Revenue Recognition - Summary of Revenues Disaggregated by Geography (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Total revenue		$ 34,394	$ 50,212	$ 70,336	$ 98,761
UNITED STATES
Disaggregation Of Revenue [Line Items]
Total revenue		18,988	34,225	41,607	67,102
Other
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	$ 15,406	$ 15,987	$ 28,729	$ 31,659

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