| Document and Entity Information | Feb. 03, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 3, 2021 |
| Entity Registrant Name | STRONGBRIDGE BIOPHARMA plc |
| Entity Incorporation, State or Country Code | L2 |
| Entity File Number | 001-37569 |
| Entity Tax Identification Number | 98-1275166 |
| Entity Address, Address Line One | 900 Northbrook Drive |
| Entity Address, Adress Line Two | Suite 200 |
| Entity Address, City or Town | Trevose |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 19053 |
| City Area Code | 610 |
| Local Phone Number | 254-9200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Ordinary shares, par value $0.01 per share |
| Trading Symbol | SBBP |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001634432 |
| Amendment Flag | false |
