Property and Equipment - Summary of Components of Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 64,676	$ 61,191
Less: Accumulated depreciation and amortization	(34,614)	(31,312)
Property and equipment, net	30,062	29,879
Computers and Purchased Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	19,063	15,706
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,506	1,340
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,970	1,949
Machinery and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	22,146	21,979
Land
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,091	3,091
Building
Property Plant And Equipment [Line Items]
Property and equipment, gross	4,765	4,765
Building Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	5,356	5,245
Trial Systems at Customers' Sites
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 6,779	$ 7,116

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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