| Document And Entity Information | Mar. 03, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 3, 2022 |
| Entity Registrant Name | Clearside Biomedical, Inc. |
| Entity Central Index Key | 0001539029 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-37783 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 45-2437375 |
| Entity Address, Address Line One | 900 North Point Parkway |
| Entity Address, Address Line Two | Suite 200 |
| Entity Address, City or Town | Alpharetta |
| Entity Address, State or Province | GA |
| Entity Address, Postal Zip Code | 30005 |
| City Area Code | 678 |
| Local Phone Number | 270-3631 |
| 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 | CLSD |
| Security Exchange Name | NASDAQ |
