Significant Agreements - Additional Information (Detail) - USD ($) $ in Millions			12 Months Ended
	May. 28, 2009	Oct. 12, 2007	Dec. 31, 2015	Dec. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial up-front payment				$ 1.1
Additional payments to UWA on successful achievement			$ 20.0	$ 6.0
Up-front payment to purchase future royalties			30.0
Charley's Fund Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development grant awarded	$ 5.0	$ 2.5
Aggregate amount of research grant			3.4
Revenue recognized from research grant			0.1
Deferred grant payment			$ 3.3