SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011 Year Entity	Dec. 31, 2010 Year	Dec. 31, 2009 Year	Dec. 31, 2008
Significant Accounting Policies [Line Items]
Internal-use software costs capitalized	$ 9,800,000	$ 4,900,000	$ 900,000
Balance of unamortized software costs	13,400,000	7,900,000
Software amortization expense	2,100,000	1,000,000
Impairment charge on internally developed software	526,000
Research and development costs	200,000	1,900,000	3,800,000
Advertising costs	2,100,000	2,000,000	1,300,000
Reporting units	3
Liabilities for uncertain tax positions	283,000	0
Accrued interest and penalties related to uncertain tax positions	48,000	0
Revenue recognition period (in years)	4	4	3
Cash equivalents
Significant Accounting Policies [Line Items]
Highly-liquid investments, original maturity	3 months
Research and Development Expense
Significant Accounting Policies [Line Items]
Internal-use software costs capitalized	$ 2,800,000	$ 900,000	$ 900,000
FCP
Significant Accounting Policies [Line Items]
Revenue recognition period (in years)	1
Developed Technology
Significant Accounting Policies [Line Items]
Estimated economic useful life of intangible assets, minimum (in years)	3
Estimated economic useful life of intangible assets, maximum (in years)	8
Patents
Significant Accounting Policies [Line Items]
Estimated economic useful life of intangible assets (in years)	15
Minimum
Significant Accounting Policies [Line Items]
Significant influence (but not control), percentage of ownership interest	20.00%
Contract, term	1 year
Maximum
Significant Accounting Policies [Line Items]
Significant influence (but not control), percentage of ownership interest	50.00%
Network equipment | Before Change In Accounting Estimate
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	3
Furniture, equipment and software
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life, minimum (in years)	3
Property, plant and equipment, useful life, maximum (in years)	7
Leasehold improvements
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	7
Leasehold improvements | Before Change In Accounting Estimate
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life, maximum (in years)	20
Office Equipment | Minimum
Significant Accounting Policies [Line Items]
Duration of lease obligations and commitments	4 years
Facilities | Maximum
Significant Accounting Policies [Line Items]
Duration of lease obligations and commitments	25 years