Equity Investments	12 Months Ended
Dec. 31, 2013
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]
Investments in and Advances to Affiliates, Schedule of Investments [Text Block]	16. Equity Investments TCC Investment In February 2008, the Company entered into an agreement with Tanaka Kikinzoku Kogyo K.K. (TKK) to form a new joint venture company, TC Catalyst, Inc. (TCC), a Japanese corporation. The joint venture is part of the Catalyst division. The Company entered the joint venture in order to improve its presence in Japan and Asia and strengthen its business flow into the Asian market. In December 2008, the Company sold shares in TCC to TKK reducing its ownership to 30%. In December 2009, the Company agreed to sell and transfer specific three-way catalyst and zero-platinum group metal, or ZPGM, patents to TKK for use in specific geographic regions. As part of the transaction, the Company also sold shares in TCC, which reduced its ownership in the joint venture to 5%. The Company remains contractually obligated to fund its portion of the losses of the joint venture based on its ownership percentage. TCC operates with a March 31 fiscal year-end. The Company’s investment in TCC is accounted for using the equity method as the Company still has significant influence over TCC as a result of having a seat on TCC’s board and due to the technological interdependence between TCC and the Company. In February 2010, the Company entered into an agreement to loan 37.5 million JPY (approximately $0.4 million) to TCC to fund continuing operations. As of December 31, 2010, the Company had loaned TCC 37.5 million JPY. If the loan is not repaid by TCC, it will offset the Company’s obligation to fund its portion of TCC’s losses. Given TCC’s historical losses, the loan has been recorded as a reduction of such obligations. TCC has repaid 21.5 million JPY as of December 31, 2013. At December 31, 2013, the Company’s loan to TCC was $0.2 million which was offset by the Company’s share of accumulated losses in the amount of $0.2 million. Joint Venture On February 19, 2013, the Company entered into a joint venture agreement (the “Joint Venture Agreement”) with Pirelli & C. Ambiente SpA (“Pirelli”) to form a joint venture entity, Eco Emission Enterprise Srl under the laws of Italy (the “Joint Venture”), through which the Company and Pirelli would jointly sell their emission control products in Europe and the Commonwealth of Independent States (“CIS”) countries. Pursuant to the agreement, both partners agreed to sell products to the Joint Venture which would earn a commission to market and sell these products. As such, all of the Company’s existing business in Sweden and the UK would be conducted through the Joint Venture. The Joint Venture commenced operations in April 2013. The Joint Venture Agreement provided that the Company and Pirelli each hold 50% of the total issued share capital of the Joint Venture. Pursuant to the Joint Venture Agreement, in February 2013, the Company and Pirelli each contributed €50,000 (approximately $66,000) to the Joint Venture as initial capital contributions. In addition, in accordance with the Joint Venture Agreement, CDTi and Pirelli provided shareholder loans of €200,000 (approximately $261,000) each in April 2013. During 2013, these loans were converted into equity contributions as required by local statutory regulations. In the fourth quarter of 2013, the Company and Pirelli each contributed an additional €262,000 (approximately $361,000) to the Joint Venture. The Company accounts for its investment in the Joint Venture using the equity method. Since the commencement of operations, the Joint Venture has incurred a loss of €0.9 million (approximately $1.2 million). The Company has recorded a loss of $0.6 million, representing its 50% share of the Joint Venture’s losses, in other expense in the accompanying consolidated statement of comprehensive loss. On November 8, 2013, as a result of slower than anticipated progress in achieving sales objectives initially established for the Joint Venture, the Company and Pirelli agreed to voluntarily dissolve the Joint Venture in accordance with the Joint Venture Agreement. The Joint Venture ceased operations on November 30, 2013 and commenced liquidation on December 9, 2013. The Company expects that dissolution will be finalized in the first half of 2014 and that its investment balance of $0.1 million, included in other assets in the accompanying consolidated balance sheet at December 31, 2013, will be collected upon dissolution. The Company has resumed its operations in Europe in a similar manner as conducted prior to the Joint Venture.

Equity Investments

12 Months Ended

Dec. 31, 2013

Investments in and Advances to Affiliates, Schedule of Investments [Abstract]

Investments in and Advances to Affiliates, Schedule of Investments [Text Block]

16. Equity Investments

TCC Investment

In February 2008, the Company entered into an agreement with Tanaka Kikinzoku Kogyo K.K. (TKK) to form a new joint venture company, TC Catalyst, Inc. (TCC), a Japanese corporation. The joint venture is part of the Catalyst division. The Company entered the joint venture in order to improve its presence in Japan and Asia and strengthen its business flow into the Asian market.

In December 2008, the Company sold shares in TCC to TKK reducing its ownership to 30%. In December 2009, the Company agreed to sell and transfer specific three-way catalyst and zero-platinum group metal, or ZPGM, patents to TKK for use in specific geographic regions. As part of the transaction, the Company also sold shares in TCC, which reduced its ownership in the joint venture to 5%. The Company remains contractually obligated to fund its portion of the losses of the joint venture based on its ownership percentage. TCC operates with a March 31 fiscal year-end.

The Company’s investment in TCC is accounted for using the equity method as the Company still has significant influence over TCC as a result of having a seat on TCC’s board and due to the technological interdependence between TCC and the Company. In February 2010, the Company entered into an agreement to loan 37.5 million JPY (approximately $0.4 million) to TCC to fund continuing operations. As of December 31, 2010, the Company had loaned TCC 37.5 million JPY. If the loan is not repaid by TCC, it will offset the Company’s obligation to fund its portion of TCC’s losses. Given TCC’s historical losses, the loan has been recorded as a reduction of such obligations. TCC has repaid 21.5 million JPY as of December 31, 2013.

At December 31, 2013, the Company’s loan to TCC was $0.2 million which was offset by the Company’s share of accumulated losses in the amount of $0.2 million.

Joint Venture

On February 19, 2013, the Company entered into a joint venture agreement (the “Joint Venture Agreement”) with Pirelli & C. Ambiente SpA (“Pirelli”) to form a joint venture entity, Eco Emission Enterprise Srl under the laws of Italy (the “Joint Venture”), through which the Company and Pirelli would jointly sell their emission control products in Europe and the Commonwealth of Independent States (“CIS”) countries. Pursuant to the agreement, both partners agreed to sell products to the Joint Venture which would earn a commission to market and sell these products. As such, all of the Company’s existing business in Sweden and the UK would be conducted through the Joint Venture. The Joint Venture commenced operations in April 2013.

The Joint Venture Agreement provided that the Company and Pirelli each hold 50% of the total issued share capital of the Joint Venture. Pursuant to the Joint Venture Agreement, in February 2013, the Company and Pirelli each contributed €50,000 (approximately $66,000) to the Joint Venture as initial capital contributions. In addition, in accordance with the Joint Venture Agreement, CDTi and Pirelli provided shareholder loans of €200,000 (approximately $261,000) each in April 2013. During 2013, these loans were converted into equity contributions as required by local statutory regulations. In the fourth quarter of 2013, the Company and Pirelli each contributed an additional €262,000 (approximately $361,000) to the Joint Venture.

The Company accounts for its investment in the Joint Venture using the equity method. Since the commencement of operations, the Joint Venture has incurred a loss of €0.9 million (approximately $1.2 million). The Company has recorded a loss of $0.6 million, representing its 50% share of the Joint Venture’s losses, in other expense in the accompanying consolidated statement of comprehensive loss.

On November 8, 2013, as a result of slower than anticipated progress in achieving sales objectives initially established for the Joint Venture, the Company and Pirelli agreed to voluntarily dissolve the Joint Venture in accordance with the Joint Venture Agreement. The Joint Venture ceased operations on November 30, 2013 and commenced liquidation on December 9, 2013. The Company expects that dissolution will be finalized in the first half of 2014 and that its investment balance of $0.1 million, included in other assets in the accompanying consolidated balance sheet at December 31, 2013, will be collected upon dissolution. The Company has resumed its operations in Europe in a similar manner as conducted prior to the Joint Venture.