Consolidated Statements of Comprehensive Loss (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Consolidated Statements of Comprehensive Loss [Abstract]
Revenues	$ 11,602	$ 10,114
Cost of revenues	2,444	2,195
Gross profit	9,158	7,919
Operating expenses:
Selling and marketing	4,381	4,592
Research and development	5,936	7,104
General and administrative	4,942	5,504
Restructuring expenses		334
Total operating expenses	15,259	17,534
Operating loss	(6,101)	(9,615)
Interest and other income, net	12	23
Loss before provision for income taxes	(6,089)	(9,592)
Provision for income tax expense	69	90
Net loss	(6,158)	(9,682)
Other comprehensive income, before tax:
Unrealized holding gains on available-for-sale securities	18	40
Income tax expense related to items of other comprehensive income		6
Other comprehensive income, net of tax	18	34
Comprehensive loss	$ (6,140)	$ (9,648)
Net loss per share:
Basic and diluted	$ (0.17)	$ (0.27)
Weighted average shares outstanding:
Basic and diluted	36,614	35,590