SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended							6 Months Ended		9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012 item	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
SEGMENT INFORMATION
Number of reportable segments				3
Segment reporting
Total Revenue	$ 60,872				$ 64,279					$ 186,934	$ 194,540
Total segment contribution	19,929				21,294					65,145	64,218
Unallocated cost of sales	10,744				11,185					31,232	35,979
Unallocated sales and marketing	34,844	32,787	37,273		36,830	35,119	38,570	70,059	73,689	104,904	110,518
Unallocated research and development	8,797				5,177					25,248	17,944
Unallocated general and administrative	13,987				14,474					40,209	41,050
Unallocated lease abandonment	7									835
Unallocated non-operating income/(expense)	293				(15)					(156)	(70)
Total operating expenses	57,635				56,481					171,196	169,512
Loss before income taxes	(7,800)				(3,372)					(15,338)	(10,881)
Unallocated expenses
Segment reporting
Unallocated cost of sales	1,504				1,326					3,005	5,049
Unallocated sales and marketing	3,708				4,512					12,480	12,877
Unallocated research and development	8,797				5,177					25,246	17,945
Unallocated general and administrative	13,420				13,666					39,073	39,297
Unallocated lease abandonment	7									835
Unallocated non-operating income/(expense)	293				(15)					(156)	(69)
Total operating expenses	27,729				24,666					80,483	75,099
North America Consumer | Operating Segment
Segment reporting
Total Revenue	38,699				39,878					120,018	119,881
Total segment contribution	15,266				15,490					50,746	47,843
Rest of World Consumer | Operating Segment
Segment reporting
Total Revenue	7,165				9,903					23,213	30,159
Total segment contribution	(537)				(622)					(1,089)	(2,491)
Global Enterprise and Education | Operating Segment
Segment reporting
Total Revenue	15,008				14,498					43,703	44,500
Total segment contribution	$ 5,200				$ 6,426					$ 15,488	$ 18,866