Annual report pursuant to Section 13 and 15(d)

Common Stock - Stock Options - Additional Information (Detail)

v3.20.1
Common Stock - Stock Options - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common shares reserved for options currently outstanding 1,010,583 665,585  
Weighted average fair value of stock options granted $ 1.33    
Unrecognized compensation expense related to stock options granted $ 1,800,000 $ 2,400,000  
Estimated grant date fair value of stock options vested 900,000 1,000,000 $ 0.6
Aggregate intrinsic value of options exercised 0 $ 0 $ 0
Aggregate intrinsic value of the outstanding options 0    
Aggregate intrinsic value of the exercisable outstanding options $ 0    
Stock Options [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Weighted-average period, restricted stock awards 2 years 1 month 6 days 2 years 1 month 6 days  
Stock Options [Member] | Minimum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award expiration period 7 years    
Stock Options [Member] | Minimum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
Stock Options [Member] | Minimum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 1 year    
Stock Options [Member] | Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award expiration period 10 years    
Stock Options [Member] | Maximum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 4 years    
Stock Options [Member] | Maximum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
Restricted Stock Unit [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 4 years    
Common shares reserved for awards currently outstanding 10,008 15,142  
Weighted-average period, restricted stock awards 1 year 6 months 29 days    
2018 Equity Incentive Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common shares reserved for issuance under incentive plan 604,055    
Award expiration period 10 years    
2018 Equity Incentive Plan [Member] | Minimum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
2018 Equity Incentive Plan [Member] | Minimum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 1 year    
2018 Equity Incentive Plan [Member] | Maximum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 4 years    
2018 Equity Incentive Plan [Member] | Maximum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
2018 Equity Incentive Plan [Member] | Stock Options [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common shares reserved for issuance under incentive plan 1,336,055    
Common shares reserved for options currently outstanding 732,000    
2017 Equity Incentive Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award expiration period 10 years    
2017 Equity Incentive Plan [Member] | Minimum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
2017 Equity Incentive Plan [Member] | Minimum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 1 year    
2017 Equity Incentive Plan [Member] | Maximum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 4 years    
2017 Equity Incentive Plan [Member] | Maximum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
2017 Equity Incentive Plan [Member] | Stock Options [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common shares reserved for issuance under incentive plan 272,660    
2010 Performance Incentive Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award expiration period 10 years    
2010 Performance Incentive Plan [Member] | Minimum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
2010 Performance Incentive Plan [Member] | Minimum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 1 year    
2010 Performance Incentive Plan [Member] | Maximum [Member] | Employees and Consultants [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 4 years    
2010 Performance Incentive Plan [Member] | Maximum [Member] | Board of Directors [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Award vesting period 3 years    
2010 Performance Incentive Plan [Member] | Stock Options [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common shares reserved for issuance under incentive plan 15,931    
Common shares reserved for options currently outstanding 5,923    
2010 Performance Incentive Plan [Member] | Restricted Stock Unit [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common shares reserved for awards currently outstanding 10,008