Collaboration, License, and Other Agreements - Sanofi, Antibody Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 01, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues		$ 2,294,000	$ 1,743,700	$ 6,074,200	$ 4,694,100
Sanofi Collaboration Agreement, Antibody
Disaggregation of Revenue [Line Items]
Percentage of Trial Costs borne by collaborating party				80.00%
Percentage of Trial Costs borne by entity				20.00%
Levels of twelve month sales at which sales milestone payments would be received				$ 1,000,000
Period for achieving sales target for milestone payment, rolling basis				12 months
Maximum amount of sales milestone payments if total sales achieve specific levels				$ 200,000
Sanofi Collaboration Agreement, Antibody | Sales-based milestone earned
Disaggregation of Revenue [Line Items]
Revenues		$ 50,000	$ 0	$ 50,000	$ 0
Praluent Agreement
Disaggregation of Revenue [Line Items]
Royalty percentage to be received on net product sales outside of the United States	5.00%
Percentage of damages company is responsible for	50.00%
Sanofi | Praluent Agreement
Disaggregation of Revenue [Line Items]
Percentage of royalty payment that can be used to offset litigation proceedings	50.00%