Leases - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jan. 31, 2018 ft²
Leases [Abstract]
Area of leased office and research development space (in square feet) | ft²					40,765
Minimum rental payments received	$ 0.1		$ 0.2
Rent expense	0.7	$ 0.7	1.4	$ 1.4
Sublease rent income	$ 0.1	$ 0.1	$ 0.3	$ 0.3