XML 55 R36.htm IDEA: XBRL DOCUMENT
v3.20.4

Common Stock and Warrants - Summary of Warrants Accounted for as Liabilities and Recorded as Derivative Financial Instruments (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Fair Value Disclosures [Abstract] |  |
Fair value of warrants at beginning of year | $ 5 | $ 13,769
Exercise of warrants |  | (35)
Foreign exchange (gains) losses | (1) | 384
Change in fair value of warrants during the year | $ (4) | (14,113)
Fair value of warrants at end of year |  | $ 5

X
- Definition Fair value of warrants liability. + References No definition available. + Details
Name: | hsdt_FairValueOfWarrantsLiability
Namespace Prefix: | hsdt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of warrants liability exercise. + References No definition available. + Details
Name: | hsdt_FairValueOfWarrantsLiabilityExercise
Namespace Prefix: | hsdt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of expense (income) related to adjustment to fair value of warrant liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section 25 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=109262497&loc=d3e20148-110875 + Details
Name: | us-gaap_FairValueAdjustmentOfWarrants
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30690-110894 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121605123&loc=d3e30226-110892 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 10 -Section 45 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=120253306&loc=d3e28228-110885 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895 + Details
Name: | us-gaap_ForeignCurrencyTransactionGainLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration