Stockholders' deficit - Options Outstanding (Details) - Options - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Beginning balance, options	480,000	480,000
Beginning balance, options exercise price	$ 0.12	$ 0.12
Ending Balance, options	480,000	480,000
Ending Balance, options exercise price	$ 0.12	$ 0.12
Weighted Average Contractual Life, options	1 year 9 months	1 year 9 months

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant