Business Segment, Geographic and Major Customer Information (Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net revenue from external customers	$ 72,509	$ 79,458	$ 85,177	$ 79,954	$ 70,604	$ 64,337	$ 64,079	$ 63,812	$ 317,098	$ 262,832	$ 269,966
Income (loss) from operations	$ 2,123	$ (3,103)	$ (1,252)	$ (623)	$ (5,575)	$ (2,253)	$ 156	$ 368	(2,855)	(7,304)	12,278
Depreciation and amortization									12,159	10,429	8,735
Capital expenditures									8,960	13,960	16,391
Operating Segments | Energy Chemistry Technologies
Segment Reporting Information [Line Items]
Net revenue from external customers									243,106	188,233	213,592
Income (loss) from operations									33,611	29,014	43,902
Depreciation and amortization									7,323	5,935	4,791
Capital expenditures									3,279	10,674	12,803
Operating Segments | Consumer and Industrial Chemistry Technologies
Segment Reporting Information [Line Items]
Net revenue from external customers									73,992	74,599	56,374
Income (loss) from operations									7,465	9,664	8,742
Depreciation and amortization									2,391	2,257	2,202
Capital expenditures									4,763	888	568
Corporate and Other
Segment Reporting Information [Line Items]
Net revenue from external customers									0	0	0
Income (loss) from operations									(43,931)	(45,982)	(40,366)
Depreciation and amortization									2,445	2,237	1,742
Capital expenditures									$ 918	$ 2,398	$ 3,020