Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Other Long-Term Liabilities
Net Deferred Tax Liabilities Related to IPR&P (Note 12)	$ 3,007	$ 3,772
Deferred Income From Sale of Tax Benefits	6,402	6,756
Other	1,267	1,344
Contingent Milestones (Note 4)	29,800	43,400
Deferred Revenue (Note 11)	1,413	2,813
Total	41,889	58,085
Less Current Portion	(8,607)	(6,566)
Long-Term Portion	$ 33,282	$ 51,519