Property, plant and equipment, net - Summary of Property, Plant and Equipment Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total property, plant and equipment	$ 158,970	$ 275,798
Less accumulated depreciation and amortization	(29,835)	(29,176)
Property, plant and equipment, net	129,135	246,622
Land [Member]
Property Plant And Equipment [Line Items]
Total property, plant and equipment	1,210	1,210
Building [Member]
Property Plant And Equipment [Line Items]
Total property, plant and equipment	14,913	180,094
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Total property, plant and equipment	6,518	6,365
Office Equipment [Member]
Property Plant And Equipment [Line Items]
Total property, plant and equipment	6,308	5,584
Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Total property, plant and equipment	40,953	35,693
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Total property, plant and equipment	21,598	183
Construction in Progress [Member]
Property Plant And Equipment [Line Items]
Total property, plant and equipment	$ 67,470	$ 46,669