Disaggregation of Revenue Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues	$ 56,131	$ 47,910
Percentage of total revenue	100.00%	100.00%
UNITED STATES
Revenues	$ 19,780	$ 17,362
Percentage of total revenue	35.00%	36.00%
Europe [Member]
Revenues	$ 17,287	$ 15,283
Percentage of total revenue	31.00%	32.00%
The rest of the world [Member]
Revenues	$ 19,064	$ 15,265
Percentage of total revenue	34.00%	32.00%