Acquisitions, Collaboration, License and Other Strategic Agreements - Assets Acquired and Liabilities Assumed Related to the Business Combination (Details) - Perosphere Pharmaceuticals Inc. $ in Millions	Jan. 16, 2019 USD ($)
Assets:
Cash	$ 2.6
Operating lease right-of-use asset	0.8
Property and equipment	1.4
IPR&D	74.9
Total Assets	79.7
Liabilities:
Accrued severance liabilities	(1.7)
Deferred revenue	(6.4)
Operating lease liability	(0.8)
Total Liabilities	$ (8.9)