The amount of future payments payable under the collaboration arrangement.

No definition available.

Name:	axsm_CollaborationArrangementFuturePotentialPayments
Namespace Prefix:	axsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.

+ References

No definition available.

+ Details

Name:	axsm_CommonStockFairValue
Namespace Prefix:	axsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the consecutive number of trading days to determine the weighted average price per share of ordinary shares.

+ References

No definition available.

+ Details

Name:	axsm_ConsecutiveTradingDays
Namespace Prefix:	axsm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Eligible to receive sales-based and other milestones

+ References

No definition available.

+ Details

Name:	axsm_EligibleToReceiveSalesBasedAndOtherMilestones
Namespace Prefix:	axsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Initial Cash Payment Per Collaboration Agreement.

+ References

No definition available.

+ Details

Name:	axsm_InitialCashPaymentPerCollaborationAgreement
Namespace Prefix:	axsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the maximum reduction percentage of the royalty due as a result of required payments to third parties.

+ References

No definition available.

+ Details

Name:	axsm_LicenseAgreementRoyaltyDueMaximumReductionPercentageAsResultOfRequiredPaymentsToThirdParties
Namespace Prefix:	axsm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of net sales of products containing the licensed products, due to licensor as a royalty.

+ References

No definition available.

+ Details

Name:	axsm_LicenseAgreementRoyaltyDuePercentageOfNetSales
Namespace Prefix:	axsm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time, after the first commercial sale of the applicable product, the license agreement is valid, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	axsm_LicenseAgreementTerm
Namespace Prefix:	axsm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of license agreements the Company has entered into.

+ References

No definition available.

+ Details

Name:	axsm_NumberOfLicenseAgreements
Namespace Prefix:	axsm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Other development and sales based milestones recognized.

+ References

No definition available.

+ Details

Name:	axsm_OtherDevelopmentAndSalesBasedMilestonesRecognized
Namespace Prefix:	axsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Royalty Revenue

+ References

No definition available.

+ Details

Name:	axsm_RoyaltyRevenue
Namespace Prefix:	axsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value price of a single share of a number of saleable stocks of a company

+ References

No definition available.

+ Details

Name:	axsm_SharePriceFairValue
Namespace Prefix:	axsm_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

upfront payment received

+ References

No definition available.

+ Details

Name:	axsm_UpfrontPaymentReceived
Namespace Prefix:	axsm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

+ References

+ Details

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

- Definition

Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480100/505-10-S45-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-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

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 480
-SubTopic 10
-Name Accounting Standards Codification
-Section S45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479887/480-10-S45-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 480
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (01)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480244/480-10-S99-1

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481372/852-10-55-10

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(22))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_CommonStockValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 730
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483041/730-20-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 730
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483041/730-20-50-1

+ Details

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

- Definition

Amount of expense for research and development. Includes, but is not limited to, cost for computer software product to be sold, leased, or otherwise marketed and writeoff of research and development assets acquired in transaction other than business combination or joint venture formation or both. Excludes write-down of intangible asset acquired in business combination or from joint venture formation or both, used in research and development activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 985
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481283/985-20-50-2

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-18

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-14

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 48
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-48

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 730
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482916/730-10-50-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 912
-SubTopic 730
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479532/912-730-25-1

+ Details

Name:	us-gaap_ResearchAndDevelopmentExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

+ Details

Name:	us-gaap_RoyaltyExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis=us-gaap_LicenseAgreementTermsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=axsm_Axs05Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=axsm_OtherTwoProductsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=axsm_PfizerIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=axsm_PharmanoviaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

License Agreements - Additional Information (Details) $ / shares in Units, € in Millions	1 Months Ended	3 Months Ended		6 Months Ended			12 Months Ended
	Jan. 31, 2020 USD ($) $ / shares shares	Jun. 30, 2026 USD ($) shares	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) Item shares	Jun. 30, 2026 EUR (€) Item	Jun. 30, 2025 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2012 Item	Dec. 31, 2025 USD ($) shares	Jan. 09, 2020 USD ($) $ / shares
Research And Development Arrangement Contract To Perform For Others [Line Items]
Number of common shares \| shares		52,299,889		52,299,889					50,882,766
Value of common stock		$ 5,000		$ 5,000					$ 5,000
Research and development expense recognized		46,227,000	$ 49,541,000	98,904,000		$ 94,326,000
License Agreement \| Antecip
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payments or royalties		$ 5,300,000	$ 3,600,000	$ 9,900,000		$ 6,500,000
Number of exclusive license agreements \| Item				3	3			3
License agreement royalty as a percent of net sales		3.00%	3.00%	3.00%	3.00%	3.00%
License agreement royalty, maximum reduction percent as a result of required third party payments								50.00%
License agreement term, from first commercial sale								10 years
License Agreement \| Antecip \| AXS-05
Research And Development Arrangement Contract To Perform For Others [Line Items]
License agreement royalty as a percent of net sales								3.00%
License Agreement \| Antecip \| Other Two Products \| Minimum
Research And Development Arrangement Contract To Perform For Others [Line Items]
License agreement royalty as a percent of net sales								1.50%
License Agreement \| Antecip \| Other Two Products \| Maximum
Research And Development Arrangement Contract To Perform For Others [Line Items]
License agreement royalty as a percent of net sales								4.50%
Pfizer Inc \| License Agreement
Research And Development Arrangement Contract To Perform For Others [Line Items]
Number of common shares \| shares	82,019
Value of common stock	$ 8,000,000
Prior trading days	10 days
Share price \| $ / shares	$ 97.54
Upfront cash payment	$ 3,000,000
Fair value share price \| $ / shares										$ 87.24
Fair value of common stock										$ 7,200,000
Research and development expense recognized							$ 10,200,000
Future milestone payments		$ 323,000,000		$ 323,000,000
Milestone payments or royalties		0	$ 0	0		$ 0
Pharmanovia \| License Agreement
Research And Development Arrangement Contract To Perform For Others [Line Items]
Non-refundable upfront payment received				65,700,000	€ 62.0
Eligible to receive sales-based and other milestones \| €					€ 94.5
Royalty revenue		1,500,000	1,100,000	2,800,000		2,200,000
Other development and sales based milestones recognized		$ 0	$ 0	$ 0		$ 0