Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Data

	Three Months Ended
	Dec. 31, 2015			Sept. 30, 2015			June 30, 2015			Mar 31, 2015			Dec. 31, 2014			Sept. 30, 2014			June 30, 2014			Mar 31, 2014
Statements of Operations Data:
Product revenue	$	394		$	388		$	334		$	238		$	193		$	143		$	97		$	27
Collaboration revenue		42			41			125			188			312			—			—			—
Revenue		436			429			459			426			505			143			97			27
Loss from operations		(10,275	)		(11,174	)		(9,635	)		(7,113	)		(7,547	)		(6,776	)		(5,946	)		(6,825	)
Net loss		(10,637	)		(11,524	)		(10,009	)		(7,578	)		(7,954	)		(7,294	)		(6,392	)		(7,008	)
Net loss attributable to common stockholders		(10,637	)		(11,524	)		(10,009	)		(7,578	)		(7,954	)		(7,294	)		(6,397	)		(7,014	)
Basic and diluted net loss attributable to common stockholders per share	$	(0.43	)	$	(0.47	)	$	(0.45	)	$	(0.35	)	$	(0.37	)	$	(0.48	)	$	(2.10	)	$	(2.45	)