Collaborative Arrangements and Licensing Agreements, AstraZeneca (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		1 Months Ended		7 Months Ended	1 Months Ended				1 Months Ended			7 Months Ended			1 Months Ended	0 Months Ended	1 Months Ended				1 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 AstraZeneca [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2013 AstraZeneca [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2014 AstraZeneca [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2013 AstraZeneca [Member] Collaborations and Licensing Agreements [Member]	Jun. 30, 2013 AstraZeneca [Member] Agreement entered into in December 2012 [Member]	Dec. 31, 2012 AstraZeneca [Member] Agreement entered into in December 2012 [Member] Target	Jun. 30, 2013 AstraZeneca [Member] Agreement entered into in December 2012 [Member]	Dec. 31, 2012 AstraZeneca [Member] Agreement entered into in December 2012 [Member] Maximum [Member] Drug	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in December 2012 [Member] Pre-specified events [Member]	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in December 2012 [Member] Development milestones [Member]	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in December 2012 [Member] Regulatory milestones [Member]	Jun. 30, 2014 AstraZeneca [Member] Agreement entered into in December 2012 [Member] ISIS-AR [Member]	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in December 2012 [Member] ISIS-AR [Member]	Jun. 30, 2013 AstraZeneca [Member] Agreement entered into in December 2012 [Member] ISIS-AR [Member]	Jun. 30, 2013 AstraZeneca [Member] Agreement entered into in December 2012 [Member] Three drugs [Member] Drug	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in December 2012 [Member] ISIS-STAT3 License [Member]	Jun. 30, 2013 AstraZeneca [Member] Agreement entered into in December 2012 [Member] ISIS-STAT3 License [Member]	Oct. 31, 2014 AstraZeneca [Member] Amended Agreement entered into in October 2014 [Member] ISIS-STAT3 License [Member] Subsequent Event [Member] Payment	Nov. 07, 2014 AstraZeneca [Member] Amended Agreement entered into in October 2014 [Member] ISIS-STAT3 License [Member] Advancement in Patients with Advanced Cancers [Member] Subsequent Event [Member]	Oct. 31, 2014 AstraZeneca [Member] Amended Agreement entered into in October 2014 [Member] ISIS-STAT3 License [Member] Advancement in Patients with Advanced Cancers [Member] Subsequent Event [Member]	Oct. 31, 2014 AstraZeneca [Member] Amended Agreement entered into in October 2014 [Member] ISIS-STAT3 License [Member] Phase 2 [Member] Subsequent Event [Member]	Oct. 31, 2014 AstraZeneca [Member] Amended Agreement entered into in October 2014 [Member] ISIS-STAT3 License [Member] Development milestones [Member]	Oct. 31, 2014 AstraZeneca [Member] Amended Agreement entered into in October 2014 [Member] ISIS-STAT3 License [Member] Regulatory milestones [Member] Subsequent Event [Member]	Aug. 31, 2013 AstraZeneca [Member] Agreement entered into in August 2013 [Member]	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in August 2013 [Member]	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in August 2013 [Member] License fee and substantive milestones [Member]	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in August 2013 [Member] Research and development milestones [Member]	Sep. 30, 2014 AstraZeneca [Member] Agreement entered into in August 2013 [Member] Regulatory milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of targets										5
Number of drugs the collaborative partner may license under a separate research program												3							3
Upfront and near-term payments										$ 31,000,000
Upfront fee received									6,000,000	25,000,000	31,000,000
Revenue earned	44,063,000	23,585,000	129,300,000	105,036,000	627,000	4,200,000	19,700,000	22,000,000			11,500,000
Deferred revenue					4,800,000		4,800,000		19,500,000		19,500,000							11,200,000	7,600,000		700,000
Milestone payment earned																15,000,000							7,500,000
Number of milestone payments to be earned																						2
Milestone payments to be earned																						15,000,000		7,500,000	10,000,000
Maximum amount of payment receivable													865,000,000	238,000,000	620,000,000											70,000,000	170,000,000			163,200,000	45,300,000	105,000,000
Cumulative milestone payments earned under collaborative arrangement at period end																	25,000,000
Next prospective milestone																				10,000,000									3,300,000
Upfront fee recorded as deferred revenue											$ 19,500,000																	$ 750,000
Percent of total revenue (in hundredths)					1.00%		15.00%