Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.2
Redeemable Preferred Stock and Stockholders' Equity - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 10, 2020
Jun. 30, 2020
Jun. 30, 2019
Mar. 31, 2019
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Dec. 31, 2019
Temporary Equity And Stockholders Equity [Line Items]                
Common stock, shares authorized   180,000,000     180,000,000   180,000,000 40,000,000
Temporary equity preferred stock, shares authorized   1,000,000     1,000,000   1,000,000 1,000,000
Temporary equity preferred stock, par value   $ 0.001     $ 0.001   $ 0.001 $ 0.001
Temporary equity preferred stock, shares issued   0     0   0 70,000
Temporary equity preferred stock, shares outstanding   0     0   0 70,000
Compensation expense related to stock options   $ 0.8 $ 0.5   $ 1.6 $ 1.2    
Total unrecognized compensation expense   $ 1.4     $ 1.4   $ 1.4  
Unrecognized share based compensation expense to be recognized over weighted-average period   1 year 2 months 12 days            
Warrant expiration period 5 years              
Proceeds from Offering $ 6.9              
Combined purchase price of share and warrant $ 0.64              
Other offering expenses $ 0.7              
Expected term (years)   5 years 6 months 6 years 1 month 6 days   5 years 6 months 6 years 1 month 6 days    
Volatility   103.10% 85.00%   102.80% 85.80%    
Risk-free interest rate   0.36% 2.50%   0.37% 2.60%    
Outstanding stock options, RSUs and warrants excluded from diluted loss per share   18,500,000   5,700,000 18,500,000 5,700,000    
Common Stock And Warrants                
Temporary Equity And Stockholders Equity [Line Items]                
Exercise price of warrants   $ 0.42     $ 0.42   $ 0.42  
Proceeds of common stock and warrants         $ 6.2      
Expected term (years)         5 years      
Closing price of common stock         $ 0.54      
Volatility         109.80%      
Risk-free interest rate         0.45%      
Dividend yield         0.00%      
Allocation to common stock and warrants before issuance costs         $ 3.9      
Allocation to common stock and warrants before issuance costs         $ 3.0      
Restricted Stock Units (RSUs)                
Temporary Equity And Stockholders Equity [Line Items]                
Granted         1.6      
Cancelled RSU due to non achievement of performance targets         1.0      
2002 Stock Incentive Plan                
Temporary Equity And Stockholders Equity [Line Items]                
Common stock authorized for issuance   3,100,000     3,100,000   3,100,000  
Common stock issued pursuant to options exercised         1,000,000      
Options and restricted stock units outstanding   1,100,000     1,100,000   1,100,000  
Options available for future grants   0     0   0  
2018 Long-Term Incentive Plan                
Temporary Equity And Stockholders Equity [Line Items]                
Common stock authorized for issuance   12,200,000     12,200,000   12,200,000  
Options and restricted stock units outstanding   4,100,000     4,100,000   4,100,000  
Options available for future grants   8,100,000     8,100,000   8,100,000  
Maximum                
Temporary Equity And Stockholders Equity [Line Items]                
Temporary equity preferred stock, shares authorized               1,000,000
Series E Convertible Preferred Stock                
Temporary Equity And Stockholders Equity [Line Items]                
Temporary equity preferred stock, shares authorized               69,565
Temporary equity preferred stock, par value               $ 0.001
Temporary equity preferred stock, shares issued   0     0   0 69,565
Temporary equity preferred stock, shares outstanding   0     0   0 69,565
Series F Preferred Stock                
Temporary Equity And Stockholders Equity [Line Items]                
Temporary equity preferred stock, shares authorized               18,000
Temporary equity preferred stock, par value               $ 0.001
Private Placement                
Temporary Equity And Stockholders Equity [Line Items]                
Common stock offered 10,800,000              
Exercise price of warrants $ 0.515              
Private Placement | Series E Convertible Preferred Stock                
Temporary Equity And Stockholders Equity [Line Items]                
Temporary equity numbers of shares sold             69,565  
Conversion Of Preferred Stock Into Common Stock   6,956,500     6,956,500   6,956,500  
Temporary equity net proceeds from conversion to common stock   $ 4.0     $ 4.0   $ 4.0