INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Reconciliation of Income Tax Expense

The reconciliation between federal income taxes at the statutory U.S. federal income tax rate and the Company’s income tax expense for the year is as follows:  

(in thousands)	December 31, 2022		December 31, 2021
Tax benefit at statutory rate	$	(5,244)	$	(2,038)
Stock based compensation	207		780
Offering issuance costs and changes in fair value of warrants and private placement option	(413)		(3,176)
Change in valuation allowance	6,066		4,718
Research and development credit	(585)		(288)
Other	(29)		4
Income tax expense	$	2	$	—

Significant Components of Deferred Taxes

Significant components of the Company’s deferred taxes as of December 31, 2022 and 2021 are as follows:

(in thousands)	December 31, 2022		December 31, 2021
Deferred tax assets (liabilities):
Net operating loss carryforward	$	104,707	$	100,346
Stock compensation	3,838		3,541
Intangible assets	6,096		7,156
Section 174 expenses, net of amortization	1,639		—
Research and development credit	18,661		18,076
Other	63		(144)
Total deferred tax assets, net of deferred tax liabilities	135,004		128,975
Valuation allowance	(135,004)		(128,975)
Net deferred tax	$	—	$	—

Summary of Net Operating Loss Carryforwards

Net operating loss carryforwards and research tax credits as of December 31, 2022 and 2021 are as follows:

(in thousands)	December 31, 2022		December 31, 2021
U.S. federal income tax net operating loss carryforwards	$	498,607	$	477,839
U.K. net operating loss carryforwards	$	—	$	—
U.S. federal research tax credits	$	13,569	$	12,985
Texas research tax credits	$	5,091	$	5,091