Net income (loss) per common share - Basic and Diluted Earnings (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018
Net Loss Per Common Share Details
Stock options	$ 480,000	$ 480,000	$ 480,000
Warrants to purchase shares of common stock	82,587,408	22,004,075	82,587,408
Convertible notes	43,916,472	3,101,093	43,916,472
Total	$ 126,983,880	$ 25,585,168	$ 126,983,880