Collaboration Agreements - Additional Information (Details) - Collaboration Agreement - Regeneron $ in Thousands	Oct. 10, 2016 USD ($)
Collaboration Agreement
Payment receivable upon exercise of option	$ 10,000
Maximum
Collaboration Agreement
Reimbursable clinical development costs	25,000
Potential increase in reimbursable clinical development costs	5,000
Potential payment receivable per Licensed Product upon the achievement of specified development and regulatory milestones	145,000
Potential payment receivable per Licensed Product upon first commercial sale of such Licensed Product	100,000
Potential payment receivable due for achievement of specified sales milestones for all Licensed Products	$ 50,000