Income taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Income Tax Reconciliation

A reconciliation of income tax expense computed at the U.S. federal statutory income tax rate to the Company’s income tax expense is as follows (in thousands):

	Years Ended December 31,
	2023			2022
Tax computed at the federal statutory rate	$	(25,927	)	$	(22,361	)
State income taxes, net of federal tax benefit		(8	)		(6	)
Nondeductible executive compensation		99			685
Stock-based compensation		1,326			1,132
Research and development and orphan drug credits		(6,205	)		(3,692	)
Uncertain tax positions		1,551			910
Other, net		228			(23	)
Valuation allowance		28,936			23,355
Income tax expense	$	—		$	—

Schedule of Deferred Tax Assets and Liabilities

The Company’s net deferred tax assets (liabilities) are as follows (in thousands):

	Years Ended December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	25,034		$	17,430
Liability to licensor		4,159			4,159
Goodwill		2,938			3,193
Lease liability		517			836
Accrued compensation		746			659
Research credit carryforwards		10,379			5,760
Section 174 cost capitalization		31,220			14,523
Section 59(e) cost capitalization		8,400			9,450
Stock-based compensation		2,790			1,628
Other		4			3
Gross deferred tax assets		86,187			57,641
Less: valuation allowance		(85,642	)		(56,706	)
Total deferred tax assets		545			935
Deferred tax liabilities:
Fixed assets		(231	)		(426	)
Operating lease right-of-use asset		(314	)		(509	)
Total deferred tax liabilities		(545	)		(935	)
Net deferred tax assets	$	—		$	—

Schedule of Unrecognized Tax Benefits

	Years Ended December 31,
	2023		2022
Unrecognized tax benefits - beginning	$	1,968	$	1,011
Gross increases - tax positions in prior period		161		11
Gross increase – current-period tax positions		1,473		946
Unrecognized tax benefits - ending	$	3,602	$	1,968