Employee Benefit Plans (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Reclassifications related to the SERP from accumulated other comprehensive loss to the statement of operations
Prior service cost	$ 1,234	$ 827
Amortization of net actuarial loss	210	794
Total prior service cost and amortization of net actuarial loss	1,444	1,621
Tax benefit	(540)	(601)
Total, net of tax	904	1,020
Research and development
Reclassifications related to the SERP from accumulated other comprehensive loss to the statement of operations
Prior service cost	408	312
Amortization of net actuarial loss	69	300
Selling, general and administrative
Reclassifications related to the SERP from accumulated other comprehensive loss to the statement of operations
Prior service cost	826	515
Amortization of net actuarial loss	$ 141	$ 494