Segment Information (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Summary of revenue by product type
Total Revenue	$ 19,942	$ 33,637	$ 47,152	$ 114,635
Core [Member]
Summary of revenue by product type
Total Revenue	1,344	6,602	9,417	61,622
Polished [Member]
Summary of revenue by product type
Total Revenue	16,580	25,117	32,709	48,077
Optical [Member]
Summary of revenue by product type
Total Revenue	1,558	1,909	4,525	4,912
Research & Development [Member]
Summary of revenue by product type
Total Revenue	422		447	15
Other [Member]
Summary of revenue by product type
Total Revenue	$ 38	$ 9	$ 54	$ 9