Income Taxes

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes

12.Income Taxes

There is no provision for income taxes because the Company has incurred operating losses since inception. The reported amounts of income tax expense for the years ended December 31, 2022 and 2021 differ from the amounts that would result from applying domestic federal statutory

tax rates to pretax losses primarily because of the changes in the valuation allowance. Significant components of the Company’s deferred tax assets at December 31, 2022 and 2021 are as follows:

	December 31,
(in thousands)	2022			2021
Deferred tax assets:
Net operating loss carryforwards	$	171,070		$	164,486
Start-up and pre-clinical studies		17,204			21,705
Research and development credit carryforwards		40,116			39,817
Stock-based compensation		698			706
Capitalized acquisition costs		2,180			2,946
Lease liability		618			1,278
Depreciation		239			102
Capitalized research expenses		5,156			-
Other		27			156
		237,308			231,196
Less valuation allowance		(236,827	)		(230,119	)
Total deferred tax assets		481			1,077
Right-of-use asset		(481	)		(1,077	)
Total deferred tax liabilities	$	(481	)	$	(1,077	)
Net deferred taxes	$	—		$	—

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. At December 31, 2022, the Company has aggregate net operating loss carryforwards for federal tax purposes of approximately $665.5 million, of which approximately $341.7 million expire at various dates through December 31, 2037 and approximately $323.8 million can be carried forward indefinitely. The Company also has approximately $497.9 million of state net operating loss carryforwards available to offset future state taxable income, expiring at various dates through 2042. Additionally, the Company has approximately $40.1 million of federal and state research and development credits at December 31, 2022, expiring in varying amounts through 2042, which may be available to reduce future taxes.

The Company has provided a valuation allowance for the full amount of its net deferred tax assets since it is more likely than not that these future benefits will not be realized. However, these deferred tax assets may be available to offset future income tax liabilities and expenses. The valuation allowance increased by $6.7 million in 2022 due primarily to net operating loss carryforwards and the increase in research and development credits.

Income taxes using the federal statutory income tax rate differ from the Company’s effective tax rate primarily due to non-deductible expenses related to the Company’s issuance of warrants along with the change in the valuation allowance on deferred tax assets.

A reconciliation of income tax expense (benefit) at the statutory federal income tax rate and income taxes as reflected in the financial statements is as follows:

	Year Ended December 31,
(in thousands)	2022			2021
Federal income tax at statutory rates		21	%		21	%
State income tax, net of federal tax benefit		3	%		3	%
Research and development credits		2	%		3	%
Research and development true-up		-2	%		0	%
Stock-based compensation		-1	%		-1	%
Federal/state rate change		-5	%		-2	%
Change in valuation allowance		-18	%		-24	%
Effective tax rate		0	%		0	%

The Company adopted ASC 740, Accounting for Uncertain Tax Positions on January 1, 2007. ASC 740 clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements in accordance with FASB Statement No. 109, “Accounting for Income Taxes.” ASC 740 prescribes a recognition threshold and measurement of a tax position taken or expected to be taken in a tax return. The

Company did not establish any additional reserves for uncertain tax liabilities upon adoption of ASC 740. There were no adjustments to its uncertain tax positions in the years ended December 31, 2022 and 2021.

The Company has not recognized any interest and penalties in the statements of operations because of the Company’s net operating losses and tax credits that are available to be carried forward. When necessary, the Company will account for interest and penalties related to uncertain tax positions as part of its provision for federal and state income taxes. The Company does not expect the amounts of unrecognized benefits will change significantly within the next twelve months.

The Company is currently open to audit under the statute of limitations by the Internal Revenue Service and state jurisdictions for the years ended December 31, 1999 through 2022 to the extent net operating losses continue to be carried forward to 2022.

Beginning in 2022, the Tax Cuts and Jobs Act of 2017, or the Tax Act, eliminated the option to deduct research and development expenditures immediately in the year incurred and requires taxpayers to capitalize and amortize them over five years pursuant to IRC Section 174. The mandatory capitalization requirement had no impact to the overall deferred tax assets due to the Company's loss position and full valuation allowance.