Stock-Based Compensation - Summary Components of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 1,661	$ 1,728	$ 3,743	$ 3,435
Cost of Services [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	147	144	306	308
Cost of Product Sales [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	36	24	79	63
Selling, General and Administrative [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,221	1,354	2,847	2,646
Product Development [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 257	$ 206	$ 511	$ 418