Summary of Revenues Disaggregated by Timing of Goods and Services Transferred (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Net revenue	$ 6,539	$ 8,646	$ 14,260	$ 27,617
Revenue Recognized Over Time
Disaggregation Of Revenue [Line Items]
Net revenue	898	1,997	3,143	5,267
Revenue Recognized at a Point in Time
Disaggregation Of Revenue [Line Items]
Net revenue	$ 5,641	$ 6,649	$ 11,117	$ 22,350