Earnings Per Share (Details) - shares
3 Months Ended 6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Convertible Series A Preferred Stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 0 2,383,745 0 2,383,745
Convertible Series B Preferred Stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 0 3,649,368 0 3,649,368
Convertible Series C Preferred Stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 0 5,406,501 0 5,406,501
Convertible Series D Preferred Stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 0 3,409,210 0 3,409,210
Common Stock Subject to Repurchase        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 0 6,166 0 6,166
Lender and Additional Lender Warrants to Purchase Common Stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 200,000 100,000 200,000 100,000
ESPP        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 141,806 0 141,806 0
Stock Options        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive securities excluded from the calculation of weighted average common shares outstanding 3,384,540 3,462,243 3,384,540 3,462,243