Note 10 - Net Loss Per Share - Reconciliation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Net loss attributable to AXT, Inc.	$ (7,008)	$ (1,516)	$ (15,806)	$ (3,599)
Less: Preferred stock dividends	(44)	(44)	(88)	(88)
Net loss available to common stockholders	$ (7,052)	$ (1,560)	$ (15,894)	$ (3,687)
Basic (in shares)	43,710,000	43,092,000	43,630,000	43,039,000
Diluted (in shares)	43,710,000	43,092,000	43,630,000	43,039,000
Basic (in dollars per share)	$ (0.16)	$ (0.04)	$ (0.36)	$ (0.09)
Diluted (in dollars per share)	$ (0.16)	$ (0.04)	$ (0.36)	$ (0.09)
Common Stock Options [Member]
Common stock options (in shares)	0	0	0	0
Restricted Stock [Member]
Common stock options (in shares)	0	0	0	0
Options excluded from diluted net loss per share as the impact is anti-dilutive (in shares)	2,289,000	1,325,000	2,289,000	1,325,000
Share-Based Payment Arrangement, Option [Member]
Options excluded from diluted net loss per share as the impact is anti-dilutive (in shares)	1,175,000	1,187,000	1,175,000	1,187,000