Consolidated Statements of Comprehensive Loss (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Revenues	$ 9,448	$ 8,746	$ 26,425	$ 30,832
Cost of revenues	2,201	2,492	7,072	7,337
Gross profit	7,247	6,254	19,353	23,495
Operating expenses:
Selling and marketing	2,139	3,705	7,471	12,655
Research and development	3,188	5,355	11,046	17,191
General and administrative	3,064	4,572	10,360	14,376
Restructuring expense		5,602	2,435	5,602
Total operating expenses	8,391	19,234	31,312	49,824
Operating loss	(1,144)	(12,980)	(11,959)	(26,329)
Interest and other income (expense), net	(3)	7	(5)	27
Loss before provision for income taxes	(1,147)	(12,973)	(11,964)	(26,302)
Provision for income tax expense (benefit)	(5)	76	40	149
Net loss	(1,142)	(13,049)	(12,004)	(26,451)
Other comprehensive income (loss), before tax:
Unrealized holding gains (losses) on available-for-sale securities	(1)	3		4
Income tax expense related to items of other comprehensive income (expense)
Other comprehensive income (expense), net of tax	(1)	3		4
Comprehensive loss	$ (1,143)	$ (13,046)	$ (12,004)	$ (26,447)
Net loss per share:
Basic and diluted	$ (0.03)	$ (0.35)	$ (0.31)	$ (0.72)
Weighted average shares outstanding:
Basic and diluted	41,225	37,036	39,165	36,967