Summary of significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Schedule of activity related to allowance for doubtful accounts

Activity related to our allowance for credit losses for trade receivables was as follows:

	Years Ended December 31,
	2021		2020		2019
	(in thousands)
Balance, beginning of period	$	530	$	200	$	60
Provision	143		824		279
Write-offs	(373)		(494)		(139)
Recoveries of amounts previously written off	91		—		—
Balance, end of period	$	391	$	530	$	200

Schedule of disaggregation of revenue

Revenue from subscription and non-subscription contractual arrangements were as follows:

	Years Ended December 31,
	2021		2020		2019
	(in thousands)
SaaS subscription and support and maintenance	$	313,950	$	223,655	$	158,493
On‑premise subscription	30,293		25,224		16,625
Subscription revenue	344,243		248,879		175,118
Professional services	16,122		14,519		19,014
Perpetual licenses	6,023		5,734		9,833
Non‑subscription revenue	22,145		20,253		28,847
Total revenue	$	366,388	$	269,132	$	203,965

Schedule of changes in contract assets and liabilities

Changes in contract liabilities, including revenue earned during the period from the beginning contract liability balance and new deferrals of revenue during the period, were as follows:

	Years Ended December 31,
	2021		2020		2019
	(in thousands)
Balance, beginning of the period	$	205,509	$	140,449	$	100,025
Acquisitions	5,200		—		—
Revenue earned	(160,002)		(127,915)		(85,471)
Deferral of revenue	231,421		192,975		125,895
Balance, end of the period	$	282,128	$	205,509	$	140,449