CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenue:
Research and development revenue under collaborative agreements	$ 108,913	$ 48,918	$ 166,583	$ 230,469
Licensing and royalty revenue	2,014	203	19,689	1,664
Total revenue	110,927	49,121	186,272	232,133
Expenses:
Research, development and patent expenses	84,631	88,508	243,169	220,962
General and administrative	10,188	8,751	30,574	23,992
Total operating expenses	94,819	97,259	273,743	244,954
Income (loss) from operations	16,108	(48,138)	(87,471)	(12,821)
Other income (expense):
Investment income	989	1,384	3,912	3,146
Interest expense	(9,746)	(9,233)	(28,861)	(27,381)
Gain on investment in Regulus Therapeutics Inc.	0	20,211	0	20,211
Income (loss) before income tax expense	7,351	(35,776)	(112,420)	(16,845)
Income tax benefit (expense)	0	0	(1)	0
Net income (loss)	$ 7,351	$ (35,776)	$ (112,421)	$ (16,845)
Basic net income (loss) per share (in dollars per share)	$ 0.06	$ (0.30)	$ (0.93)	$ (0.14)
Diluted net income (loss) per share (in dollars per share)	$ 0.06	$ (0.30)	$ (0.93)	$ (0.14)
Shares used in computing basic net income (loss) per share (in shares)	120,989	119,979	120,795	119,348
Shares used in computing diluted net income (loss) per share (in shares)	123,378	119,979	120,795	119,348