XML 72 R56.htm IDEA: XBRL DOCUMENT
v3.19.1

Related Party Transactions - Additional Information (Details) - USD ($) | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Apr. 30, 2016 | Mar. 31, 2018 | Dec. 31, 2018 | Dec. 31, 2017
Related Party Transaction [Line Items] |  |  |  |
Consulting fee owed to directors |  |  | $ 8,000 |
Change in fair value of derivative financial instruments |  |  | (3,577,000) | $ (3,443,000)
Non-employee Stock Options |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Change in fair value of derivative financial instruments |  |  | $ 300,000 | (400,000)
Minimum | A&B (HK) Company Ltd. |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage of shares outstanding |  |  | 5.00% |
Directors |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Consulting fees paid |  |  | $ 33,000 | 16,000
Montel Media, Inc. | Minimum |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Beneficially owns common stock percentage |  | 5.00% |  |
Montel Media, Inc. | Consulting Agreement |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Consulting fees paid |  |  | 45,000 | 200,000
Consulting monthly fee | $ 15,000 |  |  |
Clinvue LLC |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Consulting fees paid |  |  | $ 100,000 | $ 100,000
CEO |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage of shares outstanding |  |  | 5.00% |
CFO/CEO |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage of shares outstanding |  |  | 5.00% |
Director 1 |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage of shares outstanding |  |  | 5.00% |
Director 2 |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage of shares outstanding |  |  | 5.00% |

X
- Definition Consulting fee payable to directors. + References No definition available. + Details
Name: | hsdt_ConsultingFeePayableToDirectors
Namespace Prefix: | hsdt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of beneficially owned common stock. + References No definition available. + Details
Name: | hsdt_PercentageOfBeneficiallyOwnedCommonStock
Namespace Prefix: | hsdt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of common stock shares outstanding owned. + References No definition available. + Details
Name: | hsdt_PercentageOfCommonStockSharesOutstandingOwned
Namespace Prefix: | hsdt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cash outflow for fees classified as other. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3536-108585 + Details
Name: | us-gaap_PaymentsForFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition A fee charged for services from professionals such as doctors, lawyers and accountants. The term is often expanded to include other professions, for example, pharmacists charging to maintain a medicinal profile of a client or customer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07.2(a),(b),(c),(d)) -URI http://asc.fasb.org/extlink&oid=114873854&loc=SL114874292-224272 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 220 -Section 45 -Paragraph 3 -Subparagraph (k) -URI http://asc.fasb.org/extlink&oid=114873831&loc=SL114874205-224268 + Details
Name: | us-gaap_ProfessionalFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_RelatedPartyTransactionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=hsdt_NonEmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=hsdt_AAndBCompanyLimitedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_DirectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=hsdt_MontelMediaIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=hsdt_ConsultingAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=hsdt_ClinvueLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_ChiefExecutiveOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=hsdt_ChiefFinancialOfficerOrChiefOperatingOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=hsdt_DirectorOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=hsdt_DirectorTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |