Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Additional Information (Detail)

v3.4.0.3
Common Stock - Additional Information (Detail) - $ / shares
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common stock, shares authorized 75,000,000   75,000,000
Common stock, par value $ 0.001   $ 0.001
Preferred stock, shares authorized 5,000,000    
Preferred stock, par value $ 0.001    
Stock option exercises, shares 0 0  
Restricted stock unit settlements 101,228 82,410  
Number of warrants exercised 0 0  
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    
2010 Performance Incentive Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common shares reserved for issuance under various plans 3,797,923    
Common shares available for future equity grants 336,067    
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 various plans 2,960,766    
2010 Performance Incentive Plan [Member] | Restricted Stock Unit [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common shares reserved for issuance under various plans 501,090