15. Sales by Product (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Product Information [Line Items]
Total Sales	$ 38,966	$ 38,456
Revenues from sales by product, percentage	100.00%	100.00%
Variance [Member]
Product Information [Line Items]
Total Sales	$ 510
Revenues from sales by product, percentage	1.00%
ALUPREM [Member]
Product Information [Line Items]
Total Sales	$ 14,958	$ 16,802
Revenues from sales by product, percentage	38.00%	44.00%
ALUPREM [Member] | Variance [Member]
Product Information [Line Items]
Total Sales	$ (1,844)
Revenues from sales by product, percentage	(11.00%)
HITOX [Member]
Product Information [Line Items]
Total Sales	$ 9,349	$ 8,006
Revenues from sales by product, percentage	24.00%	21.00%
HITOX [Member] | Variance [Member]
Product Information [Line Items]
Total Sales	$ 1,343
Revenues from sales by product, percentage	17.00%
BARTEX / BARYPREM [Member]
Product Information [Line Items]
Total Sales	$ 8,383	$ 8,217
Revenues from sales by product, percentage	22.00%	21.00%
BARTEX / BARYPREM [Member] | Variance [Member]
Product Information [Line Items]
Total Sales	$ 166
Revenues from sales by product, percentage	2.00%
HALTEX / OPTILOAD [Member]
Product Information [Line Items]
Total Sales	$ 5,383	$ 4,364
Revenues from sales by product, percentage	14.00%	11.00%
HALTEX / OPTILOAD [Member] | Variance [Member]
Product Information [Line Items]
Total Sales	$ 1,019
Revenues from sales by product, percentage	23.00%
TIOPREM [Member]
Product Information [Line Items]
Total Sales	$ 585	$ 742
Revenues from sales by product, percentage	1.00%	2.00%
TIOPREM [Member] | Variance [Member]
Product Information [Line Items]
Total Sales	$ (157)
Revenues from sales by product, percentage	(21.00%)
OTHER [Member]
Product Information [Line Items]
Total Sales	$ 308	$ 325
Revenues from sales by product, percentage	1.00%	1.00%
OTHER [Member] | Variance [Member]
Product Information [Line Items]
Total Sales	$ (17)
Revenues from sales by product, percentage	(5.00%)