Collaborative Arrangements - Textual (Details) - USD ($)	1 Months Ended									3 Months Ended		5 Months Ended	9 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Sep. 30, 2015	Aug. 31, 2015	Jul. 31, 2014	Feb. 29, 2012	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2014	Sep. 30, 2017	Sep. 30, 2016
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development revenues										$ 2,929,000	$ 10,373,000		$ 8,320,000	$ 25,971,000
Supply Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue			$ 700,000							700,000			700,000
Milestone revenue			750,000
GlaxoSmithKline [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceeds from license fees received								$ 6,000,000
Revenue recognized				$ 7,500,000		$ 6,500,000						$ 5,000,000
Minimum milestone receivable													5,750,000
Maximum milestone receivable													38,500,000
Termination notice period								90 days
Term of milestone agreement								3 years
License and services revenue										0	0		0	3,000,000
Merck [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Sales revenue										1,500,000	1,700,000		6,500,000	4,400,000
Merck [Member] | Technology Transfer, Collaboration and License Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceeds from license fees received							$ 5,000,000
Maximum milestone receivable							$ 15,000,000
Termination notice period							90 days
License and services revenue										0	600,000		0	1,900,000
Right of refusal period							5 years
Upfront license fee, period for recognition							2 years
Merck [Member] | Supply Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized	$ 0
Termination notice period					24 months
License and services revenue										300,000	300,000		1,000,000	1,000,000
Upfront license fee, period for recognition									5 years
Term of collaborative research and development agreement									5 years
Optional extension period									5 years
Deferred revenue			$ 1,300,000							1,800,000			1,800,000
Fine chemical customer [Member] | Research and Development Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized										600,000			1,100,000
Term of collaborative research and development agreement		21 months
Deferred revenue										2,900,000			2,900,000
Milestone revenue		$ 3,000,000
Licenses revenue										400,000			900,000
Research and development revenues										1,100,000			1,900,000
Collaborative Arrangement [Member] | Merck [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and services revenue										900,000	600,000		2,700,000	1,300,000
Therapeutic Development Program [Member] | Collaborative Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized										$ 0	$ 0		$ 100,000	$ 1,800,000