Annual report pursuant to Section 13 and 15(d)

CONSOLIDATED BALANCE SHEETS (Parenthetical)

v3.19.3.a.u2
CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
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 121,863,515 121,456,721    
Common stock, shares outstanding 117,151,656 116,830,530    
Treasury stock, shares 4,711,859 4,626,191 4,525,870 4,447,002