Summary of significant accounting policies (Details)	Jun. 07, 2018	Sep. 30, 2019 item
Summary of significant accounting policies
Reverse stock split ratio	0.03625
Grants outstanding		0

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

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Balance Type:	na
Period Type:	duration