Schedule of calculation of diluted net loss per share allocable to common stockholders (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	34,825,554	24,945,040
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	24,590,141	22,072,469
Warrant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,782,571	1,832,571
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,422,885
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	6,029,957	1,040,000