Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Additional Information (Detail)

v3.2.0.727
Common Stock - Additional Information (Detail) - USD ($)
 1 Months Ended 2 Months Ended 3 Months Ended 6 Months Ended
Apr. 30, 2015
Aug. 13, 2015
Jun. 30, 2015
Mar. 31, 2015
Jun. 30, 2015
Jun. 30, 2014
May. 21, 2015
May. 20, 2015
Dec. 31, 2014
May. 29, 2014
May. 28, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Common stock, shares authorized     75,000,000   75,000,000   75,000,000 50,000,000 75,000,000    
Common stock, par value     $ 0.001   $ 0.001       $ 0.001    
Preferred stock, shares authorized     5,000,000   5,000,000            
Preferred stock, par value     $ 0.001   $ 0.001            
Initial purchase of units consisting of common stock and warrants issued         $ 3,213,000            
Common stock, shares issued     24,467,727   24,467,727       22,630,652    
Proceeds from issuance of common shares, net of issuance costs           $ 2,860,000          
Common stock available for sale under offering     $ 14,700,000   $ 14,700,000            
Stock option exercises, Shares         0 10,000          
Restricted stock unit settlements         253,538 49,348          
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]                      
Stock available for issuance under performance incentive plan             4,300,000 2,800,000   2,800,000 2,050,000
Common shares reserved for issuance under various plans     4,153,139   4,153,139            
Common shares available for future equity grants     1,796,296   1,796,296            
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     1,722,846   1,722,846            
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     633,997   633,997            
Subsequent Event [Member]                      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Common stock available for sale under offering   $ 0                  
Series A-1 Units [Member]                      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Exercise price per unit of warrant     $ 2.40   $ 2.40            
LPC [Member]                      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Common stock, par value $ 0.001                    
Common stock value right to sell, maximum $ 18,000,000                    
Common stock , purchase price $ 1.50                    
Additional common stock value right to sell, maximum $ 16,000,000                    
Additional purchase of common stock, maximum 125,000                    
Common stock, shares issued 126,582   500,000   500,000            
Proceeds from issuance of common shares, net of issuance costs $ 0                    
Gross proceeds     $ 1,300,000                
Offering expenses     $ 100,000                
LPC [Member] | Subsequent Event [Member]                      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Common stock, shares issued   5,358,042                  
Gross proceeds   $ 14,700,000                  
Offering expenses   $ 300,000                  
LPC [Member] | Series A-1 Units [Member]                      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Initial purchase of common stock 956,938                    
Common stock , purchase price $ 2.09                    
Purchase agreement, description         Series A-1 Unit consisting of (a) one share of Common Stock and (b) one warrant to purchase one-quarter of a share of Common Stock at an exercise price of $2.40 per share, or Series A-1 Warrant. Each Series A-1 Warrant is exercisable six months following the issuance date until the date that is five years and six months after the issuance date and is subject to customary adjustments.            
Exercise price per unit of warrant $ 2.40                    
Initial purchase of units consisting of common stock and warrants issued $ 2,000,000                    
LPC [Member] | Other Than Series A-1 Units [Member]                      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Number of warrants issued 0