Income Taxes (Tables)

12 Months Ended

Dec. 31, 2024

Income Taxes [Abstract]

Components of Provision for Income Taxes

The components of our provision for income taxes are as follows for the periods indicated:

		Year Ended
		December 31,
(in thousands)		2024		2023
Current
Federal and state	$	—	$	—
Foreign		55		147
Total provision for income taxes	$	55	$	147

Reconciliation of Taxes at the Federal Statutory Rate

	Year Ended
	December 31,
	2024		2023
Tax at federal statutory rate	21.0	%	21.0	%
Permanent differences	(4.2)		(4.3)
Research and development ("R&D") tax credit	0.8		1.4
Uncertain tax position	(0.1)		(0.3)
State, net of federal benefit	2.0		2.6
Deferred rate change	(0.3)		0.4
Change in valuation allowance	(19.3)		(21.2)
Total	(0.1)	%	(0.4)	%

Components of Net Deferred Tax Assets

		Year Ended
		December 31,
(in thousands)		2024		2023
Deferred tax assets
Net operating loss carryforwards	$	98,329	$	89,173
R&D tax credits		10,147		9,664
Capitalized R&D expenses		8,015		8,963
Non-qualified stock options		4,482		1,473
Start-up costs		452		680
Accrued vacation		227		179
Other		450		420
Total deferred tax assets		122,102		110,552
Valuation allowance		(122,102)		(110,552)
Net deferred tax assets	$	—	$	—

Changes to Gross Unrecognized Tax Benefits

The changes to our gross unrecognized tax benefits were as follows for the periods indicated:

		Year Ended
		December 31,
(in thousands)		2024		2023
Gross unrecognized tax benefits at beginning of year	$	2,221	$	2,046
Gross increases:
Prior year tax positions		—		12
Current year tax positions		182		185
Gross decreases:
Prior year tax positions		(57)		(22)
Gross unrecognized tax benefits at end of year	$	2,346	$	2,221