Commitments and Contingencies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) ft² Lease	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Number of operating leases | Lease	3
General office, laboratory, and research and development space leased | ft²	80,273
Operating lease expiring year	2026
Deferred rent liability	$ 4,257	$ 1,317
Operating lease agreement rent expense	3,200	$ 1,400	$ 1,200
Non cancellable purchase obligations	$ 9,200