Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total revenue	$ 873	$ 90,000	$ 1,338	$ 90,000
Operating costs and expenses:
Cost of goods sold	44		44
Research and development	89,059	68,980	175,457	118,250
Selling, general and administrative	88,227	43,167	172,146	72,016
Total operating costs and expenses	177,330	112,147	347,647	190,266
Loss from operations	(176,457)	(22,147)	(346,309)	(100,266)
Interest income, net	8,220	5,137	14,662	8,666
Other income, net	16	32	20	24
Net loss	$ (168,221)	$ (16,978)	$ (331,627)	$ (91,576)
Net loss per share—basic and diluted	$ (3.28)	$ (0.36)	$ (6.65)	$ (2.02)
Weighted average number of common shares outstanding—basic and diluted	51,257,640	46,541,716	49,882,377	45,439,666
Comprehensive loss:
Net loss	$ (168,221)	$ (16,978)	$ (331,627)	$ (91,576)
Other comprehensive items:
Unrealized gain (loss) on marketable securities	1,681	40	2,090	(116)
Total other comprehensive gain (loss)	1,681	40	2,090	(116)
Total comprehensive loss	(166,540)	(16,938)	(329,537)	(91,692)
Product Revenue [Member]
Total revenue	519		519
Collaboration Revenue [Member]
Total revenue	$ 354	$ 90,000	$ 819	$ 90,000