Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net loss per share
Net loss	$ (11,937)	$ (3,384)
Weighted average common shares outstanding, basic and diluted	18,050,597	14,923,136
Net loss per share attributable to common stockholders	$ (0.66)	$ (0.23)
Potentially dilutive securities
Potentially dilutive securities	2,247,827	2,199,253
Stock options to purchase common stock
Potentially dilutive securities
Potentially dilutive securities	2,200,117	2,151,543
Warrants
Potentially dilutive securities
Potentially dilutive securities	47,710	47,710