Stockholders' deficit - Options Outstanding (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Options
Beginning balance, options	480,000
Beginning balance, options exercise price	$ 0.12
Options Exercisable, shares	480,000
Ending Balance, options	480,000
Ending Balance, options exercise price	$ 0.12
Weighted Average Contractual Life, options	2 years 4 months 2 days
Warrants
Options Exercisable, shares		(6,000,000)
Options Exercisable, price		$ 0.15