| Cover | Aug. 05, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Amendment Flag | false |
| Document Period End Date | Aug. 5, 2021 |
| Entity File Number | 001-38720 |
| Entity Registrant Name | Twist Bioscience Corporation |
| Entity Central Index Key | 0001581280 |
| Entity Tax Identification Number | 46-2058888 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 681 Gateway Boulevard |
| Entity Address, City or Town | South San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94080 |
| City Area Code | 800 |
| Local Phone Number | 719-0671 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | TWST |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
