Restatement - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011	Sep. 30, 2015
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Decrease in revenue due to adjustments		$ 14.0	$ 12.0	$ 6.0
Decrease in remeasurement gains due to adjustments				$ 4.0
Liability for royalty credit earned					$ 5.3
Scenario Forecast
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Decrease in revenue due to adjustments	$ 10.0