Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Restricted Stock Awards and Restricted Stock Units) (Details)

v3.21.1
Stockholders' Equity (Restricted Stock Awards and Restricted Stock Units) (Details) - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Restricted Stock Awards and Restricted Stock Units [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares, Unvested balance 15,507,504 13,768,014 12,645,982
Weighted average grant price, Unvested balance $ 2.49 $ 2.46 $ 2.72
Restricted Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares Granted 1,873,072 1,546,408  
Number of shares, Vested (230,000) (220,000)  
Weighted average grant price, Granted $ 2.57 $ 0.88  
Weighted average grant price, Vested $ 2.78 $ 3.16  
Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares Granted 630,126 290,000  
Number of shares, Vested (384,958) (358,960)  
Number of shares, Forfeited (148,750) (135,416)  
Weighted average grant price, Granted $ 3.82 $ 1.49  
Weighted average grant price, Vested 3.49 3.61  
Weighted average exercise price, Forfeited $ 3.30 $ 3.91