Revenue Recognition - Summary of Revenues Disaggregated by Geography (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation Of Revenue [Line Items]
Total revenue		$ 35,471	$ 46,224	$ 105,806	$ 144,984
UNITED STATES
Disaggregation Of Revenue [Line Items]
Total revenue		21,613	29,430	63,219	96,532
Other
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	$ 13,858	$ 16,794	$ 42,587	$ 48,452

[1] No single country outside of the United States represented 10% or more of the Company’s revenues in the periods presented.