Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Stock Options - Additional Information (Detail)

v3.19.2
Common Stock - Stock Options - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Common shares reserved for options currently outstanding 1,010,935   1,010,935   665,585
Stock options, granted     345,350 0  
Unrecognized compensation expense related to stock options granted $ 2.3   $ 2.3   $ 1.8
Anti-dilutive securities excluded from earning per share computation 5,174,021 3,460,843 5,174,021 3,460,843  
Warrant [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Anti-dilutive securities excluded from earning per share computation 4,148,077   4,148,077    
Stock Options [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Anti-dilutive securities excluded from earning per share computation 1,010,935   1,010,935    
Restricted Stock Unit [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Anti-dilutive securities excluded from earning per share computation 15,009   15,009    
Stock Options [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Weighted-average period, restricted stock awards     2 years 6 months    
Stock Options [Member] | Employees and Consultants [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Award vesting period     4 years    
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] | 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] | 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 15,009   15,009   15,142
Weighted-average period, restricted stock awards     2 years 1 month 2 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   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   1,336,055    
Common shares reserved for options currently outstanding 732,000   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   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 20,932   20,932    
Common shares reserved for options currently outstanding 5,923   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 15,009   15,009