CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue:
Research and development revenue under collaborative agreements	$ 281,360	$ 202,514	$ 144,194
Licensing and royalty revenue	2,343	11,647	3,091
Total revenue	283,703	214,161	147,285
Expenses:
Research, development and patent expenses	322,292	241,751	184,033
General and administrative	37,173	20,140	14,918
Total operating expenses	359,465	261,891	198,951
Loss from operations	(75,762)	(47,730)	(51,666)
Other income (expense):
Investment income	4,302	2,682	2,085
Interest expense	(36,732)	(22,209)	(19,355)
Gain on investments, net	75	1,256	2,378
Gain on investment in Regulus Therapeutics Inc.	20,211	19,902	0
Loss on early retirement of debt	0	(8,292)	0
Loss before income tax (expense) benefit	(87,906)	(54,391)	(66,558)
Income tax (expense) benefit	(372)	15,407	5,914
Net loss	$ (88,278)	$ (38,984)	$ (60,644)
Basic and diluted net loss per share (in dollars per share)	$ (0.74)	$ (0.33)	$ (0.55)
Shares used in computing basic and diluted net loss per share (in shares)	119,719	117,691	110,502