Related parties (Details) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($)
Atlas Venture Life Science Advisors, LLC
Related parties
Related party expense	$ 5

The amount of any current tax-related balances due to affiliates as of the date of each statement of financial position presented.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32809-109319

Name:	us-gaap_RelatedPartyTaxExpenseDueToAffiliatesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration