Income Taxes
The Company recorded income tax expense of $1.2 million during the year ended December 31, 2025. Of the $1.2 million recorded, $0.4 million was related to foreign withholding taxes on the milestone payments received in connection with the Huadong Agreement and the remaining related to U.S. state income tax expense and other foreign tax expense. The Company recorded income tax expense of $0.6 million during the year ended December 31, 2024. Of the $0.6 million recorded, $0.5 million was related to foreign withholding taxes on the up-front fee in connection with the Huadong Agreement and the remaining was related to other foreign tax expense. The Company recorded income tax expense of $3.1 million during the year ended December 31, 2023. Of the $3.1 million recorded, $3.0 million was related to foreign withholding taxes on the up-front fee in connection with the Huadong Agreement and the remaining was related to other foreign tax expense.
A reconciliation of loss before income taxes for domestic and foreign locations for the years ended December 31, 2025, 2024 and 2023 (in thousands):
Year Ended December 31,
202520242023
United States$(8,244)$(130,372)$(255,653)
Foreign(6,726)(9,020)(3,374)
Loss before income taxes
$(14,970)$(139,392)$(259,027)
A reconciliation of provision for income taxes for the years ended December 31, 2025, 2024 and 2023 is as follows (in thousands):    
Year Ended December 31,
202520242023
Current tax provision:
Federal$— $— $— 
State273 — — 
Foreign844 799 3,113 
Total current
1,117 799 3,113 
Deferred tax provision:
Federal— — — 
State— — — 
Foreign54 (152)— 
Total deferred
54 (152)— 
Provision for income taxes
$1,171 $647 $3,113 
A reconciliation of income tax computed at federal statutory rates to the reported provision for income taxes for the years ended December 31, 2025, 2024 and 2023 is as follows (in thousands)(1):
Year Ended December 31,
202520242023
Tax U.S. federal statutory rate
$(3,144)21.0 %$(29,272)21.0 %$(54,396)21.0 %
State and local income tax, net of federal income tax effect(2)
836 (5.6)%(11,367)8.2 %1,512 (0.6)%
Foreign tax effects
United Kingdom
Statutory tax rate differential
(319)2.1 %(389)0.3 %(160)0.1 %
Change in valuation allowances
2,071 (13.8)%2,427 (1.7)%999 (0.4)%
Other
(77)0.5 %— — %— — %
China
402 (2.7)%500 (0.4)%3,000 (1.2)%
Other
233 (1.6)%— — %(6)— %
Tax credits
(1,288)8.6 %(804)0.6 %(4,763)1.8 %
Change in valuation allowances
(3,145)21.1 %37,731 (27.1)%52,716 (20.2)%
Nontaxable or nondeductible items
Sec. 162(m) limitation
1,426 (9.5)%633 (0.5)%3,386 (1.3)%
Stock-based compensation
3,197 (21.4)%(185)0.1 %1,787 (0.7)%
Other857 (5.7)%654 (0.5)%(95)— %
Other adjustments
122 (0.8)%719 (0.5)%(867)0.3 %
Provision for income taxes
$1,171 (7.8)%$647 (0.5)%$3,113 (1.2)%
(1) The prior years included in the effective tax rate table have been recast from the financial statements filed previously to align with the new presentation created through adherence to ASU 2023-09. Consideration has only been given to 2025 amounts in terms of the balances that are separately stated within the table.
(2) The states and local jurisdictions that contribute to a majority (greater than 50%) of the tax effect in this category include Texas, California and New York based on the distribution of sales and the current year state income tax obligations.
The components deferred tax assets and liabilities were as follows (in thousands):
December 31,
20252024
Deferred tax assets:
Net operating loss carryforwards$180,809 $171,681 
Intangibles1,958 1,400 
Research and development tax credits15,698 14,944 
Research and expenditure capitalization
23,848 36,255 
Accruals and reserves25,226 16,085 
Lease liability
1,413 837 
Stock-based compensation7,744 15,761 
Gross deferred tax assets256,696 256,963 
Less valuation allowance(255,482)(256,270)
Net deferred tax assets1,214 693 
Deferred tax liabilities:
Property and equipment— (58)
Right-of-use asset(1,110)(483)
Gross deferred tax liabilities(1,110)(541)
Total net deferred tax assets
$104 $152 
The Company regularly evaluates the positive and negative evidence in determining the realizability of its deferred tax assets. Based upon the weight of available evidence, which includes historical operating performance and reported cumulative net losses since inception, a valuation allowance on the majority of net deferred tax assets has been recorded as of December 31, 2025 and 2024. The Company intend to maintain its substantially full valuation allowance on its deferred tax assets until sufficient positive evidence exists to support reversal of the valuation allowance. The Company has an immaterial deferred tax asset related to a foreign jurisdiction. The valuation allowance decreased by approximately $0.8 million and increased by approximately $40.1 million during the years ended December 31, 2025 and 2024, respectively, due to similar changes in the underlying deferred tax asset balances.
The Company has net operating loss (NOL) carryforwards for federal and state income tax purposes of $761.3 million and $636.1 million, respectively, as of December 31, 2025. Of the federal NOLs, $3.5 million originated before the 2018 tax year and will expire beginning in 2036. Under the Tax Cuts and Jobs Act of 2017, the remaining $757.8 million of NOLs generated after December 31, 2017 will be carried forward indefinitely and will be available to offset 80% of taxable income in future years. Of the $636.1 million in state net operating loss carryforwards, $550.2 million will begin to expire in 2027 and the remaining NOLs carry forward indefinitely. In addition, the Company has foreign NOL carry forwards of $23.2 million as of December 31, 2025, which can be carried forward indefinitely.
As of December 31, 2025, the Company also had federal and California research and development tax credit carryforwards of $23.2 million and $4.6 million, respectively. The federal research and development tax credit carryforwards will begin to expire in 2037. The California research and development tax credit carryforwards are available indefinitely.
Under Internal Revenue Code Sections 382, as amended, and 383, substantial restrictions exist on the utilization of tax attributes in the event a corporation experienced an “ownership change.” Generally, a Section 382 “ownership change” occurs if one or more stockholders or groups of stockholders who owns at least 5% of a corporation’s stock increases its ownership by more than 50 percentage points over its lowest ownership percentage within a specified testing period. Accordingly, the Company's ability to utilize net operating loss and tax credit carryforwards may be limited as a result of such ownership changes, and such a limitation could result in the
expiration of carryforwards before they are utilized. The Company has completed Section 382 studies that concluded the Company has experienced ownership changes since inception. However, this is not expected to result in the expiration of federal tax attribute carryforwards prior to utilization. Similar rules may apply under state tax laws.
On July 4, 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted into law. The OBBBA contains numerous business tax provisions, including business extenders made permanent such as restoration of 100% bonus depreciation, IRC Section 174 expensing for US-based research, and the EBITDA-based business interest expense limitation under Section 163(j). The enacted legislation had an immaterial impact on the Company’s effective tax rate for the year ended December 31, 2025.
The following table summarizes the activity related to the unrecognized tax benefits (in thousands):
Year Ended December 31,
202520242023
Beginning balance
$42,286 $41,390 $42,505 
Increases related to tax positions taken during a prior year
403 — — 
Decreases related to tax positions taken during a prior year
(91)(131)(3,097)
Increases related to tax positions taken during the current year
784 1,027 1,982 
Ending balance
$43,382 $42,286 $41,390 
Included in unrecognized tax benefits of $43.4 million at December 31, 2025 was $36.2 million of tax benefits that, if recognized, would not impact the Company's income tax benefit or effective tax rate to the extent that the Company continues to maintain a full valuation allowance against its deferred tax assets.
The Company files tax returns in the United States, state jurisdictions, Canada, and the United Kingdom. The tax years for 2016 and forward are subject to examination by the U.S. tax authorities and the tax years for 2016 and forward are subject to examination by the state tax authorities. Due to net operating loss carryforwards and research and development credits in the United States and state tax jurisdictions, all years effectively remain open. The Company is subject to examination by the tax authorities in Canada and the United Kingdom for the year ended December 31, 2022 to the present period.
It is the Company's policy to recognize interest and/or penalties related to uncertain tax benefits as a component of the provision for income taxes. For the years ended December 31, 2025, 2024 and 2023, the Company has not recognized any interest or penalties related to income taxes. The Company has no accrued interest and penalties as of December 31, 2025 and 2024 due to available tax losses.
The amount of cash income taxes paid were not material for the years ended December 31, 2025, 2024 and 2023.

Historical Timeline

Fiscal YearFiled
2025Feb 25, 2026Showing above
2024Feb 25, 2025
2023Feb 27, 2024
2022Feb 28, 2023
2021Feb 22, 2022
2020Feb 16, 2021

About Income Taxes Disclosures

The income tax disclosure reveals how much a company actually pays in taxes versus what the statutory rate would predict. Analysts focus on the effective tax rate (ETR) reconciliation, which breaks down every item driving the gap between the 21% federal rate and the company's reported ETR — including R&D credits, foreign rate differentials, and state taxes. Deferred tax assets (DTAs) and their valuation allowances signal management's confidence in future profitability: a rising allowance suggests the company doubts it can use accumulated tax benefits. Uncertain tax benefit (UTB) reserves quantify exposure to IRS challenges on aggressive positions.

Key signals to watch: sudden ETR drops without clear operational reasons, large increases in valuation allowances, growing UTB balances, and significant unremitted foreign earnings. Post-TCJA, pay attention to GILTI and BEAT provisions that affect multinational tax structures. Compare the cash taxes paid (from the cash flow statement) against the income tax provision to gauge earnings quality.