Stockholders' deficit - Options Outstanding (Details) - Options	12 Months Ended
Dec. 31, 2018 $ / shares shares
Beginning balance, options \| shares	480,000
Beginning balance, options exercise price \| $ / shares	$ 0.12
Ending Balance, options \| shares	480,000
Ending Balance, options exercise price \| $ / shares	$ 0.12
Weighted Average Contractual Life, options	10 months 29 days

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&loc=d3e5070-113901

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