Summary of Significant Accounting Policies - Research and Development (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Research and Development
Customer-funded service sales	$ 10,302	$ 5,470	$ 1,061
Customer-funded costs included in costs of service sales	$ 2,387	$ 3,424	$ 412