CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Product revenue, net	$ 9,698	$ 0	$ 10,849	$ 0
Cost of goods sold	3,058	0	3,482	0
Gross profit	6,640	0	7,367	0
Operating expenses:
Research and development	42,425	175,977	98,495	216,980
Selling, general and administrative	124,802	23,231	220,403	36,689
Total operating expenses	167,227	199,208	318,898	253,669
Loss from operations	(160,587)	(199,208)	(311,531)	(253,669)
Other income (expense):
Interest expense	(172)	0	(227)	0
Non-cash interest expense on mandatorily redeemable preferred shares	(6,993)	(3,955)	(12,554)	(3,955)
Non-cash interest expense on liability related to sale of future royalties	(11,570)	(5,155)	(19,995)	(11,972)
Change in fair value of derivative liability	650	(1,263)	(5,131)	(1,263)
Loss from equity method investment	(1,485)	(1,415)	(2,865)	(2,315)
Other	(119)	(16)	(216)	(33)
Total other expense, net	(19,689)	(11,804)	(40,988)	(19,538)
Loss before provision for income taxes	(180,276)	(211,012)	(352,519)	(273,207)
Provision for income taxes	658	58	1,352	167
Net loss and comprehensive loss	$ (180,934)	$ (211,070)	$ (353,871)	$ (273,374)
Net loss per share - basic and diluted (in dollars per share)	$ (3.08)	$ (4.67)	$ (6.15)	$ (6.11)
Weighted average common shares outstanding - basic and diluted (shares)	58,742,329	45,226,434	57,577,384	44,736,971