Supplemental Balance Sheet Information - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 19,081	$ 18,622
Less accumulated depreciation and amortization	(13,236)	(11,307)
Property and equipment, net	$ 5,845	7,315
Office and Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Property and equipment, gross	$ 538	409
Software [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Property and equipment, gross	$ 762	751
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Property and equipment, gross	$ 4,747	4,636
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 194	200
Furniture [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Furniture [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	7 years
Manufacturing Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Property and equipment, gross	$ 672	695
Manufacturing Tooling and Molds [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	6 months
Property and equipment, gross	$ 255	255
T2-Owned Instruments and Components [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Property and equipment, gross	$ 6,775	6,796
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,497	3,437
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,641	$ 1,443

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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