CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue:
Research and development revenue under collaborative agreements	$ 48,918	$ 43,798	$ 230,469	$ 119,975
Licensing and royalty revenue	203	265	1,664	9,325
Total revenue	49,121	44,063	232,133	129,300
Expenses:
Research, development and patent expenses	88,508	61,086	220,962	173,798
General and administrative	8,751	4,470	23,992	13,313
Total operating expenses	97,259	65,556	244,954	187,111
Loss from operations	(48,138)	(21,493)	(12,821)	(57,811)
Other income (expense):
Investment income	1,185	675	2,946	2,003
Interest expense	(9,233)	(4,998)	(27,381)	(14,902)
Gain on investments, net	199	3	200	140
Gain on investment in Regulus Therapeutics Inc.	20,211	535	20,211	535
Loss before income tax expense	(35,776)	(25,278)	(16,845)	(70,035)
Income tax expense	0	(1,398)	0	(2)
Net loss	$ (35,776)	$ (26,676)	$ (16,845)	$ (70,037)
Basic and diluted net loss per share (in dollars per share)	$ (0.30)	$ (0.23)	$ (0.14)	$ (0.60)
Shares used in computing basic and diluted net loss per share (in shares)	119,979	117,811	119,560	117,511