Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 18,251	$ 16,930
Depreciation and amortization	$ 4,900	4,000	$ 3,300
Lease and loaner instruments
Property, Plant and Equipment [Line Items]
Accumulated depreciation		$ 2,400