Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Long-Term Liabilities
Net Deferred Tax Liabilities related to IPR&D (Note 14)	$ 3,772	$ 28,054
Deferred Income from Sale of Tax Benefits	6,756	9,436
Other	1,344	2,091
Contingent Milestones (Note 4)	43,400	44,200
Deferred Revenue	2,813	3,749
Total	58,085	87,530
Less Current Portion	(6,566)	(4,826)
Long-Term Portion	$ 51,519	$ 82,704