Legal Matters (Details) $ in Millions	Jul. 16, 2020 claim	Jul. 31, 2017 claim	Sep. 26, 2016 EUR (€)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Feb. 25, 2019 claim	Feb. 14, 2019 claim
Loss Contingencies [Line Items]
Loss contingency accrual | $				$ 132.2	$ 100.0
Amgen v.s. Regeneron | Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, damages sought, per unit produced | €			€ 10,000
Loss contingency, damages sought | €			€ 10,000,000.0
'165 Patent | Amgen v.s. Regeneron | Pending Litigation
Loss Contingencies [Line Items]
Pending claims						2
Invalid claims						2
'741 Patent | Amgen v.s. Regeneron | Pending Litigation
Loss Contingencies [Line Items]
Pending claims						1
'487 Patent
Loss Contingencies [Line Items]
Number of IPR filed		2
Number of claims invalidated							17
'631 Patent | Subsequent Event
Loss Contingencies [Line Items]
Number of IPR filed	2