Summary of Significant Accounting Policies - Schedule of Revenue Disaggregated by Revenue Type, Geographic Region and Customer (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Total revenue	$ 264,400	$ 253,119
Percentage of total revenue	100.00%	100.00%
Broadband/Cable/Satellite
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	54.00%	57.00%
Telecommunications
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	19.00%	18.00%
Other
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	27.00%	25.00%
Americas (principally the U.S.)
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	84.00%	86.00%
Europe, Middle East and Africa
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	12.00%	10.00%
Asia Pacific
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	4.00%	4.00%
SaaS and Related Solutions
Disaggregation Of Revenue [Line Items]
Total revenue	$ 234,977	$ 227,019
Software and Services
Disaggregation Of Revenue [Line Items]
Total revenue	18,436	14,779
Maintenance
Disaggregation Of Revenue [Line Items]
Total revenue	$ 10,987	$ 11,321