Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Stock Options - Additional Information (Detail)

v3.20.1
Common Stock - Stock Options - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2019
Mar. 31, 2020
Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common shares reserved for options currently outstanding   2,489,426 1,010,583
Unrecognized compensation expense related to stock options granted   $ 2.2  
Anti-dilutive securities excluded from earning per share computation 5,038,584 29,615,486  
Warrant [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Anti-dilutive securities excluded from earning per share computation   27,116,712  
Stock Options [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Anti-dilutive securities excluded from earning per share computation   2,489,426  
Restricted Stock Unit [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Anti-dilutive securities excluded from earning per share computation   9,348  
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   9,348 10,008
Weighted-average period, restricted stock awards   1 year 4 months 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   594,209  
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   2,810,314  
Common shares reserved for options currently outstanding   2,216,105  
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   267,398  
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   15,271  
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   9,348