REVENUE RECOGNITION (Tables)

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Summary of Revenue Disaggregation

Disaggregated revenue by primary geographical market and timing of revenue recognition for the Company’s single product line are as follows:

	Years Ended December 31,
	2019		2018
	(In thousands)
Primary geographical markets:
United States	$	523,577	$	219,600
International	100,756		96,559
Total	$	624,333	$	316,159
Timing of revenue recognition:
Products delivered at a point in time	$	584,556	$	270,778
Products and services delivered over time	39,777		45,381
Total	$	624,333	$	316,159

Summary of Contract Assets and Contract Liabilities, and Changes in Balances from Contracts with Customers

Significant changes in the balances of contract assets (prepaid expenses and other assets) during the period are as follows (in thousands):

Contract Assets
Balance on December 31, 2018	$	47,664
Amount recognized	(15,144		)
Increase	24,622
Balance as of December 31, 2019	$	57,142

Receivables, and contract assets and contract liabilities from contracts with customers are as follows:

	December 31, 2019		December 31, 2018
	(In thousands)
Receivables	$	145,413	$	78,938
Short-term contract assets (Prepaid expenses and other assets)	15,055		13,516
Long-term contract assets (Other assets)	42,087		34,148
Short-term contract liabilities (Deferred revenues)	81,783		33,119
Long-term contract liabilities (Deferred revenues)	100,204		76,911

Significant changes in the balances of contract liabilities (deferred revenues) during the period are as follows (in thousands):

Contract Liabilities
Balance on December 31, 2018	$	110,030
Revenue recognized	(39,777		)
Increase due to billings	61,825
Increase due to safe harbor prepayments	49,909
Balance as of December 31, 2019	$	181,987

Summary of Estimated Revenue Expected to be Recognized in Future Periods

Estimated revenue expected to be recognized in future periods related to performance obligations that are unsatisfied or partially unsatisfied at the end of the reporting period are as follows:

	December 31, 2019
	(In thousands)
Fiscal year:
2020	$	81,783
2021	30,665
2022	25,633
2023	19,841
2024	14,650
Thereafter	9,415
Total	$	181,987

Estimated revenue expected to be recognized in fiscal year 2020 of $81.8 million includes $44.5 million of safe harbor prepayments from customers in the fourth quarter of 2019 for product delivery to the customer in the first quarter of 2020. Remaining $5.4 million of safe harbor prepayments from customers in the fourth quarter of 2019 for product delivery to the customer in the first quarter of 2020 relates to the sale of Envoy communications gateway which will be recognized ratably over the service period.