Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Collaboration revenue	$ 630	$ 0	$ 1,699	$ 0
Operating expenses:
Research and development	28,372	27,608	79,820	77,329
Selling, general and administrative	15,762	11,016	42,139	27,663
Acquired in-process research and development and related costs	249,437	0	249,437	0
Change in fair value of contingent purchase consideration	400	5,700	2,700	3,200
Total operating expenses	293,971	44,324	374,096	108,192
Loss from operations	(293,341)	(44,324)	(372,397)	(108,192)
Other income (expense):
Interest income	2,382	2,133	8,521	3,995
Other income (expense)	481	(73)	433	2,914
Total other income (expense)	2,863	2,060	8,954	6,909
Net loss from continuing operations	(290,478)	(42,264)	(363,443)	(101,283)
Loss from discontinued operations, net of taxes	0	0	0	(198)
Net loss	$ (290,478)	$ (42,264)	$ (363,443)	$ (101,481)
Net loss per share, basic and diluted:
Continuing operations (in dollars per share)	$ (6.75)	$ (1.08)	$ (8.54)	$ (2.78)
Discontinued operations (in dollars per share)	0	0	0	0
Net loss per share, basic and diluted (in dollars per share)	$ (6.75)	$ (1.08)	$ (8.54)	$ (2.78)
Weighted average common shares used in the calculation of basic and diluted net loss per common share (shares)	43,029	39,242	42,577	36,485