Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	$ 57,389	$ 58,712
Accumulated amortization	(53,366)	(54,759)
Intangible asset, Net amount	4,023	3,953
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	18,703	19,350
Accumulated amortization	(18,703)	(19,350)
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	26,861	27,791
Accumulated amortization	(26,861)	(27,791)
Intellectual Property Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, Gross amount	11,825	11,571
Accumulated amortization	(7,802)	(7,618)
Intangible asset, Net amount	$ 4,023	$ 3,953