Leases (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($) ft²	Jun. 30, 2019 USD ($) ft²
Lessee, Lease, Description [Line Items]
Area of property (square feet) | ft²	86,500	86,500
Remaining lease term (years)		3 years 9 months
Renewal term (years)	5 years	5 years
Operating lease cost	$ 0.4	$ 0.7
Remaining lease term- operating lease, in years	8 years 9 months	8 years 9 months
Cash payments on operating lease		$ 0.7
Discount rate - operating lease	25.49%	25.49%
Selling, General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 0.3	$ 0.6
Research and Development Expense
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 0.1	$ 0.1