Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.2
Convertible Preferred Stock and Stockholders' Equity - Warrants for common stock outstanding and exercisable (Details) - Warrant [Member]
 6 Months Ended
Jun. 30, 2020
$ / shares
shares
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 35.82
Warrants Outstanding 7,337,199
Remaining Life (years) 5 years 22 days
Warrants Exercisable 7,213,049
Exercise Price Range One [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 6,861,779
Remaining Life (years) 4 years 3 days
Warrants Exercisable 6,761,779
Exercise Price Range One [Member] | Minimum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 2.32
Exercise Price Range One [Member] | Maximum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 3.90
Exercise Price Range Two [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 78,423
Remaining Life (years) 4 years 8 months 1 day
Warrants Exercisable 58,023
Exercise Price Range Two [Member] | Minimum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 6.40
Exercise Price Range Two [Member] | Maximum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 9.80
Exercise Price Range Three [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 93,562
Remaining Life (years) 2 years 5 months 26 days
Warrants Exercisable 89,812
Exercise Price Range Three [Member] | Minimum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 15.80
Exercise Price Range Three [Member] | Maximum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 17.50
Exercise Price Range Four Member [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 230,571
Remaining Life (years) 1 year 6 months
Warrants Exercisable 230,571
Exercise Price Range Four Member [Member] | Minimum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 24.80
Exercise Price Range Four Member [Member] | Maximum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 99.00
Exercise Price Range Five Member [Member]  
Class of Stock [Line Items]  
Warrants Outstanding 72,864
Remaining Life (years) 2 years 1 month 6 days
Warrants Exercisable 72,864
Exercise Price Range Five Member [Member] | Minimum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 108
Exercise Price Range Five Member [Member] | Maximum  
Class of Stock [Line Items]  
Exercise Price | $ / shares $ 207.00