Income Taxes - Summary of Changes in Deferred Tax Asset Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 53,923	$ 36,012	$ 25,047
Balance at End of Year	70,629	53,923	36,012
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Charged to Costs and Expenses	16,706	17,911	10,965
Write-offs	$ 0	$ 0	$ 0