Income Taxes - Differences in Statutory Rate and Effective Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. statutory rate	$ (2,411)	$ 6,012	$ 10,405
Permanent items	1,406	3,210	152
Acquisition costs - Progenics	2,723	0	0
Recognition of deferred tax asset - assets held for sale	(3,000)	0	0
Section 162	717	527	353
Uncertain tax positions	2,818	(13,156)	3,227
Other tax credits	(1,065)	(1,685)	(742)
State and local taxes	1,457	1,914	2,125
Foreign tax rate differential	(254)	(238)	30
Valuation allowance	(318)	(22)	(4,073)
Benefit of windfall related to stock compensation	(128)	(2,768)	(1,760)
Change in indemnification deferred tax asset	(590)	2,531	(731)
Other	639	635	44
Income tax expense (benefit)	$ 1,994	$ (3,040)	$ 9,030