Intangible assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, gross	$ 19,010		$ 19,762
Less: Accumulated amortization	2,775		2,263
Impairment	5,134		4,379
Intangible assets, net of accumulated amortization	11,101		13,120
Amortization of intangible assets	827	$ 791	1,000
Software licenses | Utrophin program acquired
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, gross	4,275		4,379
Software licenses | Discuva platform acquired
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, gross	13,734		14,070
Option over non-financial assets
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, gross	859		881
Impairment	900
Other patents and licenses
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, gross	$ 142		$ 432