The valuation allowance decreased by $0.7 million for the year ended December 31, 2023 and increased by $0.4 million for the year ended December 31, 2022.

Deferred tax assets and liabilities are provided for significant revenue and expense items recognized in different years for tax and financial reporting purposes. The Company periodically assesses the likelihood that it will be able to recover its deferred tax assets. The Company considers all available evidence, both positive and negative, including historical levels of income, expectations and risks associated with estimates of future taxable income, and ongoing prudent and feasible profits. As of December 31, 2023 and 2022, the Company established valuation allowances equal to the full amount of its deferred tax assets, net of certain tax liabilities, due to the uncertainties regarding the realization of the deferred tax assets in future years.

As of December 31, 2023, the Company had federal, California, and other state net operating loss (“NOL”) carryforwards of $40.2 million, $27.5 million, and $8.0 million, respectively, which are available to offset future taxable income. Federal NOL carryforwards arising after 2017 of $33.0 million do not expire. Federal NOL carryforwards arising before 2018 of $7.2 million expire from 2036 to 2037. California NOL carryforwards of $27.5 million expire from 2036 to 2043. Other state NOL carryforwards of $8.0 million have various expirations from 2036 to 2043.

As of December 31, 2023, the Company had federal and California R&D credit carryforwards of approximately $0.7 million and $0.4 million, respectively, which are available to offset future taxable income. Federal R&D credit carryforwards expire from 2036 to 2041. California R&D credit carryforwards do not expire.

The NOL carryforward may be subject to an annual limitation under Sections 382 and 383 of the Internal Revenue Code of 1986 (the “Code”), and similar state provisions if the Company experienced one or more ownership changes, which would limit the amount of NOL and tax credit carryforwards that can be utilized to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382 and 383, results from the transactions increasing ownership of certain stockholders or public groups in the stock of the corporation of more than 50% over a three-year period. The Company completed a Section 382 and 383 analysis regarding the limitation of NOL and credit carryforwards from inception in December 2010 through November 4, 2019. The Company experienced multiple ownership changes for the purposes of Section 382 and 383 of the Code with the latest change in April 2017. The ownership changes did not result in the forfeiture of any NOLs or credits generated prior to this date. If a change in ownership occurs in the future, the NOL and tax credits carryforwards could be eliminated or restricted.

The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits, and uncertain income tax positions must meet a more likely than not recognition threshold to be recognized. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the statements of operations.

The Company does not anticipate a significant change in its uncertain tax benefits over the next 12 months. The Company is subject to taxation in the U.S. and California state jurisdictions. Due to net operating losses all tax years since inception remain open to examination.