Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Financial Information

The following table contains quarterly financial information for 2018 and 2017. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period.

	2018
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter			Total
	(in thousands, except per share amounts)
Total revenue	$	—		$	90,000		$	—		$	273		$	90,273
Total operating expenses		78,119			112,147			128,745			164,500			483,511
Loss from operations		(78,119	)		(22,147	)		(128,745	)		(164,227	)		(393,238	)
Net loss		(74,598	)		(16,978	)		(122,918	)		(158,388	)		(372,882	)
Net loss per share—basic and diluted	$	(1.68	)	$	(0.36	)	$	(2.63	)	$	(3.38	)	$	(8.08	)

	2017
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter			Total
	(in thousands, except per share amounts)
Total revenue	$	—		$	—		$	—		$	—		$	—
Total operating expenses		57,480			70,854			74,373			70,448			273,155
Loss from operations		(57,480	)		(70,854	)		(74,373	)		(70,448	)		(273,155	)
Net loss		(56,778	)		(70,202	)		(73,719	)		(69,421	)		(270,120	)
Net loss per share—basic and diluted	$	(1.52	)	$	(1.88	)	$	(1.97	)	$	(1.75	)	$	(7.09	)