Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Collaborative arrangement revenue	$ 1,670	$ 109,674	$ 3,190	$ 111,976
Total revenues	7,472	198,890	20,267	220,753
Operating expenses:
Research and development	144,315	156,308	298,793	310,431
Selling, general and administrative	78,576	68,628	165,451	141,876
Share of collaboration loss	10,071	0	10,071	0
Cost of royalty and other revenue	15,301	1,554	17,582	2,579
Change in fair value of contingent consideration	47	(1,655)	416	(4,763)
Total operating expenses	248,310	224,835	492,313	450,123
Loss from operations	(240,838)	(25,945)	(472,046)	(229,370)
Interest income, net	439	2,939	1,149	8,294
Other (expense) income, net	(1,087)	1,551	23,669	(2,896)
Loss before income taxes	(241,486)	(21,455)	(447,228)	(223,972)
Income tax expense	(216)	(10)	(282)	(104)
Net loss	$ (241,702)	$ (21,465)	$ (447,510)	$ (224,076)
Net loss per share - basic: (in dollars per share)	$ (3.58)	$ (0.36)	$ (6.66)	$ (3.86)
Net loss per share - diluted: (in dollars per share)	$ (3.58)	$ (0.36)	$ (6.66)	$ (3.86)
Weighted-average number of common shares used in computing net loss per share - basic: (in shares)	67,487,000	60,384,000	67,233,000	57,987,000
Weighted-average number of common shares used in computing net loss per share - diluted: (in shares)	67,487,000	60,384,000	67,233,000	57,987,000
Other comprehensive (loss) income:
Other comprehensive (loss) income, net of tax benefit (expense) of $0.0 million and $(0.1) million for the three and six months ended June 30, 2021 and 2020, respectively.	$ (328)	$ 399	$ (272)	$ (507)
Comprehensive loss	(242,030)	(21,066)	(447,782)	(224,583)
Service revenue
Revenue:
Revenue	5,314	78,357	11,232	95,190
Royalty and other revenue
Revenue:
Revenue	$ 488	$ 10,859	$ 5,845	$ 13,587