XML 63 R52.htm IDEA: XBRL DOCUMENT
v3.25.3

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% |  |  |

X
- Definition Cash per share to be received upon exchange of each share of common stock as per business combination agreement. + References No definition available. + Details
Name: | atxs_BusinessCombinationCashConsiderationPerShare
Namespace Prefix: | atxs_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- 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

X
- 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

X
- 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

X
- 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

X
- 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

X
- 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

X
- 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

X
- 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

X
- Definition Face amount or stated value per share of common stock. + 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(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- 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

X
- 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

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

X
- Details
Name: | dei_LegalEntityAxis=atxs_BiocrystPharmaceuticalsIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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