6,325	The Company’s inventory consisted of the following at December 31, 2020 and 2019, respectively (in thousands): December 31, 2020 December 31, 2019 Finished goods $ 1,351 $ 352 Raw materials 2,277 1,272 Work in process 2,359 73 Tooling 338 — Total $ 6,325 $ 1,697

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consist of the following as of September 30, 2021 and December 31, 2020, respectively (in thousands): September 30, December 31, Machinery & equipment $ 37,695 $ 25,214 Furniture & fixtures 930 812 Property and leasehold Improvements 6,556 2,838 Construction in progress 2,656 576 47,837 29,440 Accumulated depreciation and amortization (6,806 ) (3,054 ) Total $ 41,031 $ 26,386	Property and equipment consist of the following as of December 31, 2020 and 2019, respectively (in thousands): December 31, 2020 December 31, 2019 Machinery & equipment $ 25,214 $ 10,600 Furniture & fixtures 812 397 Property and leasehold Improvements 2,838 720 Construction in progress 576 256 $ 29,440 11,973 Accumulated depreciation and amortization (3,054 ) (1,164 ) Total $ 26,386 $ 10,809

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in the Carrying Amount of Goodwill	The carrying amount of goodwill as of September 30, 2021 and December 31, 2020 is as follows, respectively (in thousands): Dec. 31, 2020 Goodwill September 30, Goodwill $ 63,215 $ 19,898 $ 83,113	The changes in the carrying amount of goodwill for the years ended December 31, 2020 and 2019 were as follows: (in thousands) Dec. 31, 2018 Goodwill Dec. 31, 2019 Goodwill Dec. 31, 2020 Goodwill $ 8,775 $ 24,232 $ 33,007 $ 30,208 $ 63,215
Schedule of Intangible Assets Other Than Goodwill	Intangible assets other than goodwill at September 30, 2021 and December 31, 2020 were as follows: September 30, 2021 December 31, 2020 Useful Weighted (in thousands) Gross Accumulated Net Gross Accumulated Net Trade name $ 15,100 $ 2,133 $ 12,967 $ 12,200 $ 919 $ 11,281 5-15 11.4 Customer relationships 100,700 9,492 91,208 67,600 4,448 63,152 5 - 14.3 Developed software 6,400 1,680 4,720 6,400 720 5,680 5 7.4 Developed technology 4,500 1,822 2,678 4,500 1,147 3,353 5 8.0 Total intangible assets $ 126,700 $ 15,127 $ 111,573 $ 90,700 $ 7,234 $ 83,466	Intangible assets other than goodwill for the years ended December 31, 2020 and 2019 were as follows: Year Ended December 31, 2020 Year Ended December 31, 2019 (in thousands) Gross Accumulated Net Gross Accumulated Net Useful Weighted Trade name $ 12,200 $ 919 $ 11,281 $ 6,800 $ 249 $ 6,551 5-15 12.7 Customer relationships 67,600 4,448 63,152 25,600 1,591 24,009 5-16 13.3 Developed software 6,400 720 5,680 1,300 21 1,279 5 4.5 Developed technology 4,500 1,147 3,353 4,500 244 4,256 5 3.7 Total intangible assets $ 90,700 $ 7,234 $ 83,466 $ 38,200 $ 2,105 $ 36,095
Schedule of Estimated Amortization Expense	Estimated amortization expense for each of the next five years (in thousands): Remaining 2021 $ 2,887 2022 11,533 2023 11,533 2024 11,278 2025 9,706 Thereafter 64,637 Total $ 111,574	Estimated amortization expense for each of the next five years: 2021 $ 8,864 2022 $ 8,864 2023 $ 8,864 2024 $ 8,605 2025 $ 7,027 Thereafter $ 41,242 Total $ 83,466

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The Company’s debt as of September 30, 2021 and December 31, 2020 is as follows (in thousands): As of September 30, 2021 As of December 31, 2020 Debt Description Interest Rate Amount Interest Rate Amount 2018 Term Loan, as amended $ — 7.75% $ 29,700 2018 DDTL — 7.75% 2,990 2020 Term Loan — 3 month LIBOR 19,401 2020 DDTL — 3 month LIBOR 40,500 2021 Term Loan 3 month LIBOR + 172,000 — Total principal debt 172,000 92,591 Debt issuance costs (1,743 ) (1,867 ) PPP and other loans — 2,615 Total debt, net 170,257 93,339 Less: current portion of long-term debt — 2,853 Less: current 2021 Term Loan 172,000 — Less: current portion of debt issuance costs (1,743 ) — Long-term debt, net of current portion $ — $ 90,486	Subsequent to December 31, 2020, the Company has submitted requests for forgiveness. The Company expects to receive forgiveness for the entire loan balance in 2021. There can be no assurance that any portion of the PPP loans will be forgiven. (in thousands) As of December 31, 2020 As of December 31, 2019 Debt Description Interest Rate Amount Interest Amount 2018 Term Loan, as amended 7.75% $ 29,700 8.30 % $ 29,775 2018 DDTL 7.75% 2,990 8.30 % 993 2020 Term Loan 3 month LIBOR 19,401 — 2020 DDTL 3 month LIBOR 40,500 — Total principal long-term debt 92,591 30,768 Debt issuance costs (1,867 ) (862 ) PPP and other loans $ 2,615 — Total debt 93,339 29,906 Less: current portion of long-term debt 2,853 309 Long-term debt, net of current portion $ 90,486 $ 29,597
Schedule of Maturities of Long-term Debt	The balance of the above debt matures as follows: 2021 $ — 2022 172,000 Thereafter — Total $ 172,000	The balance of the above debt matures as follows: 2021 $ 2,853 2022 2,699 2023 31,614 2024 603 2025 603 Thereafter 56,834 Total 95,206

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases, Operating [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The Company determines if an arrangement is a lease at inception. Operating leases are off balance sheet arrangements with rent expense included in Cost of revenue and Selling, general and administrative in the Consolidated Statements of Comprehensive Loss. Future noncancelable operating lease commitments are as follows (in thousands): Year ended Total 2021 $ 2,585 2022 2,179 2023 1,834 2024 1,030 2025 589 Thereafter 465 Total lease payments $ 8,682

Other Income and Expense, Net (

Other Income and Expense, Net (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Other Income and Expenses [Abstract]
Schedule Of Other Income and Expense Net	Other Income and expense, net is comprised of the following for the nine months ended September 30, 2021 and September 30, 2020: September 30, 2021 September 30, 2020 Acquisition expenses $ 4,045 $ 1,925 Loss on debt extinguishment 2,031 — Loan prepayment fees 1,463 — Other 1,384 599 Loss on sale of assets 84 — Other expense $ 9,007 $ 2,524 Gain on sale of assets $ — $ (393 ) Gain on PPP forgiveness (1,624 ) — Change in FV of contingent consideration (1,120 ) — Other (471 ) (30 ) Other (income) (3,215 ) (423 ) Other expense and (income), net $ 5,792 $ 2,101	Other Income and expense, net is comprised of the following for the years ended December 31, 2020 and 2019: December 31, December 31, Acquisition expenses $ 3,765 $ 2,006 Change in fair value of contingent consideration 1,055 1,181 Other 1,515 — Other expense 6,335 3,187 Gain on sale of assets (214 ) — Other income (371 ) (189 ) Other (income) and expense, net 5,750 2,998

Class A Contingently Redeemab_2

Class A Contingently Redeemable Preferred Units (Tables)	12 Months Ended
	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
Schedule Of Class A Contingently Redeemable Preferred Units Issued and Outstanding	Shares Shares Original Carrying Accumulated Amount Class A Preferred Units 1,167,418 1,167,418 $ 46.35 $ 54,105 $ 9,253 $ 63,358 The Company has the following contingently redeemable preferred units issued and outstanding at December 31, 2019 (in thousands, except unit and per unit data): Shares Shares Original Carrying Accumulated Amount Class A Preferred Units 702,493 702,493 $ 45.32 $ 31,836 $ 3,209 $ 35,045

Members' Equity (Tables)

Members' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Members' Equity [Abstract]
Summary Of Members Equity	The following table represents a summary of the Company’s Member’s Equity as of December 31, 2020 and December 31, 2019: December 31, December 31, Class A Common Units 5,480,611 2,883,452 Class B Common Units 2,242,981 1,567,546 December 31, December 31, Class A Common Units $ 35,869 $ 18,701 Class B Common Units 14,450 10,467 $ 50,319 $ 29,168

Earnings Per Unit (Tables)

Earnings Per Unit (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Earnings Per Unit [Abstract]
Schedule of Computation of Basic and Diluted Earnings Per Units	September 30, 2021 September 30, 2020 (in thousands, except for unit and per unit amounts) Class A Class B Class A Class B Basic Earnings Per Unit: Numerator Net loss $ (5,718 ) $ (2,340 ) $ (734 ) $ (371 ) Less: annual dividends on redeemable preferred units (8,692 ) (3,557 ) (2,781 ) (1,405 ) Net loss attributable to common unitholders (14,410 ) (5,897 ) (3,515 ) (1,776 ) Denominator Weighted-average units used to compute basic earnings per unit 5,480,611 2,242,981 3,227,744 1,631,064 Basic and Diluted Earnings Per Unit $ (2.63 ) $ (2.63 ) $ (1.09) $ (1.09)	December 31, 2020 December 31, 2019 (in thousands, except for unit and per unit amounts) Class A Class B Class A Class B Basic Earnings Per Unit: Numerator Net income (loss) $ (5,380 ) $ (2,584 ) $ (3,201 ) $ (1,571 ) Less: annual dividends on redeemable preferred units (4,083 ) (1,961 ) (1,753 ) (860 ) Net income (loss) attributable to common unitholders (9,463 ) (4,545 ) (4,954 ) (2,431 ) Denominator Weighted-average units used to compute basic earnings per unit 3,531,681 1,696,135 1,578,164 774,500 Basic Earnings Per Unit $ (2.68 ) $ (2.68 ) $ (3.14 ) $ (3.14 )

Share Based Compensation (Table

Share Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule The fair value of awards granted was determined using the Black-Scholes pricing model	The fair value of awards granted was determined using the Black-Scholes pricing model and the following weighted-average assumptions in the table below as of the grant date. Expected volatility is based on the historic volatility of our guideline companies, which we believe best represent our company. 2020 2019 Risk-free interest rate 0.28 % 2.24 % Expected Term 4.65 4.47 Expected Volatility 76.67 % 73.55 % Expected dividend yield 0.00 % 0.00 %
Twenty Twenty Activity Plan [Member]
Summary of the activity in the plan	A summary of the activity in the plan for 2020 follows: Shares Weighted-Average Grant-Date Fair Value Nonvested at January 1, 2020 3,814 $ 96.74 Granted 5,250 51.02 Vested 380 90.07 Forfeited — — Nonvested at December 31, 2020 8,684 $ 63.74
Two Thousand Nineteen Plan Activity [Member]
Summary of the activity in the plan	A summary of the activity in the plan for 2019 follows: Shares Weighted-Average Grant-Date Fair Value Nonvested at January 1, 2019 — $ — Granted 4,000 97.34 Vested 186 109.59 Forfeited — — Nonvested at December 31, 2019 3,814 $ 96.74

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Fair Value Measurements, Recurring and Nonrecurring	Assets and liabilities measured at fair value on a recurring basis, are summarized below: Fair Value Measurement at September 30, 2021 Using: Quoted Prices Significant Other Significant Total Contingent consideration $ — $ — $ 8,630 $ 8,630 Fair Value Measurement at December 31, 2020 Using: Quoted Prices Significant Other Significant Total Contingent consideration $ — $ — $ 11,439 $ 11,439	Assets and liabilities measured at fair value on a recurring basis, are summarized below: Fair Value Measurement at December 31, 2020 Using: Quoted Prices in (Level 1) Significant Other (Level 2) Significant (Level 3) Total Contingent consideration $ — $ — $ 11,439 $ 11,439
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The table below presents a reconciliation of all liabilities measured at fair value on a recurring basis using significant on observable inputs (Level 3) as of and for the nine months ended September 30, 2021 and as of and for the twelve months ended December 31, 2020: Contingent Consideration September 30, December 31, Balance of recurring Level 3 liabilities at January 1 $ 11,439 $ — Total gains or losses for the period: Included in earnings (1,120 ) 1,055 Included in other comprehensive loss — — Issuances 1,295 11,737 Payments (2,984 ) (1,353 ) Transfers into Level 3 — — Transfers out of Level 3 — — Balance of recurring Level 3 liabilities at end of period $ 8,630 $ 11,439	The table below presents a reconciliation of all liabilities measured at fair value on a recurring basis using significant on observable inputs (Level 3) for the year ended December 31: Contingent Consideration 2020 2019 Balance of recurring Level 3 liabilities at January 1 $ — $ 2,319 Total gains or losses for the period: Included in earnings 1,055 1,181 Included in other comprehensive loss — — Issuances 11,737 — Payments (1,353 ) (3,500 ) Transfers into Level 3 — — Transfers out of Level 3 — — Balance of recurring Level 3 liabilities at December 31 $ 11,439 $ —
Disclosure Details Of Fair Value Measurements Of Assets And Liabilities Using Unobservable Inputs		The following table presents quantitative information about recurring Level 3 fair value measurements at December 31, 2020: Fair December 31, 2020 Contingent consideration $ 11,439
ALTIMAR ACQUISITION CORP. II [Member]
Schedule Of Fair Value Measurement Of Assets And Liabilities Based On Hierarchy	The following table presents information about the Company’s assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2021 and indicates the fair value hierarchy of the valuation inputs the Company utilized to determine such fair value: Description Level September 30, Assets: Investments held in the Trust Account 1 345,011,697 Liabilities: Warrant liability — Public Warrants 1 $ 9,070,433 Warrant liability — Private Placement Warrants 3 $ 10,572,537
Schedule Of Assumptions Used In Estimating The Fair Value Of Warrants	The following table provides quantitative information regarding Level 3 fair value meas ureme As of Stock price $ 9.85 Strike price $ 11.50 Term (in years) 5.0 Volatility 16.5 % Risk-free rate 1.00 % Dividend yield 0.0 %
Summary of changes in the fair value of warrant liabilities	The following table presents the changes in the fair value of Level 3 Warrant Private Public Warrant Fair value as of February 9, 2021 $ 17,144,332 $ 12,933,516 $ 30,077,848 Change in valuation inputs or other assumptions (3,784,363 ) (2,932,167 ) (6,716,530 ) Fair value of Warrants transferred out of Level 3 — (10,001,349 ) (10,001,349 ) Fair value of Level 3 Warrant $ 13,359,969 $ — $ 13,359,969 Change in valuation inputs or other assumptions $ (2,787,432 ) $ — $ (2,787,432 ) Fair value of Level 3 Warrant Liabilities as of September 30, 2021 $ 10,572,537 $ — $ 10,572,537

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Summary of income tax expense benefit	Significant components of the Company’s tax expense for the nine months ended September 30, 2021 and September 30, 2020, are as follows (in thousands): Nine Months Ended September 30 2021 2020 Current expense State 14 — Federal 1,044 — Subtotal 1,058 — Deferred tax benefit State (18 ) — Federal (233 ) — Subtotal (251 ) — Total 807 —
Summary of deferred tax assets and liabilities	Significant components of the Company’s net deferred tax liability as of September 30, 2021 and December 31, 2020, are as follows (in thousands): September 30, 2021 December 31, 2020 Deferred tax assets Net operating losses 68 — Allowance for bad debts 17 — Inventory reserves 116 — Other accruals 8 — Interest expense limitation 38 — Total deferred tax assets 247 — Deferred tax liabilities Fixed assets (487 ) — Intangibles (2,647 ) — Cash-to-accrual (122 ) — Total deferred tax liabilities (3,256 ) — Total net deferred tax liabilities (3,009 ) —

Nature of Business (Details)

Nature of Business (Details) - USD ($)

Apr. 30, 2021

Feb. 09, 2021

Dec. 31, 2020

Sep. 30, 2021

Sep. 30, 2021

Dec. 31, 2020

Dec. 31, 2018

Jul. 09, 2021

Dec. 18, 2020

Dec. 17, 2020

Dec. 15, 2020

Jul. 27, 2020

Dec. 02, 2019

Sep. 23, 2019

Aug. 31, 2018

Subsidiary, Sale of Stock [Line Items]

Limited Liability Company or Limited Partnership, Business, Formation Date

Apr. 16, 2021

Apr. 16, 2021

Threshold minimum cash proceeds from spac transaction

$ 313,000,000

Two Thousand And Twenty One Term Loan [Member]

Subsidiary, Sale of Stock [Line Items]

Proceeds from issuance of long term debt

172,000,000

Debt instrument face value

172,000,000

Term Loan [Member] | New Credit Agreement [Member]

Subsidiary, Sale of Stock [Line Items]

Debt instrument face value

125,000,000

$ 125,000,000

Revolving Credit Facility [Member] | New Credit Agreement [Member]

Subsidiary, Sale of Stock [Line Items]

Line of credit maximum borrowing capacity

$ 50,000,000

$ 50,000,000

Debt instrument maturity year

2026

Fathom LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

ICO Mold LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

MCT Holdings [Member]

Subsidiary, Sale of Stock [Line Items]

Subsidiary of Limited Liability Company or Limited Partnership, Date

Aug. 27, 2018

MCT Holdings [Member] | Equity Interest [Member]

Subsidiary, Sale of Stock [Line Items]

Ownership Interest

100.00%

100.00%

MCT Holdings [Member] | Midwest Composite Technologies, LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

MCT Holdings [Member] | Fathom LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

MCT Holdings [Member] | ICO Mold LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

Incodema Holding [Member]

Subsidiary, Sale of Stock [Line Items]

Subsidiary of Limited Liability Company or Limited Partnership, Date

Jul. 15, 2020

Incodema Holding [Member] | Equity Interest [Member]

Subsidiary, Sale of Stock [Line Items]

Ownership Interest

100.00%

100.00%

Incodema Holding [Member] | Incodema And Newchem LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

Incodema Holding [Member] | Daholquist Machine LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

Incodema Holding [Member] | Majestic Metals LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

Incodema Holding [Member] | Mark Two Engineering, LLC [Member]

Subsidiary, Sale of Stock [Line Items]

Business combination voting interests acquired

100.00%

ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Term of restricted investments

185 days

Warrant purchase price (in dollars per share)

$ 1

Transaction costs allocated to the Warrants

$ 0

$ 755,071

Threshold minimum aggregate fair market value as a percentage of the assts held in the Trust Account

80.00%

80.00%

Threshold percentage of public shares subject to redemption without the Company's prior written consent

50.00%

50.00%

Minimum net tangible assets upon consummation of the Business Combination

$ 5,000,001

5,000,001

$ 5,000,001

$ 5,000,001

Redemption threshold as percent of outstanding

15.00%

15.00%

Obligation to redeem public shares if entity does not complete a business combination

100.00%

100.00%

Days for redemption of public shares

10 days

10 days

Maximum net interest to pay dissolution expenses

$ 100,000

$ 100,000

Warrant Liabilities Private Warrants [Member] | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Class of warrants or rights subscribed but not issued

9,000,000

9,000,000

Class A common stock | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Shares issued price per share

$ 10

$ 10

Over-allotment | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Number of units issued (in shares)

4,500,000

Share price (in dollars per share)

$ 10

Number of warrants issued (in shares)

9,900,000

9,900,000

Proceeds from issuance of warrants

$ 9,900,000

Deferred underwriting fees

$ 12,075,000

$ 12,075,000

$ 12,075,000

$ 12,075,000

Over-allotment | Class A common stock | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Common stock shares subscribed but not issued

34,500,000

34,500,000

Share price (in dollars per share)

$ 10

$ 10

Private Placement | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Number of warrants issued (in shares)

9,900,000

9,000,000

9,000,000

Warrant purchase price (in dollars per share)

$ 1

$ 1

$ 1

Proceeds from issuance of warrants

$ 9,900,000

$ 9,000,000

Private Placement | Warrant Liabilities Private Warrants [Member] | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Class of warrants or rights subscribed but not issued

9,900,000

9,900,000

Initial Public Offering | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Share price (in dollars per share)

$ 10

10

$ 10

Assets held in trust

$ 345,000,000

Cash underwriting fees

6,900,000

Deferred underwriting fees

12,075,000

$ 10,500,000

$ 10,500,000

Other offering costs

515,958

Transaction costs allocated to the Warrants

$ 755,071

Transaction costs

$ 19,490,958

Initial Public Offering | Class A common stock | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Number of units issued (in shares)

34,500,000

Common stock shares subscribed but not issued

30,000,000

30,000,000

Share price (in dollars per share)

$ 10

$ 10

$ 10

Assets held in trust

$ 345,000,000

IPO Including Overallotment [Member] | Class A common stock | ALTIMAR ACQUISITION CORP. II [Member]

Subsidiary, Sale of Stock [Line Items]

Common stock shares subscribed but not issued

34,500,000

34,500,000

Restatement of Previously Iss_3

Restatement of Previously Issued Financial Statements (Details) - USD ($)		1 Months Ended	3 Months Ended			6 Months Ended	9 Months Ended
		Dec. 31, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Sep. 30, 2021	Feb. 09, 2021	Dec. 06, 2020	Dec. 31, 2019
Revision Of Prior Period Financial Statements [Line Items]
Class A Ordinary Shares subject to possible redemption		$ 54,105,000	$ 54,105,000				$ 54,105,000
Accumulated deficit		(14,232,000)	(22,290,000)				(22,290,000)			$ (6,269,000)
ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Class A Ordinary Shares subject to possible redemption			345,000,000	$ 345,000,000	$ 345,000,000	$ 345,000,000	345,000,000	$ 345,000,000
Class A Ordinary Shares								0
Additional paid-in capital		24,137	0				0	0
Accumulated deficit		(5,000)	(30,894,714)	(33,497,231)	(47,375,919)	(33,497,231)	(30,894,714)	(39,649,671)
Total shareholders' equity (deficit)		$ 20,000	$ (30,893,851)	$ (33,496,368)	(47,375,056)	(33,496,368)	$ (30,893,851)	(39,648,808)	$ 0
Initial classification of Class A Ordinary Shares subject to possible redemption					0	0
Change in value of Class A ordinary shares subject to possible redemption					$ 0	$ 0
Weighted average shares outstanding (in shares)	[1]	7,500,000
Basic and diluted net income (loss) per ordinary shares		$ 0
Redeemable Class A Ordinary Shares [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Weighted average shares outstanding (in shares)			34,500,000	34,500,000	19,550,000	27,066,298	29,571,429
Basic and diluted net income (loss) per ordinary shares			$ 0.06	$ 0.32	$ (0.57)	$ (0.05)	$ 0.02
Non Redeemable Class B Ordinary Shares [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Weighted average shares outstanding (in shares)			8,625,000	8,625,000	8,125,000	8,376,381	8,460,165
Basic and diluted net income (loss) per ordinary shares			$ 0.06	$ 0.32	$ (0.57)	$ (0.05)	$ 0.02
Previously Reported [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Class A Ordinary Shares subject to possible redemption				$ 306,503,630	$ 292,624,940	$ 306,503,630		300,351,190
Class A Ordinary Shares				385	524	385		446
Additional paid-in capital				6,850,719	20,729,270	6,850,719		13,003,096
Accumulated deficit				(1,851,965)	(15,730,653)	(1,851,965)		(8,004,403)
Total shareholders' equity (deficit)				$ 5,000,002	5,000,004	5,000,002		5,000,002
Initial classification of Class A Ordinary Shares subject to possible redemption					300,351,190	300,351,192
Change in value of Class A ordinary shares subject to possible redemption					$ (7,726,250)	$ 6,152,436
Previously Reported [Member] | Redeemable Class A Ordinary Shares [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Weighted average shares outstanding (in shares)				34,500,000	34,500,000	34,500,000
Basic and diluted net income (loss) per ordinary shares				$ 0	$ 0	$ 0
Previously Reported [Member] | Non Redeemable Class B Ordinary Shares [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Weighted average shares outstanding (in shares)				8,625,000	8,125,000	8,376,381
Basic and diluted net income (loss) per ordinary shares				$ 1.61	$ (1.94)	$ (0.22)
Revision of Prior Period, Adjustment [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Class A Ordinary Shares subject to possible redemption				$ 38,496,370	$ 52,375,060	$ 38,496,370		44,648,810
Class A Ordinary Shares				(385)	(524)	(385)		(446)
Additional paid-in capital				(6,850,719)	(20,729,270)	(6,850,719)		(13,003,096)
Accumulated deficit				(31,645,266)	(31,645,266)	(31,645,266)		(31,645,268)
Total shareholders' equity (deficit)				$ (38,496,370)	(52,375,060)	(38,496,370)		$ (44,648,810)
Initial classification of Class A Ordinary Shares subject to possible redemption					(300,351,190)	(300,351,192)
Change in value of Class A ordinary shares subject to possible redemption					$ 7,726,250	$ (6,152,436)
Revision of Prior Period, Adjustment [Member] | Redeemable Class A Ordinary Shares [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Weighted average shares outstanding (in shares)				0	(14,950,000)	(7,433,702)
Basic and diluted net income (loss) per ordinary shares				$ 0.32	$ (0.57)	$ (0.05)
Revision of Prior Period, Adjustment [Member] | Non Redeemable Class B Ordinary Shares [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Revision Of Prior Period Financial Statements [Line Items]
Weighted average shares outstanding (in shares)				0	0	0
Basic and diluted net income (loss) per ordinary shares				$ (1.29)	$ 1.37	$ 0.17
[1]	Includes an aggregate of up to 1,125,000 shares of Class B ordinary shares subject to forfeiture if the over-allotment option is not exercised in full or in part by the underwriters (see Note 5).

Restatement of Previously Iss_4

Restatement of Previously Issued Financial Statements - Additional Information (Details) - ALTIMAR ACQUISITION CORP. II [Member]	Sep. 30, 2021USD ($)$ / shares
Temporary equity redemption price per share | $ / shares	$ 10
Minimum tangible assets needed post redemption of temporary equity | $	$ 5,000,001

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Subsidiary, Sale of Stock [Line Items]
Income tax provision		$ 807,000	$ 0
Increase to accounts payable		866,000	$ (1,716,000)	$ 442,000	$ 1,886,000
Accounts Receivable, Allowance for Credit Loss				649	386
Goodwill, Impairment Loss					0
Impairments of intangible assets				0	0
Unbilled Revenues [Member]
Subsidiary, Sale of Stock [Line Items]
Unbilled Contracts Receivable				$ 173	$ 634
Revenue from Rights Concentration Risk [Member] | Revenue Benchmark [Member]
Subsidiary, Sale of Stock [Line Items]
Concentration Risk, Percentage				10.00%	10.00%
Revision of Prior Period, Error Correction, Adjustment [Member]
Subsidiary, Sale of Stock [Line Items]
Decrease in contingent consideration				$ 8,726
Decrease to accounts receivable				101
Decrease to other current assets				144
Decrease to property and equipment, net				418
Decrease to other non-current assets				48
Increase to accounts payable				253
Increase to other non-current liabilities				389
Increase to long-term contingent consideration				7,373
ALTIMAR ACQUISITION CORP. II [Member]
Subsidiary, Sale of Stock [Line Items]
Offering costs paid		397,461
Unrecognized tax benefits	$ 0	0		0
Unrecognized tax benefits accrued for interest and penalties	0	0		0
Investments held in the Trust Account	345,011,697	345,011,697		$ 0
Income tax provision	0	0
Maximum [Member] | Revenue from Rights Concentration Risk [Member] | Revenue Benchmark [Member]
Subsidiary, Sale of Stock [Line Items]
Concentration Risk, Percentage				19.00%
Minimum [Member] | Revenue from Rights Concentration Risk [Member] | Revenue Benchmark [Member]
Subsidiary, Sale of Stock [Line Items]
Concentration Risk, Percentage					12.00%
Minimum [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Subsidiary, Sale of Stock [Line Items]
Cash insured with federal depository insurance corporation	$ 250,000	$ 250,000
Class A common stock | ALTIMAR ACQUISITION CORP. II [Member]
Subsidiary, Sale of Stock [Line Items]
Temporary equity, shares outstanding	34,500,000	34,500,000		0
Initial Public Offering | ALTIMAR ACQUISITION CORP. II [Member]
Subsidiary, Sale of Stock [Line Items]
Stock issuance costs		$ 18,735,887
Offering costs paid		755,071
Offering costs		19,490,958
Transaction costs allocated to the Warrants		$ 755,071

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Basic and Diluted Net Income (Loss) Per Ordinary Share (Details) - USD ($)	1 Months Ended	3 Months Ended			9 Months Ended				12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2021		Sep. 30, 2020		Dec. 31, 2020		Dec. 31, 2019
Numerator—earnings allocable to redeemable Class A Ordinary Shares interest income
Allocation of net income (loss)					$ (8,058,000)		$ (1,105,000)		$ (7,963,000)		$ (4,771,000)
Denominator -weighted average shares
Weighted average shares outstanding basic (in shares)					7,723,592		4,858,808		5,227,816		2,352,664
Weighted average shares outstanding diluted (in shares)					7,723,592		4,858,808		5,227,816		2,352,664
Basic net income (loss) per share (in dollars per share)					$ (2.63)	[1]	$ (1.09)	[1]	$ (2.68)	[2]	$ (3.14)	[2]
Diluted net income (loss) per share (in dollars per share)					$ (2.63)	[1]	$ (1.09)	[1]	$ (2.68)	[2]	$ (3.14)	[2]
Class B Ordinary Shares Numerator—net income (loss) minus redeemable net earnings
Net income (loss)					$ (8,058,000)		$ (1,105,000)		$ (7,963,000)		$ (4,771,000)
ALTIMAR ACQUISITION CORP. II [Member]
Numerator—earnings allocable to redeemable Class A Ordinary Shares interest income
Allocation of net income (loss)	$ (5,000)	$ 2,602,517	$ 13,878,688	$ (15,725,653)	755,552
Class B Ordinary Shares Numerator—net income (loss) minus redeemable net earnings
Net income (loss)	$ (5,000)	2,602,517	$ 13,878,688	$ (15,725,653)	755,552
Redeemable Common Class A | ALTIMAR ACQUISITION CORP. II [Member]
Numerator—earnings allocable to redeemable Class A Ordinary Shares interest income
Allocation of net income (loss)		$ 2,082,014			$ 587,479
Denominator -weighted average shares
Weighted average shares outstanding basic (in shares)		34,500,000			29,571,429
Weighted average shares outstanding diluted (in shares)		34,500,000			29,571,429
Basic net income (loss) per share (in dollars per share)		$ 0.06			$ 0.02
Diluted net income (loss) per share (in dollars per share)		$ 0.06			$ 0.02
Class B Ordinary Shares Numerator—net income (loss) minus redeemable net earnings
Net income (loss)		$ 2,082,014			$ 587,479
Non Redeemable Common Class B | ALTIMAR ACQUISITION CORP. II [Member]
Numerator—earnings allocable to redeemable Class A Ordinary Shares interest income
Allocation of net income (loss)		$ 520,503			$ 168,073
Denominator -weighted average shares
Weighted average shares outstanding basic (in shares)		8,625,000			8,460,165
Weighted average shares outstanding diluted (in shares)		8,625,000			8,460,165
Basic net income (loss) per share (in dollars per share)		$ 0.06			$ 0.02
Diluted net income (loss) per share (in dollars per share)		$ 0.06			$ 0.02
Class B Ordinary Shares Numerator—net income (loss) minus redeemable net earnings
Net income (loss)		$ 520,503			$ 168,073
[1]	Basic and diluted net loss per unit amounts are the same for both Class A and Class B common units, see Note 10.
[2]	Basic and diluted net loss per unit amounts are the same for each class of common units, see Note 14.

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Temporary Equity Reconciliation of Cash Flows to Outstanding Value (Detail) - USD ($)	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Feb. 09, 2021	Dec. 31, 2020
Class A Ordinary Shares subject to possible redemption	$ 54,105,000				$ 54,105,000
ALTIMAR ACQUISITION CORP. II [Member]
Gross proceeds	345,000,000
Plus / (less) adjustments to carrying value:Proceeds allocated to the Public Warrants	(12,933,516)
Plus / (less) adjustments to carrying value:Class A Ordinary Shares issuance costs	(18,735,887)
Plus:Accretion of carrying value to redemption value	31,669,403
Class A Ordinary Shares subject to possible redemption	$ 345,000,000	$ 345,000,000	$ 345,000,000	$ 345,000,000

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of the Assets are Depreciated Over Their Estimated Useful Lives as Follows (Details)	12 Months Ended
	Dec. 31, 2020
Maximum [Member] | Property and leasehold Improvements [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Maximum [Member] | Machinery and Equipment [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	6 years
Maximum [Member] | Furniture and Fixtures [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Maximum [Member] | Vehicles And Equipment [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	4 years
Maximum [Member] | Software Development [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum [Member] | Property and leasehold Improvements [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	4 years
Minimum [Member] | Machinery and Equipment [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Minimum [Member] | Furniture and Fixtures [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Minimum [Member] | Vehicles And Equipment [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Minimum [Member] | Software Development [Member]
Schedule Of Property, Plant And Equipment, Estimated Useful Lives [Line Items]
Property, Plant and Equipment, Useful Life	1 year

Business Combination - Addition

Business Combination - Additional Information (Details) - USD ($) $ in Thousands	Dec. 18, 2020	Aug. 18, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Feb. 01, 2021	Dec. 17, 2020	Dec. 16, 2020	Jul. 27, 2020	Dec. 02, 2019	Sep. 23, 2019
Business Acquisition [Line Items]
Business combination total consideration transferred	$ 6,639				$ 47,067
Business combination provisional information initial accounting adjustment accounting incomplete adjustment inventory			$ 0	$ 1,063	649	$ (649)
Business combination provisional information initial accounting adjustment incoomplete adjustment property plant and equipment			306	2,045	2,282	2,139
Business combination provisional information initial accounting incomplete adjustment intangibles			773	5,349	3,821	7,223
Business combination provisional information initial accounting incomplete adjustment financial liabilities			(8,902)	$ 4,129	3,659	4,923
Incodema Holdings LLC
Business Acquisition [Line Items]
Business combination total consideration transferred			18,720
Fathom LLC
Business Acquisition [Line Items]
Business combination voting interests acquired												100.00%
Business combination acquistion costs expensed					1,094
Business combination total consideration transferred					29,835
ICO Mold LLC
Business Acquisition [Line Items]
Business combination voting interests acquired											100.00%
Business combination acquistion costs expensed						965
Payment of transaction fee to affiliate						$ 230
Incodema And Newchem LLC | Incodema LLC
Business Acquisition [Line Items]
Business combination voting interests acquired										100.00%
Business combination acquistion costs expensed					1,489
Payment of transaction fee to affiliate					400
Incodema
Business Acquisition [Line Items]
Business combination total consideration transferred					40,564
Incodema | Incodema LLC
Business Acquisition [Line Items]
Business combination undiscounted contingent consideration year one					3,260
Business combination undiscounted contingent consideration year two					3,480
Business combination undiscounted contingent consideration year three					3,020
Daholquist Machine
Business Acquisition [Line Items]
Business combination total consideration transferred					17,632
Daholquist Machine | Incodema Holdings LLC
Business Acquisition [Line Items]
Business combination voting interests acquired									100.00%
Business combination acquistion costs expensed					804
Payment of transaction fee to affiliate					252
Business combination contingent consideration arrangements range of outcomes low					600
Business combination contingent consideration arrangements range of outcomes high					4,600
Business combination total consideration transferred					35,028
Majestic Metals LLC | Incodema Holdings LLC
Business Acquisition [Line Items]
Business combination voting interests acquired								100.00%
Business combination acquistion costs expensed					1,145
Payment of transaction fee to affiliate					$ 361
GPI Prototype And Manufacturing Services | Midwest Composite Technologies, LLC
Business Acquisition [Line Items]
Business combination total consideration transferred		$ 2,441
GPI Prototype And Manufacturing Services | Indocema Buyer LLC
Business Acquisition [Line Items]
Business combination voting interests acquired	100.00%
Summit Tooling And Summit Plastics
Business Acquisition [Line Items]
Business combination voting interests acquired							100.00%
Business combination acquistion costs expensed			892
Payment of transaction fee to affiliate			225
Business combination total consideration transferred			$ 10,875
PPP
Business Acquisition [Line Items]
Business combination voting interests acquired			100.00%
Business combination acquistion costs expensed			$ 984
Payment of transaction fee to affiliate			264
Business combination total consideration transferred			$ 25,721
Centex And Laser | Incodema Holdings LLC
Business Acquisition [Line Items]
Business combination voting interests acquired			100.00%
Business combination acquistion costs expensed			$ 1,226
Payment of transaction fee to affiliate			$ 190
Micropulse West
Business Acquisition [Line Items]
Business combination voting interests acquired			100.00%
Business combination acquistion costs expensed			$ 869
Payment of transaction fee to affiliate			130
Business combination undiscounted contingent consideration year one			4,000
Business combination undiscounted contingent consideration year two			0
Business combination undiscounted contingent consideration year three			4,000
Business combination total consideration transferred			$ 13,747

Business Combination - Schedule

Business Combination - Schedule of Fair Value of the Total Purchase Consideration Transferred (Details) - USD ($) $ in Thousands	Dec. 18, 2020	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Cash			$ 37,268
Equity instruments			1,103
Contingent consideration			8,696
Fair value of total consideration transferred	$ 6,639		47,067
Incodema Holdings LLC
Business Acquisition [Line Items]
Cash		$ 18,720
Fair value of total consideration transferred		18,720
Fathom LLC
Business Acquisition [Line Items]
Cash			26,912
Equity instruments			2,923
Fair value of total consideration transferred			29,835
ICO Mold
Business Acquisition [Line Items]
Cash			15,998
Equity instruments			3,219
Fair value of total consideration transferred			19,217
Incodema
Business Acquisition [Line Items]
Cash			30,948
Equity instruments			920
Contingent consideration			8,696
Fair value of total consideration transferred			40,564
Newchem
Business Acquisition [Line Items]
Cash			6,320
Equity instruments			183
Contingent consideration			0
Fair value of total consideration transferred			6,503
Daholquist Machine
Business Acquisition [Line Items]
Cash			16,098
Equity instruments			368
Contingent consideration			1,166
Fair value of total consideration transferred			17,632
Daholquist Machine | Incodema Holdings LLC
Business Acquisition [Line Items]
Cash			33,557
Equity instruments			1,471
Fair value of total consideration transferred			$ 35,028
Summit Tooling And Summit Plastics
Business Acquisition [Line Items]
Cash		10,875
Fair value of total consideration transferred		10,875
PPP
Business Acquisition [Line Items]
Cash		25,721
Fair value of total consideration transferred		25,721
Centex | Incodema Holdings LLC
Business Acquisition [Line Items]
Cash		11,774
Fair value of total consideration transferred		11,774
Laser | Incodema Holdings LLC
Business Acquisition [Line Items]
Cash		6,946
Fair value of total consideration transferred		6,946
Micropulse West
Business Acquisition [Line Items]
Cash		12,452
Contingent consideration		1,295
Fair value of total consideration transferred		$ 13,747

Business Combination - Schedu_2

Business Combination - Schedule of Fair Values of the Assets Acquired and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Cash		$ 357
Accounts receivable		1,215
Inventory		1,597
Indemnification asset - PPP Loan		518
Prepaid expenses		8
Fixed assets		3,753
Intangible assets		8,300
Total assets acquired		15,748
Accounts payable		68
Paycheck Protection Program (PPP) loan		518
Accrued expenses		475
Total liabilities assumed		1,061
Total identifiable net assets		14,687
Goodwill		2,945
Fathom LLC
Business Acquisition [Line Items]
Cash		125
Accounts receivable		2,298
Inventory		333
Prepaid expenses		351
Fixed assets		4,627
Intangible assets		14,100
Total assets acquired		21,834
Accounts payable		1,852
Accrued expenses		491
Other current liabilities		141
Taxes payable		158
Long-term debt		63
Total liabilities assumed		2,705
Total identifiable net assets		19,129
Goodwill		10,706
ICO Mold
Business Acquisition [Line Items]
Cash		105
Accounts receivable		800
Inventory		88
Prepaid expenses		20
Fixed assets		62
Intangible assets		5,500
Total assets acquired		6,575
Accounts payable		678
Accrued expenses		194
Taxes payable		12
Total liabilities assumed		884
Total identifiable net assets		5,691
Goodwill		13,526
Incodema
Business Acquisition [Line Items]
Cash		63
Accounts receivable		2,370
Inventory		735
Other current assets		3
Prepaid expenses		77
Fixed assets		2,277
Intangible assets		19,300
Total assets acquired		24,825
Accounts payable		324
Accrued expenses		110
Taxes payable		286
Total liabilities assumed		720
Total identifiable net assets		24,105
Goodwill		16,459
Newchem
Business Acquisition [Line Items]
Cash		69
Accounts receivable		741
Inventory		487
Other current assets		1
Prepaid expenses		8
Fixed assets		1,949
Intangible assets		2,800
Total assets acquired		6,055
Accounts payable		223
Accrued expenses		35
Taxes payable		61
Total liabilities assumed		319
Total identifiable net assets		5,736
Goodwill		767
Daholquist Machine | Incodema Holdings LLC
Business Acquisition [Line Items]
Cash		0
Accounts receivable		2,645
Inventory		1,184
Other current assets		30
Prepaid expenses		201
Fixed assets		4,229
Intangible assets		20,100
Total assets acquired		28,389
Accounts payable		244
Accrued expenses		231
Other current liabilities		644
Total liabilities assumed		1,119
Total identifiable net assets		27,270
Goodwill		$ 7,758
Summit Tooling And Summit Plastics
Business Acquisition [Line Items]
Cash	$ 40
Accounts receivable	627
Inventory	339
Fixed assets	4,371
Intangible assets	5,000
Total assets acquired	10,377
Accounts payable	40
Deferred revenue	776
Other current liabilities	95
Other noncurrent liabilities	1,323
Total liabilities assumed	2,234
Total identifiable net assets	8,143
Goodwill	2,732
PPP
Business Acquisition [Line Items]
Cash	162
Accounts receivable	899
Inventory	480
Fixed assets	2,413
Intangible assets	14,200
Total assets acquired	18,154
Accounts payable	148
Accrued expenses	79
Total liabilities assumed	227
Total identifiable net assets	17,927
Goodwill	7,794
Centex | Incodema Holdings LLC
Business Acquisition [Line Items]
Cash	0
Accounts receivable	1,775
Inventory	524
Other current assets	1
Prepaid expenses	108
Fixed assets	1,787
Intangible assets	6,243
Total assets acquired	10,438
Accounts payable	252
Paycheck Protection Program (PPP) loan	649
Accrued expenses	271
Other current liabilities	23
Other noncurrent liabilities	1,234
Total liabilities assumed	2,429
Total identifiable net assets	8,009
Goodwill	3,765
Laser | Incodema Holdings LLC
Business Acquisition [Line Items]
Cash	68
Accounts receivable	900
Inventory	622
Other current assets	2
Prepaid expenses	1
Fixed assets	760
Intangible assets	3,557
Total assets acquired	5,910
Accounts payable	568
Paycheck Protection Program (PPP) loan	0
Accrued expenses	27
Other current liabilities	44
Other noncurrent liabilities	703
Total liabilities assumed	1,342
Total identifiable net assets	4,568
Goodwill	2,378
Micropulse West
Business Acquisition [Line Items]
Cash	70
Accounts receivable	866
Inventory	333
Other current assets	10
Fixed assets	2,490
Intangible assets	7,000
Total assets acquired	10,769
Accounts payable	139
Accrued expenses	13
Other current liabilities	99
Total liabilities assumed	251
Total identifiable net assets	10,518
Goodwill	$ 3,229

Business Combination - Summary

Business Combination - Summary of the Intangible Assets Acquired in the Acquisition (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 8,300
Fathom LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		14,100
ICO Mold
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		5,500
Incodema
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		19,300
Newchem
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		2,800
Daholquist Machine | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		20,100
Summit Tooling And Summit Plastics
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 5,000
PPP
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	14,200
Centex | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	6,243
Laser | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	3,557
Micropulse West
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	7,000
Trade Name
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 500
Estimated Life (Years)		5 years
Trade Name | Fathom LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 4,300
Estimated Life (Years)		15 years
Trade Name | ICO Mold
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 700
Estimated Life (Years)		5 years
Trade Name | Incodema
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 2,700
Estimated Life (Years)		15 years
Trade Name | Newchem
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 300
Estimated Life (Years)		5 years
Trade Name | Daholquist Machine | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 1,500
Estimated Life (Years)		5 years
Trade Name | Summit Tooling And Summit Plastics
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 400
Estimated Life (Years)	5 years
Trade Name | PPP
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 1,100
Estimated Life (Years)	5 years
Trade Name | Centex | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 510
Estimated Life (Years)	5 years
Trade Name | Laser | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 290
Estimated Life (Years)	5 years
Trade Name | Micropulse West
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 600
Estimated Life (Years)	5 years
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 7,800
Estimated Life (Years)		14 years
Customer Relationships | Fathom LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 5,300
Estimated Life (Years)		10 years
Customer Relationships | ICO Mold
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 3,500
Estimated Life (Years)		6 years
Customer Relationships | Incodema
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 11,500
Estimated Life (Years)		9 years
Customer Relationships | Newchem
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 2,500
Estimated Life (Years)		16 years
Customer Relationships | Daholquist Machine | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 18,600
Estimated Life (Years)		16 years
Customer Relationships | Summit Tooling And Summit Plastics
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 4,600
Estimated Life (Years)	11 years
Customer Relationships | PPP
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 13,100
Estimated Life (Years)	17 years
Customer Relationships | Centex | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 5,733
Estimated Life (Years)	17 years
Customer Relationships | Laser | Incodema Holdings LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 3,267
Estimated Life (Years)	17 years
Customer Relationships | Micropulse West
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 6,400
Estimated Life (Years)	17 years
Developed Technology Rights | Fathom LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 4,500
Estimated Life (Years)		5 years
Developed Technology Rights | ICO Mold
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 1,300
Estimated Life (Years)		5 years
Developed Technology Rights | Incodema
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value		$ 5,100
Estimated Life (Years)		5 years

Business Combination - Schedu_3

Business Combination - Schedule of Amounts of Revenue and Net (Loss) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Revenue		$ 310
Net income (loss)		(940)
Fathom LLC [Member]
Business Acquisition [Line Items]
Revenue		20,899	$ 6,569
Net income (loss)		370	(1,488)
ICO Mold [Member]
Business Acquisition [Line Items]
Revenue		10,884	672
Net income (loss)		641	$ (982)
Incodema [Member]
Business Acquisition [Line Items]
Revenue		6,900
Net income (loss)		(1,085)
Newchem [Member]
Business Acquisition [Line Items]
Revenue		2,369
Net income (loss)		184
Daholquist Machine [Member] | Incodema Holdings LLC [Member]
Business Acquisition [Line Items]
Revenue		911
Net income (loss)		$ (1,129)
Summit Tooling And Summit Plastics [Member]
Business Acquisition [Line Items]
Revenue	$ 4,496
Net income (loss)	(1,029)
PPP [Member]
Business Acquisition [Line Items]
Revenue	4,571
Net income (loss)	(262)
Centex [Member] | Incodema Holdings LLC [Member]
Business Acquisition [Line Items]
Revenue	3,049
Net income (loss)	(1,102)
Laser [Member] | Incodema Holdings LLC [Member]
Business Acquisition [Line Items]
Revenue	2,707
Net income (loss)	425
Micropulse West [Member]
Business Acquisition [Line Items]
Revenue	3,022
Net income (loss)	$ (187)

Business Combination - Schedu_4

Business Combination - Schedule of Supplemental and Unaudited Pro Forma Information (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Business Combinations [Abstract]
Revenue	$ 118,254	$ 111,945	$ 110,583	$ 97,020
Net income (loss)	$ 2,261	$ (1,203)	$ (7,441)	$ (11,223)

Revenue - Schedule of Revenue b

Revenue - Schedule of Revenue by Product Line (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 107,887	$ 42,249	$ 61,289	$ 20,618
Additive manufacturing
Disaggregation of Revenue [Line Items]
Total revenue	13,322	12,755	19,032	11,461
Injection molding
Disaggregation of Revenue [Line Items]
Total revenue	20,941	12,999	17,093	2,056
CNC machining
Disaggregation of Revenue [Line Items]
Total revenue	30,063	8,093	9,173	3,833
Precision sheet metal
Disaggregation of Revenue [Line Items]
Total revenue	38,494	4,150	9,811	0
Other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 5,067	$ 4,252	$ 6,180	$ 3,268

Revenue - Additional Informatio

Revenue - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Deferred Revenue	$ 1,679	$ 1,210	$ 368

Inventory - Summary of Inventor

Inventory - Summary of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Inventory, Net [Abstract]
Finished goods	$ 3,338	$ 1,351	$ 352
Raw materials	2,788	2,277	1,272
Work in process	2,684	2,359	73
Tooling	363	338	0
Total	$ 9,173	$ 6,325	$ 1,697

Initial Public Offering (Detail

Initial Public Offering (Details) - ALTIMAR ACQUISITION CORP. II [Member]	Feb. 09, 2021$ / sharesshares	Sep. 30, 2021$ / shares	Dec. 31, 2020$ / sharesshares
Public Warrants
Subsidiary, Sale of Stock [Line Items]
Exercise price of warrants (in dollars per share)			$ 11.50
Over-allotment
Subsidiary, Sale of Stock [Line Items]
Sale of Class A Ordinary Shares (in shares) | shares	4,500,000
Share Price	$ 10
Exercise price of warrants (in dollars per share)	11.50
Initial Public Offering
Subsidiary, Sale of Stock [Line Items]
Share Price	$ 10	$ 10
Number of shares in a unit (in shares) | shares	1
Number of warrants issued per unit (in shares)	0.25
Shares issuable per warrant (in shares) | shares	1
Class A common stock
Subsidiary, Sale of Stock [Line Items]
Sale of Class A Ordinary Shares (in shares) | shares	34,500,000
Shares issued price per share			$ 10
Class A common stock | Over-allotment
Subsidiary, Sale of Stock [Line Items]
Share Price		10
Common stock shares subscribed but not issued | shares			34,500,000
Class A common stock | Initial Public Offering
Subsidiary, Sale of Stock [Line Items]
Share Price	$ 10	$ 10
Common stock shares subscribed but not issued | shares			30,000,000

Private Placement (Details)

Private Placement (Details) - ALTIMAR ACQUISITION CORP. II [Member] - USD ($)	Feb. 09, 2021	Dec. 31, 2020
Subsidiary, Sale of Stock [Line Items]
Warrant purchase price (in dollars per share)	$ 1
Private Placement
Subsidiary, Sale of Stock [Line Items]
Number of warrants issued (in shares)	9,900,000	9,000,000
Warrant purchase price (in dollars per share)	$ 1	$ 1
Proceeds from issuance of warrants	$ 9,900,000	$ 9,000,000
Shares issuable per warrant (in shares)	1	1
Exercise price of warrants (in dollars per share)	$ 11.50	$ 11.50
Over-allotment
Subsidiary, Sale of Stock [Line Items]
Number of warrants issued (in shares)		9,900,000
Proceeds from issuance of warrants		$ 9,900,000
Exercise price of warrants (in dollars per share)	$ 11.50

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 47,837	$ 29,440	$ 11,973
Accumulated depreciation and amortization	(6,806)	(3,054)	(1,164)
Total	41,031	26,386	10,809
Machinery & equipment
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	37,695	25,214	10,600
Furniture & fixtures
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	930	812	397
Property and leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	6,556	2,838	720
Construction in progress
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 2,656	$ 576	$ 256

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 9,327	$ 2,797	$ 4,825	$ 1,605
Operating Expense [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	2,110	105	598	135
Cost of Revenue [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 2,679	$ 2,196	$ 2,567	$ 1,054

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Changes in the Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 63,215	$ 33,007	$ 8,775
Goodwill acquired	19,898	30,208	24,232
Goodwill	$ 83,113	$ 63,215	$ 33,007

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Intangible Assets Other Than Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 126,700	$ 90,700	$ 38,200
Finite-Lived Intangible Assets, Accumulated Amortization	15,127	7,234	2,105
Finite-Lived Intangible Assets, Net	111,573	83,466	36,095
Trade name
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	15,100	12,200	6,800
Finite-Lived Intangible Assets, Accumulated Amortization	2,133	919	249
Finite-Lived Intangible Assets, Net	$ 12,967	$ 11,281	6,551
Finite-Lived Intangible Assets, Weighted Average Useful Life Remaining	11 years 4 months 24 days	12 years 8 months 12 days
Trade name | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years	15 years
Trade name | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years	5 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 100,700	$ 67,600	25,600
Finite-Lived Intangible Assets, Accumulated Amortization	9,492	4,448	1,591
Finite-Lived Intangible Assets, Net	$ 91,208	$ 63,152	24,009
Finite-Lived Intangible Assets, Weighted Average Useful Life Remaining	14 years 3 months 18 days	13 years 3 months 18 days
Customer relationships | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years	16 years
Customer relationships | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years	5 years
Developed software
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 6,400	$ 6,400	1,300
Finite-Lived Intangible Assets, Accumulated Amortization	1,680	720	21
Finite-Lived Intangible Assets, Net	$ 4,720	$ 5,680	1,279
Finite-Lived Intangible Asset, Useful Life	5 years	5 years
Finite-Lived Intangible Assets, Weighted Average Useful Life Remaining	7 years 4 months 24 days	4 years 6 months
Developed technology
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 4,500	$ 4,500	4,500
Finite-Lived Intangible Assets, Accumulated Amortization	1,822	1,147	244
Finite-Lived Intangible Assets, Net	$ 2,678	$ 3,353	$ 4,256
Finite-Lived Intangible Asset, Useful Life	5 years	5 years
Finite-Lived Intangible Assets, Weighted Average Useful Life Remaining	8 years	3 years 8 months 12 days

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Remaining 2021	$ 2,887
2022 and 2021	11,533	$ 8,864
2023 and 2022	11,533	8,864
2024 and 2023	11,278	8,864
2025 and 2024	9,706	8,605
2025		7,027
Thereafter	64,637
Thereafter		41,242
Total	111,573	83,466	$ 36,095
Intangible Assets, Amortization Period [Member]
Total	$ 111,574	$ 83,466

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 7,892	$ 3,368	$ 5,129	$ 1,714
Intangible assets other than goodwill with indefinite useful lives	0		0
Operating expenses	$ 7,217	$ 2,692	$ 4,227	$ 1,470

Long -Term Debt - Schedule of L

Long -Term Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total principal debt	$ 172,000	$ 92,591	$ 30,768
Debt issuance costs	(1,743)	(1,867)	(862)
Total debt, net	170,257	93,339	29,906
Less: current portion of long-term debt	170,257	2,853	309
Less: current 2021 Term Loan	172,000	0
Less: current portion of debt issuance costs	(1,743)	0
Long-term debt, net of current portion	0	90,486	29,597
Two Thousand And Eighteen Term Loan As Amended [Member]
Debt Instrument [Line Items]
Principal debt	0	$ 29,700	$ 29,775
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate		7.75%	8.30%
Two Thousand And Eighteen Delay Draw Down Term Loan [Member]
Debt Instrument [Line Items]
Principal debt	0	$ 2,990	$ 993
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate		7.75%	8.30%
Two Thousand And Twenty Term Loan [Member]
Debt Instrument [Line Items]
Principal debt	0	$ 19,401	$ 0
Debt Instrument, Interest Rate Terms		3 month LIBOR + 7.50%
Two Thousand And Twenty Delay Draw Term Loan [Member]
Debt Instrument [Line Items]
Principal debt	0	$ 40,500	0
Debt Instrument, Interest Rate Terms		3 month LIBOR + 7.50%
Two Thousand And Twenty One Term Loan [Member]
Debt Instrument [Line Items]
Principal debt	$ 172,000	$ 0
Debt Instrument, Interest Rate Terms	3 month LIBOR +3.5%
Paycheck Protection Programme And Other Loans [Member]
Debt Instrument [Line Items]
Principal debt	$ 0	$ 2,615	$ 0

Long -Term Debt - Schedule of_2

Long -Term Debt - Schedule of Long-term Debt Instruments (Parenthetical) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Two Thousand And Twenty One Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	3.50%
Two Thousand And Twenty Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		7.50%
Two Thousand And Twenty Delay Draw Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		7.50%

Long -Term Debt - Schedule of M

Long -Term Debt - Schedule of Maturities of Long Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
2021 (Remainder of 2021)	$ 0
2021	172,000	$ 2,853
2022		2,699
2023		31,614
2024		603
2025		603
Thereafter		56,834
Thereafter	0
Total	$ 172,000	$ 95,206

Long - Term Debt - Additional I

Long - Term Debt - Additional Information (Details) - USD ($)

Apr. 30, 2021

Aug. 18, 2020

Jul. 27, 2020

May 31, 2020

Aug. 31, 2018

Sep. 30, 2021

Sep. 30, 2020

Dec. 31, 2020

Dec. 31, 2019

Jul. 09, 2021

Dec. 16, 2020

Dec. 02, 2019

Sep. 23, 2019

Sep. 23, 2018

Debt Instrument [Line Items]

Long term debt date of maturity

Jul. 27, 2026

Amortization of debt issuance costs

$ 1,342,000

$ 153,000

$ 205,000

$ 56,000

Subsequent Event [Member]

Debt Instrument [Line Items]

Amortization of debt issuance costs

1,342,000

153,000

205,000

56,000

Interest and debt expense

8,800,000

$ 2,335,000

3,665,000

$ 1,616,000

New Credit Agreement [Member]

Debt Instrument [Line Items]

Increase decrease in term loan facility and revolving credit facility

$ 100,000,000

Revolving Credit Facility [Member] | New Credit Agreement [Member]

Debt Instrument [Line Items]

Line of credit maximum borrowing capacity

$ 50,000,000

50,000,000

Revolving Credit Facility [Member] | New Credit Agreement [Member] | Letter of Credit [Member]

Debt Instrument [Line Items]

Line of credit maximum borrowing capacity

5,000,000

Revolving Credit Facility [Member] | New Credit Agreement [Member] | Subsequent Event [Member]

Debt Instrument [Line Items]

Line of credit maximum borrowing capacity

50,000,000

Paycheck Protection Programme Loan [Member]

Debt Instrument [Line Items]

Proceeds from issuance of long term debt

$ 1,624,000

Long term debt term

2 years

Period for which the loan may be used for qualifying expenses

168 days

Long term debt moratorium period

10 months

Long term debt fixed interest rate percentage

1.00%

Forgiveness of debt

$ 1,624,000

Paycheck Protection Programme Loan [Member] | Dahlquist And Mark Two [Member]

Debt Instrument [Line Items]

Business combination recognized identifiable assets acquired and liabilities assumed non current liabilities long term debt

$ 991,000

Business combination indemnification amount assets amount as of acquistion date

$ 991,000

Two Thousand And Twenty One Term Loan [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 172,000,000

Long term debt date of maturity

Apr. 29, 2022

Proceeds from issuance of long term debt

$ 172,000,000

Two Thousand And Twenty One Term Loan [Member] | Subsequent Event [Member]

Debt Instrument [Line Items]

Debt instrument face value

172,000,000

Proceeds from issuance of long term debt

172,000,000

Term Loan [Member] | New Credit Agreement [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 125,000,000

125,000,000

Term Loan [Member] | New Credit Agreement [Member] | Subsequent Event [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 125,000,000

Two Thousand And Eighteen Credit Facility [Member] | Delayed Draw Term Loan [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 10,000,000

Long term debt date of maturity

Aug. 23, 2023

Two Thousand And Eighteen Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Term Loan [Member]

Debt Instrument [Line Items]

Long term debt variable interest rate percentage

8.30%

7.75%

Debt instrument face value

$ 15,000,000

Long term debt borrowing fees percentage

1.00%

Debt issuance costs capitalized

$ 390,000

Two Thousand And Eighteen Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Term Loan [Member] | Third Amendement Agreement [Member] | Additional Term Loan For Business Acquuistion [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 15,000,000

Debt issuance costs capitalized

344,000

Debt issuance costs gross

461,000

Amortization of debt issuance costs

117,000

Two Thousand And Eighteen Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Delayed Draw Term Loan [Member]

Debt Instrument [Line Items]

Proceeds from issuance of long term debt

$ 2,000,000

Two Thousand And Eighteen Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Delayed Draw Term Loan [Member] | Second Amendment Agreement [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 8,500,000

$ 10,000,000

Two Thousand And Eighteen Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Delayed Draw Term Loan [Member] | Third Amendement Agreement [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 3,500,000

Two Thousand And Eighteen Credit Facility [Member] | Revolving Credit Facility [Member] | Second And Third Amendment Agreement To The Credit Facility [Member]

Debt Instrument [Line Items]

Line of credit facility capacity available for specific purposes other than trade purchases

$ 3,100,000

$ 2,750,000

Two Thousand And Eighteen Credit Facility [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]

Debt Instrument [Line Items]

Line of credit maximum borrowing capacity

$ 1,500,000

Line of credit facility expiration date

Aug. 31, 2023

Line of credit unused commitement capacity fees percentage

0.50%

Long term debt variable interest rate percentage

7.75%

8.30%

Line of credit outstanding

$ 0

$ 0

Two Thousand And Eighteen Credit Facility [Member] | Delayed Draw Term Loan [Member] | Second And Third Amendment Agreement To The Credit Facility [Member]

Debt Instrument [Line Items]

Debt instrument unused borrowing capacity

510,000

$ 7,507,000

Two Thousand And Eighteen Credit Facility [Member] | Delayed Draw Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Third Amendement Agreement [Member]

Debt Instrument [Line Items]

Date of expiry of availability of borrowings

Feb. 26, 2021

Two Thousand And Twenty Credit Facility [Member] | Secured Subordinated Credit Facility [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 34,500,000

$ 40,500,000

Two Thousand And Twenty Credit Facility [Member] | Secured Subordinated Credit Facility [Member] | Term Loan [Member]

Debt Instrument [Line Items]

Debt instrument face value

19,500,000

Debt issuance costs capitalized

520,000

Debt issuance costs gross

520,000

Proceeds from issuance of long term debt

$ 19,500,000

Debt instrument periodic payment principal

$ 50,000

Debt instrument date of first required payment

Sep. 30, 2020

Debt instrument frequency of periodic payment

quarterly

Two Thousand And Twenty Credit Facility [Member] | Secured Subordinated Credit Facility [Member] | Delayed Draw Term Loan [Member]

Debt Instrument [Line Items]

Long term debt variable interest rate percentage

7.738%

7.738%

Debt instrument face value

$ 15,000,000

Debt issuance costs capitalized

$ 32,000

Amortization of debt issuance costs

$ 32,000

Debt instrument periodic payment principal

$ 100,000

Debt instrument date of first required payment

Mar. 31, 2021

Debt instrument frequency of periodic payment

quarterly

Debt instrument unused borrowing capacity commitement fee percentage

1.00%

1.00%

0.50%

Two Thousand And Twenty Credit Facility [Member] | Secured Subordinated Credit Facility [Member] | Delayed Draw Term Loan [Member] | For The First Six Months [Member]

Debt Instrument [Line Items]

Debt issuance costs capitalized

$ 660,000

Debt issuance costs gross

$ 692,000

Amortization of debt issuance costs

$ 660,000

Operating Leases - Schedule of

Operating Leases - Schedule of Future Minimum Rental Payments for Operating Leases (Details)	Dec. 31, 2020USD ($)
Leases, Operating [Abstract]
2021	$ 2,585
2022	2,179
2023	1,834
2024	1,030
2025	589
Thereafter	465
Total lease payments	$ 8,682

Operating Leases - Additional I

Operating Leases - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases Operating [Line Items]
Rental expense	$ 1,536	$ 795
Other Noncurrent Liabilities [Member]
Leases Operating [Line Items]
Deferred rent	$ 48	$ 35
Maximum [Member]
Leases Operating [Line Items]
Lease terms	7 years
Minimum [Member]
Leases Operating [Line Items]
Lease terms	2 years

Retirement Plans - Additional I

Retirement Plans - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items]
Total employer matching contributions to the plans	$ 330	$ 96

Other Income and Expense, Net -

Other Income and Expense, Net - Schedule of Other Income and Expense Net (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Other Income and Expenses [Abstract]
Acquisition expenses	$ 4,045,000	$ 1,925,000	$ 3,765	$ 2,006
Loss on debt extinguishment	2,031,000	0
Loan prepayment fees	1,463,000	0
Other	1,384,000	599,000	1,515	0
Loss on sale of assets	84,000	0
Other expense	9,007,000	2,524,000	6,335	3,187
Gain on sale of assets	0	(393,000)	(214)	0
Gain on PPP forgiveness	(1,624,000)	0
Change in FV of contingent consideration	(1,120,000)	0	1,055	1,181
Other	(471,000)	(30,000)
Other (income)	(3,215,000)	(423,000)	(371)	(189)
Other expense and (income), net	$ 5,792,000	$ 2,101,000	$ 5,750	$ 2,998

Class A Contingently Redeemab_3

Class A Contingently Redeemable Preferred Units - Schedule of Class A Contingently Redeemable Preferred Units Issued and Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Temporary Equity, Carrying value	$ 54,105	$ 54,105
Class A Preferred Units [Member]
Temporary Equity [Line Items]
Temporary Equity, Shares Authorized		1,167,418	702,493
Temporary Equity, Shares Issued		1,167,418	702,493
Temporary Equity, Shares Outstanding		1,167,418	702,493
Temporary Equity, Original Issuance Price		$ 46.35	$ 45.32
Temporary Equity, Carrying value		$ 54,105	$ 31,836
Temporary Equity, Accumulated Unpaid Dividends		9,253	3,209
Temporary Equity, Amount contingently redeemable		$ 63,358	$ 35,045

Class A Contingently Redeemab_4

Class A Contingently Redeemable Preferred Units - Additional Information (Details) - Class A Preferred Units [Member] - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Temporary equity, par value (in dollars per share)	$ 100
Temporary equity accumulated preferred return percentage	8.00%
Dividends	$ 0	$ 0
Payments of dividends	$ 0	$ 0

Members' Equity - Schedule Of M

Members' Equity - Schedule Of Members Equity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Members Equity [Line Items]
Common Unit, Issuance Value		$ 50,319	$ 29,168
Class A Common Units [Member]
Members Equity [Line Items]
Common Unit, Outstanding	5,480,611	5,480,611	2,883,452
Common Unit, Issuance Value	$ 35,869	$ 35,869	$ 18,701
Class B Common Units [Member]
Members Equity [Line Items]
Common Unit, Outstanding	2,242,981	2,242,981	1,567,546
Common Unit, Issuance Value	$ 14,481	$ 14,450	$ 10,467

Members' Equity - Additional In

Members' Equity - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020
Class A Common Units [Member]
Members Equity [Line Items]
Common units voting rights	one
Class B Common Units [Member]
Members Equity [Line Items]
Common units voting rights	not entitled to vote

Earnings Per Unit - Schedule of

Earnings Per Unit - Schedule of Computation of Basic and Diluted Earnings Per Units (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended				12 Months Ended
	Sep. 30, 2021		Sep. 30, 2020		Dec. 31, 2020		Dec. 31, 2019
Numerator
Net income (loss)	$ (8,058)		$ (1,105)		$ (7,963)		$ (4,771)
Weighted-average units used to compute basic earnings per unit	7,723,592		4,858,808		5,227,816		2,352,664
Basic Earnings Per Unit	$ (2.63)	[1]	$ (1.09)	[1]	$ (2.68)	[2]	$ (3.14)	[2]
Class A Common Units [Member]
Numerator
Net income (loss)	$ (5,718)		$ (734)		$ (5,380)		$ (3,201)
Less: annual dividends on redeemable preferred units	(8,692)		(2,781)		(4,083)		(1,753)
Net income (loss) attributable to common unitholders	$ (14,410)		$ (3,515)		$ (9,463)		$ (4,954)
Weighted-average units used to compute basic earnings per unit	5,480,611		3,227,744		3,531,681		1,578,164
Basic Earnings Per Unit					$ (2.68)		$ (3.14)
Basic and Diluted Earnings Per Unit	$ (2.63)		$ (1.09)
Class B Common Units [Member]
Numerator
Net income (loss)	$ (2,340)		$ (371)		$ (2,584)		$ (1,571)
Less: annual dividends on redeemable preferred units	(3,557)		(1,405)		(1,961)		(860)
Net income (loss) attributable to common unitholders	$ (5,897)		$ (1,776)		$ (4,545)		$ (2,431)
Weighted-average units used to compute basic earnings per unit	2,242,981		1,631,064		1,696,135		774,500
Basic Earnings Per Unit					$ (2.68)		$ (3.14)
Basic and Diluted Earnings Per Unit	$ (2.63)		$ (1.09)
[1]	Basic and diluted net loss per unit amounts are the same for both Class A and Class B common units, see Note 10.
[2]	Basic and diluted net loss per unit amounts are the same for each class of common units, see Note 14.

Earnings Per Unit - Additional

Earnings Per Unit - Additional Information (Details) - shares	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Unit [Line Items]
Dilutive instruments outstanding	0	0	0	0
Class A Preferred Units
Earnings Per Unit [Line Items]
Accrued cumulative dividends rate percentage	8.00%		8.00%

Related Party Transactions - Fo

Related Party Transactions - Founder Shares (Details) - ALTIMAR ACQUISITION CORP. II [Member] - $ / shares	Jan. 28, 2021	Dec. 15, 2020	Sep. 30, 2021	Feb. 09, 2021
Related Party Transaction [Line Items]
Shares subject to forfeiture (in shares)	1,125,000	1,125,000
Common stock, shares subject to forfeiture, as a percent of issued and outstanding shares	20.00%	20.00%
Number of shares no longer subject to forfeiture (in shares)				1,125,000
Stock price trigger to transfer, assign or sell any shares or warrants of the company, after the completion of the initial business combination (in dollars per share)		$ 12	$ 12
Threshold period for not to transfer, assign or sell any of their shares or warrants after the completion of the initial business combination		150 days	150 days
Maximum
Related Party Transaction [Line Items]
Threshold period after the business combination in which the 20 trading days within any 30 trading day period commences		20 days	20 days
Sponsor
Related Party Transaction [Line Items]
Threshold period after the business combination in which the 20 trading days within any 30 trading day period commences		30 days	30 days
Sponsor | Founder Shares
Related Party Transaction [Line Items]
Founder Shared held by Sponsor (in shares)	8,450,000	8,625,000
Class B common stock | Sponsor
Related Party Transaction [Line Items]
Shares transferred (in shares)	25,000	25,000

Related Party Transactions - Ad

Related Party Transactions - Additional information (Details) - USD ($)	Feb. 09, 2021	Feb. 04, 2021	Dec. 31, 2020	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 15, 2020
Management Services Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses					$ 1,431,000	$ 355,000	$ 742,000	$ 308,000
ALTIMAR ACQUISITION CORP. II [Member]
Related Party Transaction [Line Items]
Repayment of promissory note—related party					94,890
Affiliate
Related Party Transaction [Line Items]
Related party transaction purchases from related party					6,200,000	$ 4,434,000	6,438,000	$ 1,092,000
Affiliate | ALTIMAR ACQUISITION CORP. II [Member]
Related Party Transaction [Line Items]
Administrative expenses - related party		$ 10,000	$ 10,000
Related Party Loans | ALTIMAR ACQUISITION CORP. II [Member]
Related Party Transaction [Line Items]
Maximum loans converted into warrants			$ 2,000,000	$ 2,000,000	$ 2,000,000		$ 2,000,000
Exercise price of warrants (in dollars per share)			$ 1	$ 1	$ 1		$ 1
Amounts outstanding under the working capital loans			$ 0	$ 0	$ 0		$ 0
Administrative Support Agreement | ALTIMAR ACQUISITION CORP. II [Member]
Related Party Transaction [Line Items]
Transaction amount				30,000	80,000
Due to related parties				$ 10,000	$ 10,000
Sponsor | Promissory Note | ALTIMAR ACQUISITION CORP. II [Member]
Related Party Transaction [Line Items]
Principal amount									$ 300,000
Interest rate									0.00%
Repayment of promissory note—related party	$ 94,890		$ 5,000

Share Based Compensation - Sche

Share Based Compensation - Schedule The fair value of awards granted was determined using the Black-Scholes pricing model (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate	0.28%	2.24%
Expected Term	4 days 15 hours	4 days 11 hours
Expected Volatility	76.67%	73.55%
Expected dividend yield	0.00%	0.00%

Share Based Compensation - Summ

Share Based Compensation - Summary of the activity in the plan (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Twenty Twenty Activity Plan [Member]
Nonvested ,Share	3,814
Granted , Shares	5,250
Vested , Shares	380
Forfeited , Shares	0
Nonvested ,Shares	8,684	3,814
Nonvested	$ 96.74
Granted	51.02
Vested	90.07
Forfeited	0
Nonvested	$ 63.74	$ 96.74
Two Thousand Nineteen Plan Activity [Member]
Nonvested ,Share	3,814	0
Granted , Shares		4,000
Vested , Shares		186
Forfeited , Shares		0
Nonvested ,Shares		3,814
Nonvested	$ 96.74	$ 0
Granted		97.34
Vested		109.59
Forfeited		0
Nonvested		$ 96.74

Share Based Compensation - Addi

Share Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Total compensation cost	$ 34	$ 21
Percentage of vesting of award under share-based payment arrangement	10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0	0
Two Thousand Nineteen Phantom Equity Bonus Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	10,000
Two Thousand Nineteen Phantom Equity Bonus Plan [Member] | Minimum [Member]
Percentage of vesting of award under share-based payment arrangement	25.00%
Two Thousand Nineteen Phantom Equity Bonus Plan [Member] | Maximum [Member]
Percentage of vesting of award under share-based payment arrangement	75.00%
Twenty Twenty Activity Plan [Member] | Phantom Units [Member]
Total unrecognized compensation cost	$ 554
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 9 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$ 34
Two Thousand Nineteen Plan Activity [Member] | Phantom Units [Member]
Total unrecognized compensation cost	$ 368
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	3 years 9 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$ 21

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Maximum [Member] | Measurement Input, Discount Rate [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Business combination contingent consideration liability measurement input	0.188	0.188
Maximum [Member] | Measurement Input, Price Volatility [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Business combination contingent consideration liability measurement input	0.802	0.802
Maximum [Member] | Measurement Input, Credit Spread [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Business combination contingent consideration liability measurement input	0.066	0.066
Minimum [Member] | Measurement Input, Discount Rate [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Business combination contingent consideration liability measurement input	0.029	0.029
Minimum [Member] | Measurement Input, Price Volatility [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Business combination contingent consideration liability measurement input	0.153	0.153
Minimum [Member] | Measurement Input, Credit Spread [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Business combination contingent consideration liability measurement input	0.052	0.052
ALTIMAR ACQUISITION CORP. II [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Cash	$ 331,112,000	$ 0
Money Market Funds | ALTIMAR ACQUISITION CORP. II [Member]
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Cash	$ 345,011,697

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value Measurement of Assets And Liabilities Based on Hierarchy (Details) - ALTIMAR ACQUISITION CORP. II [Member]	Sep. 30, 2021USD ($)
Investments held in the Trust Account | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 345,011,697
Public Warrants | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	9,070,433
Private Placement Warrants | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	$ 10,572,537

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Assumptions Used in Estimating the Fair Value of Measurements (Details) - Valuation Technique, Option Pricing Model - ALTIMAR ACQUISITION CORP. II [Member]	Sep. 30, 2021yr
Stock price
Disclosure Of Assumptions Used In Estimating The Fair Value Of Warrants [Line Items]
Fair value measurements	9.85
Strike price
Disclosure Of Assumptions Used In Estimating The Fair Value Of Warrants [Line Items]
Fair value measurements	11.50
Term (in years)
Disclosure Of Assumptions Used In Estimating The Fair Value Of Warrants [Line Items]
Fair value measurements	5
Volatility
Disclosure Of Assumptions Used In Estimating The Fair Value Of Warrants [Line Items]
Fair value measurements	0.165
Risk-free rate
Disclosure Of Assumptions Used In Estimating The Fair Value Of Warrants [Line Items]
Fair value measurements	0.0100
Dividend yield
Disclosure Of Assumptions Used In Estimating The Fair Value Of Warrants [Line Items]
Fair value measurements	0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes in the Fair Value of Level 3 Warrant Liabilities (Details) - Warrant - ALTIMAR ACQUISITION CORP. II [Member] - USD ($)	3 Months Ended	5 Months Ended
	Sep. 30, 2021	Jun. 30, 2021
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Beginning Balance	$ 13,359,969	$ 30,077,848
Change in valuation inputs or other assumptions	(2,787,432)	(6,716,530)
Fair value of the Warrants transferred out of Level 3		(10,001,349)
Fair Value, Ending Balance	10,572,537	13,359,969
Private Placement Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Beginning Balance	13,359,969	17,144,332
Change in valuation inputs or other assumptions	(2,787,432)	(3,784,363)
Fair value of the Warrants transferred out of Level 3		0
Fair Value, Ending Balance	10,572,537	13,359,969
Public Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Beginning Balance	0	12,933,516
Change in valuation inputs or other assumptions	0	(2,932,167)
Fair value of the Warrants transferred out of Level 3		(10,001,349)
Fair Value, Ending Balance	$ 0	$ 0

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Measured on Recurring and Non Recurring Basis (Details) - Fair Value, Recurring [Member] - Business Combination Contingent Consideration Liability [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	$ 8,630	$ 11,439
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	$ 8,630	$ 11,439

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Measured on Recurring Basis Unobservable Input Reconciliation (Details) - Business Combination Contingent Consideration Liability [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Beginning Balance	$ 11,439	$ 0	$ 2,319
Included in earnings	(1,120)	1,055	1,181
Included in other comprehensive loss	0	0	0
Issuances	1,295	11,737	0
Payments	(2,984)	(1,353)	(3,500)
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Fair Value, Ending Balance	$ 8,630	$ 11,439	$ 0

Fair Value Measurement - Summ_3

Fair Value Measurement - Summary of Fair Value Measurements of Assets and Liabilities Using Unobservable Inputs (Details) - Business Combination Contingent Consideration Liability [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	$ 8,630	$ 11,439	$ 0	$ 2,319
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration		$ 11,439

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	1 Months Ended
	Dec. 31, 2020	Sep. 30, 2021	Jul. 15, 2021	Feb. 09, 2021	Apr. 21, 2020	Apr. 17, 2020
Commitments And Contingencies [Line Items]
Business combination, indemnification assets	$ 518,000
PPP Loan [Member] | Mark Two [Member]
Commitments And Contingencies [Line Items]
Indemnification assets offset on PPP loan						$ 473,000
PPP Loan [Member] | Dahlquist [Member]
Commitments And Contingencies [Line Items]
Indemnification assets offset on PPP loan					$ 518,000
Other Assets [Member]
Commitments And Contingencies [Line Items]
Business combination, indemnification assets	$ 991,000
Fathom Inc [Member] | ALTIMAR ACQUISITION CORP. II [Member]
Commitments And Contingencies [Line Items]
Business combination proforma equity value			$ 1,500,000,000
Souce of funding the business combination private investment in common stock			$ 80,000,000
Investment owned value per share			$ 10
Underwriting Agreement | ALTIMAR ACQUISITION CORP. II [Member]
Commitments And Contingencies [Line Items]
Underwriting discount per share	$ 0.20
Over-allotment | ALTIMAR ACQUISITION CORP. II [Member]
Commitments And Contingencies [Line Items]
Deferred underwriting fee per unit (in dollars per share)	$ 0.35	$ 0.35
Deferred underwriting fees	$ 12,075,000	$ 12,075,000
Over-allotment | Underwriting Agreement | ALTIMAR ACQUISITION CORP. II [Member]
Commitments And Contingencies [Line Items]
Period granted to subscribe for the shares	45 days
Common stock shares subscribed but not issued	4,500,000
IPO | ALTIMAR ACQUISITION CORP. II [Member]
Commitments And Contingencies [Line Items]
Deferred underwriting fees	$ 10,500,000			$ 12,075,000
IPO | Underwriting Agreement | ALTIMAR ACQUISITION CORP. II [Member]
Commitments And Contingencies [Line Items]
Cash underwriting discount payable	6,000,000
IPO Including Overallotment | Underwriting Agreement | ALTIMAR ACQUISITION CORP. II [Member]
Commitments And Contingencies [Line Items]
Cash underwriting discount payable	$ 6,900,000

Shareholders' Equity - Preferre

Shareholders' Equity - Preferred Stock Shares (Details) - ALTIMAR ACQUISITION CORP. II [Member] - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

Shareholders' Equity - Common S

Shareholders' Equity - Common Stock Shares (Details) - ALTIMAR ACQUISITION CORP. II [Member]	1 Months Ended	9 Months Ended
	Dec. 31, 2020vote$ / sharesshares	Sep. 30, 2021vote$ / sharesshares
Class A common stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Common stock, voting rights (in votes) | vote	1	1
Common stock, shares issued (in shares)	0
Common stock, shares outstanding (in shares)	0
Possible redemption (in shares)	0	34,500,000
Class B common stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Common stock, voting rights (in votes) | vote	1	1
Common stock, shares issued (in shares)	8,625,000	8,625,000
Common stock, shares outstanding (in shares)	8,625,000	8,625,000
Common stock, conversion basis	20	20
Common stock shares subject to forfeiture	1,125,000
Percentage of common stock issued and outstanding	20.00%

Shareholders' Equity - Warrants

Shareholders' Equity - Warrants (Details) - ALTIMAR ACQUISITION CORP. II [Member]	Feb. 09, 2021$ / shares	Dec. 31, 2020Day$ / shares	Sep. 30, 2021Day
Class of Warrant or Right [Line Items]
Minimum threshold written notice period for redemption of public warrants	30 days	30 days
Public Warrants exercisable term from the closing of the initial public offering	1 year	1 year
Warrant term	5 years	5 years
Threshold period for filling registration statement after business combination	20 days	20 days
Maximum threshold period for registration statement to become effective after business combination	60 days	60 days
Percentage of gross proceeds on total equity proceeds	60.00%	60.00%
Adjustment of exercise price of warrants based on market value and newly issued price	115.00%	115.00%
Adjustment of redemption price of stock based on market value and newly issued price 1	180.00%	180.00%
Public Warrants | Redemption of Warrants When the Price per Share of Class A Common Stock Equals or Exceeds $18.00
Class of Warrant or Right [Line Items]
Minimum threshold written notice period for redemption of public warrants	30 days	30 days
Stock price trigger for redemption of public warrants (in dollars per share)	$ 18	$ 18
Redemption price per public warrant (in dollars per share)	$ 0.01	$ 0.01
Threshold trading days for redemption of public warrants | Day		20	20
Threshold consecutive trading days for redemption of public warrants | Day		30	30
Notice period	3 days	3 days
Public Warrants | Redemption of Warrants When the Price per Share of Class A Common Stock Equals or Exceeds $10.00
Class of Warrant or Right [Line Items]
Minimum threshold written notice period for redemption of public warrants	30 days	30 days
Stock price trigger for redemption of public warrants (in dollars per share)	$ 10	$ 10
Redemption price per public warrant (in dollars per share)	$ 0.10	$ 0.10
Threshold trading days for redemption of public warrants | Day		20	20
Threshold consecutive trading days for redemption of public warrants | Day		30	30
Notice period	3 days	3 days
Class A common stock | Maximum
Class of Warrant or Right [Line Items]
Share price (in dollars per share)	$ 9.20	$ 9.20

Warrant Liability - Additional

Warrant Liability - Additional Information (Details) - ALTIMAR ACQUISITION CORP. II [Member]	Feb. 09, 2021$ / shares	Dec. 31, 2020Day$ / sharesshares	Sep. 30, 2021Dayshares
Class of Warrant or Right [Line Items]
Minimum threshold written notice period for redemption of public warrants	30 days	30 days
Public Warrants exercisable term from the closing of the initial public offering	1 year	1 year
Warrant term	5 years	5 years
Threshold period for filling registration statement after business combination	20 days	20 days
Maximum threshold period for registration statement to become effective after business combination	60 days	60 days
Percentage of gross proceeds on total equity proceeds	60.00%	60.00%
Adjustment of exercise price of warrants based on market value and newly issued price	115.00%	115.00%
Adjustment of redemption price of stock based on market value and newly issued price 1	180.00%	180.00%
Public Warrants
Class of Warrant or Right [Line Items]
Class of warrants or rights outstanding (in shares) | shares		0	8,625,000
Public Warrants | Redemption of Warrants When the Price per Share of Class A Common Stock Equals or Exceeds $18.00
Class of Warrant or Right [Line Items]
Minimum threshold written notice period for redemption of public warrants	30 days	30 days
Stock price trigger for redemption of public warrants (in dollars per share)	$ 18	$ 18
Redemption price per public warrant (in dollars per share)	$ 0.01	$ 0.01
Threshold trading days for redemption of public warrants | Day		20	20
Threshold consecutive trading days for redemption of public warrants | Day		30	30
Notice period	3 days	3 days
Public Warrants | Redemption of Warrants When the Price per Share of Class A Common Stock Equals or Exceeds $10.00
Class of Warrant or Right [Line Items]
Minimum threshold written notice period for redemption of public warrants	30 days	30 days
Stock price trigger for redemption of public warrants (in dollars per share)	$ 10	$ 10
Redemption price per public warrant (in dollars per share)	$ 0.10	$ 0.10
Threshold trading days for redemption of public warrants | Day		20	20
Threshold consecutive trading days for redemption of public warrants | Day		30	30
Notice period	3 days	3 days
Private Warrants
Class of Warrant or Right [Line Items]
Class of warrants or rights outstanding (in shares) | shares		0	9,900,000
Class A common stock | Maximum
Class of Warrant or Right [Line Items]
Share price (in dollars per share)	$ 9.20	$ 9.20

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Expense Benefit (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Current expense
State	$ 14	$ 0
Federal	1,044	0
Subtotal	1,058	0
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
State	(18)	0
Federal	(233)	0
Subtotal	(251)	0
Total	$ 807	$ 0

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Deferred tax assets
Net operating losses	$ 68	$ 0
Allowance for bad debts	17	0
Inventory reserves	116	0
Other accruals	8	0
Interest expense limitation	38	0
Total deferred tax assets	247	0
Deferred tax liabilities
Fixed assets	(487)	0
Intangibles	(2,647)	0
Cash-to-accrual adjustments	(122)	0
Total deferred tax liabilities	(3,256)	$ 0
Total net deferred tax liabilities	$ (3,009)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Effective Income Tax Rate Reconciliation, Percent	(11.10%)	0.00%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Unrecognized Tax Benefits, Income Tax Penalties Expense	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	Nov. 16, 2021	Apr. 30, 2021	Feb. 01, 2021	Dec. 18, 2020	Dec. 31, 2020	Dec. 31, 2019	Jul. 09, 2021
Subsequent Event [Line Items]
Business combination total consideration transferred				$ 6,639,000	$ 47,067,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents					$ 357,000
Shares Granted, Shares, Share-based Payment Arrangement, Forfeited					0	0
Two Thousand And Twenty One Term Loan [Member]
Subsequent Event [Line Items]
Proceeds from issuance of long term debt		$ 172,000,000
Debt instrument face value		172,000,000
New Credit Agreement [Member] | Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Line of credit maximum borrowing capacity		50,000,000					$ 50,000,000
New Credit Agreement [Member] | Term Loan [Member]
Subsequent Event [Line Items]
Debt instrument face value		$ 125,000,000					125,000,000
Subsequent Event | Summit Tooling And Summit Plastics LLC [Member]
Subsequent Event [Line Items]
Business combination voting interests acquired			100.00%
Business combination total consideration transferred			$ 10,990,000
Subsequent Event | Centex Machine and Welding Inc And Laser Manufacturing inc [Member]
Subsequent Event [Line Items]
Business combination voting interests acquired		100.00%
Business combination total consideration transferred		$ 18,839,000
Subsequent Event | Sureshot Precision LLC [Member]
Subsequent Event [Line Items]
Business combination voting interests acquired		100.00%
Business combination total consideration transferred		$ 12,542,000
Subsequent Event | Precision Process Corporation [Member]
Subsequent Event [Line Items]
Business combination voting interests acquired		100.00%
Business combination total consideration transferred		$ 24,135,000
Subsequent Event | Two Thousand And Twenty One Term Loan [Member]
Subsequent Event [Line Items]
Proceeds from issuance of long term debt		172,000,000
Debt instrument face value		$ 172,000,000
Subsequent Event | Delayed Draw Term Loan [Member] | Summit Tooling And Summit Plastics LLC [Member] | Two Thousand And Twenty Amended Credit Facility [Member]
Subsequent Event [Line Items]
Proceeds from issuance of long term debt			$ 5,500,000
Subsequent Event | New Credit Agreement [Member] | Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Line of credit maximum borrowing capacity							50,000,000
Subsequent Event | New Credit Agreement [Member] | Term Loan [Member]
Subsequent Event [Line Items]
Debt instrument face value							$ 125,000,000
Subsequent Event | Business Combination Agreement [Member] | Fathom Digital Manufacturing Corporation [Member]
Subsequent Event [Line Items]
Shares Granted, Shares, Share-based Payment Arrangement, Forfeited	2,587,500,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	1,000
Business Acquisition, Share Price	$ 10,000
Business acquisition equity interest issued or issuable increase in number of shares issued	1,293,750
Subsequent Event | Business Combination Agreement [Member] | Fathom Digital Manufacturing Corporation [Member] | Maximum
Subsequent Event [Line Items]
Payments to Acquire Businesses, Gross	$ 313,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	25,000,000
Business Combination, Separately Recognized Transactions, Liabilities Recognized	22,000,000
Subsequent Event | Business Combination Agreement [Member] | Fathom Digital Manufacturing Corporation [Member] | Minimum
Subsequent Event [Line Items]
Payments to Acquire Businesses, Gross	90,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	10,000,000
Business Combination, Separately Recognized Transactions, Liabilities Recognized	$ 20,000,000