Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Numerator:
Net income (loss) attributable to AXT, Inc.	$ (3,348)	$ 3,165
Less: Preferred stock dividends	(44)	(44)
Net income (loss) available to common stockholders	$ (3,392)	$ 3,121
Denominator:
Denominator for basic net income (loss) per share - weighted-average common shares	42,498,000	41,871,000
Effect of dilutive securities:
Denominator for dilutive net income (loss) per common shares	42,498,000	42,662,000
Net income (loss) attributable to AXT, Inc. per common share:
Basic	$ (0.08)	$ 0.07
Diluted	$ (0.08)	$ 0.07
Preferred stock, shares issued (in shares)	883,000		883,000
Preferred stock, shares outstanding (in shares)	883,000		883,000
Preferred stock, par value (in dollars per share)	$ 0.001		$ 0.001
Preferred stock, value	$ 3,532		$ 3,532
Cumulative annual dividend rate (as a percent)	5.00%		5.00%
Liquidation preference over common stock (in dollars per share)	$ 4		$ 4
Options
Effect of dilutive securities:
Effect of dilutive securities (in shares)		474,000
Net income (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)	1,203,000	201,000
Restricted stock awards
Effect of dilutive securities:
Effect of dilutive securities (in shares)		317,000
Net income (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)	1,081,000	218,000