Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 24, 2020	Oct. 02, 2019	Jul. 02, 2019
Income Taxes [Line Items]
Increase (decrease) in income tax provision		$ 6,754	$ (12,537)
Increase (decrease) in deferred income taxes		7,431	6,334	$ 19,152
Amortization	$ 3,701	3,701	11,602
Deferred income tax expense (benefit)		680	(5,453)	(18,223)
Bankruptcy claims, amount paid to settle claims					$ 800
Unrecognized tax benefits	2,483	2,483	3,806	4,597
Income tax penalties and interest expense		203	555	725
Income tax penalties and interest accrued	1,475	1,475	1,612
Unremitted earnings		3,725
Deferred tax assets, tax credit carryforwards, research	6,771	6,771	8,429
Orphan drug and R&D tax credit		2,793	0	0
CARES Act, change in tax rate, deferred tax liability, income tax benefit	9,124
CARES Act, cash tax refunds		3,351
CARES Act, cash refund claims		18,753
Provisional charge related to the re-measurement of its net deferred tax assets				$ 274
Ireland
Income Taxes [Line Items]
Increase (decrease) in deferred income taxes			(5,536)
Increase (decrease) in valuation allowance, deferred tax asset, , amount			(5,536)
Net operating loss carryforwards	118,070	118,070
Operating loss carryforwards, valuation allowance (decrease)	4,171	4,171
Gross research tax credit		375	821
U.S.
Income Taxes [Line Items]
Amortization			8,190
Deferred income tax expense (benefit)			(8,190)
Net operating loss carryforwards	46,003	46,003
Operating loss carryforwards, valuation allowance (decrease)	60	60
France
Income Taxes [Line Items]
Operating loss carryforwards, valuation allowance (decrease)			(3,259)
Gross research tax credit		6,396	$ 7,608
Internal Revenue Service (IRS) | Speciality Pharama
Income Taxes [Line Items]
Bankruptcy claims, amount of filed claims likely to be denied	1,937	1,937				$ 9,302	$ 50,695
Bankruptcy claims, amount paid to settle claims	1,937	1,937
FSC
Income Taxes [Line Items]
Net operating loss carryforwards	10,365	10,365
U.S. Holdings
Income Taxes [Line Items]
Net operating loss carryforwards	$ 35,638	$ 35,638