Quarterly report pursuant to Section 13 or 15(d)

Convertible Preferred Stock and Stockholders' Equity (Deficit) - Warrants for common stock outstanding and exercisable (Details)

v3.20.1
Convertible Preferred Stock and Stockholders' Equity (Deficit) - Warrants for common stock outstanding and exercisable (Details) - Warrant [Member]
 3 Months Ended
Mar. 31, 2020
$ / shares
shares
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 35.82
Warrants Outstanding 703,099
Remaining Life (years) 3 years 8 months 19 days
Warrants Exercisable 672,835
Exercise Price Range One [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 306,102
Remaining Life (years) 4 years 3 days
Warrants Exercisable 285,702
Exercise Price Range One [Member] | Minimum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 6.40
Exercise Price Range One [Member] | Maximum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 9.80
Exercise Price Range Two [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 93,562
Remaining Life (years) 2 years 7 months 21 days
Warrants Exercisable 89,812
Exercise Price Range Two [Member] | Minimum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 15.80
Exercise Price Range Two [Member] | Maximum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 17.50
Exercise Price Range Three [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 230,571
Remaining Life (years) 2 years 5 months 26 days
Warrants Exercisable 224,457
Exercise Price Range Three [Member] | Minimum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 24.80
Exercise Price Range Three [Member] | Maximum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 99.00
Exercise Price Range Four Member [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 72,864
Remaining Life (years) 2 years 4 months 6 days
Warrants Exercisable 72,864
Exercise Price Range Four Member [Member] | Minimum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 108.00
Exercise Price Range Four Member [Member] | Maximum [Member]  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 207.00