Collaborations (Details)	1 Months Ended							3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Aug. 31, 2020 USD ($)	Nov. 30, 2018 USD ($)	Feb. 28, 2014 USD ($)	Jun. 30, 2013 USD ($)	Jul. 31, 2012 target	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Nov. 30, 2020 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues (less than in 2020)								$ 0	$ 5,000,000	$ 0	$ 5,006,000
Revenue under collaborations
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues (less than in 2020)								0	$ 5,000,000	0	$ 5,000,000
Sanofi
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of collaborative areas granted | target							4
Initial upfront option payment	$ 4,000,000	$ 1,000,000	$ 1,000,000
Potential revenue through milestone payments				$ 6,800,000
Agreement period				24 months
Upfront payment non-creditable portion recognized												$ 6,800,000
Enrollment Milestone			10,000,000
Contract with customer, asset													$ 5,000,000
Development milestone not achievable								25,000,000		$ 25,000,000
Sanofi | Minimum | United States
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalties based on percentage of net sales										10.00%
Sanofi | Minimum | Outside of the United States
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalties based on percentage of net sales										10.00%
Sanofi | Maximum | United States
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalties based on percentage of net sales										20.00%
Sanofi | Maximum | Outside of the United States
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalties based on percentage of net sales										20.00%
Sanofi | Development Commercialization And License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue creditable against future milestones					$ 1,250,000					$ 1,250,000
Initial upfront option payment						$ 2,500,000
Sanofi | Proof-of-Concept Trial
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential revenue through milestone payments								38,800,000		38,800,000
Sanofi | Clinical
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential revenue through milestone payments								25,000,000		25,000,000
Sanofi | Regulatory and Commercialization Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential revenue through milestone payments								$ 130,000,000		$ 130,000,000
Sanofi | Development Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential revenue through milestone payments			25,000,000	$ 40,000,000
Sanofi | Enrollment Milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential revenue through milestone payments				$ 10,000,000
Sanofi | Materials Sold
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential revenue through milestone payments			4,000,000
Sanofi | Achievement of Enrollment Milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential revenue through milestone payments			$ 5,000,000