The Company and Summary of Significant Accounting Policies - Comprehensive Income (loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accumulated other comprehensive loss:
Accumulated other comprehensive income (loss) attributable to AXT, Inc.	$ (5,999)	$ (3,118)
Accumulated other comprehensive income including noncontrolling interest
Accumulated other comprehensive loss:
Unrealized loss on investments, net	(20)	(303)
Cumulative translation adjustment	(6,530)	(3,042)
Accumulated other comprehensive income (loss) attributable to AXT, Inc.	(6,550)	(3,345)
Accumulated other comprehensive income attributable to noncontrolling interest
Accumulated other comprehensive loss:
Less: Cumulative translation adjustment attributable to noncontrolling interests and redeemable noncontrolling interests	$ (551)	$ (227)