Quarterly Financial Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Data [Abstract]

Summary of Unaudited Quarterly Financial Data

The following table summarizes the unaudited quarterly financial data for the last two fiscal years (in thousands, except per share data):

(in thousands, except per share amounts)	First			Second			Third			Fourth
	Quarter			Quarter			Quarter			Quarter
2018
Revenues	$	5,331		$	6,639		$	9,188		$	12,400
Total operating expenses		23,931			26,130			26,867			30,281
Net loss		(17,820	)		(18,413	)		(15,789	)		(15,676	)
Net loss per common share, basic and diluted	$	(0.50	)	$	(0.49	)	$	(0.39	)	$	(0.39	)
Weighted average number of shares, basic and diluted		35,827,235			37,440,024			40,116,644			40,259,575
2017, As Revised (Note 2)
Revenues	$	2,410		$	3,001		$	3,077		$	2,954
Total operating expenses		17,393			18,771			20,245			13,700
Net loss		(14,762	)		(15,461	)		(16,721	)		(10,066	)
Net loss per common share, basic and diluted	$	(0.47	)	$	(0.50	)	$	(0.50	)	$	(0.28	)
Weighted average number of shares, basic and diluted		31,089,310			31,200,773			33,525,567			35,684,201