Income Taxes - Additional Information (Detail) - USD ($)		1 Months Ended	12 Months Ended
	Dec. 17, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Decrease in valuation of allowance			$ 400,000	$ 700,000	$ 47,900,000
Effective tax rate			39.70%	57.40%	(221.60%)
Unrealized excess tax benefits from stock options exercised		$ 21,700,000	$ 21,700,000	$ 21,500,000
Unrecognized tax benefit		463,000	463,000	393,000	$ 393,000	$ 393,000
Significant change in uncertain tax benefit reasonably possible amount of unrecorded benefit		0	0
Accrued interest or penalties		0	$ 0
Term of cumulative pretax net losses			3 years
Term of improvement in book income			5 years
Lemon Inc.
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, amount expired					$ 5,000,000
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		231,300,000	$ 231,300,000
Net operating loss carryforwards expiration date description			expire in the years 2025 through 2033
Internal Revenue Service (IRS) | Minimum
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, expiration year			2027
Federal alternative tax credit carryover		1,000,000	$ 1,000,000
Internal Revenue Service (IRS) | Maximum
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, expiration year			2035
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		99,900,000	$ 99,900,000
Net operating loss carryforwards expiration date description			expire between 2015 and 2033
State and Local Jurisdiction | Minimum
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, expiration year			2016
State and Local Jurisdiction | Maximum
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, expiration year			2035
Research Tax Credit Carryforward | Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Federal alternative tax credit carryover		1,100,000	$ 1,100,000
Research Tax Credit Carryforward | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Federal alternative tax credit carryover		900,000	900,000
Settled litigation | FTC Contempt Action
Operating Loss Carryforwards [Line Items]
Payments for legal settlements	$ 100,000,000	100,000,000
Loss contingency, cumulative accrual		16,000,000
Settlement amount	$ (100,000,000)	$ 116,000,000
Legal Reserves
Operating Loss Carryforwards [Line Items]
Reserves			$ 96,000,000	$ 20,000,000