Commitments and Contingencies - Cystic Fibrosis Foundation Agreement and Joint Venture Agreement (Details) - CF Foundation	1 Months Ended
	Dec. 31, 2016 USD ($) item	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Nov. 30, 2018 USD ($)
Cystic Fibrosis Foundation Agreement
Amount of award received for advance research on potential drugs	$ 2,900,000			$ 7,500,000
Excess amount recorded as liability		$ 0	$ 0
Period for payment of annual installments	90 days
Maximum percentage of awarded amount of net sales	15.00%
Payment of amount received in connection with Disposition Transaction (as a percent)	15.00%
Number of multiplication on awarded amount payable if change of control prior to completion of the first commercial sale | item	9
Maximum
Cystic Fibrosis Foundation Agreement
Number of annual installments for repayment of award	5