REVISION OF PRIOR YEAR INTERIM FINANCIAL STATEMENTS - Error Corrections and Prior Period Adjustments (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Condensed Consolidated Statement of Operations
Revenue	$ 63,593	$ 68,981	$ 169,544	$ 178,383
Costs and expenses	42,648	44,104	108,799	116,502
Research and development	3,981	4,863	13,900	14,250
General and administrative	21,591	19,739	68,379	69,452
Selling, general and administrative expenses	28,614	29,965	95,314	97,935
Operating loss	(7,669)	(5,088)	(34,569)	(36,054)
Loss before income taxes	(7,332)	(5,263)	(34,479)	(37,638)
Net loss		(5,222)		(37,644)
Net loss attributable to Telos Corporation	$ (7,340)	$ (5,222)	$ (34,612)	$ (37,644)
Net loss per share attributable to Telos Corporation
Basic (in dollars per share)	$ (0.11)	$ (0.08)	$ (0.51)	$ (0.57)
Diluted (in dollars per share)	$ (0.11)	$ (0.08)	$ (0.51)	$ (0.57)
Condensed Consolidated Statement of Comprehensive Loss
Net loss	$ (7,340)	$ (5,222)	$ (34,612)	$ (37,644)
Comprehensive loss attributable to Telos Corporation	(7,361)	(5,235)	(34,615)	(37,684)
Condensed Consolidated Statement of Cash Flows
Net loss	(7,340)	(5,222)	(34,612)	(37,644)
Stock-based compensation			44,225	47,378
Changes in other operating assets and liabilities				(4,362)
Cash used in operating activities			20,118	9,637
Capitalized software development costs			(8,580)	(6,672)
Cash used in investing activities			(9,395)	(14,242)
Distributions to Telos ID Class B member – non-controlling interest			0	(2,436)
Cash provided by financing activities			(11,821)	32,695
Condensed Consolidated Statement of Changes in Stockholders' Equity
Net loss	(7,340)	(5,222)	(34,612)	(37,644)
Total Stockholders' equity	177,033	172,922	177,033	172,922	$ 174,312	$ 180,254	$ 165,785	$ 127,104
Additional Paid-in Capital
Condensed Consolidated Statement of Changes in Stockholders' Equity
Total Stockholders' equity	398,546	354,300	398,546	354,300	388,464	367,153	341,928	270,800
Accumulated Deficit
Condensed Consolidated Statement of Operations
Net loss attributable to Telos Corporation	(7,340)	(5,222)	(34,612)	(37,644)
Condensed Consolidated Statement of Comprehensive Loss
Net loss	(7,340)	(5,222)	(34,612)	(37,644)
Condensed Consolidated Statement of Cash Flows
Net loss	(7,340)	(5,222)	(34,612)	(37,644)
Condensed Consolidated Statement of Changes in Stockholders' Equity
Net loss	(7,340)	(5,222)	(34,612)	(37,644)
Total Stockholders' equity	(221,589)	(181,487)	(221,589)	(181,487)	$ (214,249)	$ (186,977)	(176,265)	(143,843)
Previously Reported
Condensed Consolidated Statement of Operations
Revenue		70,066		178,383
Research and development		5,396		14,783
General and administrative		20,562		69,271
Selling, general and administrative expenses		31,321		98,287
Operating loss		(5,253)		(37,304)
Loss before income taxes		(5,428)		(38,888)
Net loss		(5,387)		(38,894)
Net loss attributable to Telos Corporation		$ (5,387)		$ (38,894)
Net loss per share attributable to Telos Corporation
Basic (in dollars per share)		$ (0.08)		$ (0.59)
Diluted (in dollars per share)		$ (0.08)		$ (0.59)
Condensed Consolidated Statement of Comprehensive Loss
Net loss		$ (5,387)		$ (38,894)
Comprehensive loss attributable to Telos Corporation		(5,400)		(38,934)
Condensed Consolidated Statement of Cash Flows
Net loss		(5,387)		(38,894)
Stock-based compensation				47,197
Changes in other operating assets and liabilities				(5,900)
Cash used in operating activities				6,668
Capitalized software development costs				(6,139)
Cash used in investing activities				(13,709)
Distributions to Telos ID Class B member – non-controlling interest				0
Cash provided by financing activities				35,131
Condensed Consolidated Statement of Changes in Stockholders' Equity
Net loss		(5,387)		(38,894)
Total Stockholders' equity		171,491		171,491
Previously Reported | Additional Paid-in Capital
Condensed Consolidated Statement of Changes in Stockholders' Equity
Total Stockholders' equity		354,119		354,119
Previously Reported | Accumulated Deficit
Condensed Consolidated Statement of Changes in Stockholders' Equity
Total Stockholders' equity		(182,737)		(182,737)			(177,350)	(143,843)
Error Correction
Condensed Consolidated Statement of Operations
Revenue		(1,085)		0
Research and development		(533)		(533)
General and administrative		(823)		181
Selling, general and administrative expenses		(1,356)		(352)
Operating loss		165		1,250
Loss before income taxes		165		1,250
Net loss		165		1,250
Net loss attributable to Telos Corporation		$ 165		$ 1,250
Net loss per share attributable to Telos Corporation
Basic (in dollars per share)		$ 0		$ 0.02
Diluted (in dollars per share)		$ 0		$ 0.02
Condensed Consolidated Statement of Comprehensive Loss
Net loss		$ 165		$ 1,250
Comprehensive loss attributable to Telos Corporation		165		1,250
Condensed Consolidated Statement of Cash Flows
Net loss		165		1,250
Stock-based compensation				181
Changes in other operating assets and liabilities				1,538
Cash used in operating activities				2,969
Capitalized software development costs				(533)
Cash used in investing activities				(533)
Distributions to Telos ID Class B member – non-controlling interest				(2,436)
Cash provided by financing activities				(2,436)
Condensed Consolidated Statement of Changes in Stockholders' Equity
Net loss		165		1,250
Total Stockholders' equity		1,431		1,431
Error Correction | Additional Paid-in Capital
Condensed Consolidated Statement of Changes in Stockholders' Equity
Total Stockholders' equity		181		181
Error Correction | Accumulated Deficit
Condensed Consolidated Statement of Changes in Stockholders' Equity
Total Stockholders' equity		1,250		1,250			$ 1,085	$ 0
Service [Member]
Condensed Consolidated Statement of Operations
Revenue	55,305	62,955	153,683	164,016
Costs and expenses	36,746	40,137	97,913	108,236
Service [Member] | Previously Reported
Condensed Consolidated Statement of Operations
Revenue		63,690		163,366
Costs and expenses		40,031		109,134
Service [Member] | Error Correction
Condensed Consolidated Statement of Operations
Revenue		(735)		650
Costs and expenses		106		(898)
Product [Member]
Condensed Consolidated Statement of Operations
Revenue	8,288	6,026	15,861	14,367
Costs and expenses	$ 5,902	3,967	$ 10,886	8,266
Product [Member] | Previously Reported
Condensed Consolidated Statement of Operations
Revenue		6,376		15,017
Product [Member] | Error Correction
Condensed Consolidated Statement of Operations
Revenue		(350)		(650)
Products And Services
Condensed Consolidated Statement of Operations
Costs and expenses		44,104		116,502
Products And Services | Previously Reported
Condensed Consolidated Statement of Operations
Costs and expenses		43,998		117,400
Products And Services | Error Correction
Condensed Consolidated Statement of Operations
Costs and expenses		$ 106		$ (898)