Income Taxes Expense - Components of the Company's Deferred Income Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jun. 09, 2020	Dec. 31, 2019
Deferred tax assets:
Convertible bond hedge	$ 12,420		$ 17,197
Accrued product returns and rebates	17,529		15,123
Accrued compensation and stock based compensation	13,547		10,349
Non-recourse liability related to sale of future royalties	3,777		5,320
Research and development credit carryforwards	3,151		3,817
Amortization of intangibles	0		4,617
Net operating loss carryforwards	13,164		2,245
Operating lease liability	14,542		8,187
Other	5,303		2,510
Total deferred tax assets	83,433		69,365
Less: valuation allowance	(582)	$ (600)	(11)
Total deferred tax asset, net of valuation allowance	82,851		69,354
Deferred tax liabilities:
Amortization of intangibles	79,545		0
Debt discount on 2023 Notes	(10,190)		(14,109)
Patent infringement legal costs	(10,897)		(10,613)
Operating lease assets	(10,674)		(5,237)
Depreciation	(3,458)		(2,778)
IRC Section 481(a) liability	(315)		(2,126)
Unrealized gain on marketable securities	(2,987)		(2,428)
Total deferred tax liabilities	(118,066)		(37,291)
Net deferred tax (liabilities) assets	$ (35,215)
Net deferred tax (liabilities) assets			$ 32,063