CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares
Dec. 31, 2018
Dec. 31, 2017
Convertible preferred stock, shares authorized ( in shares)   44,070,808
Convertible preferred stock, shars issued (in shares)   43,933,006
Convertible preferred stock, shars outstanding (in shares) 0 43,933,006
Preferred stock, par value (in dollars per share) $ 0.001 $ 0.001
Preferred stock, share authorized (in shares) 10,000,000 0
Preferred stock, shares issued (in shares) 0 0
Preferred stock, shares outstanding (in shares) 0 0
Common stock, par value (in dollars per share) $ 0.001 $ 0.001
Common stock, share authorized (in shares) 150,000,000 65,000,000
Common stock, shares issued (in shares) 79,234,853 14,977,317
Common stock, shares outstanding (in shares) 79,234,853 14,977,317
Convertible preferred stock    
Convertible preferred stock, par value (in dollars per share) $ 0.001 $ 0.001
Convertible preferred stock, shares authorized ( in shares) 0 44,070,808
Convertible preferred stock, shars issued (in shares) 0 43,933,006
Convertible preferred stock, shars outstanding (in shares) 0 43,933,006