Property and Equipment (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment, Gross, Total	$ 2,649	$ 2,436
Less: Accumulated depreciation	(1,051)	(735)
Property and equipment, net	1,598	1,701
Laboratory equipment
Property, Plant and Equipment, Gross, Total	1,279	1,045
Computer equipment and software
Property, Plant and Equipment, Gross, Total	206	179
Furniture and fixtures
Property, Plant and Equipment, Gross, Total	49	15
Leasehold improvements
Property, Plant and Equipment, Gross, Total	772	448
Construction-in-process
Property, Plant and Equipment, Gross, Total	$ 343	$ 749