Subsequent events (Details) $ in Thousands	Feb. 14, 2020 USD ($) ft²	Dec. 31, 2019 USD ($)
Subsequent events
Minimum payments during the lease term		$ 401
Subsequent events
Subsequent events
Lease agreement term	7 years
Area of office space \| ft²	6,647
Minimum payments during the lease term	$ 2,300

Amount of lessee's undiscounted obligation for lease payments for operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980

Name:	us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant