Investments in Privately-held Companies, Minority Investment Entities (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
AXT, Inc. [Member]
Summarized income information of all the minority investment entities that are not consolidated and accounted for under the equity method [Abstract]
Revenue	$ 9,325,000	$ 13,480,000
Gross profit	2,295,000	3,963,000
Operating income	1,051,000	2,664,000
Net income	957,000	2,119,000
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	$ 200,000	$ 487,000