Accounting Policies, by Policy (Policies)

3 Months Ended

Mar. 31, 2013

Basis of Accounting, Policy [Policy Text Block]

a. Basis of Presentation

        The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC for interim financial reporting. In the opinion of management, all adjustments (consisting of normal recurring adjustments) necessary for a fair presentation have been reflected. The results reported in these condensed consolidated financial statements should not necessarily be taken as indicative of results that may be expected for the entire year. Certain financial information that is normally included in annual financial statements prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP"), but is not required for interim reporting purposes, has been condensed or omitted. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in Clean Diesel Technologies, Inc.’s Annual Report on Form 10-K for the fiscal year ended December 31, 2012.

Consolidation, Policy [Policy Text Block]

b. Principles of Consolidation

        The condensed consolidated financial statements include the financial statements of the Company and its wholly owned subsidiaries. Intercompany transactions and balances have been eliminated in consolidation.

Use of Estimates, Policy [Policy Text Block]

c. Use of Estimates

 The preparation of financial statements in conformity with U.S. GAAP requires management of the Company to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. These estimates and assumptions are based on management’s best estimates and judgment. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to impairment of goodwill and long-lived assets, stock-based compensation, the fair value of financial instruments including warrants, allowance for doubtful accounts, inventory valuation, taxes and contingent and accrued liabilities. The Company bases its estimates on historical experience and various other factors, including the current economic environment, which it believes to be reasonable under the circumstances. Estimates and assumptions are adjusted when facts and circumstances dictate. Actual results may differ from these estimates under different assumptions and conditions. Management believes that the estimates are reasonable.

Concentration Risk, Credit Risk, Policy [Policy Text Block]

d. Concentration of Risk

        For the periods presented below, one customer accounted for 10% or more of the Company’s revenue as follows:

	Three Months Ended March 31,
Customer	2013	2012
A	40%	24%
	.

        Customer A is an automotive original equipment manufacturer (“OEM”) and sales to this customer are within the Catalyst segment.

        For the periods presented below, certain customers accounted for 10% or more of the Company’s accounts receivable balance as follows:

Customer	March 31, 2013	December 31, 2012
A	32%	31%
B	10%	6%
C	─	12%

        Customer A above is an automotive OEM and customers B and C are diesel system distributors.

        For the periods presented below, certain vendors accounted for 10% or more of the Company’s raw material purchases as follows:

	Three Months Ended March 31,
Vendor	2013	2012
A	16%	9%
B	16%	8%
C	13%	15%
D	13%	4%

Vendors A and D above are substrate suppliers, vendor B is a rare earth materials supplier and vendor C is a catalyst supplier.

Earnings Per Share, Policy [Policy Text Block]

e. Net Loss per Share

Basic net loss per share is computed using the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed using the weighted average number of common shares and dilutive potential common shares. Dilutive potential common shares include employee stock options and restricted share units (“RSUs”) and warrants and debt that are convertible into the Company’s common stock.

        Diluted net loss per share excludes certain dilutive potential common shares outstanding as their effect is anti-dilutive. Because the Company incurred net losses in the three months ended March 31, 2013 and 2012, the effect of potentially dilutive securities has been excluded in the computation of net loss per share and net loss from continuing operations per share as their impact would be anti-dilutive. Potential common stock equivalents excluded consist of the following (in thousands):

	March 31,
	2013	2012
Common stock options	786	754
RSUs	371	178
Warrants	923	935
Convertible notes	250	370
Total	2,330	2,237

Fair Value of Financial Instruments, Policy [Policy Text Block]

f. Fair Value of Financial Instruments

Accounting Standards Codification ("ASC") Topic 825, “Financial Instruments,” requires disclosure of the fair value of financial instruments for which the determination of fair value is practicable. The fair values of the Company’s cash, trade accounts receivable, prepaid expenses and other current assets, accounts payable and accrued expenses and other current liabilities approximate carrying values due to the short maturity of these instruments. The fair value of borrowings under the line of credit approximates their carrying value due to the variable interest rates. The fair value of shareholder notes payable, noncurrent, calculated using level 3 inputs, including a Black-Scholes option-pricing model to value the debt’s conversion factor, a Monte Carlo simulation model to value warrants and a net present value modelis $7.4 million at March 31, 2013.

Reclassification, Policy [Policy Text Block]

g. Reclassifications 

        Certain prior-period amounts have been reclassified to conform to the current period presentation. These changes had no impact on the previously reported consolidated results of operations or stockholders' equity.

New Accounting Pronouncements, Policy [Policy Text Block]

h. Recently Adopted Accounting Guidance

In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ASU No. 2013-02, "Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income," which requires disclosure of significant amounts reclassified out of accumulated other comprehensive income by component and their corresponding effect on the respective line items of net income. This guidance is effective for reporting periods beginning after December 15, 2012.  Adoption of this guidance on January 1, 2013 did nothave a material impact on the Company’s consolidated financial statements or financial statement disclosures.

Recently Issued Accounting Guidance, Policy [Policy Text Block]

i. Recently Issued Accounting Guidance In March 2013, the FASB issued ASU No. 2013-05, "Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entit y ," ("ASU 2013-05"). The objective of ASU 2013-05 is to resolve the diversity in practice regarding the release into net income of the cumulative translation adjustment upon derecognition of a subsidiary or group of assets within a foreign entity. ASU 2013-05 is effective for reporting periods beginning after December 15, 2013 and is not expected to have a material impact on the Company's consolidated financial statements or financial statement disclosures.