Consolidated Statements of Convertible Preferred Stock and Stockholders Deficit (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011 Series E [Member]	Dec. 31, 2012 Series F [Member]	Dec. 31, 2012 Series F-1 [Member]
Issuance of stock, issuance costs		$ 102	$ 194	$ 98
Issuance of common stock in connection with initial public offering, issuance costs	$ 11,451