Stock-Based Compensation - Stock-Based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock compensation expense	$ 1,039	$ 1,001	$ 1,657	$ 1,563
Cost of Revenues [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock compensation expense	65	74	134	146
Research and Development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock compensation expense	140	145	282	282
Sales and Marketing [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock compensation expense	226	164	386	314
General and Administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock compensation expense	$ 608	$ 618	$ 855	$ 821