| Cover | Aug. 12, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 12, 2021 |
| Entity File Number | 001-38630 |
| Entity Registrant Name | Aridis Pharmaceuticals, Inc. |
| Entity Central Index Key | 0001614067 |
| Entity Tax Identification Number | 47-2641188 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 983 University Avenue |
| Entity Address, Address Line Two | Bldg. B |
| Entity Address, City or Town | Los Gatos |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 95032 |
| City Area Code | 408 |
| Local Phone Number | 385-1742 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | ARDS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
