| Cover | Nov. 03, 2021 | Sep. 30, 2021 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Entity Registrant Name | BioDelivery Sciences International, Inc. | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 001-31361 | |
| Entity Tax Identification Number | 35-2089858 | |
| Entity Address, Address Line One | 4131 ParkLake Ave., Suite 225 | |
| Entity Address, City or Town | Raleigh, | |
| Entity Address, Postal Zip Code | 27612 | |
| City Area Code | 919 | |
| Local Phone Number | 582-9050 | |
| 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 | |
| Trading Symbol | BDSI | |
| Security Exchange Name | NASDAQ | |
| Entity Emerging Growth Company | false | |
| Amendment Flag | false | |
| Document Period End Date | Nov. 3, 2021 | |
| Entity Address, State or Province | NC | |
| Entity Central Index Key | 0001103021 |
