Cash per share to be received upon exchange of each share of common stock as per business combination agreement.

No definition available.

Name:	atxs_BusinessCombinationCashConsiderationPerShare
Namespace Prefix:	atxs_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of common shares issuable upon exchange for each share of common stock in a business combination.

+ References

No definition available.

+ Details

Name:	atxs_BusinessCombinationExchangeRatio
Namespace Prefix:	atxs_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of termination fee payable upon termination of agreement.

+ References

No definition available.

+ Details

Name:	atxs_BusinessCombinationTerminationFee
Namespace Prefix:	atxs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of warrants exercised during the period.

+ References

No definition available.

+ Details

Name:	atxs_ClassOfWarrantOrRightExercised
Namespace Prefix:	atxs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum outstanding percentage of common stock issued and outstanding prior to the effective time as per business combination agreement.

+ References

No definition available.

+ Details

Name:	atxs_MaximumOutstandingPercentageOfCommonStockIssuedAndOutstanding
Namespace Prefix:	atxs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash-out reference price established under the merger agreement for determining the value of in-the-money stock options.

+ References

No definition available.

+ Details

Name:	atxs_ShareBasedPaymentArrangementCancellationCashOutReferencePrice
Namespace Prefix:	atxs_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum exercise price per share that will be considered for vesting and cancellation with consideration as per business combination agreement.

+ References

No definition available.

+ Details

Name:	atxs_ShareBasedPaymentArrangementCancellationWithConsiderationMaximumExercisePricePerShare
Namespace Prefix:	atxs_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum exercise price per share that will be considered for vesting and cancellation without consideration as per business combination agreement.

+ References

No definition available.

+ Details

Name:	atxs_ShareBasedPaymentArrangementCancellationWithoutConsiderationMinimumExercisePricePerShare
Namespace Prefix:	atxs_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-3

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Face amount or stated value per share of common stock.

+ References

+ Details

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

- Definition

Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=atxs_BiocrystPharmaceuticalsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=atxs_AstriaTherapeuticsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details)	Oct. 14, 2025 USD ($) $ / shares	Oct. 16, 2025 shares	Sep. 30, 2025 $ / shares	Dec. 31, 2024 $ / shares
Subsequent Events
Common stock, par value (in dollars per share)			$ 0.001	$ 0.001
Preferred stock, par value (in dollars per share)			$ 0.001
Subsequent Event
Subsequent Events
Preferred stock, par value (in dollars per share)	$ 0.001
Shares issued upon warrant exercises \| shares		649,944
Number of warrants exercised \| shares		650,000
Subsequent Event \| BioCryst Pharmaceuticals, Inc
Subsequent Events
Common stock, par value (in dollars per share)	$ 0.01
Exchange ratio	0.59
Per share cash amount	$ 8.55
Termination fee payable \| $	$ 32,250,000
Subsequent Event \| Astria Therapeutics, Inc
Subsequent Events
Maximum exercise price for cancellation with consideration (in dollars per share)	$ 13
Cancellation reference price	13
Minimum exercise price for cancellation without consideration (in dollars per share)	$ 13
Subsequent Event \| Astria Therapeutics, Inc \| BioCryst Pharmaceuticals, Inc
Subsequent Events
Maximum outstanding percentage	19.90%