Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Additional Information (Detail)

v3.7.0.1
Common Stock - Additional Information (Detail) - $ / shares
6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
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 118,986 196,732  
Common shares reserved for options currently outstanding 1,095,890   1,378,805
Number of stock options granted 0    
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]      
Common shares reserved for awards currently outstanding 115,906   253,221
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 2,281,448    
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]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award expiration period 10 years    
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 various plans 3,493,244    
Common shares reserved for options currently outstanding 1,095,890    
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 115,906