Commitments and Contingencies - Additional Information (Details) $ in Millions	Dec. 31, 2020 USD ($)
Product Liability Contingency [Line Items]
Other Commitment, Due in Next Twelve Months	$ 1.5
Drug Supplier Project Plan [Member]
Product Liability Contingency [Line Items]
Other Commitment	1.9
Manufacturer Of Prexigebersen [Member]
Product Liability Contingency [Line Items]
Other Commitment	1.4
Manufacture Of Drug Substance [Member]
Product Liability Contingency [Line Items]
Other Commitment	0.2
Manufacturing Development [Member]
Product Liability Contingency [Line Items]
Other Commitment	0.2
Testing Services [Member]
Product Liability Contingency [Line Items]
Other Commitment	$ 0.1