Collaboration and Licensing Agreements - Additional Information (Details) ¥ in Millions, $ in Millions		1 Months Ended					3 Months Ended							12 Months Ended
	Nov. 02, 2018 USD ($)	Nov. 30, 2019 USD ($) item	Feb. 28, 2019 USD ($)	Dec. 31, 2017 USD ($)	Nov. 30, 2017 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 CAD ($)	Dec. 31, 2019 JPY (¥)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Mar. 31, 2019 USD ($)	Jan. 01, 2018 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue							$ 2,250,000	$ 3,013,000	$ 18,000	$ 85,000	$ 172,000	$ 30,000	$ 2,320,000			$ 5,281,000	$ 2,607,000	$ 42,000,000
Current assets							252,062,000			176,371,000						252,062,000	176,371,000
Current liabilities							22,220,000			17,728,000						22,220,000	17,728,000
Unbilled revenue							750,000			5,000,000						750,000	5,000,000
Uncharged license fees										$ 1,000,000							1,000,000
Total payments, including an up-front payment and development and sales milestones to be received																19,200,000
Cost of revenue																600,000	466,000	8,400,000
Licensing
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																4,500,000	2,320,000	42,000,000
Other
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																322,000	287,000
Adjustments | ASU 2014-09
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Current assets							5,000,000									5,000,000
Current liabilities							1,000,000									1,000,000
Kyowa Hakko Kirin
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment received					$ 30,000,000
Kyowa Hakko Kirin | Product supply
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																300,000	300,000
Kyowa Hakko Kirin | Adjustments | ASU 2014-09
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Current assets																				$ 5,000,000
Current liabilities																				$ 1,000,000
Unbilled revenue							0									0
Shanghai Fosun Pharmaceutical Industrial Development
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																3,000,000	0
Upfront payment received				$ 12,000,000
Future development milestones	$ 110,000,000
Threshold percentage of net sales for tiered royalties				20.00%
Shanghai Fosun Pharmaceutical Industrial Development | Adjustments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue			$ 0
Xuanzhu Hk Biopharmaceutical Limited Or Xuanzhu [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue		$ 1,500,000
License fee recognized		1,500,000
Second milestone payment		750,000
Upfront payment received		$ 750,000
Cost of revenue																0
Xuanzhu Hk Biopharmaceutical Limited Or Xuanzhu [Member] | Licensing
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																1,500,000
Astra Zeneca
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Uncharged license fees																			$ 1,000,000
Cost of revenue																600,000	466,000	9,400,000
Cost of revenue, aggregate amount recognized							10,466,000									10,466,000
Cost of revenue, Amount Paid																1,002,000	2,864,000	$ 6,000,000
Payments of uncharged license fees, aggregate amount paid							9,866,000									9,866,000
Remaining balance							65,134,000									65,134,000
Astra Zeneca | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment per termination agreement						$ 75,000,000
Astra Zeneca | Adjustments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cost of revenue						$ 1,000,000
Kyowa Kirin Co. Ltd
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of pre-clinical study-ready compounds | item		2
Number of compounds inhibiting the first undisclosed target | item		1
Upfront payment recognized		$ 10,000,000
License fee receivable, first installment		$ 5,000,000
Term of payment of license fee, first installment		30 days
License fee receivable, Second instalment		$ 5,000,000
Term of agreement		2 years
Initial transaction price		$ 10,000,000
Revenue																500,000
Transaction price allocated to partially unsatisfied performance obligations							9,500,000									9,500,000
Uncharged license fees							$ 4,500,000									4,500,000
Kyowa Kirin Co. Ltd | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of development candidates | item		1
Number of separate collaborative agreements | item		1
Development and Commercialization [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue																0	2,300,000
Cost of revenue																0	$ 500,000
Development and Commercialization [Member] | Kyowa Hakko Kirin
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestones																55,000,000
Development milestones Received																5,000,000
Commercialization milestones															¥ 8.5	$ 78,300,000
Development and Commercialization [Member] | Astra Zeneca
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty revenue (as a percent)						10.00%
Percentage of non royalty revenue (as a percent)						20.00%
Development and Commercialization [Member] | Knight
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total payments, including an up-front payment and development and sales milestones to be received														$ 25