Total Net Revenue Based on Disaggregation Criteria (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]
Total net revenue	$ 24,859	$ 23,026	$ 62,084	$ 64,785
Point-in-Time
Disaggregation Of Revenue [Line Items]
Total net revenue	23,939	21,580	58,804	60,796
Over Time
Disaggregation Of Revenue [Line Items]
Total net revenue	920	1,446	3,280	3,989
Americas
Disaggregation Of Revenue [Line Items]
Total net revenue	15,050	17,825	42,588	48,495
Americas | Point-in-Time
Disaggregation Of Revenue [Line Items]
Total net revenue	14,217	16,471	39,587	44,755
Americas | Over Time
Disaggregation Of Revenue [Line Items]
Total net revenue	833	1,354	3,001	3,740
Europe and the Middle East
Disaggregation Of Revenue [Line Items]
Total net revenue	2,082	2,436	7,312	8,790
Europe and the Middle East | Point-in-Time
Disaggregation Of Revenue [Line Items]
Total net revenue	1,995	2,344	7,033	8,541
Europe and the Middle East | Over Time
Disaggregation Of Revenue [Line Items]
Total net revenue	87	92	279	249
Asia-Pacific
Disaggregation Of Revenue [Line Items]
Total net revenue	7,727	2,765	12,184	7,500
Asia-Pacific | Point-in-Time
Disaggregation Of Revenue [Line Items]
Total net revenue	$ 7,727	$ 2,765	$ 12,184	$ 7,500