Organization and Description of Business (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Organization and Description of Business
Product revenue	$ 0
Accumulated deficit	(164,727)	$ (134,392)
Cash and cash equivalents	$ 34,395	$ 40,182	$ 2,120	$ 20,014