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

Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=68058157&loc=d3e18780-107790

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 35
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68071081&loc=d3e1205-110223

Name:	us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration