Collaborative Arrangements (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended			9 Months Ended		12 Months Ended		1 Months Ended	3 Months Ended				9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Janssen Pharmaceutica, N.V.	Dec. 31, 2013 Janssen Pharmaceutica, N.V.	Sep. 30, 2013 Janssen Pharmaceutica, N.V.	Sep. 30, 2014 Janssen Pharmaceutica, N.V.	Sep. 30, 2013 Janssen Pharmaceutica, N.V.	Dec. 31, 2006 Janssen Pharmaceutica, N.V.	Nov. 30, 2013 Janssen Pharmaceutica, N.V.	Apr. 30, 2011 Cystic Fibrosis Foundation Therapeutics Incorporated	Sep. 30, 2014 Cystic Fibrosis Foundation Therapeutics Incorporated	Sep. 30, 2013 Cystic Fibrosis Foundation Therapeutics Incorporated	Mar. 31, 2013 Cystic Fibrosis Foundation Therapeutics Incorporated	Sep. 30, 2012 Cystic Fibrosis Foundation Therapeutics Incorporated	Sep. 30, 2014 Cystic Fibrosis Foundation Therapeutics Incorporated payment	Sep. 30, 2013 Cystic Fibrosis Foundation Therapeutics Incorporated	Sep. 30, 2013 Alios Bio Pharma Inc	Sep. 30, 2013 Alios Bio Pharma Inc	Dec. 31, 2014 Scenario, Forecast Janssen Pharmaceutica, N.V.
Schedule of Collaborative Arrangements
Drug development costs to be paid by collaborator (as a percent)										50.00%
Up-front license payment					$ 30,000,000			$ 30,000,000		$ 165,000,000											$ 5,000,000
Deferred revenue related to up-front license payment					3,300,000			3,300,000			32,100,000
License fee paid upon amendment of agreement						152,000,000
Collaborative revenues recognized
Royalty revenues (INCIVO)	8,386,000	27,012,000	32,134,000	119,705,000	2,284,000		20,994,000	12,917,000	104,108,000
Up-front and amendment payments revenues					0		3,107,000	0	9,321,000
Net reimbursement for telaprevir development costs					1,390,000		1,413,000	4,262,000	1,422,000
Reimbursement for manufacturing services					0		0	0	10,299,000
Total collaborative revenues attributable to the Janssen HCV collaboration	33,502,000	8,035,000	40,846,000	32,290,000	1,390,000	182,400,000	4,520,000	4,262,000	21,042,000				1,983,000	3,515,000			6,455,000	11,318,000
Total revenues attributable to the Janssen HCV collaboration	178,987,000	221,700,000	435,859,000	860,818,000	3,674,000		25,514,000	17,179,000	125,150,000
Collaborative funding												75,000,000
Number of years over which funding will be made (in years)												5 years
Collaborative revenues attributable to the CFFT collaboration	33,502,000	8,035,000	40,846,000	32,290,000	1,390,000	182,400,000	4,520,000	4,262,000	21,042,000				1,983,000	3,515,000			6,455,000	11,318,000
Milestone payment made															9,300,000	9,300,000
Number of commercial milestone payments for achievement of certain sales levels for corrector compound such as VX-809 or VX-661 (in payments)																	2
Noncontrolling Interest (Alios)
Loss before benefit from income taxes																			9,056,000	21,177,000
Decrease in fair value of contingent milestone and royalty payments																			(1,220,000)	1,600,000
Benefit from income taxes	3,419,000	2,555,000	4,915,000	(123,774,000)															(3,306,000)	(9,089,000)
Loss from discontinued operations attributable to noncontrolling interest (Alios)																			$ 4,530,000	$ 13,688,000