Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($)	Mar. 31, 2024	Sep. 30, 2023
Payables and Accruals [Abstract]
Compensation and benefits	$ 127,161	$ 2,091,196
Research and development	657,889	913,145
Professional fees	145,415	224,031
Other	3,282	2,550
Accrued expenses and other current liabilities	$ 933,747	$ 3,230,922

Accrued compensation and benefits, current.

No definition available.

Name:	SONN_AccruedCompensationAndBenefitsCurrent
Namespace Prefix:	SONN_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Accrued research and development current.

+ References

No definition available.

+ Details

Name:	SONN_AccruedResearchAndDevelopmentCurrent
Namespace Prefix:	SONN_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of liabilities incurred to vendors for goods and services received, and accrued liabilities classified as other, payable within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

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

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ 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(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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

- Definition

Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

+ References

+ Details

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

- References

No definition available.

+ Details

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