Segments and Major Customers (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Major Customer Disclosure
Revenues	$ 66,866	$ 62,863
United States
Major Customer Disclosure
Revenues	25,569	16,189
South Korea
Major Customer Disclosure
Revenues	22,025	23,247
Japan
Major Customer Disclosure
Revenues	14,609	17,569
Europe
Major Customer Disclosure
Revenues	2,127	1,129
Canada
Major Customer Disclosure
Revenues	1,786	1,979
Asia-Other
Major Customer Disclosure
Revenues	$ 750	$ 2,750