Summary of business and significant accounting policies - Narrative (Details) $ in Thousands	9 Months Ended
Mar. 31, 2019 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unrealized gain on non-marketable equity securities	$ 1,259

Amount of unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84241550&loc=SL75117546-209714

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration