Summary of Fair Value of Financial Assets and Liabilities (Parenthetical) (Detail) (Longboard Media, Inc, USD $) Share data in Millions, unless otherwise specified	1 Months Ended			1 Months Ended
	Nov. 05, 2012	Jul. 31, 2013 Contingent Consideration Subject to Certain Requirements	Apr. 30, 2013 Contingent Consideration Subject to Certain Requirements	Nov. 30, 2012 Common Stock	Jul. 31, 2013 Scenario, Before Adjustment Accrued Expenses and Other Current Liabilities	Apr. 30, 2013 Scenario, Before Adjustment Accrued Expenses and Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash paid in business acquisition	$ 26,900,000
Shares of common stock issued in business acquisition				0.5
Contingent consideration acquisition fair value	$ 4,300,000	$ 1,000,000	$ 1,500,000		$ 3,300,000	$ 3,300,000