Stockholders' Equity - Series A Preferred Stock and Stock Repurchases (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 12 Months Ended
May. 31, 2014
shares
Dec. 31, 2013
USD ($)
shares
Nov. 30, 2013
USD ($)
$ / shares
shares
Dec. 31, 2012
USD ($)
shares
Dec. 31, 2015
USD ($)
shares
Dec. 31, 2014
USD ($)
shares
Dec. 31, 2013
USD ($)
$ / shares
shares
Convertible Preferred Stock and Stockholders' Equity              
Common stock, shares authorized     150,000,000 147,000,000 1,000,000,000 1,000,000,000  
Cash paid for repurchase of common stock | $         $ 0 $ 0 $ 1,000
Common Stock              
Convertible Preferred Stock and Stockholders' Equity              
Shares sold           8,941,250  
Shares of common stock issued for conversion of Series A 2,857,143            
Common Stock | Employment Agreement | Former CEO              
Convertible Preferred Stock and Stockholders' Equity              
Shares repurchased   112,422   130,080     112,422
Repurchase price (in dollars per share) | $ / shares             $ 8.90
Cash paid for repurchase of common stock | $             $ 1,000
Right to sell value of shares of common stock | $   $ 1,000   $ 1,000     $ 1,000
Vesting period             6 months
Vulcan              
Convertible Preferred Stock and Stockholders' Equity              
Aggregate purchase price for preferred stock and warrants | $     $ 30,000        
Vulcan | Common Stock Purchase Warrants              
Convertible Preferred Stock and Stockholders' Equity              
Number of shares that may be purchased under warrant     666,666        
Exercise price of warrants (in dollars per share) | $ / shares     $ 15.00        
Aggregate purchase price for preferred stock and warrants | $     $ 700        
Series A              
Convertible Preferred Stock and Stockholders' Equity              
Preferred stock, shares authorized     4,500,000        
Series A | Vulcan              
Convertible Preferred Stock and Stockholders' Equity              
Shares sold     2,857,143        
Private placement price per share (in dollars per share) | $ / shares     $ 10.50        
Aggregate purchase price for preferred stock and warrants | $     $ 29,200        
Conversion ratio 1