Summary of Significant Accounting Policies - Additional information (Detail) ¥ in Millions |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Apr. 01, 2026
USD ($)
|
Apr. 01, 2026
JPY (¥)
|
Mar. 19, 2026
USD ($)
|
Mar. 19, 2026
JPY (¥)
|
Jun. 30, 2026
USD ($)
|
Mar. 31, 2026
USD ($)
|
Jun. 30, 2025
USD ($)
|
Mar. 31, 2025
USD ($)
|
Jun. 30, 2026
USD ($)
|
Jun. 30, 2025
USD ($)
|
Dec. 31, 2025
USD ($)
Segment
|
Dec. 31, 2024
USD ($)
|
Jun. 30, 2026
JPY (¥)
|
Dec. 31, 2025
JPY (¥)
|
Dec. 31, 2024
JPY (¥)
|
|
| Accounting Policies [Line Items] | |||||||||||||||
| Cash and cash equivalents | $ 12,151,777 | $ 12,151,777 | $ 16,546,908 | $ 25,892,723 | |||||||||||
| Deposits in federal deposit insurance corporation | 200,000 | 200,000 | 800,000 | 1,000,000 | |||||||||||
| FDIC Indemnification Asset | 11,600,000 | 11,600,000 | 15,400,000 | 24,500,000 | |||||||||||
| Deposits in deposit insurance corporation of japan | 60,000.00 | 60,000.00 | 60,000.00 | ¥ 10.0 | ¥ 10.0 | ||||||||||
| Deposits in japanese financial institution | 50,000.00 | 50,000.00 | 100,000 | ¥ 16.3 | |||||||||||
| Deposits in excess of deposit insurance corporation of japan | 40,000.00 | 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 | 28,232 | 28,232 | $ 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 | (3,375) | $ (5,471) | $ (2,820) | $ 252 | (8,846) | $ (2,568) | $ (10,876) | $ (10,141) | |||||||
| Number of reportable segments | Segment | 1 | ||||||||||||||
| Segment Reporting, Expense Information Used by CODM, Description | The CODM assesses the financial performance for the Company’s segment based on net loss. 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 | $ 10 | ¥ 1.5 | |||||||||||
| Amount fixed consideration of software agreement | $ 114,000 | ¥ 18.0 | $ 114 | ¥ 18.0 | |||||||||||
| Deferred Transaction Costs | 0.7 | 0.7 | |||||||||||||
| Two Thousand Twenty Six Agreement [Member] | |||||||||||||||
| Accounting Policies [Line Items] | |||||||||||||||
| Revenue from Contract with Customer, Including Assessed Tax | $ 28,000 | $ 28,000 | |||||||||||||