Net Loss per Share - Weighted Average Shares (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Numerator:      
Net Loss $ (196,547) $ (167,731) $ (163,458)
Denominator:      
Weighted average common shares outstanding, basic and diluted 87,950,440 80,624,608 78,688,878
Net loss per share, basic and diluted $ (2.23) $ (2.08) $ (2.08)