| Document and Entity Information | Dec. 04, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 4, 2020 |
| Title of 12(b) Security | Common Stock $0.0001 par value per share |
| Security Exchange Name | NASDAQ |
| Trading Symbol | DRRX |
| Entity Registrant Name | DURECT CORP |
| Entity Central Index Key | 0001082038 |
| Entity Emerging Growth Company | false |
| Entity File Number | 000-31615 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 94-3297098 |
| Entity Address, Address Line One | 10260 Bubb Road |
| Entity Address, City or Town | Cupertino |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 95014 |
| City Area Code | 408 |
| Local Phone Number | 777-1417 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
