Summary of Significant Accounting Policies - Additional information (Detail) ¥ in Millions |
3 Months Ended | 9 Months Ended | 12 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Apr. 01, 2026
USD ($)
|
Apr. 01, 2026
JPY (¥)
|
Mar. 19, 2026
USD ($)
|
Mar. 19, 2026
JPY (¥)
|
Sep. 30, 2026
USD ($)
|
Sep. 30, 2025
USD ($)
|
Sep. 30, 2026
USD ($)
Segment
|
Sep. 30, 2025
USD ($)
|
Dec. 31, 2025
USD ($)
Segment
|
Dec. 31, 2024
USD ($)
|
Sep. 30, 2026
JPY (¥)
|
Dec. 31, 2025
JPY (¥)
|
Dec. 31, 2024
JPY (¥)
|
|
| Accounting Policies [Line Items] | |||||||||||||
| Cash and cash equivalents | $ 33,022,000 | $ 33,022,000 | $ 16,547,000 | ||||||||||
| Deposits in federal deposit insurance corporation | 3,000,000 | 3,000,000 | 800,000 | $ 1,000,000 | |||||||||
| FDIC Indemnification Asset | 29,700,000 | 29,700,000 | 15,400,000 | 24,500,000 | |||||||||
| Deposits in deposit insurance corporation of japan | 64,000 | 64,000 | 60,000.00 | ¥ 10.0 | ¥ 10.0 | ||||||||
| Deposits in japanese financial institution | 100,000 | ¥ 16.3 | |||||||||||
| Deposits in excess of deposit insurance corporation of japan | 40,000.00 | ¥ 6.3 | |||||||||||
| Revenue from Contract with Customer, Including Assessed Tax | $ 56,000 | 0 | |||||||||||
| Revenue, Remaining Performance Obligation, Percentage | 100.00% | 100.00% | |||||||||||
| Accounts Receivable, after Allowance for Credit Loss, Current | 10,000 | 10,000 | $ 56,000 | 0 | |||||||||
| Accounts Receivable, Allowance for Credit Loss | $ 0 | 0 | |||||||||||
| Percentage of income tax benefit | 50.00% | 50.00% | |||||||||||
| Short term operating lease term | 12 months | ||||||||||||
| Foreign currency translation adjustments | (1,000) | $ (3,000) | $ (10,000) | $ (6,000) | $ (10,876) | $ (10,141) | |||||||
| Number of reportable segments | Segment | 1 | ||||||||||||
| Segment Reporting, Expense Information Used by CODM, Description | The CODM also uses internal budget versus forecasted expense and cash forecast models in making certain decisions. Such models are reviewed to assess the entity-wide/single-segment operating results and performance, including how long cash-on-hand is expected to be sufficient. | ||||||||||||
| Software license fee | $ 9,500 | ¥ 15.0 | |||||||||||
| Amount fixed consideration of software agreement | $ 114,000 | ¥ 18.0 | |||||||||||
| Number of operating segments | Segment | 1 | ||||||||||||
| Deposit Insurance Corporation of Japan [Member] | |||||||||||||
| Accounting Policies [Line Items] | |||||||||||||
| Cash | 100,000 | $ 100,000 | $ 100,000 | ||||||||||
| Deposit Insurance Corporation of Japan [Member] | Over The Limit [Member] | |||||||||||||
| Accounting Policies [Line Items] | |||||||||||||
| Cash | $ 30,000.00 | $ 30,000.00 | $ 40,000.00 | ||||||||||
| Two Thousand Twenty Six Agreement [Member] | |||||||||||||
| Accounting Policies [Line Items] | |||||||||||||
| Software license fee | $ 10,000 | ¥ 1.5 | |||||||||||
| Amount fixed consideration of software agreement | $ 114,000 | ¥ 18.0 | |||||||||||