Equity-Based Compensation (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity-based compensation expense
Total equity-based compensation expense	$ 8,625	$ 8,004	$ 7,024
Cost of Sales [Member]
Equity-based compensation expense
Total equity-based compensation expense	122	121	225
Research and Development Expense [Member]
Equity-based compensation expense
Total equity-based compensation expense	1,596	2,149	1,994
Selling, General and Administrative Expenses [Member]
Equity-based compensation expense
Total equity-based compensation expense	$ 6,907	$ 5,734	$ 4,805