Quarterly Results (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Results

	Three Month Ended
	March 31, 2016			June 30, 2016			September 30, 2016			December 31, 2016
	(in thousands, expect per share data)
	(unaudited)
Collaboration and licensing revenue	$	1,203		$	193		$	992		$	127
Operating expenses		8,435			7,335			6,585			9,553
Loss from operations		(7,232	)		(7,142	)		(5,593	)		(9,426	)
Change in fair value warranty liability		—			(996	)		1,178			4,569
Other expense, net		(378	)		(468	)		(551	)		(748	)
Net loss	$	(7,710	)	$	(8,606	)	$	(4,966	)	$	(5,605	)
Net loss per share	$	(0.13	)	$	(0.13	)	$	(0.07	)	$	(0.07	)
	Three Month Ended
	March 31, 2015			June 30, 2015			September 30, 2015			December 31, 2015
	(in thousands, expect per share data)
	(unaudited)
Collaboration and licensing revenue	$	134		$	134		$	15,158		$	3,598
Restructuring and lease exit		4,333			25			—			—
Operating expenses		5,950			4,730			6,691			9,721
(Loss) income from operations		(10,149	)		(4,621	)		8,467			(6,123	)
Other expense, net		(725	)		(835	)		(553	)		(462	)
Net (loss) income	$	(10,874	)	$	(5,456	)	$	7,914		$	(6,585	)
Net (loss) income per share	$	(0.21	)	$	(0.10	)	$	0.14		$	(0.11	)