| Cover | Mar. 01, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 1, 2021 |
| Entity File Number | 001-38942 |
| Entity Registrant Name | ARCTURUS THERAPEUTICS HOLDINGS INC. |
| Entity Central Index Key | 0001768224 |
| Entity Tax Identification Number | 32-0595345 |
| Entity Incorporation, State or Country Code | DE |
| 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 | CA |
| Entity Address, Postal Zip Code | 92121 |
| City Area Code | (858) |
| Local Phone Number | 900-2660 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, par value $0.001 per share |
| Trading Symbol | ARCT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
