Collaborative Agreements - Additional Information (Detail) (USD $)	6 Months Ended		1 Months Ended	6 Months Ended		12 Months Ended					1 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jan. 31, 2010 Collaboration and License Agreement	Jun. 30, 2013 Collaboration and License Agreement	Jun. 30, 2012 Collaboration and License Agreement	Dec. 31, 2011 Collaboration and License Agreement Preclinical Development Activities	Jun. 30, 2013 Collaboration and License Agreement Preclinical Development Activities	Jun. 30, 2013 Collaboration and License Agreement Clinical Milestone Events	Jun. 30, 2013 Collaboration and License Agreement Regulatory Approvals	Jun. 30, 2013 Collaboration and License Agreement Sales Milestones	Sep. 30, 2012 Service Agreements	Aug. 31, 2010 Service Agreements	Jun. 30, 2013 Service Agreements	Jun. 30, 2012 Service Agreements	Jun. 30, 2013 Service Agreements	Jun. 30, 2012 Service Agreements	Aug. 31, 2010 Service Agreements Maximum Employees
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non refundable upfront license fee			$ 5,000,000
Collaborative arrangement shares issued value			2,000,000
Collaborative arrangement shares issued fair value			3,300,000
Collaborative arrangement agreement research and collaboration term			2 years
Deferred revenue, additions			3,700,000
Deferred revenue, revenue recognized				0	78,000
Research revenue				252,000	429,000
Collaborative arrangement expected service revenue				206,600,000			600,000	26,000,000	45,000,000	135,000,000
Milestone method, revenue recognized						600,000
Service revenue												13,000,000	100,000	1,000,000	300,000	2,200,000
Collaborative arrangement agreement service term												4 years
Number of candidates																	2
Revenues from other services											3,500,000
Revenue From Research Work	$ 118,000	$ 198,000