Balance Sheet Components - Summary of Property Plant and Equipment and Rental Equipment with Associated Accumulated Depreciation (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment	$ 65,491	$ 64,294
Accumulated depreciation	45,824	44,856
Property and equipment, net	19,667	19,438
Rental equipment
Property Plant And Equipment [Line Items]
Property and equipment	38,995	39,308
Accumulated depreciation	31,035	30,984
Property and equipment, net	7,960	8,324
Other property and equipment
Property Plant And Equipment [Line Items]
Property and equipment	26,496	24,986
Accumulated depreciation	14,789	13,872
Property and equipment, net	$ 11,707	$ 11,114