Zai Lab License Agreement - Additional Information (Details) - License and Collaboration Agreement (the “Zai Agreement”) [Member] - USD ($)		3 Months Ended
	Sep. 10, 2018	Sep. 30, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Non-refundable up-front license fee, amount	$ 15,000,000
Expects to receive up-front license fee		$ 15,000,000
Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory and commercial milestone payments	$ 78,000,000
Minimum [Member] | License [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of tiered royalties rates on net sales	10.00%