Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Summary of Selected Unaudited Consolidated Quarterly Financial Information

The selected consolidated quarterly financial results from operations for the years ended December 31, 2017 and 2016 are set forth therein.

	Fiscal 2017 Quarter Ended
	March 31, 2017			June 30, 2017			September 30, 2017			December 31, 2017
	(in thousands, except per share amounts)
Operating expenses	$	11,154		$	10,477		$	10,183		$	10,805
Net loss	$	(11,092	)	$	(10,329	)	$	(9,995	)	$	(10,599	)
Basic and diluted net loss per share	$	(0.26	)	$	(0.20	)	$	(0.19	)	$	(0.20	)

	Fiscal 2016 Quarter Ended
	March 31, 2016			June 30, 2016			September 30, 2016			December 31, 2016
	(in thousands, except per share amounts)
Operating expenses	$	10,613		$	12,946		$	15,283		$	9,233
Net loss	$	(10,538	)	$	(12,872	)	$	(15,209	)	$	(9,248	)
Basic and diluted net loss per share	$	(0.35	)	$	(0.43	)	$	(0.50	)	$	(0.30	)