Summary of Significant Accounting Policies - Summary of Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2016
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	3 years
Lab Equipment [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	5 years
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	5 years
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment estimated useful lives	Shorter of lease term or estimated useful life