Sec Form 13G Filing - CANAAN EQUITY II LP @ DEXCOM INC

Insider filing report for Changes in Beneficial Ownership

Schedule 13G & 13D forms are used to report a party's ownership of stock which exceeds 5% of a company's total stock issue.
Schedule 13G is a shorter version of Schedule 13D with fewer reporting requirements.

"Insiders might sell their shares for any number of reasons, but they buy them for only one: they think the price will rise"
- Peter Lynch
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. 1)*

DexCom, Inc.

(Name of Issuer)

Common Stock, $.0001 par value

(Title of Class of Securities)

252131107

(CUSIP Number)

December 31, 2006

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

o Rule 13d-1(b)

o Rule 13d-1(c)

þ Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).


CUSIP No.		252131107		Page		2		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Canaan Equity II L.P.

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware Limited Partnership

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	PN


CUSIP No.		252131107		Page		3		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Canaan Equity II L.P. (QP)

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware Limited Partnership

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	PN


CUSIP No.		252131107		Page		4		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Canaan Equity II Entrepreneurs LLC

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE O F ORGANIZATION:

	Delaware Limited Liability Company

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	OO


CUSIP No.		252131107		Page		5		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Canaan Equity Partners II LLC

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware Limited Liability Company

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.
< /td>
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	OO


CUSIP No.		252131107		Page		6		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Stephen L. Green

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	United States

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	IN


CUSIP No.		252131107		Page		7		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Deepak Kamra

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	United States

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	IN


CUSIP No.		252131107		Page		8		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Gregory Kopchinsky

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	United States

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	IN


CUSIP No.		252131107		Page		9		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Guy M. Russo

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	United States

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	0;
	IN


CUSIP No.		252131107		Page		10		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	John V. Balen

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	United States

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	IN


CUSIP No.		252131107		Page		11		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Eric A. Young

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	United States

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	IN


CUSIP No.		252131107		Page		12		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Charmers Landing LLC

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware Limited Liability Company

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PE RSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	OO


CUSIP No.		252131107		Page		13		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Stonehenge LLC

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware Limited Liability Company

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	OO


CUSIP No.		252131107		Page		14		of		25


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Waubeeka LLC

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) þ

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware Limited Liability Company

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			See Item 5.

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		8	SHARED DISPOSITIVE POWER:

			See Item 5.

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:

	See Item 5.

10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	See Item 5.

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	OO


CUSIP No.		252131107		Page		15		of		25


Item 1(a).		Name of Issuer

DexCom, Inc.


Item 1(b).		Address of Issuer’s Principal Executive Offices

5555 Oberlin Drive
San Diego, CA 92121


Item 2(a).		Name of Person Filing

This statement is filed by (i) Canaan Equity II L.P. (“CE II”), a Delaware limited partnership, (ii) Canaan Equity II L.P. (QP) (“CE II QP”), a Delaware limited partnership, (iii) Canaan Equity II Entrepreneurs, LLC (“Entrepreneurs”), a Delaware limited liability company, (iv) Canaan Equity Partners II LLC (“CEP II”), a Delaware limited liability company and the general partner of CE II and CE II QP and the manager of Entrepreneurs, (v) John V. Balen, (vi) Stephen L. Green, (vii) Deepak Kamra, (viii) Gregory Kopchinsky, (ix) Guy M. Russo, (x) Eric A. Young, (xi) Charmers Landing LLC (“Charmers”), a Delaware limited liability company, (xii) Stonehenge LLC (“Stonehenge”), a Delaware limited liability company, and (xiii) Waubeeka LLC (“Waubeeka”) a Delaware limited liability company. The sole managers of Charmers, Stonehenge, and Waubeeka are Messrs. Green, Kopchinsky and Russo, respectively. We refer to the individuals and entities identified in (i)-(xiii) above collectively as the “Reporting Persons.”


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

Except in the case of Messrs. Balen, Kamra and Young, the principal business address of the Reporting Persons is 285 Riverside Avenue, Suite 205, Westport, CT 06880. The principal business address of Messrs. Balen, Kamra and Young is 2765 Sand Hill Road, Menlo Park, CA 94025.


Item 2(c).		Citizenship

Each of CE II and CE II QP is a limited partnership organized under the laws of Delaware. Each of Entrepreneurs, CEP II, Charmers, Stonehenge and Waubeeka is a limited liability company organized under the laws of Delaware. Each of the individuals named above is a citizen of the United States.


Item 2(d).		Title of Class of Securities

This Schedule 13G report relates to the Common Stock, par value $0.01 per share (“Common Stock”), of DexCom, Inc.


Item 2(e).		CUSIP Number

CUSIP number 252131107


Item 3.		If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

	(a)		o Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

	(b)		o Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

	(c)		o Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

	(d)		o Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a-8).

	(e)		o An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);


CUSIP No.		252131107		Page		16		of		25

	(f)		o An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);

	(g)		o A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

	(h)		o A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

	(i)		o A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

	(j)		o Group, in accordance with §240.13d-1(b)(1)(ii)(J).

None.


Item 4.		Ownership

(a)		Amount Beneficially Owned

		See Item 5.

(b)		Percent of Class:

		Each Reporting Person: %.


CE II		See Item 5.
CE II QP		See Item 5.
Entrepreneurs		See Item 5.
CEP II		See Item 5.

John V. Balen		See Item 5.
Stephen L. Green		See Item 5.
Deepak Kamra		See Item 5.
Gregory Kopchinsky		See Item 5.
Guy M. Russo		See Item 5.
Eric A. Young		See Item 5.
Charmers		See Item 5.
Stonehenge		See Item 5.
Waubeeka		See Item 5.


CUSIP No.		252131107		Page		17		of		25

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

(i)		Sole power to vote or direct the vote

(ii)		Shared power to vote or to direct the vote

(iii)		Sole power to dispose or to direct the disposition of

(iv)		Shared power to dispose or to direct the disposition of

None.


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

		If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following þ.


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

		Not applicable.


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

		Not applicable.


Item 8.		Identification and Classification of Members of the Group

		Each of the Reporting Persons expressly disclaims membership in a “Group” as defined in Rule 13d-1 (b) (1) (ii) (J).


Item 9.		Notice of Dissolution of Group

		Not applicable.


Item 10.		Certification

		Not applicable. This Schedule 13G is not filed pursuant to Rule 13d-1(b) or Rule 13d-1(c).


CUSIP No.		252131107		Page		18		of		25

SIGNATURES

After reasonable inquiry and to the best of the undersigned’s knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: February 13, 2007


		Canaan Equity II L.P.

		By:		Canaan Equity Partners II LLC
				Its General Partner

		By:		*

				Manager

		Canaan Equity II L.P. (QP)

		By:		Canaan Equity Partners II LLC
				Its General Partner

		By:		*

				Manager

		Canaan Equity II Entrepreneurs LLC.

		By:		Canaan Equity Partners II LLC
				Its Manager

		By:		*

				Manager

		Canaan Equity Partners II LLC

		By:		*

				Manager

				*

		John V. Balen

				*

		Stephen L. Green

				*

		Deepak Kamra

				*

		Gregory Kopchinsky


CUSIP No.		252131107		Page		19		of		25



	/s/ Guy M. Russo
	Guy M. Russo

	*
	Eric A. Young

	Charmers Landing LLC
	By:	*
		Manager

	Stonehenge LLC
	By:	*
		Manager

	Waubeeka LLC
	By:	/s/ Guy M. Russo
		Manager



	* By:	/s/ Guy M. Russo
		Guy M. Russo
		Attorney-in-Fact


	This Amendment No. 1 to Schedule 13G was executed by Guy M. Russo pursuant to Powers of Attorney, copies of which are filed herewith as Exhibit 2.


CUSIP No.		252131107		Page		20		of		25

Exhibit 1

Joint Filing Agreement

In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned agree that only one statement containing the information required by Schedule 13G need be filed by each of the undersigned with respect to the ownership by each of the undersigned of shares of stock of DexCom, Inc. This Agreement may be executed in any number of counterparts, each of which shall be deemed an original.

Executed as of February 1, 2006


	Canaan Equity II L.P. By: Canaan Equity Partners II LLC Its General Partner
	By:	*
		Manager

	Canaan Equity II L.P. (QP) By: Canaan Equity Partners II LLC Its General Partner
	By:	*
		Manager

	Canaan Equity II Entrepreneurs LLC By: Canaan Equity Partners II LLC Its Manager
	By:	*
		Manager

	Canaan Equity Partners II LLC
	By:	*
		Manager
		&#x A0;
	*
	John V. Balen

	*
	James C. Furnivall

	*
	Stephen L. Green

	*
	Deepak Kamra


CUSIP No.		252131107		Page		21		of		25


		*

		Gregory Kopchinsky


		/s/ Guy M. Russo

		Guy M. Russo


		*

		Eric A. Young

		Charmers Landing LLC


		By:		*

				Manager


		Stonehenge LLC

		By:		*
				Manager

		Waubeeka LLC


		By:		/s/ Guy M. Russo
				Manager




		* By:		/s/ Guy M. Russo
				Guy M. Russo
				Attorney-in-Fact

		This Joint Filing Agreement was executed by Guy M. Russo pursuant to Powers of Attorney, copies of which are filed herewith as Exhibit 2.


CUSIP No.		252131107		Page		22		of		25

Exhibit 2

POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoin ts Guy M. Russo his true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities (until revoked in writing) to sign any and all instruments, certificates and documents required to be executed on behalf of himself as an individual or in his capacity as a general partner or authorized signatory, as the case may be, on behalf of any of Canaan Equity II L.P., Canaan Equity II L.P. (QP), Canaan Equity II Entrepreneurs LLC and Canaan Equity Partners II LLC pursuant to the Securities Act of 1933, as amended, (the “Securities Act”), or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and any and all regulations promulgated thereunder and to file the same, with all exhibits thereto, and any other documents in connection therewith, with the Securities and Exchange Commission, and with any other entity when and if such is mandated by the Securities Act, the Exchange Act or by the By-laws of the National Association of Securities Dealers, Inc., granting unto said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary fully to all intents and purposes as he might or could do in person thereby, and ratifying and confirming all that said attorney-in-fact and agent, or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof, or may have done in connection with the matters described above.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


CUSIP No.		252131107		Page		23		of		25

IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 14th day of February, 2001.

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		CANAAN EQUITY II L.P.

		By:		Canaan Equity Partners II LLC
				Its General Partner

		By:		/s/ Harry T. Rein

				Member/Manager

		CANAAN EQUITY II L.P. (QP)

		By:		Canaan Equity Partners II LLC
				Its General Partner

		By:		/s/ Harry T. Rein

				Member/Manager

		CANAAN EQUITY II ENTREPRENEURS LLC

		By:		Canaan Equity Partners II LLC
				Its General Partner

		By:		/s/ Harry T. Rein

				Member/Manager

		CANAAN EQUITY PARTNERS II LLC

		By:		/s/ Harry T. Rein

				Member/Manager

		/s/ Harry T. Rein

		Harry T. Rein

		/s/ John V. Balen

		John V. Balen

		/s/ James C. Furnivall

		James C. Furnivall

		/s/ Stephen L. Green

		Stephen L. Green

		/s/ Deepak Kamra

		Deepak Kamra

		/s/ Guy M. Russo

		Guy M. Russo


CUSIP No.		252131107		Page		24		of		25


		/s/ Gregory Kopchinsky Gregory Kopchinsky

		/s/ Eric A. Young Eric A. Young


CUSIP No.		252131107		Page		25		of		25

Exhibit 2

POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each entity whose signature appears below hereby constitutes and appoints Guy M. Russo its true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for such entity in its name, place and stead, in any and all capacities (until revoked in writing) to sign any and all instruments, certificates and documents required to be executed on behalf of such entity, as applicable pursuant to the Securities Act of 1933, as amended, (the “Securities Act”), or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and any and all regulations promulgated thereunder and to file the same, with all exhibits thereto, and any other documents in connection therewith, with the Securities and Exchange Commission, and with any other entity when and if such is mandated by the Securities Act, the Exchange Act or by the By-laws of the National Association of Securities Dealers, Inc., granting unto said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary fully to all intents and purposes as he might or could do in person thereby, and ratifying and confirming all that said attorney-in-fact and agent, or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof, or may have done in connection with the matters described above.

IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 11th day of February, 2005.


		CHARMERS LANDING LLC

		By:		/s/ Stephen L. Green Manager

		STONEHENGE LLC

		By:		/s/ Gregory Kopchinsky Manager

Sec Form 13G Filing - CANAAN EQUITY II LP filing for DEXCOM INC (DXCM) - 2007-02-14