| Document and Entity Information | Dec. 14, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 14, 2020 |
| Entity Registrant Name | Calyxt, Inc. |
| Entity Central Index Key | 0001705843 |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | CLXT |
| Security Exchange Name | NASDAQ |
| Entity File Number | 001-38161 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 27-1967997 |
| Entity Address, Address Line One | 2800 Mount Ridge Road |
| Entity Address, City or Town | Roseville |
| Entity Address, State or Province | MN |
| Entity Address, Postal Zip Code | 55113-1127 |
| City Area Code | (651) |
| Local Phone Number | 683-2807 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
