Consolidated Statements of Changes in Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical)
$ in Thousands
12 Months Ended
Dec. 31, 2014
USD ($)
Issuance of redeemable convertible preferred stock, issuance costs $ 2,312
Series E Preferred Stock [Member]  
Issuance of redeemable convertible preferred stock, issuance costs $ 1