Revenue Recognition

6 Months Ended

Jun. 30, 2020

Revenue from Contract with Customer [Abstract]

Revenue Recognition

Revenue Recognition

Disaggregation of Revenue

The following table presents a summary of revenue:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2020		2019		2020		2019
Subscription revenue	$	92,010	$	69,370	$	178,400	$	134,107
Perpetual license and maintenance revenue	12,179		13,553		25,598		27,080
Professional services and other revenue	3,020		2,461		5,859		4,498
Revenue	$	107,209	$	85,384	$	209,857	$	165,685

Concentrations

We sell and market our products and services through our field sales force that works closely with our channel partners, which includes a network of distributors and resellers, in developing sales opportunities. We use a two-tiered channel model whereby we sell our products and services to our distributors, which in turn sell to resellers, which then sell to end-users. We derived 91% of revenue through our channel network in the three and six months ended June 30, 2020 and 90% of revenue in the three and six months ended June 30, 2019. One of our distributors accounted for 43% of revenue in each of the three and six months ended June 30, 2020 and 2019. That same distributor accounted for 40% of accounts receivable at June 30, 2020 and December 31, 2019.

Contract Balances

We generally bill our customers in advance and accounts receivable are recorded when we have the right to invoice the customer. Contract liabilities consist of deferred revenue and include customer billings and payments received in advance of performance under the contract. In the three months ended June 30, 2020 and 2019 and the six months ended June 30, 2020 and 2019, we recognized revenue of $99.5 million, $78.3 million, $175.0 million and $136.7 million, respectively, that was included in the deferred revenue balance at the beginning of each of the respective periods.

Remaining Performance Obligations

At June 30, 2020, the future estimated revenue related to unsatisfied performance obligations was $378.2 million, of which approximately 74% is expected to be recognized as revenue over the succeeding twelve months, and the remainder is expected to be recognized over the four years thereafter.

Deferred Commissions

The following summarizes the activity of deferred incremental costs of obtaining a contract:

	Three Months Ended June 30,						Six Months Ended June 30,
(in thousands)	2020			2019			2020			2019
Beginning balance	$	70,742		$	59,811		$	72,265		$	59,434
Capitalization of contract acquisition costs	8,892			8,608			15,013			15,234
Amortization of deferred contract acquisition costs	(7,866		)	(6,553		)	(15,510		)	(12,802		)
Ending balance	$	71,768		$	61,866		$	71,768		$	61,866