Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Total revenues	$ 8,343	$ 5,110	$ 14,510	$ 5,840
Cost and operating expenses:
Cost of sales	127		150
Research and development	91,079	87,101	175,225	161,351
Selling, general and administrative	42,174	21,923	77,829	38,476
Total cost and operating expenses	133,380	109,024	253,204	199,827
Other income (expense):
Interest income, net	1,586	4,275	4,490	6,985
Other income, net	(23)	(42)	(224)	(86)
Total other income	1,563	4,233	4,266	6,899
Net loss	(123,474)	(99,681)	(234,428)	(187,088)
Other comprehensive loss:
Unrealized gain (losses) on available-for-sale investments	(1,057)	845	1,435	1,115
Currency translation adjustments	6	7	(21)	(8)
Comprehensive loss	$ (124,525)	$ (98,829)	$ (233,014)	$ (185,981)
Net loss per share - basic and diluted	$ (2.28)	$ (2.04)	$ (4.39)	$ (4.03)
Weighted-average number of common shares used in net loss per share - basic and diluted	54,217	48,843	53,436	46,458
Product revenue, net
Revenues:
Total revenues	$ 5,680		$ 9,138
Collaboration revenue
Revenues:
Total revenues	$ 2,663	$ 5,110	$ 5,372	$ 5,840