Investments in Privately Held Companies - Minority Investment Entities (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
AXT, Inc. Stockholders' Equity
Summarized income information of all the minority investment entities that are not consolidated and accounted for under the equity method [Abstract]
Net Revenue	$ 7,760,000	$ 11,004,000	$ 11,276,000	$ 20,329,000
Gross profit	(629,000)	3,625,000	(579,000)	5,920,000
Operating income (loss)	(1,676,000)	2,292,000	(2,860,000)	3,343,000
Net income (loss)	(1,644,000)	1,784,000	(3,418,000)	2,741,000
Equity Method Investments [Member]
Summarized income information of all the minority investment entities that are not consolidated and accounted for under the equity method [Abstract]
Net income (loss)	$ (400,000)	$ 410,000	$ (856,000)	$ 610,000