Stockholders' Equity (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2015
May 31, 2021
Expenses related to issuance of warrants   $ 16    
Common stock        
Stock options exercised (in shares) 1,160,930 1,097,370    
Warrants        
Warrants to purchase shares of common stock   45,730 276,000 1,755,557
Exercise price of warrants   $ 0.53 $ 0.00001088 $ 0.01
Expenses related to issuance of warrants   $ 16 $ 18