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		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Products segment net sales:
Products segment net sales	$ 7,381	$ 7,672	$ 12,714	$ 12,974
Products segment gross profit (loss):
Products segment gross profit (loss)	2,022	1,704	3,223	2,489
Pool and Commercial Products [Member]
Products segment net sales:
Products segment net sales	3,375	4,905	5,891	7,195
Products segment cost of sales:
Products segment cost of sales	2,112	3,554	3,822	5,185
Products segment gross profit (loss):
Products segment gross profit (loss)	1,263	1,351	2,069	2,010
Government Products/ Research and Development Services [Member]
Products segment net sales:
Products segment net sales	2,023	662	3,033	2,034
Products segment cost of sales:
Products segment cost of sales	1,472	736	2,371	2,060
Products segment gross profit (loss):
Products segment gross profit (loss)	551	(74)	662	(26)
Products Segment [Member]
Products segment net sales:
Products segment net sales	5,398	5,567	8,924	9,229
Products segment cost of sales:
Products segment cost of sales	3,584	4,290	6,193	7,245
Products segment gross profit (loss):
Products segment gross profit (loss)	$ 1,814	$ 1,277	$ 2,731	$ 1,984