Property, Plant and Equipment, Net - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 68,830	$ 66,050
Less: Accumulated depreciation	(5,848)	(5,525)
Property, plant and equipment, net	62,982	60,525
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,374	2,366
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,013	6,038
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,651	1,815
Software, computer and other equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,786	2,702
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,174	4,072
Construction-in-progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 51,832	$ 49,057