Commitments and contingencies (Details)	Mar. 10, 2017 patent
Implicit, LLC
Long-term Purchase Commitment [Line Items]
Loss contingency, patents allegedly infringed upon, number	2

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_LongTermPurchaseCommitmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration