| Cover | Jan. 28, 2025 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jan. 28, 2025 |
| Entity File Number | 001-38024 |
| Entity Registrant Name | BeyondSpring Inc. |
| Entity Central Index Key | 0001677940 |
| Entity Incorporation, State or Country Code | E9 |
| Entity Address, Address Line One | 100 Campus Drive, West Side, 4th Floor, Suite 410 |
| Entity Address, City or Town | Florham Park |
| Entity Address, State or Province | NJ |
| Entity Address, Postal Zip Code | 07932 |
| City Area Code | 646 |
| Local Phone Number | 305-6387 |
| 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 $0.0001 per share |
| Trading Symbol | BYSI |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
