Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other Long-Term Liabilities
Net Deferred Tax Liabilities Related to IPR&D (Note 12)	$ 3,007	$ 3,007
Deferred Income From Sale of Tax Benefits	1,831	1,831
Contingent Milestones (Note 3)	12,719	12,485
Deferred Revenue	199	254
Total	17,756	17,577
Less Current Portion	(1,993)	(2,026)
Long-Term Portion	$ 15,763	$ 15,551