Investments in Privately-held Companies (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Summary of investments [Abstract]
Investments, consolidated	$ 4,333,000		$ 4,333,000		$ 1,998,000
Equity Method Investment by Parent	7,138,000		7,138,000		7,049,000
Number of consolidated joint ventures	3	3	3	3
Income from three consolidated joint ventures	1,800,000	3,300,000	7,000,000	10,400,000
Income allocated to minority interests	512,000	1,378,000	2,957,000	4,463,000
Net income from joint ventures attributable to parent	1,200,000	1,900,000	4,100,000	6,000,000
Number of equity investment entities	3		3		3
Number of entities not considered as variable interest entities	3		3
Net equity earnings (losses) from three minority-owned joint ventures that are not consolidated, recorded as other expenses	206,000	124,000	78,000	506,000
Net income generated by all joint ventures, consolidated and equity method investments	1,500,000	2,100,000	4,200,000	6,500,000
Undistributed retained earnings relating to investments in all companies	28,000,000		28,000,000		23,800,000
Minority investment in consolidated joint venture, included in other assets	2,000,000		2,000,000		1,300,000
Number of entities in which investment is accounted under cost method	2		2
Investments in unconsolidated privately-held entities, included in other assets	392,000		392,000		392,000
Beijing JiYa Semiconductor Material Co., Ltd [Member]
Summary of investments [Abstract]
Investments, consolidated	3,331,000		3,331,000		996,000
Percentage of ownership, consolidated method (in hundredths)	46.00%		46.00%
Nanjing Jin Mei Gallium Co., Ltd [Member]
Summary of investments [Abstract]
Investments, consolidated	592,000		592,000		592,000
Percentage of ownership, consolidated method (in hundredths)	83.00%		83.00%
Beijing BoYu Semiconductor Vessel Craftwork Technology Co., Ltd [Member]
Summary of investments [Abstract]
Investments, consolidated	410,000		410,000		410,000
Percentage of ownership, consolidated method (in hundredths)	70.00%		70.00%
Donghai County Dongfang High Purity Electronic Materials Co., Ltd. [Member]
Summary of investments [Abstract]
Equity Method Investment by Parent	2,045,000		2,045,000		2,167,000
Percentage of ownership, equity method (in hundredths)	46.00%		46.00%
Xilingol Tongli Germanium Co. Ltd [Member]
Summary of investments [Abstract]
Equity Method Investment by Parent	3,992,000		3,992,000		3,881,000
Percentage of ownership, equity method (in hundredths)	25.00%		25.00%
Emeishan Jia Mei High Purity Metals Co., Ltd [Member]
Summary of investments [Abstract]
Equity Method Investment by Parent	$ 1,101,000		$ 1,101,000		$ 1,001,000
Percentage of ownership, equity method (in hundredths)	25.00%		25.00%