Segment Information (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of revenue by product type
Total Revenue	$ 17,003	$ 43,028	$ 27,210	$ 80,998
Core [Member]
Summary of revenue by product type
Total Revenue	5,315	27,447	8,073	55,020
Polished [Member]
Summary of revenue by product type
Total Revenue	10,448	14,048	16,129	22,960
Optical [Member]
Summary of revenue by product type
Total Revenue	1,208	1,538	2,967	3,003
Other [Member]
Summary of revenue by product type
Total Revenue	$ 32	$ (5)	$ 41	$ 15