Condensed Consolidated Statements of 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	$ 277,998	$ 218,447	$ 512,512	$ 413,646
Costs and expenses:
Research and development	198,077	163,929	393,276	322,194
Selling, general and administrative	125,642	82,331	247,891	162,602
Total costs and expenses	371,963	257,157	718,832	505,993
Loss from operations	(93,965)	(38,710)	(206,320)	(92,347)
Investment and other income (loss), net	72,775	(40,528)	16,728	(220)
Net loss	$ (21,190)	$ (79,238)	$ (189,592)	$ (92,567)
Net loss per share - basic and diluted (in dollars per share)	$ (0.12)	$ (0.49)	$ (1.10)	$ (0.57)
Shares used in computation of per share amounts - basic and diluted (in shares)	173,406	161,436	172,878	161,049
Comprehensive loss:
Net loss	$ (21,190)	$ (79,238)	$ (189,592)	$ (92,567)
Other comprehensive income (loss):
Unrealized gain (loss) on securities available-for-sale, net of tax	(2,042)	252	1,231	474
Foreign currency translation gain	32	18	8	52
Total other comprehensive income (loss)	(2,010)	270	1,239	526
Comprehensive loss	(23,200)	(78,968)	(188,353)	(92,041)
Product [Member]
Revenues:
Total revenues	240,465	158,980	438,979	293,981
Costs and expenses:
Cost of sales	48,244	10,897	77,665	21,197
Royalty [Member]
Revenues:
Total revenues	31,235	23,337	51,595	38,957
License and Service [Member]
Revenues:
Total revenues	$ 6,298	$ 36,130	$ 21,938	$ 80,708