XML 57 R38.htm IDEA: XBRL DOCUMENT
v3.20.4

Common Stock and Warrants - Warrants Outstanding and Exercisable (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 $ / shares shares | Dec. 31, 2020 $ / shares shares
Class Of Warrant Or Right [Line Items] |  |
Number of Warrants Outstanding | 341,905 | 341,905
Warrants Expiration Date, April 21, 2021 |  |
Class Of Warrant Or Right [Line Items] |  |
Number of Warrants Outstanding | 68,351 | 68,351
Exercise price | $ / shares |  | $ 428.75
Expiration Date | Apr. 21, 2021 |
Warrants Expiration Date, March 20, 2025 |  |
Class Of Warrant Or Right [Line Items] |  |
Number of Warrants Outstanding | 178,776 | 178,776
Exercise price | $ / shares | $ 16.10 |
Expiration Date | Mar. 20, 2025 |
Warrants Expiration Date, October 26, 2023 |  |
Class Of Warrant Or Right [Line Items] |  |
Number of Warrants Outstanding | 17,431 | 17,431
Exercise price | $ / shares |  | $ 16.1665
Expiration Date | Oct. 26, 2023 |
Warrants Expiration Date, October 26, 2023 |  |
Class Of Warrant Or Right [Line Items] |  |
Number of Warrants Outstanding | 76,386 | 76,386
Exercise price | $ / shares | $ 15.82 |
Expiration Date | Oct. 26, 2023 |
Warrants Expiration Date, October 26, 2023 |  |
Class Of Warrant Or Right [Line Items] |  |
Number of Warrants Outstanding | 961 | 961
Exercise price | $ / shares | $ 19.775 |
Expiration Date | Oct. 26, 2023 |

X
- Definition Warrants expiration date. + References No definition available. + Details
Name: | hsdt_WarrantsExpirationDate
Namespace Prefix: | hsdt_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ClassOfWarrantOrRightLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of warrants or rights outstanding. + References No definition available. + Details
Name: | us-gaap_ClassOfWarrantOrRightOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=hsdt_WarrantsOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=hsdt_WarrantsTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=hsdt_WarrantsThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=hsdt_WarrantsFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=hsdt_WarrantsFiveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |