Note 10 - 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, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Products segment net sales:
Products segment net sales	$ 6,699	$ 5,653	$ 11,618	$ 10,111
Products segment gross profit:
Products segment gross profit	2,174	1,238	3,596	2,121
Pool and Commercial Products [Member]
Products segment net sales:
Products segment net sales	1,929	1,647	3,095	3,288
Products segment cost of sales:
Products segment cost of sales	1,194	1,168	1,965	2,321
Products segment gross profit:
Products segment gross profit	735	479	1,130	967
Government Products [Member]
Products segment net sales:
Products segment net sales	3,620	1,603	5,162	1,856
Products segment cost of sales:
Products segment cost of sales	2,387	1,060	3,525	1,301
Products segment gross profit:
Products segment gross profit	1,233	543	1,637	555
Research and Development Services [Member] | Products Segment [Member]
Products segment net sales:
Products segment net sales	5,566	3,670	8,297	6,321
Products segment cost of sales:
Products segment cost of sales	3,577	2,640	5,509	4,692
Products segment gross profit:
Products segment gross profit	1,989	1,030	2,788	1,629
Research and Development Services [Member]
Products segment net sales:
Products segment net sales	17	420	40	1,177
Products segment cost of sales:
Products segment cost of sales	(4)	412	19	1,070
Products segment gross profit:
Products segment gross profit	21	8	21	107
Products Segment [Member]
Products segment net sales:
Products segment net sales	5,566	3,670	8,297	6,321
Products segment gross profit:
Products segment gross profit	$ 1,989	$ 1,030	$ 2,788	$ 1,629