Property and Equipment - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 51,126	$ 37,745
Less accumulated depreciation and amortization	(8,410)	(2,108)
Property and equipment, net	42,716	35,637
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, at cost	10,837	9,309
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Property and equipment, at cost	4,911
Computers and Purchased Software
Property Plant And Equipment [Line Items]
Property and equipment, at cost	640	248
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, at cost	1,363	1,066
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, at cost	30,862	24,520
Assets Not Yet in Service
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 2,513	$ 2,602