Collaboration and License Agreements (Details) (USD $)	3 Months Ended		6 Months Ended		1 Months Ended	3 Months Ended		6 Months Ended		1 Months Ended	6 Months Ended		1 Months Ended					6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2007 Collaboration agreement Forest Laboratories, Inc.	Jun. 30, 2013 Collaboration agreement Forest Laboratories, Inc.	Jun. 30, 2012 Collaboration agreement Forest Laboratories, Inc.	Jun. 30, 2013 Collaboration agreement Forest Laboratories, Inc.	Jun. 30, 2012 Collaboration agreement Forest Laboratories, Inc.	Sep. 30, 2009 Collaboration agreement Forest Laboratories, Inc. Convertible preferred stock	Jun. 30, 2013 Collaboration agreement Forest Laboratories, Inc. Development and sales milestones item	Jun. 30, 2013 Collaboration agreement Forest Laboratories, Inc. Sales milestones	Sep. 30, 2012 Collaboration agreement Forest Laboratories, Inc. Development milestones	Aug. 31, 2012 Collaboration agreement Forest Laboratories, Inc. Development milestones item	Oct. 31, 2011 Collaboration agreement Forest Laboratories, Inc. Development milestones item	Jul. 31, 2009 Collaboration agreement Forest Laboratories, Inc. Development milestones	Sep. 30, 2008 Collaboration agreement Forest Laboratories, Inc. Development milestones	Jun. 30, 2013 Collaboration agreement Forest Laboratories, Inc. Development milestones item	Jun. 30, 2013 Collaboration agreement Forest Laboratories, Inc. Commercialization milestone
Collaboration and License Agreements
Up-front fee received					$ 70,000,000
Cumulative license fees and development milestone payments received																		205,000,000
Equity investment in the entity's capital stock								25,000,000
Milestone payment to be received by company upon milestone achievement												100,000,000
Asset value for contingent equity investment by collaborative party recorded at inception of agreement					9,000,000
Incremental deferred revenue related to contingent equity investment					9,000,000
Collaboration expense	11,162,000	3,101,000	35,892,000	5,156,000		11,162,000	3,101,000	35,892,000	5,156,000
Selling and marketing costs incurred by the Company						8,271,000	1,109,000	16,810,000	2,291,000
The Company's share of net loss						19,433,000	4,210,000	52,702,000	7,447,000
Issuance of Convertible preferred stock (in shares)										2,083,333
Number of milestones achieved under collaboration agreement														2	2			6
Milestone payment received													85,000,000		20,000,000	20,000,000	10,000,000
Number of milestone payments recognized											4
Collaborative arrangements revenue	9,663,000	14,604,000	12,918,000	26,852,000		0	5,400,000	0	10,900,000
Net cost sharing offset or incremental expense related to research and development expense						50,000	1,300,000	3,000,000	400,000
Percentage of net profit from commercialization																			50.00%
Percentage of net loss from commercialization																			50.00%
Research and development expense	$ 24,093,000	$ 32,238,000	$ 56,846,000	$ 61,748,000