Notes payable (Detail Textuals)	1 Months Ended		12 Months Ended
	Jan. 20, 2017 USD ($) $ / shares	Feb. 25, 2014 USD ($) Investor	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of notes payable			$ 383,163	$ (1,187,608)
Notes payable			1,351,021	1,365,132
Conversion of notes payable into common stock			$ 231,915	442,845
Senior Secured Promissory Notes
Debt Instrument [Line Items]
Number of investors | Investor		3
Proceeds from issuance of initial notes		$ 501,000
Maturity date of notes payable		Feb. 25, 2014	Dec. 31, 2018
Monthly interest rate percentage		12.00%
Proceeds from issuance of notes payable		$ 1,500,000
Notes payable			$ 0	23,000	$ 334,000
Accrued interest			0	6,000
Conversion rights per share | $ / shares	$ 0.16
Aggregate amount of remaining outstanding notes			$ 334,000
Conversion rights granted, price per share | $ / shares			$ 0.16
Prinicipal amount of debt converted			$ 23,000
Accrued interest of debt converted			$ 6,000
Number of shares issued in conversion of debt | shares			179,000
Interest expense			$ 0	$ 31,000
Conversion of notes payable into common stock	$ 167,000