Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenues	$ 7,459	$ 9,386	$ 14,673	$ 19,915
Cost of revenues	1,913	2,071	4,026	4,189
Gross profit	5,546	7,315	10,647	15,726
Operating expenses:
Selling and marketing	2,478	2,228	4,848	4,419
Research and development	4,107	3,447	8,030	6,788
General and administrative	2,870	2,865	5,356	5,742
Total operating expenses	9,455	8,540	18,234	16,949
Operating loss	(3,909)	(1,225)	(7,587)	(1,223)
Change in fair value of contingent liability	657		657
Interest and other income (expense), net	(17)		(19)	(1)
Loss before provision for income taxes	(3,269)	(1,225)	(6,949)	(1,224)
Provision for income tax expense	11	6	37	17
Net loss	(3,280)	(1,231)	(6,986)	(1,241)
Other comprehensive income, before tax:
Unrealized holding gains on available-for-sale securities			2	1
Other comprehensive income, net of tax			2	1
Comprehensive loss	$ (3,280)	$ (1,231)	$ (6,984)	$ (1,240)
Net loss per share:
Basic and diluted	$ (0.07)	$ (0.03)	$ (0.15)	$ (0.03)
Weighted average shares outstanding:
Basic and diluted	46,964	46,257	46,529	45,881