XML 61 R47.htm IDEA: XBRL DOCUMENT
v3.19.1

Subsequent Events - Additional Information (Detail) - USD ($) |  |  | 3 Months Ended |  |
--- | --- | --- | --- | --- | ---
May 08, 2019 | Apr. 08, 2019 | Jun. 30, 2019 | Apr. 30, 2019 | Mar. 31, 2019
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Termination fees |  |  |  |  | $ 700,000
Scenario, Forecast [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Loss on settlement of lease obligation |  |  | $ (500,000) |  |
Ocugen [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Termination fees |  |  |  |  | $ 600,000
Subsequent Event [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Payment on lease termination | $ 300,000 |  |  | $ 1,300,000 |
Security deposit | 100,000 |  |  |  |
Subsequent Event [Member] | Medavate Corp [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Cash paid to purchase assets | $ 6,500,000 |  |  |  |
Subsequent Event [Member] | Ocugen [Member] | Before Merger [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Percentage of ownership prior to merger |  | 90.00% |  |  |
Subsequent Event [Member] | Ocugen [Member] | Before Merger [Member] | Maximum [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Termination fees |  | $ 600,000 |  |  |
Subsequent Event [Member] | Ocugen [Member] | After Merger [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Stock percentage of ownership prior merger |  | 10.00% |  |  |
Subsequent Event [Member] | Ocugen [Member] | After Merger [Member] | Maximum [Member] |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Termination fees |  | $ 700,000 |  |  |

X
- Definition Lease Termination Payment + References No definition available. + Details
Name: | hsgx_LeaseTerminationPayment
Namespace Prefix: | hsgx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Payments to acquire assets. + References No definition available. + Details
Name: | hsgx_PaymentsToAcquireAssets
Namespace Prefix: | hsgx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Ownership interest in the Reis Services business prior to May 2007 Merger + References No definition available. + Details
Name: | hsgx_PercentageOfOwnershipPriorToMerger
Namespace Prefix: | hsgx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Stock percentage of ownership prior to merger. + References No definition available. + Details
Name: | hsgx_StockPercentageOfOwnershipPriorToMerger
Namespace Prefix: | hsgx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) on termination of lease before expiration of lease term. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 40 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=77888415&loc=SL77918607-209975 + Details
Name: | us-gaap_GainLossOnTerminationOfLease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of early contract termination fees included in liabilities subject to compromise. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 55 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56145-112766 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=114872137&loc=d3e55717-112764 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6918054&loc=d3e56015-112765 + Details
Name: | us-gaap_LiabilitiesSubjectToCompromiseEarlyContractTerminationFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_RestructuringCostAndReserveLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of an asset, typically cash, provided to a counterparty to provide certain assurance of performance by the entity pursuant to the terms of a written or oral agreement, such as a lease. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.8,17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_SecurityDeposit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=hsgx_OcugenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | hsgx_MergerAgreementAxis=hsgx_BeforeMergerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | hsgx_MergerAgreementAxis=hsgx_AfterMergerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |