Note 10 - Income Taxes (Detail) - Deferred tax assets and liabilities (USD $)	Dec. 31, 2012	Dec. 31, 2011
Allowance for doubtful accounts	$ 13,618	$ 10,873
Inventory capitalization	15,792	10,509
Depreciation and amortization	(585,231)	(622,307)
Investment tax credits	600,000	600,000
Research & development tax credits	435,051	431,006
Compensation costs	235,384	250,931
Vacation accrual	250,046	268,104
Capital loss carryforward	268,237	105,474
Gross deferred tax asset	1,232,897	1,054,590
Less valuation allowance	(475,000)	(475,000)
Net deferred tax asset	757,897	579,590
Net current deferred tax asset	189,153	189,510
Net long-term deferred tax asset	$ 568,744	$ 390,080