Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other Long-Term Liabilities
Net Deferred Tax Liabilities Related to IPR&P (Note 14)	$ 3,007	$ 3,772
Deferred Income From Sale of Tax Benefits	4,218	6,756
Other	1,083	1,344
Contingent Milestones (Note 4)	13,779	43,400
Deferred Revenue	1,586	2,813
Total	23,673	58,085
Less Current Portion	(4,526)	(6,566)
Long-Term Portion	$ 19,147	$ 51,519