CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Preferred Stock [Member]	Common Stock [Member]	Additional Paid In Capital [Member]	Accumulated Deficit [Member]	Other Comprehensive Income/(Loss) [Member]	AXT, Inc. stockholders' equity [Member]	Noncontrolling interest [Member]	Total	Comprehensive Income/(Loss) [Member]
Balance at Dec. 31, 2008	$ 3,532	$ 30	$ 186,754	$ (99,232)	$ 2,580	$ 93,664	$ 3,212	$ 96,876	$ (391)
Balance (in shares) at Dec. 31, 2008	883	30,513
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock options exercised			351			351		351
Common stock options exercised (in shares)		246
Stock-based compensation			766			766		766
Issuance of common stock in the form of restricted stock (in shares)		121
Comprehensive income:
Net income (loss)				(1,898)		(1,898)	393	(1,898)	(1,898)
Dividend declared by joint ventures							(957)	(957)
Change in unrealized (loss) gain on marketable securities					1,750	1,750		1,750	1,750
Currency translation adjustment					(30)	(30)		(30)	(30)
Balance at Dec. 31, 2009	3,532	30	187,871	(101,130)	4,300	94,603	2,648	97,251	(178)
Balance (in shares) at Dec. 31, 2009	883	30,880
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock options exercised		2	1,495			1,497		1,497
Common stock options exercised (in shares)		876
Stock-based compensation			655			655		655
Issuance of common stock in the form of restricted stock (in shares)		121
Comprehensive income:
Net income (loss)				18,653		18,653	1,723	18,653	18,653
Dividend declared by joint ventures							(527)	(527)
Change in unrealized (loss) gain on marketable securities					(144)	(144)		(144)	(144)
Currency translation adjustment					496	496	200	696	496
Balance at Dec. 31, 2010	3,532	32	190,021	(82,477)	4,652	115,760	4,044	119,804	19,005
Balance (in shares) at Dec. 31, 2010	883	31,877
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock options exercised			637			637		637
Common stock options exercised (in shares)		251
Stock-based compensation			896			896		896
Issuance of common stock in the form of restricted stock (in shares)		94
Comprehensive income:
Net income (loss)				20,320		20,320	5,503	20,320	20,320
Dividend declared by joint ventures							(1,636)	(1,636)
Change in unrealized (loss) gain on marketable securities					(161)	(161)		(161)	(161)
Currency translation adjustment					1,327	1,327	359	1,686	1,327
Balance at Dec. 31, 2011	$ 3,532	$ 32	$ 191,554	$ (62,157)	$ 5,818	$ 138,779	$ 8,270	$ 147,049	$ 21,486
Balance (in shares) at Dec. 31, 2011	883	32,222