Annual report pursuant to Section 13 and 15(d)

CONSOLIDATED BALANCE SHEETS (Parenthetical)

v3.20.4
CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Statement Of Financial Position [Abstract]        
Common stock, par value $ 0.001 $ 0.001    
Common stock, shares authorized 300,000,000 300,000,000    
Common stock, shares issued 123,627,080 121,863,515    
Common stock, shares outstanding 118,576,099 117,151,656    
Treasury stock, shares 5,050,981 4,711,859 4,626,191 4,525,870