Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net income attributable to AXT, Inc.	$ 1,341	$ 5,759	$ 5,546	$ 3,165	$ 2,965	$ 3,800	$ 4,385	$ 3,425	$ 15,811	$ 14,575	$ 3,238
Less: Preferred stock dividends									(177)	(177)	(177)
Net income available to common stockholders									$ 15,634	$ 14,398	$ 3,061
Denominator:
Denominator for basic net income per share - weighted-average common shares									42,104	41,367	40,152
Effect of dilutive securities:
Denominator for dilutive net income per common shares									42,715	42,720	41,025
Basic net income per share:
Basic	$ 0.03	$ 0.14	$ 0.13	$ 0.07	$ 0.07	$ 0.09	$ 0.11	$ 0.08	$ 0.37	$ 0.35	$ 0.08
Diluted net income per share:
Diluted	$ 0.03	$ 0.13	$ 0.13	$ 0.07	$ 0.07	$ 0.09	$ 0.10	$ 0.08	$ 0.37	$ 0.34	$ 0.07
Common stock options
Effect of dilutive securities:
Effect of dilutive securities (in shares)									333	803	602
Weighted-average shares:
Securities excluded from diluted net income per share as the impact is anti-dilutive (in shares)									220	21	862
Restricted stock awards
Effect of dilutive securities:
Effect of dilutive securities (in shares)									278	550	271
Weighted-average shares:
Securities excluded from diluted net income per share as the impact is anti-dilutive (in shares)									291	118	161