| Document and Entity Information | Dec. 17, 2021 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Dec. 17, 2021 |
| Entity File Number | 001-40592 |
| Entity Registrant Name | RAPID MICRO BIOSYSTEMS, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 20-8121647 |
| Entity Address State Or Province | MA |
| Entity Address, Address Line One | 1001 Pawtucket Boulevard West |
| Entity Address, Adress Line Two | Suite 280 |
| Entity Address, City or Town | Lowell |
| Entity Address, Postal Zip Code | 01854 |
| City Area Code | 978 |
| Local Phone Number | 349-3200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A Common Stock, $0.01 par value per share |
| Trading Symbol | RPID |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001380106 |
| Amendment Flag | false |
