REVENUE (Tables)

9 Months Ended

Sep. 30, 2021

Revenue from Contract with Customer [Abstract]

Revenue by Type

The following table is a summary of our revenues by type for the three and nine months ended September 30, 2021 and 2020 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Products and solutions net revenues	$	36,850	$	35,775	$	107,295	$	98,121
Subscription services	28,008		17,907		74,384		48,292
Maintenance	30,702		30,826		90,997		93,190
Professional services, training and other services	6,080		5,923		18,204		16,562
Total net revenues	$	101,640	$	90,431	$	290,880	$	256,165

Revenue by Geographic Region

The following table sets forth our revenues by geographic region for the three and nine months ended September 30, 2021 and 2020 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Revenues:
United States	$	45,026	$	36,190	$	126,084	$	105,166
Other Americas	5,222		4,505		15,030		15,841
Europe, Middle East and Africa	38,782		37,537		109,400		99,478
Asia-Pacific	12,610		12,199		40,366		35,680
Total net revenues	$	101,640	$	90,431	$	290,880	$	256,165

Contract Asset

Contract Asset

Contract asset activity for the nine months ended September 30, 2021 and 2020 was as follows (in thousands):

	September 30, 2021		September 30, 2020
Contract asset at beginning of year	$	18,579	$	19,494
Revenue in excess of billings	43,757		22,045
Customer billings	(39,724)		(26,263)
Contract asset at end of period	$	22,612	$	15,276

Deferred Revenue

Deferred revenue activity for the nine months ended September 30, 2021 and 2020 was as follows (in thousands):

	September 30, 2021		September 30, 2020
Deferred revenue at beginning of period	$	99,258	$	97,901
Billings deferred	56,846		47,723
Recognition of prior deferred revenue	(69,337)		(64,460)
Deferred revenue at end of period	$	86,767	$	81,164

A summary of the significant performance obligations included in deferred revenue is as follows (in thousands):

	September 30, 2021
Product	$	4,364
Subscription	7,380
Maintenance contracts	66,676
Implied PCS	6,400
Professional services, training and other	1,947
Deferred revenue at September 30, 2021	$	86,767