Supplemental Balance Sheet Information - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 16,461	$ 16,509
Less accumulated depreciation and amortization	(14,944)	(14,851)
Property and equipment, net	1,517	1,658
Office and Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	710	710
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	778	778
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	5,094	5,104
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	198	198
Manufacturing Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,127	1,109
Manufacturing Tooling and Molds [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	371	371
T2-Owned Instruments and Components [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,667	3,549
Leased T2 Owned Instruments [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	899	1,059
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,608	3,608
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 9	$ 23