Note 9 - Segments and Geographic Information (Details) - Additional Business Unit Gross Profitability Detail for Products Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Products segment net sales:
Products segment net sales	$ 4,919	$ 4,458
Products segment gross profit:
Products segment gross profit	1,422	883
Pool and Commercial Products [Member]
Products segment net sales:
Products segment net sales	1,166	1,641
Products segment cost of sales:
Products segment cost of sales	771	1,153
Products segment gross profit:
Products segment gross profit	395	488
Government Products/ Research and Development Services [Member]
Products segment net sales:
Products segment net sales	1,565	1,010
Products segment cost of sales:
Products segment cost of sales	1,161	899
Products segment gross profit:
Products segment gross profit	404	111
Products Segment [Member]
Products segment net sales:
Products segment net sales	2,731	2,651
Products segment cost of sales:
Products segment cost of sales	1,932	2,052
Products segment gross profit:
Products segment gross profit	$ 799	$ 599