Net Income (loss) Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Numerator [Abstract]
Net loss attributable to AXT, Inc.	$ (2,040)	$ (2,400)
Less: Preferred stock dividends	(44)	(44)
Net loss available to common stockholders	(2,084)	(2,444)
Denominator [Abstract]
Denominator for basic net loss per share - weighted average common shares (in shares)	32,364	32,297
Effect Of Dilutive Securities On Earnings Per Share [Line Items]
Denominator for dilutive net loss per common share (in shares)	32,364	32,297
Net loss attributable to AXT, Inc. per common share [Abstract]
Basic (in dollars per share)	$ (0.06)	$ (0.08)
Diluted (in dollars per share)	$ (0.06)	$ (0.08)
Weighted-average shares [Abstract]
Preferred stock, shares issued (in shares)	883		883
Preferred stock, shares outstanding (in shares)	883		883
Preferred stock, par value (in dollars per share)	$ 0.001		$ 0.001
Preferred stock, value	$ 3,532		$ 3,532
Cumulative annual dividend rate (in hundredths)	5.00%		5.00%
Liquidation preference over common stock (in dollars per share)	$ 4		$ 4
Options [Member]
Weighted-average shares [Abstract]
Securities excluded from diluted net loss per share as the impact is anti-dilutive (in shares)	2,607	2,656
Restricted stock awards [Member]
Weighted-average shares [Abstract]
Securities excluded from diluted net loss per share as the impact is anti-dilutive (in shares)	241	239
Common stock options [Member]
Effect Of Dilutive Securities On Earnings Per Share [Line Items]
Effect of dilutive securities (in shares)	0	0
Restricted stock awards [Member]
Effect Of Dilutive Securities On Earnings Per Share [Line Items]
Effect of dilutive securities (in shares)	0	0