Investments in Companies (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Summary of investments [Abstract]
Income allocated to minority interests	$ 226,000	$ 230,000	$ 673,000	$ 1,105,000
Investments in unconsolidated privately-held entities, included in other assets	200,000		200,000		200,000
AXT, Inc. [Member]
Summary of investments [Abstract]
Gross equity earnings (losses) from minority-owned joint ventures that are not consolidated, recorded as other income	1,759,000	1,631,000	6,485,000	4,960,000
Equity Method Investments [Member]
Summary of investments [Abstract]
Equity method investment by parent	8,104,000		8,104,000		7,537,000
Number of equity investment entities	3		3		3
Gross equity earnings (losses) from minority-owned joint ventures that are not consolidated, recorded as other income	390,000	346,000	1,500,000	1,100,000
Joint Ventures [Member]
Summary of investments [Abstract]
Number of consolidated joint ventures	3	3	3	3
Income from three consolidated joint ventures	1,100,000	565,000	2,900,000	3,300,000
Income allocated to minority interests	226,000	230,000	673,000	1,100,000
Net income from joint ventures attributable to parent	837,000	355,000	2,200,000	2,200,000
Minority investment in consolidated joint venture, included in other assets	4,000,000		4,000,000		3,400,000
Majority-owned Subsidiaries [Member]
Summary of investments [Abstract]
Investments, consolidated	5,269,000		5,269,000		5,269,000
Beijing JiYa Semiconductor Material Co., Ltd [Member] | Majority-owned Subsidiaries [Member]
Summary of investments [Abstract]
Investments, consolidated	3,331,000		3,331,000		3,331,000
Percentage of ownership, consolidated method (in hundredths)			46.00%
Nanjing Jin Mei Gallium Co., Ltd [Member] | Majority-owned Subsidiaries [Member]
Summary of investments [Abstract]
Investments, consolidated	592,000		592,000		592,000
Percentage of ownership, consolidated method (in hundredths)			83.00%
Beijing BoYu Semiconductor Vessel Craftwork Technology Co., Ltd [Member] | Majority-owned Subsidiaries [Member]
Summary of investments [Abstract]
Investments, consolidated	1,346,000		1,346,000		1,346,000
Percentage of ownership, consolidated method (in hundredths)			70.00%
Donghai County Dongfang High Purity Electronic Materials Co., Ltd [Member] | Equity Method Investments [Member]
Summary of investments [Abstract]
Equity method investment by parent	1,761,000		1,761,000		1,900,000
Percentage of ownership, equity method (in hundredths)	46.00%		46.00%
Xilingol Tongli Germanium Co. Ltd [Member] | Equity Method Investments [Member]
Summary of investments [Abstract]
Equity method investment by parent	5,355,000		5,355,000		4,692,000
Percentage of ownership, equity method (in hundredths)	25.00%		25.00%
Emeishan Jia Mei High Purity Metals Co., Ltd [Member] | Equity Method Investments [Member]
Summary of investments [Abstract]
Equity method investment by parent	$ 988,000		$ 988,000		$ 945,000
Percentage of ownership, equity method (in hundredths)	25.00%		25.00%