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Stock Plans - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Oct. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total intrinsic value of stock options exercised $ 0.0 $ 0.0  
Granted (in shares) 6,179,000    
Weighted-average fair values of options granted (in USD per share) $ 0.80 $ 0.93  
Unrecognized stock-based compensation expense related to awards $ 16.1    
Unrecognized stock-based compensation, weighted-average period (in years) 2 years 3 months 18 days    
Stock-Based Compensation      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common stock shares authorized for issuance (in shares) 41,905,487    
Shares available for future grants (in shares) 3,158,755    
Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award price as a percentage of grant date fair value, minimum 100.00%    
Incentive Stock Options (ISOs) and Non-Qualified Stock Options (NSOs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award price as a percentage of grant date fair value, minimum 110.00%    
Significant stockholder threshold ownership percentage 10.00%    
Performance Shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares of performance units both performance and service vesting conditions (in shares)   400,000  
Restricted stock units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unrecognized stock-based compensation, weighted-average period (in years) 1 year 4 months 24 days    
Shares of performance units both performance and service vesting conditions (in shares) 560,000    
Total fair values of RSUs vested $ 1.5 $ 2.8  
Unrecognized compensation cost $ 1.0    
Restricted stock units | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Awards granted to employees and non-employees vesting period (in years) 2 years    
Restricted stock units | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Awards granted to employees and non-employees vesting period (in years) 4 years    
2014 Equity Incentive Award Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares available for future issuance (as percent) 4.00%    
2017 Inducement Plan | Stock Options and Restricted Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common stock shares available for future grant (in shares)     600,000
2014 Plan And Inducement Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Awards granted to employees and non-employees vesting period (in years) 4 years    
2014 Plan And Inducement Plan | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options granted period 10 years    
2014 Plan And Inducement Plan | Performance Shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted (in shares) 0 2,500,000  
2014 Employee Stock Purchase Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common stock shares available for future grant (in shares) 208,833    
Shares available for future grants (in shares) 6,219,258    
Unrecognized compensation cost $ 0.1    
Percentage increase in shares issued 1.00%    
Common stock issued (in shares) 824,223