Revenue - Disaggregation of revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue
Revenue	$ 56,492	$ 47,608
Percent of Total	100.00%	100.00%
Products and Licenses transferred at a point in time
Revenue
Revenue	$ 38,260	$ 31,861
Services transferred over time
Revenue
Revenue	18,232	15,747
EMEA
Revenue
Revenue	$ 33,726	$ 25,599
Percent of Total	60.00%	54.00%
Americas
Revenue
Revenue	$ 12,333	$ 12,731
Percent of Total	22.00%	27.00%
APAC
Revenue
Revenue	$ 10,433	$ 9,278
Percent of Total	18.00%	19.00%
Hardware products
Revenue
Revenue	$ 19,738	$ 24,290
Software licenses
Revenue
Revenue	18,522	7,571
Subscription
Revenue
Revenue	5,829	5,251
Professional services
Revenue
Revenue	1,421	809
Maintenance, support and other
Revenue
Revenue	$ 10,982	$ 9,686