Summary of Significant Accounting Policies - Schedule of Property and Equipment Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2017
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	Shorter of remaining lease term or expected useful life
Minimum | Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	3 years
Minimum | Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	2 years
Minimum | Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	3 years
Minimum | Equipment Acquired Under Capital Leases
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	3 years
Maximum | Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	5 years
Maximum | Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	5 years
Maximum | Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	7 years
Maximum | Equipment Acquired Under Capital Leases
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives (Years)	7 years