Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024
Statement of Cash Flows [Abstract]
Related parties accounts payable, accrued expenses and other long-term liabilities	$ 0	$ 3

Increase decrease in accounts payable accrued expenses and other long-term liabilities related parties.

No definition available.

Name:	hlvx_IncreaseDecreaseInAccountsPayableAccruedExpensesAndOtherLongTermLiabilitiesRelatedParties
Namespace Prefix:	hlvx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration