Summary of Sales by End Market (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Net revenue	$ 37,799	$ 46,155	$ 46,926
End-customer
Disaggregation Of Revenue [Line Items]
Net revenue	25,173	30,478	31,886
Distributors
Disaggregation Of Revenue [Line Items]
Net revenue	$ 12,626	$ 15,677	$ 15,040