Stockholders' Equity (Deficit) - Warrants (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 11, 2013
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Class of Warrant or Right [Line Items]        
Expense related to warrant   $ 0 $ 2,639 $ 135
Class A [Member]        
Class of Warrant or Right [Line Items]        
Number of securities called by warrant (in shares) 175,000      
Exercise price of warrants (in dollars per share) $ 5.00      
Class of warrant term (in years) 10 years      
Expense related to warrant     $ 2,600