Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Total property and equipment	$ 406	$ 44
Less: accumulated depreciation	(85)	(5)
Property and equipment, net	321	39
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	65
Machinery and Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	38	38
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	194
Computers
Property Plant And Equipment [Line Items]
Total property and equipment	76	$ 6
Office Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	11
Software
Property Plant And Equipment [Line Items]
Total property and equipment	$ 22