License Agreements and Grants - National Institute of Health Grant (Details) - National Institute of Health Grant - USD ($) $ in Millions	1 Months Ended	12 Months Ended			35 Months Ended
	Feb. 28, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Length of project (years)	5 years
Total grant funding	$ 5.0	$ 0.3	$ 0.2	$ 0.2
Cumulative sub-award					$ 1.3