Revenue (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Apr. 30, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue
Revenues		$ 31	$ 0	$ 0	$ 0	$ 232	$ 3,000	$ 2,500	$ 0	$ 31	$ 5,732	$ 0
Revenue, Product and Service [Extensible List]		us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember
Pharmbio Korea Inc
Revenue
License revenues	$ 3,000
Revenues											$ 3,000
Revenue, Product and Service [Extensible List]											us-gaap:LicenseMember
Jiangsu Nhwa Pharmaceutical Co Ltd
Revenue
License revenues	$ 2,500
Revenues											$ 2,700
Revenue, Product and Service [Extensible List]											us-gaap:LicenseMember