Stockholders' Equity (Deficit) - Schedule of Warrants (Details) - $ / shares
Dec. 31, 2021
May 20, 2021
Jun. 09, 2020
Apr. 24, 2020
Jun. 10, 2019
Apr. 11, 2019
Jun. 26, 2018
May 24, 2018
Jun. 11, 2014
Aug. 17, 2012
Mar. 30, 2012
Class of Warrant or Right [Line Items]                      
Underlying Common Stock to be Purchased (in shares) 67,767,107                    
Stock option warrant to purchase, exercise price per share (in dollars per share) $ 1.54                    
Common warrants                      
Class of Warrant or Right [Line Items]                      
Underlying Common Stock to be Purchased (in shares)   57,341,000 2,049,180 3,073,770 2,777,779 1,666,667 182 848,674 7,806 1,171 878
Stock option warrant to purchase, exercise price per share (in dollars per share)   $ 1.00 $ 2.44 $ 2.44 $ 6.38 $ 6.38 $ 7.50 $ 7.50 $ 3.69 $ 51.24 $ 51.24