Income Taxes (Details) - Deferred tax assets and liabilities (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Research and development credits	$ 1,824	$ 1,707
Other credits	378	347
Operating loss carry forwards	12,592	10,562
Inventories	338	469
Allowance for doubtful accounts	118	563
Depreciation	349	246
Deferred research and development expenses for income tax	327	327
Non-cash compensation	957	706
Other	794	536
Total gross deferred tax assets	17,677	15,463
Valuation allowance	(17,293)	(14,906)
Net deferred tax assets	384	557
Deferred tax liabilities
Other identifiable intangible assets	(1,070)	(1,354)
Total gross deferred tax liabilities	(1,070)	(1,354)
Net deferred tax liabilities	$ (686)	$ (797)