Quarterly Financial Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Data [Abstract]

Summary of Unaudited Quarterly Financial Information

The following table presents certain unaudited quarterly financial information. This information has been prepared on the same basis as the audited financial statements and includes all adjustments (consisting only of normal recurring adjustments) necessary to present fairly the unaudited quarterly results of operations set forth herein (in thousands, except share and per share data):

	2017
	March 31,			June 30,			September 30,			December 31,
Revenue	$	—		$	—		$	198		$	2,414
Operating expenses		69,954			78,441			83,911			99,248
Net loss		(68,290	)		(72,891	)		(79,227	)		(81,731	)
Net loss per share, basic and diluted	$	(1.63	)	$	(1.72	)	$	(1.87	)	$	(1.89	)

	2016
	March 31,			June 30,			September 30,			December31,
Revenue	$	—		$	17		$	111		$	5
Operating expenses		53,622			58,070			65,894			70,554
Net loss		(52,757	)		(56,923	)		(64,907	)		(71,287	)
Net loss per share, basic and diluted	$	(1.35	)	$	(1.46	)	$	(1.64	)	$	(1.75	)