Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Collaboration revenue	$ 1,249	$ 0
Operating expenses:
Research and development	33,240	24,352
Selling, general and administrative	21,318	10,918
Acquired in-process research and development expense	1,500	0
Change in fair value of contingent consideration	(7,900)	3,000
Total operating expenses	48,158	38,270
Loss from operations	(46,909)	(38,270)
Other income (expense):
Interest income	1,088	3,156
Other income (expense), net	20,021	(88)
Total other income	21,109	3,068
Net loss	$ (25,800)	$ (35,202)
Net loss per share, basic and diluted
Net loss per share, basic and diluted (in dollars per share)	$ (0.54)	$ (0.83)
Weighted average number of shares used in the calculation of basic and diluted net loss per common share (shares)	48,185	42,236