Annual report pursuant to Section 13 and 15(d)

Equity Compensation Plans - Grant Date Fair Value (Details)

v3.20.4
Equity Compensation Plans - Grant Date Fair Value (Details) - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Employee Consultants and Directors Stock Options      
Stock Option Disclosures      
Weighted average estimated grant date fair value per share $ 9.29 $ 18.07 $ 15.05
Restricted and performance stock units      
Stock Option Disclosures      
Weighted average estimated grant date fair value per share $ 9.57 $ 17.60 $ 23.34