Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)		12 Months Ended
	Jul. 02, 2015	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Line Items]
Maximum maturity days for cash equivalents		90 days
Restricted cash		$ 1,539,000	$ 139,000
Deferred offering costs			1,684,000
Reclassification of deferred offering costs to additional paid in capital	$ 3,748,000
Impairment losses on long lived assets		$ 0
Minimum percentage of likelihood of tax benefit being realized upon settlement		50.00%
Revenue		$ 0
Laboratory Equipment [Member]
Accounting Policies [Line Items]
Useful life of asset		5 years
Computer Equipment [Member]
Accounting Policies [Line Items]
Useful life of asset		3 years
Furniture and Office Equipment [Member]
Accounting Policies [Line Items]
Useful life of asset		3 years
Initial Public Offering ("IPO") [Member]
Accounting Policies [Line Items]
Deferred offering costs		$ 0	$ 1,684,000