Collaboration and License Agreements - Mylan Collaboration Agreement (Details) - Mylan Agreement	3 Months Ended	9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($) security
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable upfront payment		$ 45,000,000
Percentage of cost sharing arrangement under collaborative and license agreements	50.00%	50.00%
Milestone payment on collaboration agreement		$ 200,000,000
Number of years for ceasing agreement		2 years
Decrease in research and development expenses under cost sharing arrangement		$ 19,800,000
Decrease in general and administrative expenses under cost sharing arrangement		$ 1,000,000
Accounting Standards Update 2009 to 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of additional follow-on biologic products for research and development services | security		5
Number of additional follow-on biologic products for development and product licenses | security		5
Total arrangement consideration		$ 45,000,000
Portion of revised arrangement consideration reallocated to the remaining deliverables		45,000,000
Portion of revised arrangement consideration allocated to the first initial product license as a result of termination of product		8,200,000
Portion of revised arrangement consideration allocated to the joint steering committee unit of accounting as a result of termination of product		$ 51,000
Estimate performance period for the first initial product		4 years
Estimate performance period for the additional five product		7 years
Estimate performance period for the joint steering committee		8 years
Deferred revenue amortized to research and development revenue	$ 40,400,000	$ 40,400,000
Deferred revenue included in current liabilities		7,100,000
Deferred revenue included in non-current liabilities		33,300,000
Minimum | Accounting Standards Update 2009 to 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Portion of revised arrangement consideration allocated to each of the three additional product licenses as a result of termination of product		5,700,000
Maximum | Accounting Standards Update 2009 to 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Portion of revised arrangement consideration allocated to each of the three additional product licenses as a result of termination of product		$ 9,000,000