SUPPLEMENTARY FINANCIAL DATA (UNAUDITED) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
SUPPLEMENTARY FINANCIAL DATA (UNAUDITED) [Abstract]
Net revenue	$ 22,533	$ 19,426	$ 19,591	$ 15,727	$ 18,542	$ 15,232	$ 14,895	$ 11,621	$ 77,277	$ 60,290	$ 53,274
Cost of revenue	9,790	8,828	9,274	7,845	7,506	6,772	6,476	5,224	35,737	25,978	23,058
Gross profit	12,743	10,598	10,317	7,882	11,036	8,460	8,419	6,397	41,540	34,312	30,216
Operating expenses:
Sales and marketing	7,101	7,014	7,112	7,437	6,779	6,426	6,348	5,946	28,664	25,499	24,735
Research and development	2,122	2,217	1,872	2,216	2,313	2,352	2,346	2,130	8,427	9,141	7,004
General and administrative	2,452	2,475	2,854	3,495	2,878	2,310	2,588	2,328	11,276	10,104	9,576
Total operating expenses	11,675	11,706	11,838	13,148	11,970	11,088	11,282	10,404	48,367	44,744	41,315
Income (loss) from operations	1,068	(1,108)	(1,521)	(5,266)	(934)	(2,628)	(2,863)	(4,007)	(6,827)	(10,432)	(11,099)
Interest and other income, net	105	152	144	96	140	91	199	184	497	614	583
Loss before income taxes	1,173	(956)	(1,377)	(5,170)	(794)	(2,537)	(2,664)	(3,823)	(6,330)	(9,818)	(10,516)
Provision (benefit) for income taxes	96	(64)	89	97	93	326	(208)	32	218	243	2
Net Loss	$ 1,077	$ (892)	$ (1,466)	$ (5,267)	$ (887)	$ (2,863)	$ (2,456)	$ (3,855)	$ (6,548)	$ (10,061)	$ (10,518)
Net income (loss) per share-basic (in dollars per share)	$ 0.08	$ (0.06)	$ (0.1)	$ (0.38)	$ (0.06)	$ (0.21)	$ (0.18)	$ (0.28)
Net income (loss) per share-diluted (in dollars per share)	$ 0.08	$ (0.06)	$ (0.1)	$ (0.38)	$ (0.06)	$ (0.21)	$ (0.18)	$ (0.28)
Weighted average number of shares used in per share calculations:
Basic (in shares)	14,173	14,127	14,095	13,960	13,930	13,862	13,765	13,667
Diluted (in shares)	14,272	14,127	14,095	13,960	13,930	13,862	13,765	13,667