Commitments and Contingencies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Other Commitments [Line Items]
Security deposit | $	$ 381
Rental expense paid | $	$ 1,630	$ 513	$ 198
Corporate office and laboratory space [Member] | San Diego, California [Member]
Other Commitments [Line Items]
Leased office space	43,000
Non-cancelable operating lease amended, expiration date	Dec. 31, 2025
Laboratory and office space [Member] | San Diego, California [Member]
Other Commitments [Line Items]
Leased office space	6,350
Non-cancelable operating lease amended, expiration date	Jun. 30, 2018
Laboratory space [Member] | San Diego, California [Member]
Other Commitments [Line Items]
Leased office space	5,000
Non-cancelable operating lease amended, expiration date	Mar. 31, 2016
Office space [Member] | Cary, North Carolina [Member]
Other Commitments [Line Items]
Leased office space	1,800
Non-cancelable operating lease amended, expiration date	Mar. 31, 2016