Assets and Liabilities of Angel Dot Com Business Classified as Held for Sale (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Assets:
Cash and cash equivalents	$ 0	$ 1,350	$ 3,880	$ 5,300
Angel. Com
Assets:
Cash and cash equivalents		1,350
Accounts receivable, net of unpaid deferred revenue of $554 and allowance for doubtful accounts of $347, respectively		4,720
Prepaid expenses and other assets		738
Property and equipment, net		3,763
Total assets		10,571
Liabilities:
Accounts payable and accrued expenses		1,587
Accrued compensation and employee benefits		2,364
Gross deferred revenue and advance payments, net of unpaid deferred revenue of $554		639
Other liabilities		99
Total liabilities		4,689
Net assets and liabilities of disposal group		$ 5,882