STOCK-BASED COMPENSATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Non-cash compensation expense related to equity awards
Total non-cash compensation expense	$ 1,412	$ 1,309	$ 4,278	$ 3,565
Cost of revenue
Non-cash compensation expense related to equity awards
Total non-cash compensation expense	4	2	9	6
Selling and marketing expense
Non-cash compensation expense related to equity awards
Total non-cash compensation expense	242	145	765	504
General and administrative expense
Non-cash compensation expense related to equity awards
Total non-cash compensation expense	976	1,026	2,885	2,662
Product development
Non-cash compensation expense related to equity awards
Total non-cash compensation expense	$ 190	$ 136	$ 619	$ 393