Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 15, 2023	Jun. 30, 2022
Document Information Line Items
Entity Registrant Name	SeqLL Inc.
Trading Symbol	SQL
Document Type	10-K
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		13,886,379
Entity Public Float			$ 4,786,725
Amendment Flag	false
Entity Central Index Key	0001605888
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Document Annual Report	true
Document Transition Report	false
Entity File Number	333-254886
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5319744
Entity Address, Address Line One	3 Federal Street
Entity Address, City or Town	Billerica
Entity Address, Country	MA
Entity Address, Postal Zip Code	01821
City Area Code	(781)
Local Phone Number	460-6016
Title of 12(b) Security	Common Stock, par value $.00001 per share
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Auditor Firm ID	392
Auditor Name	Wolf & Company, P.C.
Auditor Location	Boston, MA