Convertible Preferred Stock and Stockholders' Deficit - Schedule of Total Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Stock-based compensation expense | $ 59 | $ 61 | $ 123 | $ 161 |
| Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense | ||||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Stock-based compensation expense | 49 | 46 | 102 | 120 |
| Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense | ||||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Stock-based compensation expense | $ 10 | $ 15 | $ 21 | $ 41 |