Name:	tsha_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantCancelledInPeriod
Namespace Prefix:	tsha_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Share based compensation arrangement by share based payment award number of shares available for grant granted in period..

No definition available.

Name:	tsha_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedInPeriod
Namespace Prefix:	tsha_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Share based compensation arrangement by share based payment award number of shares available for grant plan adjustments and amendments in period.

No definition available.

Name:	tsha_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantPlanAdjustmentsAndAmendmentsInPeriod
Namespace Prefix:	tsha_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

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

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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