v3.22.1

Cover Page - USD ($)	12 Months Ended
Cover Page - USD ($)	Dec. 31, 2021	Apr. 25, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36289
Entity Registrant Name	GENOCEA BIOSCIENCES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	51-0596811
Entity Address, Address Line One	100 Acorn Park Drive
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02140
City Area Code	617
Local Phone Number	876-8191
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	GNCA
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		58,783,503
Entity Central Index Key	0001457612
Document Fiscal Year Focus	2021
Amendment Flag	false
Document Fiscal Period Focus	FY
Security Exchange Name	NASDAQ
Entity Public Float			$ 108,805,512
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts

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Local phone number for entity.

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GENOCEA BIOSCIENCES, INC. 10-K/A