Note 10 - Business Segments (Details) - Segment Information - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Revenue	$ 15,049	$ 15,574	$ 30,409	$ 30,887
Operating income (loss)	1,064	1,786	2,203	2,907
Package Testing Segment [Member]
Segment Reporting Information [Line Items]
Revenue	6,473	7,354	13,229	13,979
Operating income (loss)	531	679	1,419	729
Permeation Segment [Member]
Segment Reporting Information [Line Items]
Revenue	5,966	5,044	12,068	10,892
Operating income (loss)	1,071	661	1,749	1,675
Industrial Analyzers and Other Segment [Member]
Segment Reporting Information [Line Items]
Revenue	2,610	3,176	5,112	6,016
Operating income (loss)	$ (538)	$ 446	$ (965)	$ 503