Investments in Companies, Minority Investment Entities (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
AXT, Inc. [Member]
Summarized income information of all the minority investment entities that are not consolidated and accounted for under the equity method [Abstract]
Net revenue	$ 11,487,000	$ 11,024,000	$ 38,433,000	$ 29,938,000
Gross profit	5,371,000	3,628,000	17,458,000	10,516,000
Operating income	2,289,000	2,393,000	8,377,000	6,566,000
Net income	1,759,000	1,631,000	6,485,000	4,960,000
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	$ 390,000	$ 346,000	$ 1,500,000	$ 1,100,000