Stock-based Compensation - Summary Components of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 1,445	$ 1,219	$ 2,969	$ 2,605
Cost of Services [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	114	158	273	333
Cost of Product Sales [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	19	10	42	22
Selling, General and Administrative [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,230	956	2,502	2,034
Product Development [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 82	$ 95	$ 152	$ 216