Collaboration and License Agreements - Baxalta Collaboration Agreement (Details) - Baxalta Agreement	1 Months Ended		3 Months Ended			9 Months Ended
	Feb. 28, 2015 USD ($) security	Jan. 31, 2011 security	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Sep. 30, 2016 USD ($) security
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of additional biosimilars under the agreement | security						4
Upfront payment paid by Baxter to the company						$ 33,000,000
Option payment which the entity is no longer eligible to receive						7,000,000
Option payments agreed to be paid by Baxter with respect to additional product candidates						$ 12,000,000
Royalty payment percentage of net sales						5.00%
Number of additional follow-on biologic products for research and development services | security						4
Additional payment to be paid						$ 28,000,000
Expected deferred income recognized on collaboration agreements, quarterly amount						3,700,000
Accounting Standards Update 2009 to 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment paid by Baxter to the company						$ 33,000,000
Number of additional follow-on biologic products for development and product licenses | security						4
Total arrangement consideration	$ 61,000,000					$ 61,000,000
Decrease in portion of revised arrangement consideration reallocated to the remaining deliverables	40,000,000
Portion of revised arrangement consideration reallocated to the remaining deliverables	40,000,000					61,000,000
Portion of revised arrangement consideration allocated to the first initial product license as a result of termination of product	39,600,000					10,300,000
Portion of revised arrangement consideration allocated to each of the three additional product licenses as a result of termination of product	$ 400,000					10,300,000
Portion of revised arrangement consideration allocated to the second initial product license as a result of termination of product						9,400,000
Portion of revised arrangement consideration allocated to the joint steering committee unit of accounting as a result of termination of product						114,000
Number of significant deliverables identified in arrangement | security	2	7
Deferred revenue						$ 14,600,000
Scenario, Forecast
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expected deferred income recognized on collaboration agreements, quarterly amount			$ 3,500,000	$ 3,700	$ 3,700