Condensed Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) $ in Millions	3 Months Ended
Mar. 31, 2021 USD ($)
Statement Of Stockholders Equity [Abstract]
At the market offering, commissions and issuance costs	$ 0.2

Issuance of common stock from at the market offering commissions and issuance costs.

No definition available.

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Namespace Prefix:	htgm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration