Cash and Cash Equivalents Cash and Cash Equivalents - Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 112,521	$ 76,174	$ 44,593	$ 29,372
United States [Member]
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	43,546	30,082
Asia [Member]
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	50,799	34,627
Europe [Member]
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	12,912	7,161
South America [Member]
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 5,264	$ 4,304