| Document and Entity Information | Nov. 05, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 5, 2020 |
| Entity Registrant Name | ExOne Co |
| Entity Central Index Key | 0001561627 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-35806 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 46-1684608 |
| Entity Address, Address Line One | 127 Industry Boulevard |
| Entity Address, City or Town | North Huntingdon |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 15642 |
| City Area Code | 724 |
| Local Phone Number | 863-9663 |
| 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 | XONE |
| Security Exchange Name | NASDAQ |
