Document and Entity Information - shares
6 Months Ended
Jun. 30, 2019
Aug. 09, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Trading Symbol ARCT  
Entity Registrant Name Arcturus Therapeutics Holdings Inc.  
Entity Central Index Key 0001768224  
Entity Current Reporting Status Yes  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity File Number 001-38942  
Entity Tax Identification Number 320595345  
Entity Address, Address Line One 10628 Science Center Drive  
Entity Address, Address Line Two Suite 250  
Entity Address, City or Town San Diego  
Entity Address, State or Province California  
Entity Address, Postal Zip Code 92121  
City Area Code 858  
Local Phone Number 900-2660  
Entity Common Stock, Shares Outstanding   14,274,378