Property and Equipment and Capitalized Software - Summary of Composition of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 3,300	$ 3,394
Less: Accumulated depreciation	(2,090)	(2,016)
Property and equipment, net	1,210	1,378
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	150	150
Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	487	487
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,062	1,050
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	273	273
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	172	172
Rental Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,156	1,262
Property and equipment, net	$ 800	$ 900

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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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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