Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Other Commitments [Line Items]
Operating lease agreement expiration date			Jan. 31, 2018
Indemnification Agreement [Member]
Other Commitments [Line Items]
Indemnification obligations accrued	$ 0		$ 0		$ 0
Office and Laboratory Space [Member]
Other Commitments [Line Items]
Rental expense related to office and laboratory space	$ 352,000	$ 118,000	$ 892,000	$ 343,000