Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands		9 Months Ended
	Oct. 10, 2016	Sep. 30, 2020
Regeneron | Collaboration Agreement | Maximum
Commitments and Contingencies
Reimbursable clinical development costs	$ 25,000
Potential increase in reimbursable clinical development costs	$ 5,000
Incept
Commitments and Contingencies
Royalties paid related to product sales		$ 481