SCHEDULE 13G

Amendment No. 1
Mannkind Corporation
Common Stock
Cusip #56400P201

Cusip #56400P201
Item 1:	Reporting Person - FMR Corp.
Item 4:	Delaware
Item 5:	0
Item 6:	0
Item 7:	3,351,225
Item 8:	0
Item 9:	3,351,225
Item 11:	9.492%
Item 12:	    HC

Cusip #56400P201
Item 1:	Reporting Person - Edward C. Johnson 3d
Item 4:	United States of America
Item 5:	0
Item 6:	0
Item 7:	3,351,225
Item 8:	0
Item 9:	3,351,225
Item 11:	9.492%
Item 12:	IN



	SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)


This filing has been made to amend a previous filing made as of
August 31, 2005.  This is due to a corrected shares outstanding figure.


Item 1(a).	Name of Issuer:

		Mannkind Corporation

Item 1(b).	Name of Issuer's Principal Executive Offices:

		28903 North Ave Paine
		Valencia, CA  91355


Item 2(a).	Name of Person Filing:

		FMR Corp.

Item 2(b).	Address or Principal Business Office or, if None, Residence:

		82 Devonshire Street, Boston, Massachusetts  02109

Item 2(c).	Citizenship:

		Not applicable

Item 2(d).	Title of Class of Securities:

		Common Stock

Item 2(e).	CUSIP Number:

		56400P201

Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b)
	and the person filing, FMR Corp., is a parent holding company in
	accordance with Section 240.13d-1(b)(ii)(G).  (Note:  See Item 7).

Item 4.	Ownership

	(a)   Amount Beneficially Owned:	3,351,225

	(b)   Percent of Class:	9.492%

	(c)   Number of shares as to which such person has:

	(i)   sole power to vote or to direct the vote:	0

	(ii)  shared power to vote or to direct the vote:	0

	(iii) sole power to dispose or to direct the disposition of:

	      3,351,225

	(iv)  shared power to dispose or to direct the disposition of:	0



Item 5.	Ownership of Five Percent or Less of a Class.

	Not applicable.

Item 6.	Ownership of More than Five Percent on Behalf of Another Person.

	Various persons have the right to receive or the power to direct
	the receipt of dividends from, or the proceeds from the sale of,
	the Common Stock of Mannkind Corporation.  The interest of one
	person, Fidelity Contrafund, an investment company registered under
	the Investment Company Act of 1940, in the Common Stock of Mannkind
	Corporation, amounted to 2,422,866 shares or 6.863% of the total
	outstanding Common Stock at August 31, 2005.

Item 7.	Identification and Classification of the Subsidiary Which Acquired
	the Security Being Reported on By the Parent Holding Company.

	See attached Exhibit A.

Item 8.	Identification and Classification of Members of the Group.

	Not applicable.  See attached Exhibit A.

Item 9.	Notice of Dissolution of Group.

	Not applicable.

Item 10.	Certification.

	By signing below I certify that, to the best of my knowledge and
	belief, the securities referred to above were acquired in the
	ordinary course of business and were not acquired for the purpose
	of and do not have the effect of changing or influencing the
	control of the issuer of such securities and were not acquired in
	connection with or as a participant in any transaction having such
	purpose or effect.

	Signature

	After reasonable inquiry and to the best of my knowledge and belief,
	I certify that the information set forth in this statement is true,
	complete and correct.

	September 23, 2005
	Date

 	/s/Eric D. Roiter
	Signature

	Eric D. Roiter
	Duly authorized under Power of Attorney
	dated December 30, 1997 by and on behalf
	of FMR Corp. and its direct and indirect
	subsidiaries

	SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)



	Pursuant to the instructions in Item 7 of Schedule 13G, Fidelity
	Management & Research Company ("Fidelity"), 82 Devonshire Street,
	Boston, Massachusetts 02109, a wholly-owned subsidiary of FMR Corp.
	and an investment adviser registered under Section 203 of the
	Investment Advisers Act of 1940, is the beneficial owner of
	3,351,225 shares or 9.492% of the Common Stock outstanding of
	Mannkind Corporation ("the Company") as a result of acting as
	investment adviser to various investment companies registered under
	Section 8 of the Investment Company Act of 1940.

	The ownership of one investment company, Fidelity Contrafund,
	amounted to 2,422,866 shares or 6.863% of the Common Stock
	outstanding. Fidelity Contrafund has its principal business office
	at 82 Devonshire Street, Boston, Massachusetts 02109.

	Edward C. Johnson 3d and FMR Corp., through its control of Fidelity,
	and the funds each has sole power to dispose of the 3,351,225 shares
	owned by the Funds.

	Members of the family of Edward C. Johnson 3d, Chairman of FMR
	Corp., are the predominant owners, directly or through trusts, of
	Series B shares of common stock of FMR Corp., representing 49% of
	the voting power of FMR Corp.  The Johnson family group and all
	other Series B shareholders have entered into a shareholders'
	voting agreement under which all Series B shares will be voted in
	accordance with the majority vote of Series B shares.  Accordingly,
	through their ownership of voting common stock and the execution of
	the shareholders' voting agreement, members of the Johnson family
	may be deemed, under the Investment Company Act of 1940, to form a
	controlling group with respect to FMR Corp.

	Neither FMR Corp. nor Edward C. Johnson 3d, Chairman of FMR Corp.,
	has the sole power to vote or direct the voting of the shares
	owned directly by the Fidelity Funds, which power resides with the
	Funds' Boards of Trustees.  Fidelity carries out the voting of the
	shares under written guidelines established by the Funds' Boards of
	Trustees.


	SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)
	RULE 13d-1(f)(1)  AGREEMENT

	The undersigned persons, on September 23, 2005, agree and consent to
	the joint filing on their behalf of this Schedule 13G in connection
	with their beneficial ownership of the Common Stock of Mannkind
	Corporation at August 31, 2005.

	FMR Corp.

	By /s/ Eric D. Roiter
	Eric D. Roiter
	Duly authorized under Power of Attorney
	dated December 30, 1997, by and on behalf
	of FMR Corp. and its direct and indirect
	subsidiaries

	Edward C. Johnson 3d

	By /s/ Eric D. Roiter
	Eric D. Roiter
	Duly authorized under Power of Attorney
	dated December 30, 1997, by and on behalf
	of Edward C. Johnson 3d

	Fidelity Management & Research Company

	By /s/ Eric D. Roiter
	Eric D. Roiter
	Senior V.P. and General Counsel

	Fidelity Contrafund

	By /s/ Eric D. Roiter
	Eric D. Roiter
	Secretary






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Exhibit A