Share-based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Non-cash, share-based compensation expense
Total expenses	$ 172	$ 34	$ 330	$ 76
Research and Development
Non-cash, share-based compensation expense
Total expenses	42	14	82	29
General and Administrative
Non-cash, share-based compensation expense
Total expenses	$ 130	$ 20	$ 248	$ 47