| Schedule of Stockholders Equity [Table Text Block] |
| | | | | | | | | | | | | | | | | | | Accumulated | | | | | | | | | | | | | |
| | | | | | | | | | | Additional | | | | | | | Other | | | AXT, Inc. | | | | | | | Total | |
| | | Preferred | | | Common | | | Paid-In | | | Accumulated | | | Comprehensive | | | Stockholders’ | | | Noncontrolling | | | Stockholders’ | |
| | | Stock | | | Stock | | | Capital | | | Deficit | | | Income (Loss) | | | Equity | | | Interests | | | Equity | |
| Balance as of December 31, 2025 | | $ | 3,532 | | | $ | 55 | | | $ | 339,922 | | | $ | (64,924 | ) | | $ | (5,295 | ) | | $ | 273,290 | | | $ | 23,285 | | | $ | 296,575 | |
| Common stock options exercised | | | — | | | | 1 | | | | 1,477 | | | | — | | | | — | | | | 1,478 | | | | — | | | | 1,478 | |
| Stock-based compensation | | | — | | | | — | | | | 1,035 | | | | — | | | | — | | | | 1,035 | | | | — | | | | 1,035 | |
| Net loss | | | — | | | | — | | | | — | | | | (1,620 | ) | | | — | | | | (1,620 | ) | | | 148 | | | | (1,472 | ) |
| Other comprehensive loss | | | — | | | | — | | | | — | | | | — | | | | 691 | | | | 691 | | | | 143 | | | | 834 | |
| Balance as of March 31, 2026 | | | 3,532 | | | | 56 | | | | 342,434 | | | | (66,544 | ) | | | (4,604 | ) | | | 274,874 | | | | 23,576 | | | | 298,450 | |
| Common stock options exercised | | | — | | | | — | | | | 489 | | | | — | | | | — | | | | 489 | | | | — | | | | 489 | |
| Stock-based compensation | | | — | | | | — | | | | 762 | | | | — | | | | — | | | | 762 | | | | — | | | | 762 | |
| Issuance of common stock, net of issuance costs of $32,417 | | | — | | | | 10 | | | | 600,073 | | | | — | | | | — | | | | 600,083 | | | | — | | | | 600,083 | |
| Net income | | | — | | | | — | | | | — | | | | 11,128 | | | | — | | | | 11,128 | | | | 1,093 | | | | 12,221 | |
| Other comprehensive loss | | | — | | | | — | | | | — | | | | — | | | | (62 | ) | | | (62 | ) | | | 170 | | | | 108 | |
| Balance as of June 30, 2026 | | | 3,532 | | | | 66 | | | | 943,758 | | | | (55,416 | ) | | | (4,666 | ) | | | 887,274 | | | | 24,839 | | | | 912,113 | |
| | | | | | | | | | | | | | | | | | | Accumulated | | | | | | | | | | | | | |
| | | | | | | | | | | Additional | | | | | | | Other | | | AXT, Inc. | | | | | | | Total | |
| | | Preferred | | | Common | | | Paid-In | | | Accumulated | | | Comprehensive | | | Stockholders’ | | | Noncontrolling | | | Stockholders’ | |
| | | Stock | | | Stock | | | Capital | | | Deficit | | | Income (Loss) | | | Equity | | | Interests | | | Equity | |
| Balance as of December 31, 2024 | | $ | 3,532 | | | $ | 45 | | | $ | 241,514 | | | $ | (43,664 | ) | | $ | (8,657 | ) | | $ | 192,770 | | | $ | 23,561 | | | $ | 216,331 | |
| Stock-based compensation | | | — | | | | — | | | | 563 | | | | — | | | | — | | | | 563 | | | | — | | | | 563 | |
| Tongmei stock-based compensation | | | — | | | | 1 | | | | 70 | | | | — | | | | — | | | | 71 | | | | 6 | | | | 77 | |
| Net loss | | | — | | | | — | | | | — | | | | (8,798 | ) | | | — | | | | (8,798 | ) | | | (610 | ) | | | (9,408 | ) |
| Other comprehensive income | | | — | | | | — | | | | — | | | | — | | | | 431 | | | | 431 | | | | 53 | | | | 484 | |
| Balance as of March 31, 2025 | | | 3,532 | | | | 46 | | | | 242,147 | | | | (52,462 | ) | | | (8,226 | ) | | | 185,037 | | | | 23,010 | | | | 208,047 | |
| Stock-based compensation | | | — | | | | — | | | | 607 | | | | — | | | | — | | | | 607 | | | | — | | | | 607 | |
| Tongmei stock-based compensation | | | — | | | | — | | | | 22 | | | | — | | | | — | | | | 22 | | | | 2 | | | | 24 | |
| Net loss | | | — | | | | — | | | | — | | | | (7,008 | ) | | | — | | | | (7,008 | ) | | | (233 | ) | | | (7,241 | ) |
| Other comprehensive income | | | — | | | | — | | | | — | | | | — | | | | 1,056 | | | | 1,056 | | | | 128 | | | | 1,184 | |
| Balance as of June 30, 2025 | | | 3,532 | | | | 46 | | | | 242,776 | | | | (59,470 | ) | | | (7,170 | ) | | | 179,714 | | | | 22,907 | | | | 202,621 | |
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