Property and equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total	$ 454	$ 41
Less accumulated depreciation and amortization	(49)	(11)
Property and equipment, net	405	30
Computer hardware and software
Property, Plant and Equipment [Line Items]
Total	22	9
Office equipment
Property, Plant and Equipment [Line Items]
Total	406	28
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total	$ 26	$ 4