Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

The components of the Company’s losses before income taxes were as follows (in thousands):

A reconciliation of the statutory U.S. federal rate to the Company’s effective tax rate is as follows:


	Year Ended December 31,
	2023		2022		2021
U.S. federal tax at statutory rate	21.0	%	21.0	%	21.0	%
Foreign tax rate differential	—		0.1		—
State, net of federal benefit	0.6		—		—
Stock-based compensation (recovery)	(1.2)		(1.3)		1.3
Change in valuation allowance	(22.8)		(19.9)		(21.8)
Other	2.4		0.1		(0.5)
Total	—	%	—	%	—	%

The components of the net deferred tax assets are as follows (in thousands):


	December 31,
	2023		2022
Deferred tax assets:
Net operating loss carryforwards	$	85,315	$	77,563
Capitalized R&D Section 174	44,456		31,964
Stock-based compensation	6,865		4,739
Research and development credit	7,156		2,918
Lease liability	—		1,132
Other temporary differences	282		435
Total gross deferred tax assets	144,074		118,751
Deferred tax liabilities:
Depreciation and amortization	(521)		(779)
ROU asset	—		(440)
Non-qualified stock options with 83(b) election	—		(15)
Total gross deferred tax liabilities	(521)		(1,234)
Net deferred tax assets before valuation allowance	143,553		117,517
Deferred tax asset valuation allowance	(143,553)		(117,517)
Net deferred tax assets	$	—	$	—

A reconciliation of the Company’s unrecognized tax benefits is as follows (in thousands):


	December 31,
	2023		2022		2021
Balance at beginning of year	$	38,697	$	25,870	$	10,346
Additions based on tax positions related to prior year	1,699		49		4,447
Additions based on tax positions related to current year	13,820		12,778		11,077
Balance at end of year	$	54,216	$	38,697	$	25,870