Long-Term Obligation (Summary of Payment Obligations under Financing Agreement) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
Total repayment obligation	$ 45,000	$ 45,000
Less interest in future periods	(822)	(2,385)
Less unamortized financing costs	(19)	(35)
Less payments made	(25,434)	(15,087)
Less current portion	(18,725)	(14,965)
Long-term obligation, net of current portion	$ 0	$ 12,528