Stock-Based Compensation - Allocation of Stock-Based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,016	$ 1,809	$ 4,053	$ 3,480
Capitalized to software and patent costs	49	49	90	93
Total stock-based compensation	2,065	1,858	4,143	3,573
Cost of Revenue [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	179	167	361	322
Sales and Marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	489	411	1,008	756
Research, Development and Engineering [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	357	350	711	648
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	927	814	1,839	1,615
Intellectual Property [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 64	$ 67	$ 134	$ 139