Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Om of Medicine	LI Lending, LLC	Share Capital	Share Capital Om of Medicine	Additional Paid-In Capital	Additional Paid-In Capital LI Lending, LLC	Deficit	Total 4Front Ventures Corp. Shareholders' Equity	Total 4Front Ventures Corp. Shareholders' Equity Om of Medicine	Total 4Front Ventures Corp. Shareholders' Equity LI Lending, LLC	Non-Controlling Interest
Beginning Balance at Dec. 31, 2019	$ 74,760			$ 252,656		$ 25,618		$ (203,497)	$ 74,777			$ (17)
Beginning Balance, Shares at Dec. 31, 2019	531,522,819			531,522,819
Conversion option and warrants for GGP notes transferred to equity	$ 411					411			411
Conversion option for convertible notes transferred to equity	5,163					5,163			5,163
Shares issued for Pure Ratios earnout	94			$ 94					94
Shares issued for Pure Ratios earnout, Shares				223,145
Share-based compensation	5,306					5,306			5,306
Exchange of stock for convertible swap notes	(13,661)			$ (13,661)					(13,661)
Exchange of stock for convertible swap notes, shares				(29,448,468)
Conversion of notes to equity	1,939			$ 1,939					1,939
Conversion of notes to equity, shares				4,479,113
Shares issued with exercise of warrants and options	1,352			$ 1,352					1,352
Shares issued with exercise of warrants and options, shares				2,686,463
Shares issued for services	$ 644								644
Shares issued for services, Shares	1,192,640
Issuance Of Stock For Purchase Of Noncontrolling Interests				$ 231					231			(231)
Issuance Of Stock For Purchase Of Noncontrolling Interests Shares				3,551,040
Derecognition of NCI with the sale of Maryland entities	$ 254											254
Issuance of stock for bought deal	$ 8,018			$ 8,018					8,018
Issuance of stock for bought deal, Shares	7,328,433			24,644,500
Issuance of broker warrants	$ 577					577			577
Share issuance costs for bought deal	(690)			$ (690)					(690)
Issuance of warrants to Advisors	381		$ 4,660			381	$ 4,660		381		$ 4,660
Net loss	(47,005)							(47,051)	(47,051)			46
Ending Balance at Dec. 31, 2020	$ 42,203			$ 250,583		42,116		(250,548)	42,151			52
Ending Balance, Shares at Dec. 31, 2020	538,851,252			538,851,252
Share-based compensation	$ 10,081					10,081			10,081
Conversion of notes to equity	17,719			$ 17,719					17,719
Conversion of notes to equity, shares				49,042,797
Shares issued with exercise of warrants and options	3,423			$ 3,423					3,423
Shares issued with exercise of warrants and options, shares				3,058,927
Shares issued with exercise of stock options	$ 1,512			$ 1,512					1,512
Issuance of stock for bought deal, Shares	55,330,352
Shares issued with exercise of stock options, shares	2,737,326			2,228,439
Shares issued for Pure Ratios earnout		722,000		473,491	535,018					722,000
Shares Issued During Period Value Earn out	$ 161			$ 161	$ 722				161
Return of treasury shares				(8,320)
Net loss	(38,289)							(38,309)	(38,309)			20
Ending Balance at Dec. 31, 2021	$ 37,532			$ 274,120		$ 52,197		$ (288,857)	$ 37,460			$ 72
Ending Balance, Shares at Dec. 31, 2021	594,181,604			594,181,604