XML 51 R25.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Income Taxes (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2023
Income Taxes [Abstract] |
Components of Provision for Income Taxes | The components of our provision for income taxes are as follows for the periods indicated:
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ |  | Year Ended
​ | ​ | ​ | December 31,
(in thousands) | ​ | ​ | 2023 | ​ |  | 2022
Current | ​ | ​ | ​ | ​ | ​ | ​
Federal and state | ​ | $ | — | ​ | $ | —
Foreign | ​ |  | 147 | ​ |  | 109
Total provision for income taxes | ​ | $ | 147 | ​ | $ | 109
Reconciliation of Taxes at the Federal Statutory Rate | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ |  | Year Ended
​ | ​ | ​ | December 31,
​ | ​ | ​ | 2023 | ​ |  | 2022 |
Tax at federal statutory rate | ​ | ​ | 21.0 | % | ​ | 21.0 | %
Permanent differences | ​ | ​ | (4.3) | ​ | ​ | (2.1) | ​
Research and development ("R&D") tax credit | ​ | ​ | 1.4 | ​ | ​ | 0.8 | ​
Uncertain tax position | ​ | ​ | (0.3) | ​ | ​ | (0.3) | ​
State, net of federal benefit | ​ | ​ | 2.6 | ​ | ​ | (0.5) | ​
Deferred rate change | ​ | ​ | 0.4 | ​ | ​ | 0.3 | ​
Change in valuation allowance | ​ |  | (21.2) | ​ |  | (19.5) | ​
Total | ​ | ​ | (0.4) | % | ​ | (0.3) | %
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Components of Net Deferred Tax Assets | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ |  | Year Ended
​ | ​ | ​ | December 31,
(in thousands) | ​ | ​ | 2023 | ​ |  | 2022
Deferred tax assets | ​ | ​ | ​ | ​ | ​ | ​
Net operating loss carryforwards | ​ | $ | 89,173 | ​ | $ | 82,050
R&D tax credits | ​ | ​ | 9,664 | ​ | ​ | 9,072
Capitalized R&D expenses | ​ | ​ | 8,963 | ​ | ​ | 8,412
Non-qualified stock options | ​ | ​ | 1,473 | ​ | ​ | 752
Start-up costs | ​ | ​ | 680 | ​ | ​ | 894
Accrued vacation | ​ | ​ | 179 | ​ | ​ | 212
Property and equipment | ​ | ​ | 59 | ​ | ​ | 144
Other | ​ | ​ | 361 | ​ | ​ | 300
Total deferred tax assets | ​ | ​ | 110,552 | ​ | ​ | 101,836
Valuation allowance | ​ | ​ | (110,552) | ​ | ​ | (101,836)
Net deferred tax assets | ​ | $ | — | ​ | $ | —
Changes to Gross Unrecognized Tax Benefits | The changes to our gross unrecognized tax benefits were as follows for the periods indicated:
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ |  | Year Ended
​ | ​ | ​ | December 31,
(in thousands) | ​ | ​ | 2023 | ​ |  | 2022
Gross unrecognized tax benefits at beginning of year | ​ | $ | 2,046 | ​ | $ | 1,939
Gross increases: | ​ | ​ | ​ | ​ | ​ | ​
Prior year tax positions | ​ | ​ | 12 | ​ | ​ | 4
Current year tax positions | ​ | ​ | 185 | ​ | ​ | 113
Gross decreases: | ​ | ​ | ​ | ​ | ​ | ​
Prior year tax positions | ​ | ​ | (22) | ​ | ​ | (10)
Gross unrecognized tax benefits at end of year | ​ | $ | 2,221 | ​ | $ | 2,046

X
- References No definition available. + Details
Name: | us-gaap_IncomeTaxDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of income tax expense attributable to continuing operations for each year presented including, but not limited to: current tax expense (benefit), deferred tax expense (benefit), investment tax credits, government grants, the benefits of operating loss carryforwards, tax expense that results from allocating certain tax benefits either directly to contributed capital or to reduce goodwill or other noncurrent intangible assets of an acquired entity, adjustments of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity, and adjustments of the beginning-of-the-year balances of a valuation allowance because of a change in circumstances that causes a change in judgment about the realizability of the related deferred tax asset in future years. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Paragraph 9 -Section 50 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-9 + Details
Name: | us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net deferred tax asset or liability recognized in an entity's statement of financial position, including the following: the total of all deferred tax liabilities, the total of all deferred tax assets, the total valuation allowance recognized for deferred tax assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Paragraph 2 -Section 50 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-2 + Details
Name: | us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Paragraph 12 -Section 50 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-12 + Details
Name: | us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the change in unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 217 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482663/740-10-55-217 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15A + Details
Name: | us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration