Segment Reporting and Geographic Information (Details) - Company`s reportable segments (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues
Revenues	$ 9,311	$ 13,309	$ 32,563	$ 37,419
(Loss) income from operations
(Loss) income from operations	(2,400)	107	(4,488)	(3,111)
Operating Segments [Member] | Heavy Duty Diesel Systems [Member]
Revenues
Revenues	3,672	7,073	16,047	19,714
(Loss) income from operations
(Loss) income from operations	(640)	678	223	205
Operating Segments [Member] | Catalyst [Member]
Revenues
Revenues	6,186	7,199	18,286	19,951
(Loss) income from operations
(Loss) income from operations	90	597	673	850
Operating Segments [Member] | Corporate Segment [Member]
(Loss) income from operations
(Loss) income from operations	(1,847)	(1,202)	(5,371)	(4,278)
Intersegment Eliminations [Member]
Revenues
Revenues	(547)	(963)	(1,770)	(2,246)
(Loss) income from operations
(Loss) income from operations	$ (3)	$ 34	$ (13)	$ 112