Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
May 20, 2019
Document And Entity Information Abstract    
Entity Registrant Name HOOKIPA Pharma Inc.  
Entity Central Index Key 0001760542  
Document Type 10-Q  
Document Period End Date Mar. 31, 2019  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status No  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Entity Common Stock, Shares Outstanding   21,588,756
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1