CONDENSED CONSOLIDATED STATEMENTS OF NONCONTROLLING INTEREST, REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Previously Reported	Legacy Gelesis Redeemable Convertible Preferred Stock	Legacy Gelesis Redeemable Convertible Preferred Stock Previously Reported	Legacy Gelesis Redeemable Convertible Preferred Stock Retroactive Application of Recapitalization	Series A-3 Redeemable Convertible Preferred Stock	Common Stock Commitment Shares	Noncontrolling Interest	Noncontrolling Interest Previously Reported	Common Stock	Common Stock Previously Reported	Common Stock Retroactive Application of Recapitalization	Common Stock Common Stock Commitment Shares	Additional Paid-in Capital	Additional Paid-in Capital Previously Reported	Additional Paid-in Capital Common Stock Commitment Shares	Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income Previously Reported	Accumulated Deficit	Accumulated Deficit Previously Reported
Balance at Dec. 31, 2020	$ (146,938)	$ (146,938)								$ 1	$ 1			$ 23,907	$ 23,907		$ 938	$ 938	$ (171,784)	$ (171,784)
Temporary Equity Balance at Dec. 31, 2020			$ 213,525	$ 213,525				$ 12,429	$ 12,429
Temporary Equity Balance, shares at Dec. 31, 2020			47,813,946	18,446,525	29,367,421
Balance, shares at Dec. 31, 2020										5,587,094	2,155,490	3,431,604
Accretion of Legacy Gelesis senior preferred stock to redemption value	(33,761)													(33,761)
Temporary Equity, Accretion of Legacy Gelesis senior preferred stock to redemption value			$ 33,761
Temporary Equity, Exercise of Legacy Gelesis preferred stock warrants						$ 2,997
Temporary Equity, Exercise of Legacy Gelesis preferred stock warrants, shares						752,709
Stock based compensation expense	1,455													1,455
Issuance of common stock upon exercise of stock options	4													4
Issuance of common stock upon exercise of stock options shares										2,634
Accretion of noncontrolling interest put option to redemption value	(94)																		(94)
Temporary Equity, Accretion of noncontrolling interest put option to redemption value								94
Foreign currency translation adjustment	(411)																(411)
Temporary Equity, Foreign currency translation adjustment								(546)
Net loss	(18,586)																		(18,586)
Balance at Mar. 31, 2021	(198,331)									$ 1				(8,395)			527		(190,464)
Temporary Equity Balance at Mar. 31, 2021				$ 250,283				11,977
Temporary Equity Balance, shares at Mar. 31, 2021			48,566,655
Balance, shares at Mar. 31, 2021										5,589,728
Balance at Dec. 31, 2020	(146,938)	(146,938)								$ 1	$ 1			23,907	23,907		938	938	(171,784)	(171,784)
Temporary Equity Balance at Dec. 31, 2020			$ 213,525	$ 213,525				12,429	12,429
Temporary Equity Balance, shares at Dec. 31, 2020			47,813,946	18,446,525	29,367,421
Balance, shares at Dec. 31, 2020										5,587,094	2,155,490	3,431,604
Net loss	(74,055)
Balance at Sep. 30, 2021	(356,892)									$ 1				(111,141)			372		(246,124)
Temporary Equity Balance at Sep. 30, 2021			$ 356,696					12,021
Temporary Equity Balance, shares at Sep. 30, 2021			48,566,655
Balance, shares at Sep. 30, 2021										5,615,192
Balance at Mar. 31, 2021	(198,331)									$ 1				(8,395)			527		(190,464)
Temporary Equity Balance at Mar. 31, 2021				$ 250,283				11,977
Temporary Equity Balance, shares at Mar. 31, 2021			48,566,655
Balance, shares at Mar. 31, 2021										5,589,728
Accretion of Legacy Gelesis senior preferred stock to redemption value	(82,365)													(82,365)
Temporary Equity, Accretion of Legacy Gelesis senior preferred stock to redemption value			$ 82,365
Temporary Equity, Exercise of Legacy Gelesis preferred stock warrants			$ 937
Stock based compensation expense	1,639													1,639
Issuance of common stock upon exercise of stock options	5													5
Issuance of common stock upon exercise of stock options shares										25,464
Accretion of noncontrolling interest put option to redemption value	(96)																		(96)
Temporary Equity, Accretion of noncontrolling interest put option to redemption value								96
Foreign currency translation adjustment	43																43
Temporary Equity, Foreign currency translation adjustment								152
Net loss	(24,739)																		(24,739)
Balance at Jun. 30, 2021	(303,844)									$ 1				(89,116)			570		(215,299)
Temporary Equity Balance at Jun. 30, 2021				333,585				12,225
Temporary Equity Balance, shares at Jun. 30, 2021			48,566,655
Balance, shares at Jun. 30, 2021										5,615,192
Accretion of Legacy Gelesis senior preferred stock to redemption value	(23,111)													(23,111)
Temporary Equity, Accretion of Legacy Gelesis senior preferred stock to redemption value			$ 23,111
Stock based compensation expense	1,086													1,086
Accretion of noncontrolling interest put option to redemption value	(95)																		(95)
Temporary Equity, Accretion of noncontrolling interest put option to redemption value								95
Foreign currency translation adjustment	(198)																(198)
Temporary Equity, Foreign currency translation adjustment								(299)
Net loss	(30,730)																		(30,730)
Balance at Sep. 30, 2021	(356,892)									$ 1				(111,141)			372		(246,124)
Temporary Equity Balance at Sep. 30, 2021			$ 356,696					12,021
Temporary Equity Balance, shares at Sep. 30, 2021			48,566,655
Balance, shares at Sep. 30, 2021										5,615,192
Balance at Dec. 31, 2021	(329,836)	(329,836)								$ 1	$ 1			(64,549)	(64,549)		219	219	(265,507)	(265,507)
Temporary Equity Balance at Dec. 31, 2021			$ 311,594	$ 311,594				11,855	11,855
Temporary Equity Balance, shares at Dec. 31, 2021			48,566,655	18,736,936	29,829,719
Balance, shares at Dec. 31, 2021										6,248,192	2,410,552	3,837,640
Accretion of legacy gelesis senior preferred stock to redemption value prior to business combination	(37,934)													(37,934)
Temporary Equity, Accretion of legacy gelesis senior preferred stock to redemption value prior to business combination			$ 37,934
Conversion of legacy gelesis convertible preferred stock into common stock upon business combination	349,528													349,528
Conversion of legacy gelesis convertible preferred stock into common stock upon business combination, shares										48,566,655
Temporary Equity, Conversion of legacy gelesis convertible preferred stock into common stock upon business combination			$ (349,528)
Temporary Equity, Conversion of legacy gelesis convertible preferred stock into common stock upon business combination, shares			(48,566,655)
Proceeds from business combination, net of issuance costs and assumed liabilities	70,478									$ 6				70,472
Proceeds from business combination, net of issuance costs and assumed liabilities, shares										17,399,440
Conversion of legacy gelesis preferred stock warrants into common stock warrants upon business combination	16,747													16,747
Recognition of earnout liability upon Business Combination	(58,871)													(58,871)
Assumed private placement warrant liability upon business combination	(8,140)													(8,140)
Exercise of warrants	4													4
Exercise of warrants, shares										176,126
Stock based compensation expense	13,989													13,989
Accretion of noncontrolling interest put option to redemption value	(88)																		(88)
Temporary Equity, Accretion of noncontrolling interest put option to redemption value								88
Foreign currency translation adjustment	(137)																(137)
Temporary Equity, Foreign currency translation adjustment								(239)
Net loss	(5,703)																		(5,703)
Balance at Mar. 31, 2022	10,037									$ 7				281,246			82		(271,298)
Temporary Equity Balance at Mar. 31, 2022								11,704
Balance, shares at Mar. 31, 2022										72,390,413
Balance at Dec. 31, 2021	$ (329,836)	$ (329,836)								$ 1	$ 1			(64,549)	$ (64,549)		219	$ 219	(265,507)	$ (265,507)
Temporary Equity Balance at Dec. 31, 2021			$ 311,594	$ 311,594				11,855	$ 11,855
Temporary Equity Balance, shares at Dec. 31, 2021			48,566,655	18,736,936	29,829,719
Balance, shares at Dec. 31, 2021										6,248,192	2,410,552	3,837,640
Issuance of common stock upon exercise of stock options shares	162,064
Net loss	$ (32,365)
Balance at Sep. 30, 2022	(3,595)									$ 7				295,333			(810)		(298,125)
Temporary Equity Balance at Sep. 30, 2022								10,474
Temporary Equity Balance, shares at Sep. 30, 2022			0
Balance, shares at Sep. 30, 2022										72,983,488
Balance at Mar. 31, 2022	10,037									$ 7				281,246			82		(271,298)
Temporary Equity Balance at Mar. 31, 2022								11,704
Balance, shares at Mar. 31, 2022										72,390,413
Stock based compensation expense	7,976													7,976
Issuance of common stock upon exercise of stock options	110													110
Issuance of common stock upon exercise of stock options shares										162,064
Accretion of noncontrolling interest put option to redemption value	(85)																		(85)
Temporary Equity, Accretion of noncontrolling interest put option to redemption value								85
Foreign currency translation adjustment	(426)																(426)
Temporary Equity, Foreign currency translation adjustment								(702)
Net loss	(12,513)																		(12,513)
Balance at Jun. 30, 2022	5,099									$ 7				289,332			(344)		(283,896)
Temporary Equity Balance at Jun. 30, 2022								11,087
Balance, shares at Jun. 30, 2022										72,552,477
Stock based compensation expense	4,574													4,574
Release of restricted stock units, shares										41,404
Issuance of common stock							$ 500									$ 500
Issuance of common stock, shares													355,361
Sale of common stock, net of commissions	37													37
Sale of common stock net of commissions, shares										34,246
Issuance of common stock warrants	890													890
Accretion of noncontrolling interest put option to redemption value	(80)																		(80)
Temporary Equity, Accretion of noncontrolling interest put option to redemption value								80
Foreign currency translation adjustment	(466)																(466)
Temporary Equity, Foreign currency translation adjustment								(693)
Net loss	(14,149)																		(14,149)
Balance at Sep. 30, 2022	$ (3,595)									$ 7				$ 295,333			$ (810)		$ (298,125)
Temporary Equity Balance at Sep. 30, 2022								$ 10,474
Temporary Equity Balance, shares at Sep. 30, 2022			0
Balance, shares at Sep. 30, 2022										72,983,488