STOCK-BASED COMPENSATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Non-cash compensation expense related to equity awards
Non-cash compensation expense	$ 1,432	$ 1,072	$ 2,866	$ 2,256
Cost of revenue
Non-cash compensation expense related to equity awards
Non-cash compensation expense	3	1	5	4
Selling and marketing expense
Non-cash compensation expense related to equity awards
Non-cash compensation expense	306	202	523	359
General and administrative expense
Non-cash compensation expense related to equity awards
Non-cash compensation expense	879	761	1,909	1,636
Product development
Non-cash compensation expense related to equity awards
Non-cash compensation expense	$ 244	$ 108	$ 429	$ 257