Revenue - Disaggregate of Revenue by Reportable Segment and Revenue Category (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation Of Revenue [Line Items]
Revenue	$ 226,173	$ 323,912
Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	69,767	79,336
Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	81,312	96,820
Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	75,094	147,756
Network Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	181,273	282,418
Network Solutions [Member] | Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	60,369	70,287
Network Solutions [Member] | Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	67,777	84,554
Network Solutions [Member] | Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	53,127	127,577
Services & Support [Member]
Disaggregation Of Revenue [Line Items]
Revenue	44,900	41,494
Services & Support [Member] | Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	9,399	9,049
Services & Support [Member] | Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	13,535	12,266
Services & Support [Member] | Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 21,966	$ 20,179