Annual report pursuant to Section 13 and 15(d)

Stock Plans and Stock-Based Compensation - Additional Information (Detail)

v3.3.1.900
Stock Plans and Stock-Based Compensation - Additional Information (Detail) - USD ($)
1 Months Ended 12 Months Ended
Jan. 01, 2016
Jun. 03, 2014
Jun. 30, 2014
Sep. 30, 2013
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2007
Apr. 30, 2014
Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Expected dividend yield         0.00% 0.00% 0.00%      
Fair value of options vested         $ 2,200,000 $ 1,000,000        
Share based compensation, stock option, unamortized expense         $ 4,800,000 $ 1,900,000        
Share based compensation, stock option, unamortized expense vesting period         2 years 7 months 6 days 3 years        
Share reserved for issue         3,951,819 3,317,963        
Conversion of incentive award from liability to equity accounting           $ 121,000        
Allocated share-based compensation expense         $ 2,466,000 1,284,000        
Options to purchase common stock         114,436          
Scientific Advisors and Consultants [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, expiration period         10 years          
Share based compensation arrangement by share based payment award, award vesting period         60 months          
Allocated share-based compensation expense         $ 21,000 $ 8,000        
Options to purchase common stock         10,000 10,000        
Options to purchase common stock, unvested         18,945          
Incentive award issued         2,335          
Incentive awards outstanding, Unvested         1,167          
2013 Equity Incentive Plan [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, expiration period       10 years            
Share based compensation arrangement percentage increase in share reserved       5.00%            
Number of additional shares authorized     500,000              
Shares available for grant         235,367          
2013 Equity Incentive Plan [Member] | Subsequent Event [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Increased in shares available for issuance 1,172,350                  
2013 Equity Incentive Plan [Member] | Incentive Stock Options for Employees and Directors [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage       100.00%            
2013 Equity Incentive Plan [Member] | Nonqualified Options to Employees, Directors and Consultants [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage       85.00%            
2013 Equity Incentive Plan [Member] | Restricted Stock [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage       85.00%            
2013 Equity Incentive Plan [Member] | Restricted Stock [Member] | Minimum [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, award vesting period       4 years            
2013 Equity Incentive Plan [Member] | Restricted Stock [Member] | Maximum [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, award vesting period       5 years            
2013 Equity Incentive Plan [Member] | Stock Options to 10% Stockholders [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, exercise price percentage               110.00%    
Share based compensation arrangement by share based payment award, award vesting period               5 years    
Incentive Awards [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share based compensation arrangement by share based payment award, expiration period             10 years      
Share based compensation arrangement by share based payment award, award vesting period   2 years     4 years          
Share reserved for issue             252,752   252,752 252,752
Exercisable weighted average price per share             $ 5.21   $ 5.21 $ 5.21
Stock option plan, Description         Vest monthly over four years effective from their grant date.          
Conversion of incentive award from liability to equity accounting   $ 121,000,000                
Allocated share-based compensation expense         $ 323,000 $ 285,000        
Incentive Awards [Member] | First Tranche [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Incentive awards vested percentage             100.00%