Segment Information (Tables)

12 Months Ended

Dec. 31, 2024

Segment Information.

Reconciliation of collaboration revenue to net (loss) income for segement

	Year ended December 31, 2024		Year ended December 31, 2023		Year ended December 31, 2022
Collaboration revenue	$	80,001	$	250,008	$	40,907
External research and development (1):
Anti-tau antibody program		15,647		16,923		1,190
SOD1 silencing gene therapy program		15,818		6,251		3,082
Tau silencing gene therapy program		7,455		696		—
Partnered programs (2)		4,985		7,650		3,229
Other programs and platforms (3)		14,176		14,488		14,721
Internal research and development (4)		38,422		27,860		20,505
Facilities and other research and development (5)		30,865		18,304		18,037
General and administrative		35,920		35,822		30,980
Interest income		18,328		11,721		1,792
Other income		622		3		2,653
Income tax provision		665		1,408		16
Net (loss) income	$	(65,002)	$	132,330	$	(46,408)

1)External research and development is allocated to the Company’s programs and platforms, and includes laboratory supplies, and non-employee consultant and contractor costs.

2)Partnered programs include programs in which the Company is collaborating with partners to develop AAV gene therapy products and product candidates under the Company’s 2019 and 2023 Neurocrine Collaboration Agreements, and the 2023 Novartis Collaboration Agreement.

3) Other programs and platforms consist of expenses related to other early research programs and platforms which are not considered quantitatively and qualitatively significant, including capsid discovery, non-viral delivery, and early research programs.

4) Internal research and development consist of employee-related expenses including salaries, benefits, and stock-based compensation expense.

5) Depreciation and amortization are included within facilities and other research and development, which are the same as the amounts in the accompanying consolidated statements of operations as the Company operates as a single operating segment.