Property, Plant and Equipment, Net - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 63,180	$ 34,940
Less: Accumulated depreciation	(4,820)	(3,008)
Total property, plant and equipment, net	58,360	31,932
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,307	2,082
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,915	3,602
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,536	1,209
Software and computer equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,321	1,932
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,685	1,887
Construction-in-progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 48,416	$ 24,228