| Document and Entity Information | Mar. 14, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 14, 2022 |
| Entity Registrant Name | HELIUS MEDICAL TECHNOLOGIES, INC. |
| Entity Central Index Key | 0001610853 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-38445 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 36-4787690 |
| Entity Address, Address Line One | 642 Newtown Yardley Road |
| Entity Address, Address Line Two | Suite 100 |
| Entity Address, City or Town | Newtown |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 18940 |
| City Area Code | (215) |
| Local Phone Number | 944-6100 |
| 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 | HSDT |
| Security Exchange Name | NASDAQ |
