Segment Information, Geographic Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Segment Information [Abstract]
Percentage of revenues derived from customers in the nuclear power industry	91.00%	89.00%
Segments, Geographical Areas [Abstract]
Total revenue	$ 55,183	$ 57,620
Operating income (loss)	(5,974)	(9,538)
Assets	$ 39,051	$ 39,190
Percentage of revenues derived from international sales	12.00%	17.00%
Intersegment Eliminations [Member]
Segments, Geographical Areas [Abstract]
Total revenue	$ 0	$ 0
Geography Eliminations [Member]
Segments, Geographical Areas [Abstract]
Total revenue	(474)	(496)
Operating income (loss)	0	0
Assets	(134,184)	(128,352)
United States [Member]
Segments, Geographical Areas [Abstract]
Total revenue	54,589	57,093
Operating income (loss)	(3,351)	(13,041)
Assets	170,116	161,672
United States [Member] | Operating Segments [Member]
Segments, Geographical Areas [Abstract]
Total revenue	54,203	56,628
United States [Member] | Intersegment Eliminations [Member]
Segments, Geographical Areas [Abstract]
Total revenue	386	465
Europe [Member]
Segments, Geographical Areas [Abstract]
Total revenue	0	0
Operating income (loss)	(1,746)	3,231
Assets	0	2,679
Europe [Member] | Operating Segments [Member]
Segments, Geographical Areas [Abstract]
Total revenue	0	0
Europe [Member] | Intersegment Eliminations [Member]
Segments, Geographical Areas [Abstract]
Total revenue	0	0
Asia [Member]
Segments, Geographical Areas [Abstract]
Total revenue	1,068	1,023
Operating income (loss)	(877)	272
Assets	3,119	3,191
Asia [Member] | Operating Segments [Member]
Segments, Geographical Areas [Abstract]
Total revenue	980	992
Asia [Member] | Intersegment Eliminations [Member]
Segments, Geographical Areas [Abstract]
Total revenue	$ 88	$ 31