Development and Other Agreements - Additional Information (Detail) - Google Life Sciences LLC - Collaborative Arrangement - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2018	Dec. 31, 2015	Aug. 10, 2015
Development Agreements [Line Items]
Sales revenue, goods, net		$ 750,000,000
Commitment amount, royalty eligible sales threshold not achieved				$ 0
Collaborative Arrangement, Initial Payment
Development Agreements [Line Items]
Upfront fee				$ 35,000,000
Shares, issued	404,591
Share Price				$ 90.29
Collaborative Arrangement, Milestone Payments
Development Agreements [Line Items]
Development & regulatory milestone payments				$ 65,000,000
Research and Development Expense | Collaborative Arrangement, Initial Payment
Development Agreements [Line Items]
R&D expense through issuance of common stock			$ 36,500,000