Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Schedule of Collaborative Arrangement Agreements [Line Items]
Provision for (benefit from) income taxes	$ 59,711,000	$ 10,341,000	$ 111,245,000	$ (2,318,000)
Unrecognized tax benefits	27,500,000		27,500,000		$ 19,500,000
Income taxes, interest and penalties accrued	0		0
Increase in unrecognized tax benefits is reasonably possible	0		0
Income taxes, material interest or penalties related to uncertain tax positions	$ 0	$ 0	$ 0	0
BioAxone Biosciences Inc.
Schedule of Collaborative Arrangement Agreements [Line Items]
Provision for (benefit from) income taxes				$ 6,000,000.0
Domestic and Foreign Tax Authority
Schedule of Collaborative Arrangement Agreements [Line Items]
Deferred tax assets, valuation allowance					$ 168,500,000