Research, Collaboration and License Agreements - Additional Information (Details)	1 Months Ended					3 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($) shares	Oct. 31, 2020 USD ($)	Aug. 31, 2020 USD ($)	Apr. 30, 2020 Product	Dec. 31, 2019 USD ($)	Mar. 31, 2021 USD ($) shares	Mar. 31, 2020 USD ($) shares	Dec. 31, 2020 USD ($) shares	Oct. 29, 2020 USD ($)	Feb. 21, 2020 USD ($)	Nov. 30, 2019 shares
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, shares issued | shares	37,761,435					37,761,435		37,761,435
Research and development						$ 23,854,000	$ 5,514,000
TSHA-120
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development	$ 5,500,000
Upfront payment	5,500,000
Clinical, regulatory and commercial milestones to be received	$ 19,300,000					19,300,000
UT Southwestern Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Preclinical activities period under sponsored research agreements				2 years
Minimum licensed product to develop obtain regulatory approval for and commercialize | Product				1
Common stock, shares issued | shares							0				2,179,000
Percentage of fully diluted common stock shares outstanding											20.00%
Percentage of entitled to receive additional shares on fully diluted basis											10.00%
Queen's Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research grant of committed fund amount					$ 3,800,000
Percentage of interest rate					6.00%
Research grant outstanding fund amount								$ 0
Queen's Agreement | Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cash payment to acquire license agreement							$ 3,000,000
Queen's Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement regulatory milestones payment										$ 10,000,000
License agreement commercial milestones payment										$ 10,000,000
Abeona CLN1 Agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License fee payment			$ 3,000,000
Purchase of clinical materials and reimbursement incurred development costs		$ 4,000,000
Research and development								7,000,000
Additional milestone payments						0
Abeona CLN1 Agreements | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License and inventory purchase agreement regulatory related milestones payment			26,000,000
License and inventory purchase agreement sales related milestones payment			$ 30,000,000
Abeona | Abeona Rett Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments						$ 0
Payment of one-time upfront license fee								$ 3,000,000
Abeona | Maximum | Abeona Rett Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory related milestones obligation payable									$ 26,500,000
Sale-related milestones per licensed product and royalties on net sales of licensed products payable									$ 30,000,000