Revenues, net - Contract Acquisition and Fulfillment Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Contract Acquisition Costs
Increase (Decrease) In Capitalized Contract Costs [Roll Forward]
Opening Balance	$ 1,215	$ 513	$ 1,307	$ 713	$ 713
Addition	187	0	187	0	1,222
Amortization	(132)	(44)	(224)	(244)	(628)
Closing Balance	1,270	469	1,270	469	1,307
Contract Fulfillment Costs
Increase (Decrease) In Capitalized Contract Costs [Roll Forward]
Opening Balance	6,916	4,472	7,255	4,051	4,051
Addition	363	1,441	647	2,167	4,652
Amortization	(499)	(305)	(1,122)	(610)	(1,448)
Closing Balance	$ 6,780	$ 5,608	$ 6,780	$ 5,608	$ 7,255