Net Loss Per Share - Reconciliation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Numerator:
Net loss attributable to AXT, Inc.	$ (1,516)	$ (5,089)	$ (3,599)	$ (8,437)
Less: Preferred stock dividends	(44)	(44)	(88)	(88)
Net loss available to common stockholders	$ (1,560)	$ (5,133)	$ (3,687)	$ (8,525)
Denominator:
Denominator for basic net income (loss) per share - weighted-average common shares	43,092	42,586	43,039	42,542
Effect of dilutive securities:
Denominator for dilutive net income (loss) per common shares	43,092	42,586	43,039	42,542
Net loss attributable to AXT, Inc. per common share:
Basic	$ (0.04)	$ (0.12)	$ (0.09)	$ (0.20)
Diluted	$ (0.04)	$ (0.12)	$ (0.09)	$ (0.20)
Common stock options
Net loss attributable to AXT, Inc. per common share:
Securities excluded from diluted net income (loss) per share as the impact is anti-dilutive (in shares)	1,187	1,200	1,187	1,200
Restricted Stock [Member]
Net loss attributable to AXT, Inc. per common share:
Securities excluded from diluted net income (loss) per share as the impact is anti-dilutive (in shares)	1,325	1,019	1,325	1,019