Warrants (Detail) - Assumptions used in determining fair value of liability-classified warrants (Warrant [Member], USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Warrant [Member]
Expected volatility	71.30%	58.80%
Risk-free interest rate	0.30%	0.70%
Closing price of Clean Diesel Technologies, Inc. common stock (in Dollars per share)	$ 2.17	$ 2.80

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

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- Definition

Risk-free interest rate assumption used in valuing an instrument.

+ References

+ Details

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- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

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Period Type:	instant