Commitments and contingencies (Details 2) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
	Oct. 31, 2013	Dec. 31, 2013 item
Employment contracts
Number of officers with whom the entity entered into employment contracts		6
Letter of Credit | Silicon Valley Bank ("SVB") Agreement
Letters of credit
Term period of letter of Credit agreement	1 year
Amount of letter of Credit which allow customer to draw	$ 1,800
Number of drafts drawn under Letter of Credit		0