| Cover | Nov. 01, 2023 |
| Cover [Abstract] | |
| Title of 12(b) Security | Common stock, $0.001 par value |
| Document Type | 8-K |
| Document Period End Date | Nov. 01, 2023 |
| Entity Registrant Name | FORMFACTOR, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-50307 |
| Entity Tax Identification Number | 13-3711155 |
| Entity Address, Address Line One | 7005 Southfront Road |
| Entity Address, City or Town | Livermore, |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94551 |
| City Area Code | 925 |
| Local Phone Number | 290-4000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Central Index Key | 0001039399 |
| Trading Symbol | FORM |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
