Property and Equipment, Net - Summary Of Property And Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 13,022	$ 10,592
Less: accumulated depreciation	(5,438)	(6,165)
Property and equipment, net	7,584	4,427
Medical diagnostic equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	7,180	5,492
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	388	159
Office equipment [Membre]
Property, Plant and Equipment [Line Items]
Total property and equipment	1,377	1,321
Laboratory equipment and software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	3,380	2,807
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	595	507
Construction in process [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 102	$ 306