Quarterly report pursuant to Section 13 or 15(d)

Organization and Summary of Significant Accounting Policies - Additional Information (Details)

v3.3.0.814
Organization and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)
$ in Thousands
 9 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Jun. 30, 2015
Dec. 31, 2014
Dec. 31, 2013
Debt Instrument [Line Items]          
Net loss $ 21,447 $ 22,884      
Cash used in operations 7,065 11,433      
Accumulated deficit 194,072     $ 172,505  
Cash balance 11,268 $ 10,360   $ 18,247 $ 2,279
Hercules Term Loan, Liquidity Covenant          
Debt Instrument [Line Items]          
Cash balance 8,500   $ 9,000    
September 2015 Offering          
Debt Instrument [Line Items]          
Proceeds from warrant exercises 5,000        
Series B Warrant | September 2015 Offering          
Debt Instrument [Line Items]          
Proceeds from warrant exercises $ 5,000