Related Party Transactions - Additional Information (Detail) (USD $)	1 Months Ended					0 Months Ended
	Apr. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Jun. 30, 2010	Nov. 20, 2009 Series D convertible preferred stock [Member]
Related Party Transaction [Line Items]
Shares repurchased and cancelled (shares)						23,510,264
Stock repurchased and retired during period shares from founder family and chief financial officer (shares)						18,436,000
Offsetting liability withholding taxes plus potential interest and penalties			$ 5,300,000
Prepaid expenses and other current assets representing withholding taxes		5,300,000	5,300,000	5,300,000	5,300,000
Tax paid	$ 5,300,000