Summary of Significant Accounting Policies - Collaboration Revenue (Detail) $ in Thousands	1 Months Ended				3 Months Ended								12 Months Ended			22 Months Ended
	Jun. 30, 2016 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	May 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) category	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2016 USD ($)
Components of collaboration revenue
Total collaboration revenue					$ 5,322	$ 1,668	$ 28,198	$ 15,721	$ 4,782	$ 3,448	$ 1,597	$ 41,678	$ 50,909	$ 51,505	$ 41,259
Number of categories for milestones | category													3
License revenue
Components of collaboration revenue
Total collaboration revenue													$ 22,937	38,083	38,373
Research and development activity revenue
Components of collaboration revenue
Total collaboration revenue													9,741	8,378	2,000
API transfer revenue
Components of collaboration revenue
Total collaboration revenue													18,212	5,020	883
Joint operating committee revenue
Components of collaboration revenue
Total collaboration revenue													$ 19	$ 24	$ 3
Novartis Pharma AG | Licensing and Commercialization Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront fees received				$ 200,000
Novartis Pharma AG | Licensing and Commercialization Agreement | Achievement of specified patient enrollment milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Patient enrollment-based milestone revenue achieved	$ 30,000	$ 50,000	$ 50,000													$ 130,000
Milestone payment received																$ 130,000