Name:	hgen_ScheduleOfStockOptionActivityAbstract
Namespace Prefix:	hgen_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Gross number of share options (or share units) granted during the period.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Number of options outstanding, including both vested and non-vested options.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
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Number of share options (or share units) exercised during the current period.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21463-112644