Quarterly report pursuant to Section 13 or 15(d)

Redeemable Preferred Stock and Stockholders' Equity - Additional Information (Detail)

v3.21.1
Redeemable Preferred Stock and Stockholders' Equity - Additional Information (Detail) - USD ($)
 3 Months Ended 9 Months Ended 12 Months Ended
Feb. 10, 2021
Feb. 10, 2021
Jul. 23, 2020
Mar. 31, 2021
Dec. 31, 2020
Mar. 31, 2020
Sep. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Temporary Equity And Stockholders Equity [Line Items]                  
Temporary equity preferred stock, shares authorized       1,000,000 1,000,000     1,000,000  
Common stock, shares authorized       180,000,000 180,000,000     180,000,000  
Common stock, shares issued 14,000,000 14,000,000   149,427,000 97,709,000     97,709,000  
Shares Issued, Price Per Share $ 1.03 $ 1.03              
Equity raise of gross proceeds $ 14,400,000                
Series F Preferred stock, shares issued       0 1,000     1,000  
Common stock value     $ 1,000 $ 149,000 $ 98,000     $ 98,000  
Proceeds from Warrant Exercise       15,000,000.0          
Proceeds from the exercise of common stock warrants       $ 16,539,000 $ 1,500,000        
Expected term (years)       6 years 1 month 6 days   5 years 10 months 24 days      
Volatility       110.00%   82.00%      
Risk-free interest rate       0.69%   1.25%      
Series E Preferred stock, shares authorized       1,000,000 1,000,000     1,000,000  
Preferred stock, par value       $ 0.001 $ 0.001     $ 0.001  
Conversion of preferred stock into common stock       268          
Convertible preferred stock, shares issued       0 0     0  
Convertible preferred stock, shares outstanding       0 0     0  
Compensation expense related to stock options       $ 900,000   $ 700,000      
Total unrecognized compensation expense       $ 700,000   $ 1,100,000      
Unrecognized share based compensation expense to be recognized over weighted-average period       1 year 2 months 12 days          
Share-based Compensation Arrangement by Share-based Payment Award, Recognized Weighted Average Expected date       2022-06          
Outstanding stock options, RSUs and warrants excluded from diluted loss per share       25,290,000   3,400,000,000      
July 2020 Warrants                  
Temporary Equity And Stockholders Equity [Line Items]                  
Warrant issued     45,000,000            
Proceeds from issuance of warrants             $ 15,300,000    
Warrants issued in connection with debt instruments             $ 15,300,000    
July 2020 Warrants | Rights Offering                  
Temporary Equity And Stockholders Equity [Line Items]                  
Allocated to the warrants based upon fair values     $ 15,300,000            
Common Stock                  
Temporary Equity And Stockholders Equity [Line Items]                  
Other offering expenses   $ 1,100,000              
Series F Convertible Preferred Stock                  
Temporary Equity And Stockholders Equity [Line Items]                  
Conversion price     $ 0.40            
Series E Convertible Preferred Stock                  
Temporary Equity And Stockholders Equity [Line Items]                  
Temporary equity preferred stock, shares authorized       69,565          
Series E Preferred stock, shares authorized       69,565          
Convertible preferred stock, shares issued       0 0     0  
Convertible preferred stock, shares outstanding           70,000     70,000
Preferred stock par value       $ 0.001          
Series F Convertible Preferred Stock                  
Temporary Equity And Stockholders Equity [Line Items]                  
Temporary equity preferred stock, shares authorized       18,000          
Convertible preferred stock, Common shares issued upon conversion     2,500            
Series F Preferred stock, shares issued     18,000            
Proceeds from issuance of warrants       $ 2,700,000          
Conversion price     $ 0.40            
Proceeds of common stock and warrants     $ 18,000,000.0            
Stock Issued During Period Shares New Issues       17,000          
Warrants issued in connection with debt instruments       $ 2,700,000          
Sale of common stock, shares       17,000          
Deemed dividend on convertible preferred stock     2,700,000 $ 500,000       $ 14,700,000  
Series E Preferred stock, shares authorized       18,000          
Preferred stock, par value       $ 0.001          
Convertible preferred stock, shares outstanding       268 882     882  
Series F Convertible Preferred Stock | Rights Offering                  
Temporary Equity And Stockholders Equity [Line Items]                  
Proceeds allocated to the warrants based upon fair values     $ 2,700,000            
Private Placement | Series F Convertible Preferred Stock                  
Temporary Equity And Stockholders Equity [Line Items]                  
Common stock, shares issued       670,000          
Maximum                  
Temporary Equity And Stockholders Equity [Line Items]                  
Temporary equity preferred stock, shares authorized       1,000,000          
Series E Preferred stock, shares authorized       1,000,000          
2002 Stock Incentive Plan                  
Temporary Equity And Stockholders Equity [Line Items]                  
Common Stock Issued Pursuant To Options Exercised       1,036,171          
Common stock authorized for issuance       3,110,000          
Common stock issued pursuant to options exercised       1,036,171          
Options and restricted stock units outstanding       971,735          
Options available for future grants       0          
2018 Long-Term Incentive Plan                  
Temporary Equity And Stockholders Equity [Line Items]                  
Common Stock Issued Pursuant To Options Exercised       5,745,827          
Common stock authorized for issuance       12,221,101          
Common stock issued pursuant to options exercised       5,745,827          
Options available for future grants       1,812,307          
Restricted Stock Units (RSUs)                  
Temporary Equity And Stockholders Equity [Line Items]                  
Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instruments Granted       1,200,000          
Cancelled RSU due to non achievement of performance targets       500,000          
Performance Based Awards Member                  
Temporary Equity And Stockholders Equity [Line Items]                  
Compensation expense related to stock options       $ 400,000       $ 900,000