Income Taxes - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Tax Credit Carryforward [Line Items]
Deferred tax assets, net	$ 14.9
Research and development tax credit studies	12.9
Unrecognized tax benefits	$ 3.6
Overall effective tax rate, after discrete period adjustments	34.20%
Effective tax rate, before discrete period adjustment	33.80%
Federal
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits	$ 3.5
State
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits	0.1
Expiring in 2019
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	1.2
Research and Development Credits
Tax Credit Carryforward [Line Items]
Tax credit carryforward, valuation allowance	$ 1.5