Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Nov. 07, 2022
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	001-38869
Entity Registrant Name	HOOKIPA PHARMA INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-5395687
Entity Address, Address Line One	350 Fifth Avenue, 72nd Floor, Suite 7240
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10118
Country Region	+43
City Area Code	1
Local Phone Number	890 63 60
Title of 12(b) Security	Common Stock
Trading Symbol	HOOK
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Central Index Key	0001760542
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false
Common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		52,317,138
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		2,399,517