Note 8 - Segments and Geographic Information (Detail) - Additional Business Unit Gross Profitability Detail for Products Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Products segment net sales:
Products segment net sales	$ 5,333	$ 5,302
Products segment gross profit (loss):
Products segment gross profit (loss)	1,201	785
Products Segment [Member]
Products segment net sales:
Products segment net sales	3,526	3,662
Products segment cost of sales:
Products segment cost of sales	2,609	2,955
Products segment gross profit (loss):
Products segment gross profit (loss)	917	707
Pool and Commercial Products [Member]
Products segment net sales:
Products segment net sales	2,516	2,290
Products segment cost of sales:
Products segment cost of sales	1,710	1,631
Products segment gross profit (loss):
Products segment gross profit (loss)	806	659
Government Products/ Research and Development Services [Member]
Products segment net sales:
Products segment net sales	1,010	1,372
Products segment cost of sales:
Products segment cost of sales	899	1,324
Products segment gross profit (loss):
Products segment gross profit (loss)	$ 111	$ 48