Segment Information - Schedule of Net Revenues from Unaffiliated Customers by Country Based on the Location of the Customer (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 73,720	$ 78,035	$ 74,196	$ 65,269	$ 58,771	$ 56,888	$ 57,709	$ 54,462	$ 291,220	$ 227,830	$ 200,280
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									110,779	83,871	80,603
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									27,689	24,078	22,495
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									147,078	114,365	91,848
All Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 5,674	$ 5,516	$ 5,334