Revenue - Disaggregate of Revenue by Reportable Segment and Revenue Category (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2024	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Revenue	$ 242,852	$ 227,704	$ 225,991	$ 226,173	$ 452,164	$ 679,868	$ 922,720	$ 1,149,100	$ 1,025,536
Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							330,778	297,708	390,454
Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							291,006	358,418	374,002
Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							300,936	492,974	261,080
Network Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	197,009	181,488	179,194	181,273	360,467	541,955	738,964	974,389	916,793
Network Solutions [Member] | Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							295,541	263,192	364,238
Network Solutions [Member] | Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							232,934	304,074	326,934
Network Solutions [Member] | Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							210,489	407,123	225,621
Services & Support [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 45,843	$ 46,216	$ 46,797	$ 44,900	$ 91,697	$ 137,913	183,756	174,711	108,743
Services & Support [Member] | Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							35,237	34,516	26,216
Services & Support [Member] | Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							58,072	54,344	47,068
Services & Support [Member] | Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue							$ 90,447	$ 85,851	$ 35,459