Property, Plant and Equipment, Net - Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 66,050	$ 34,940
Less: Accumulated depreciation	(5,525)	(3,008)
Property, plant and equipment, net	60,525	31,932
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	2,366	2,082
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	6,038	3,602
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,815	1,209
Software, computer and other equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	2,702	1,932
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	4,072	1,887
Construction-in-progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 49,057	$ 24,228