Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Commitment And Contingencies [Line Items]
Operating leases expiration period	5 years
Rent expense	$ 1.9	$ 1.6
Minimum
Commitment And Contingencies [Line Items]
Term of warranties on certain product sales	12 months
Maximum
Commitment And Contingencies [Line Items]
Term of warranties on certain product sales	36 months