Income Taxes (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Dec. 31, 2011		Jun. 30, 2011
Schedule of Collaborative Arrangements
Provision for income taxes	$ 21,355,000		$ (27,842,000)	$ 41,450,000		$ (3,394,000)
Income taxes payable (Alios)	3,871,000	[1]		3,871,000	[1]		12,075,000	[1]
Deferred tax liability	279,466,000	[1]		279,466,000	[1]		243,707,000	[1]
U.S. federal net operating loss carryforwards							2,700,000,000
Alios BioPharma, Inc
Schedule of Collaborative Arrangements
Provision for income taxes	21,394,000		4,850,000	40,354,000		29,298,000
Income taxes payable (Alios)	3,871,000			3,871,000			12,075,000
Deferred tax liability	151,880,000			151,880,000			116,121,000
Up-front payment									60,000,000
VX-759
Schedule of Collaborative Arrangements
Provision for income taxes			(32,700,000)			(32,700,000)
Vertex
Schedule of Collaborative Arrangements
Provision for income taxes	$ (39,000)			$ 1,100,000

[1] Amounts include the assets and liabilities of Vertex's variable interest entity ("VIE"), Alios BioPharma, Inc. ("Alios"). Vertex's interests and obligations with respect to the VIE's assets and liabilities are limited to those accorded to Vertex in its agreement with Alios. See Note C, "Collaborative Arrangements," to these condensed consolidated financial statements for amounts.