Collaboration Agreements - Summary of Royalty Tiers Associated with Cumulative Calendar Year Net Sales Allocated to Each Royalty-bearing Product (Detail) - AbbVie [Member]	12 Months Ended
	Sep. 30, 2019 USD ($)
Up to $500,000 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	10.00%
Up to $500,000 [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 500,000,000
From $500,000 up to $750,000
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	12.00%
From $500,000 up to $750,000 | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 500,000,000
From $500,000 up to $750,000 | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 750,000,000
From $750,000 up to $1,000,000
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	14.00%
From $750,000 up to $1,000,000 | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 750,000,000
From $750,000 up to $1,000,000 | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 1,000,000,000
From $1,000,000 up to $2,500,000
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Tier	17.00%
From $1,000,000 up to $2,500,000 | Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 1,000,000,000
From $1,000,000 up to $2,500,000 | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	2,500,000,000
Greater than or equal to $2,500,000 [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Calendar Year Net Sales	$ 2,500,000,000
Royalty Tier	20.00%