Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax assets:
Federal net operating loss	$ 121,125	$ 101,662
State net operating loss	64,648	59,126
Foreign net operating loss	32,162	34,407
Research and development expense	1,560	2,893
Tax credits	22,989	21,669
Stock options	30,640	30,430
Accruals	17,215	6,294
Equity investments	13,495	12,904
Bad debts	445	414
Lease liability	1,064	1,370
Foreign credits	9,909	10,837
Available-for-sale securities	2,478	2,447
Operating lease asset	10,204
Other	8,395	11,668
Deferred income tax assets	336,329	296,121
Deferred income tax liabilities:
Intangible assets	(230,662)	(250,640)
Convertible Debt	(12,219)	0
Operating lease liability	(10,204)
Fixed assets	(3,976)	(3,486)
Other	(2,130)	(2,272)
Deferred income tax liabilities	(259,191)	(256,398)
Net deferred income tax assets (liabilities)	77,138	39,723
Valuation allowance	(194,869)	(154,916)
Net deferred income tax liabilities	$ (117,731)	$ (115,193)