| Cover | Dec. 16, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 16, 2021 |
| Current Fiscal Year End Date | --12-31 |
| Entity File Number | 000-56015 |
| Entity Registrant Name | QUANTUM COMPUTING INC. |
| Entity Central Index Key | 0001758009 |
| Entity Tax Identification Number | 82-4533053 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 215 Depot Court |
| Entity Address, Address Line Two | SE |
| Entity Address, Address Line Three | Suite 215 |
| Entity Address, City or Town | Leesburg |
| Entity Address, State or Province | VA |
| Entity Address, Postal Zip Code | 20175 |
| City Area Code | (703) |
| Local Phone Number | 436-2161 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common shares (par value $0.0001 per share) |
| Trading Symbol | QUBT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
