Note 10 - Income Taxes (Details) - Deferred Income Tax Asset and Liability (USD $)
Dec. 31, 2013
Dec. 31, 2012
Current deferred income tax asset:    
Accrued vacation and compensation $ 14,000 $ 19,000
Reserves for warranty and other 54,000 57,000
Net operating loss carryforward/tax credits 284,000  
Total 352,000 76,000
Non-current deferred income tax asset:    
Stock-based compensation expense 904,000 882,000
Deferred revenue/other 1,101,000 835,000
Net operating loss carryforward/tax credits 3,226,000 2,430,000
1603 cash grant basis 516,000 539,000
State depreciation adjustments 639,000 464,000
Accrued expenses 256,000  
Less valuation allowance (3,492,000) (1,965,000)
Total 3,150,000 3,185,000
Completed contract accounting 305,000  
Prepaid expenses 47,000 87,000
Total 352,000 87,000
Deferred revenue 58,000  
Depreciation 3,134,000 3,216,000
Total $ 3,192,000 $ 3,216,000