XML 56 R40.htm IDEA: XBRL DOCUMENT
v3.19.1

Share Based Payments - Summary of Stock Options Outstanding and Exercisable (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 $ / shares shares | Dec. 31, 2017 $ / shares shares | Dec. 31, 2016 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 3,308,049 | 2,448,646 | 1,969,000
Exercise Price | (per share) | $ 7.14 | $ 7.35 | $ 6.00
Number of Options Exercisable | shares | 1,918,672 |  |
Employee and Director Stock Options |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 2,951,049 |  |
Grant Date Fair Value | (per share) | $ 7.78 | 4.34 |
Number of Options Exercisable | shares | 1,599,172 |  |
Employee and Director Stock Options | Option One |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 360,000 |  |
Expiration Date | Jun. 18, 2019 |  |
Options Outstanding Remaining Contractual Life (In Years) | 5 months 15 days |  |
Exercise Price | $ 2.77 |  |
Fair Value Post Modification | $ 6.62 |  |
Number of Options Exercisable | shares | 360,000 |  |
Employee and Director Stock Options | Option Two |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 80,000 |  |
Expiration Date | Jun. 18, 2019 |  |
Options Outstanding Remaining Contractual Life (In Years) | 5 months 15 days |  |
Exercise Price | $ 2.77 |  |
Fair Value Post Modification | $ 6.62 |  |
Number of Options Exercisable | shares | 80,000 |  |
Employee and Director Stock Options | Option Three |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 20,000 |  |
Expiration Date | Dec. 08, 2019 |  |
Options Outstanding Remaining Contractual Life (In Years) | 11 months 8 days |  |
Exercise Price | $ 12.72 |  |
Fair Value Post Modification | $ 2.18 |  |
Number of Options Exercisable | shares | 20,000 |  |
Employee and Director Stock Options | Option Four |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 80,000 |  |
Expiration Date | Dec. 08, 2019 |  |
Options Outstanding Remaining Contractual Life (In Years) | 11 months 8 days |  |
Exercise Price | $ 12.72 |  |
Fair Value Post Modification | $ 2.18 |  |
Number of Options Exercisable | shares | 80,000 |  |
Employee and Director Stock Options | Option Five |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 20,000 |  |
Expiration Date | Mar. 16, 2020 |  |
Options Outstanding Remaining Contractual Life (In Years) | 1 year 2 months 15 days |  |
Exercise Price | $ 12.52 |  |
Fair Value Post Modification | $ 2.43 |  |
Number of Options Exercisable | shares | 20,000 |  |
Employee and Director Stock Options | Option Six |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 150,000 |  |
Expiration Date | Oct. 21, 2020 |  |
Options Outstanding Remaining Contractual Life (In Years) | 1 year 9 months 21 days |  |
Exercise Price | $ 3.20 |  |
Fair Value Post Modification | $ 6.57 |  |
Number of Options Exercisable | shares | 150,000 |  |
Employee and Director Stock Options | Option Seven |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 20,000 |  |
Expiration Date | Dec. 31, 2020 |  |
Options Outstanding Remaining Contractual Life (In Years) | 2 years |  |
Exercise Price | $ 4.48 |  |
Fair Value Post Modification | $ 5.86 |  |
Number of Options Exercisable | shares | 20,000 |  |
Employee and Director Stock Options | Option Eight |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 595,000 |  |
Expiration Date | Jul. 13, 2020 |  |
Options Outstanding Remaining Contractual Life (In Years) | 1 year 6 months 10 days |  |
Exercise Price | $ 5.35 |  |
Fair Value Post Modification | $ 5.18 |  |
Number of Options Exercisable | shares | 595,000 |  |
Employee and Director Stock Options | Option Nine |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 20,000 |  |
Expiration Date | Aug. 08, 2020 |  |
Options Outstanding Remaining Contractual Life (In Years) | 1 year 7 months 6 days |  |
Exercise Price | $ 4.98 |  |
Fair Value Post Modification | $ 5.42 |  |
Number of Options Exercisable | shares | 20,000 |  |
Employee and Director Stock Options | Option Ten |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 617,000 |  |
Expiration Date | Apr. 17, 2027 |  |
Options Outstanding Remaining Contractual Life (In Years) | 8 years 3 months 14 days |  |
Exercise Price | $ 8.13 |  |
Fair Value Post Modification | $ 7.54 |  |
Number of Options Exercisable | shares | 154,250 |  |
Employee and Director Stock Options | Option Eleven |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 6,146 |  |
Expiration Date | May 18, 2027 |  |
Options Outstanding Remaining Contractual Life (In Years) | 8 years 4 months 13 days |  |
Exercise Price | $ 7.35 |  |
Fair Value Post Modification | $ 4.75 |  |
Number of Options Exercisable | shares | 4,610 |  |
Employee and Director Stock Options | Option Twelve |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 10,000 |  |
Expiration Date | May 18, 2027 |  |
Options Outstanding Remaining Contractual Life (In Years) | 8 years 4 months 13 days |  |
Exercise Price | $ 7.35 |  |
Fair Value Post Modification | $ 7.65 |  |
Number of Options Exercisable | shares | 2,500 |  |
Employee and Director Stock Options | Option Thirteen |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 30,000 |  |
Expiration Date | Aug. 08, 2027 |  |
Options Outstanding Remaining Contractual Life (In Years) | 8 years 7 months 6 days |  |
Exercise Price | $ 10.38 |  |
Fair Value Post Modification | $ 7.38 |  |
Number of Options Exercisable | shares | 7,500 |  |
Employee and Director Stock Options | Option Fourteen |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 25,000 |  |
Expiration Date | Apr. 09, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 3 months 7 days |  |
Exercise Price | $ 9.03 |  |
Fair Value Post Modification | $ 8.01 |  |
Employee and Director Stock Options | Option Fifteen |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 337,500 |  |
Expiration Date | May 15, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 4 months 13 days |  |
Exercise Price | $ 10.99 |  |
Fair Value Post Modification | $ 7.89 |  |
Number of Options Exercisable | shares | 85,313 |  |
Employee and Director Stock Options | Option Sixteen |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 150,000 |  |
Expiration Date | Jul. 09, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 6 months 7 days |  |
Exercise Price | $ 9.69 |  |
Grant Date Fair Value | $ 6.83 |  |
Employee and Director Stock Options | Options Seventeen |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 75,726 |  |
Expiration Date | Aug. 22, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 7 months 20 days |  |
Exercise Price | $ 10.23 |  |
Grant Date Fair Value | $ 7.21 |  |
Employee and Director Stock Options | Option Eighteen |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 13,177 |  |
Expiration Date | Sep. 04, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 8 months 1 day |  |
Exercise Price | $ 10.19 |  |
Grant Date Fair Value | $ 7.19 |  |
Employee and Director Stock Options | Option Nineteen |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 50,000 |  |
Expiration Date | Sep. 10, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 8 months 8 days |  |
Exercise Price | $ 10.34 |  |
Grant Date Fair Value | $ 7.30 |  |
Employee and Director Stock Options | Option Twenty |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 50,000 |  |
Expiration Date | Sep. 24, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 8 months 23 days |  |
Exercise Price | $ 9.71 |  |
Grant Date Fair Value | $ 6.79 |  |
Employee and Director Stock Options | Option Twenty One |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 1,500 |  |
Expiration Date | Oct. 08, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 9 months 3 days |  |
Exercise Price | $ 8.25 |  |
Grant Date Fair Value | $ 5.84 |  |
Employee and Director Stock Options | Option Twenty Two |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 75,000 |  |
Expiration Date | Oct. 15, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 9 months 10 days |  |
Exercise Price | $ 8.75 |  |
Grant Date Fair Value | $ 6.19 |  |
Employee and Director Stock Options | Option Twenty Three |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 100,000 |  |
Expiration Date | Oct. 22, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 9 months 18 days |  |
Exercise Price | $ 10.16 |  |
Grant Date Fair Value | $ 7.20 |  |
Employee and Director Stock Options | Option Twenty Four |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 10,000 |  |
Expiration Date | Oct. 29, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 9 months 25 days |  |
Exercise Price | $ 9.71 |  |
Grant Date Fair Value | $ 6.87 |  |
Employee and Director Stock Options | Option Twenty Five |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 20,000 |  |
Expiration Date | Nov. 19, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 10 months 17 days |  |
Exercise Price | $ 8.00 |  |
Grant Date Fair Value | $ 5.66 |  |
Employee and Director Stock Options | Option Twenty Six |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 20,000 |  |
Expiration Date | Dec. 03, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 11 months 1 day |  |
Exercise Price | $ 8.66 |  |
Grant Date Fair Value | $ 6.13 |  |
Employee and Director Stock Options | Option Twenty Seven |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 15,000 |  |
Expiration Date | Dec. 17, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 11 months 15 days |  |
Exercise Price | $ 9.42 |  |
Grant Date Fair Value | $ 6.66 |  |
Consultants Stock Option |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 357,000 |  |
Grant Date Fair Value | (per share) | $ 8.87 | $ 3.88 |
Number of Options Exercisable | shares | 319,500 |  |
Consultants Stock Option | Option One |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 80,000 |  |
Expiration Date | Jun. 18, 2019 |  |
Options Outstanding Remaining Contractual Life (In Years) | 5 months 15 days |  |
Exercise Price | $ 2.77 |  |
Fair Value Post Modification | $ 6.62 |  |
Number of Options Exercisable | shares | 80,000 |  |
Consultants Stock Option | Option Two |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 30,000 |  |
Expiration Date | Dec. 08, 2019 |  |
Options Outstanding Remaining Contractual Life (In Years) | 11 months 8 days |  |
Exercise Price | $ 12.72 |  |
Fair Value Post Modification | $ 2.18 |  |
Number of Options Exercisable | shares | 30,000 |  |
Consultants Stock Option | Option Three |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 72,000 |  |
Expiration Date | Oct. 03, 2020 |  |
Options Outstanding Remaining Contractual Life (In Years) | 1 year 9 months 3 days |  |
Exercise Price | $ 5.15 |  |
Fair Value Post Modification | $ 5.35 |  |
Number of Options Exercisable | shares | 72,000 |  |
Consultants Stock Option | Option Four |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 110,000 |  |
Expiration Date | Oct. 28, 2020 |  |
Options Outstanding Remaining Contractual Life (In Years) | 1 year 9 months 25 days |  |
Exercise Price | $ 3.18 |  |
Fair Value Post Modification | $ 6.59 |  |
Number of Options Exercisable | shares | 110,000 |  |
Consultants Stock Option | Option Five |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 20,000 |  |
Expiration Date | May 18, 2027 |  |
Options Outstanding Remaining Contractual Life (In Years) | 8 years 4 months 13 days |  |
Exercise Price | $ 7.35 |  |
Fair Value Post Modification | $ 7.65 |  |
Number of Options Exercisable | shares | 5,000 |  |
Consultants Stock Option | Option Six |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 15,000 |  |
Expiration Date | Aug. 08, 2027 |  |
Options Outstanding Remaining Contractual Life (In Years) | 8 years 7 months 6 days |  |
Exercise Price | $ 10.38 |  |
Fair Value Post Modification | $ 7.38 |  |
Number of Options Exercisable | shares | 3,750 |  |
Consultants Stock Option | Option Seven |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 15,000 |  |
Expiration Date | Nov. 06, 2027 |  |
Options Outstanding Remaining Contractual Life (In Years) | 8 years 10 months 2 days |  |
Exercise Price | $ 16.20 |  |
Fair Value Post Modification | $ 6.98 |  |
Number of Options Exercisable | shares | 3,750 |  |
Consultants Stock Option | Option Eight |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Number of Options Outstanding | shares | 15,000 |  |
Expiration Date | Aug. 22, 2028 |  |
Options Outstanding Remaining Contractual Life (In Years) | 9 years 7 months 20 days |  |
Exercise Price | $ 10.23 |  |
Grant Date Fair Value | $ 8.87 |  |
Number of Options Exercisable | shares | 15,000 |  |

X
- Definition Share based compensation arrangement by share based payment award options grants in post modification period weighted average grant date fair value. + References No definition available. + Details
Name: | hsdt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPostModificationPeriodWeightedAverageGrantDateFairValue
Namespace Prefix: | hsdt_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expiration date of the option. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Footnote 5 + Details
Name: | invest_InvestmentOptionsExpirationDate
Namespace Prefix: | invest_
Data Type: | xbrli:dateItemType
Balance Type: | na
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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of options outstanding, including both vested and non-vested options. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionFiveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionSixMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionSevenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionEightMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionNineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionElevenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwelveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionThirteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionFourteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionFifteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionSixteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionsSeventeenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionEighteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionNineteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentyOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentyTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentyThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentyFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentyFiveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentySixMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=hsdt_OptionTwentySevenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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