Item 2.03 Creation of a Direct Financial Obligation or
an Obligation under an Off-Balance Sheet Arrangement of a Registrant.
As previously reported by the Company in our Current Report
on Form 8-K filed with the Securities and Exchange Commission (the “SEC”) on April 27, 2011, we entered into a Note
and Warrant Purchase Agreement dated April 21, 2011 (the “Purchase Agreement”) with HealthCor Partners Fund, LP (“HealthCor
Partners”) and HealthCor Hybrid Offshore Master Fund, LP (“HealthCor Hybrid” and, together with HealthCor Partners,
the “HealthCor Parties”). Pursuant to the Purchase Agreement, we sold Senior Secured Convertible Notes to the HealthCor
Parties in the aggregate initial principal amount of $20,000,000 (collectively the “2011 HealthCor Notes”), subject
to adjustment in accordance with anti-dilution provisions set forth in the 2011 HealthCor Notes. We also issued Warrants to purchase
an aggregate of up to 11,782,859 shares of our Common Stock at an exercise price per share equal to $1.40 per share to the HealthCor
Parties (collectively the “2011 HealthCor Warrants”).
Amendment Agreement
As previously reported in our Current Report on Form 8-K
filed with the SEC on January 6, 2012, we entered into a Note and Warrant Amendment Agreement with the HealthCor Parties on December
30, 2011 (the “First Amendment”) to (i) amend the Purchase Agreement in order to modify the HealthCor Parties’
right to restrict certain equity issuances; and (ii) amend the 2011 HealthCor Notes and the 2011 HealthCor Warrants, in order
to eliminate certain anti-dilution provisions.
Second Amendment
As previously reported in our Current Report on Form 8-K
filed with the SEC on February 2, 2012, we entered into a Second Amendment to Note and Warrant Purchase Agreement with the HealthCor
Parties on January 31, 2012 (the “Second Amendment”) which allowed us to sell additional Senior Secured Convertible
Notes to the HealthCor Parties in the aggregate initial principal amount of $5,000,000 (collectively, the “2012 HealthCor
Notes”).
Third Amendment
As previously reported in our Current Report on Form 8-K
filed with the SEC on August 26, 2013, we entered into a Third Amendment to Note and Warrant Purchase Agreement with the HealthCor
Parties (the “Third Amendment”) on August 20, 2013 to redefine our minimum cash balance requirements. All other terms
and conditions of the Purchase Agreement, including all amendments thereto, remained the same.
Fourth Amendment
As previously reported in our Current Report on Form 8-K
filed with the SEC on January 22, 2014, we entered into a Fourth Amendment to Note and Warrant Purchase Agreement with the HealthCor
Parties (the “Fourth Amendment”) on January 16, 2014 to sell and issue to the HealthCor Parties (i) additional
notes (the “2014 HealthCor Notes”) in the initial aggregate principal amount of $5,000,000, with a conversion price
per share equal to $0.40 (subject to adjustment as described therein) and (ii) additional warrants (the “2014 Supplemental
Warrants”) to purchase an aggregate of up to 4,000,000 shares of our Common Stock at an exercise price per share equal to
$0.40 (subject to adjustment as described therein).
Fifth Amendment
As previously reported in our Current Report on Form 8-K
filed with the SEC on December 19, 2014, we entered into a Fifth Amendment to Note and Warrant Purchase Agreement with the HealthCor
Parties and certain additional investors party thereto (such additional investors, the “Fifth Amendment New Investors”
and, collectively with the HealthCor Parties, the “Fifth Amendment Investors”) (the “Fifth Amendment”)
on December 15, 2014 to sell and issue to the Fifth Amendment Investors (i) additional notes (the “2015 Supplemental
Notes”) in the initial aggregate principal amount of $6,000,000, with a conversion price per share equal to $0.52 (subject
to adjustment as described therein) and (ii) additional warrants (the “2015 Supplemental Warrants”) to purchase
an aggregate of up to 3,692,308 shares of our Common Stock at an exercise price per share equal to $0.52 (subject to adjustment
as described therein). The Fifth Amendment New Investors were composed of all but one of our directors (at such time and currently)
as well as one of our officers (at such time and currently) who is not also a director. As previously reported in our Current Report
on Form 8-K filed with the SEC on February 19, 2015, the Company and the Fifth Amendment Investors closed on the transactions
contemplated by the Fifth Amendment on February 17, 2015.
Sixth Amendment
As previously reported
in our Annual Report on Form 10-K filed with the SEC on March 31, 2015, we entered into a Sixth Amendment to Note and Warrant Purchase
Agreement with the HealthCor Parties and the Fifth Amendment New Investors on March 31, 2015 (the “Sixth Amendment”),
pursuant to which, among other things, (i) the requirement to maintain a minimum cash balance of $5,000,000 was reduced to
a minimum cash balance of $2,000,000 and (ii) the amendment provision was revised to permit the Purchase Agreement to be amended
by the Company and the holders of the majority of the Common Stock underlying the outstanding notes and warrants to purchase shares
of our Common Stock sold pursuant to the Purchase Agreement (on an as-converted basis) (the “Majority Holders”). On
March 31, 2015, we also issued warrants to the HealthCor Parties to purchase up to an aggregate of 1,000,000 shares of our Common
Stock as consideration for certain prior waivers of the minimum cash balance requirement in the Purchase Agreement (the “Sixth
Amendment Supplemental Warrants”). The Sixth Amendment Supplemental Warrants have an exercise price per share equal to $0.53
(subject to adjustment as described therein).
Seventh Amendment
As previously reported
in our Current Report on Form 8-K filed with the SEC on June 30, 2015, we entered into a Seventh Amendment to Note and Warrant
Purchase Agreement with the HealthCor Parties and the Fifth Amendment New Investors on June 26, 2015 (the “Seventh Amendment”),
pursuant to which the Purchase Agreement was amended to permit the Company to enter into and perform its obligations under the
Credit Agreement, and on June 26, 2015 certain amendments were also made to each of the outstanding notes issued under the
Purchase Agreement in connection with the Company’s entrance into the Credit Agreement.
Eighth Amendment
As previously reported in our Current Report on Form 8-K
filed with the SEC on February 26, 2018, we entered into an Eighth Amendment to Note and Warrant Purchase Agreement on February 23,
2018 (the “Eighth Amendment”) with the Fifth Amendment New Investors (the “Existing Investors”), an additional
investor party thereto (such additional investor, the “New Investor” and, collectively with the Existing Investors,
the “Investors”) and the HealthCor Parties (solely in their capacity as the Majority Holders approving the Eighth Amendment
and not as investors), pursuant to which we sold and issued, for an aggregate of $2,050,000 in cash, to the Investors on such date
(i) additional notes in the initial aggregate principal amount of $2,050,000, with a conversion price per share equal to $0.05
(subject to adjustment as described therein) and a maturity date of February 22, 2028 (the “Eighth Amendment Supplemental
Closing Notes”) and (ii) additional warrants to purchase an aggregate of up to 512,500 shares of our Common Stock at
an exercise price per share equal to $0.05 (subject to adjustment as described therein) and with an expiration date of February 23,
2028 (the “Eighth Amendment Supplemental Warrants”). The Existing Investors were composed of all but one of our directors
(at such time and currently) as well as one of our officers (at such time and currently) who is not also a director. Of the total
amount of Eighth Amendment Supplemental Closing Notes and Eighth Amendment Supplemental Warrants issued and sold by the Company
pursuant to the Eighth Amendment, such directors and officer purchased, in aggregate, Eighth Supplemental Closing Notes in the
initial aggregate principal amount of $1,950,000 and Eighth Amendment Supplemental Warrants to purchase an aggregate of up to 487,500
shares of our Common Stock.
Ninth Amendment
As previously reported
in our Current Report on Form 8-K filed with the SEC on July 11, 2018, we entered into a Ninth Amendment to Note and Warrant Purchase
Agreement on July 10, 2018 (the “Ninth Amendment”) with the HealthCor Parties and the Investors, pursuant to which
the parties agreed to amend the Purchase Agreement, the 2011 HealthCor Notes (“2011 Allonges”), the 2012 HealthCor
Notes (“2012 Allonges”), the 2014 HealthCor Notes (“2014 Allonges”), the 2015 Supplemental Notes (“2015
Allonge”) and the Eighth Amendment Supplemental Closing Notes (“2018 Allonge”), as applicable, to (i) remove
the rights of the holders of the 2011 HealthCor Notes and the 2012 HealthCor Notes to convert such notes to Common Stock after
June 30, 2018; (ii) suspend the accrual of interest on the 2011 HealthCor Notes and the 2012 HealthCor Notes for periods
after June 30, 2018; (iii) provide for the potential earlier repayment of the 2011 HealthCor Notes and the 2012 HealthCor
Notes by the Company, 120 calendar days following a written demand for payment by the holder of such notes; provided, however,
that such written demand may not be given prior to the twelve-month anniversary of the date on which the obligations of the Company
under the Credit Agreement are repaid in full; (iv) cancel the 2011 HealthCor Warrants; (v) provide for the seniority
of the 2011 HealthCor Notes and the 2012 HealthCor Notes in right of payment over notes subsequently issued pursuant to the Purchase
Agreement, including the 2014 HealthCor Notes, the 2015 Supplemental Notes and the Eighth Amendment Supplemental Closing Notes;
(vi) amend the terms of the 2014 HealthCor Notes, the 2015 Supplemental Notes and the Eighth Amendment Supplemental Closing
Notes to reflect the seniority in payment of the 2011 HealthCor Notes and 2012 HealthCor Notes; and (vii) reduce the number
of shares of Common Stock that the Company must at all times have authorized and reserved for the purpose of issuance upon conversion
of the notes issued pursuant to the Purchase Agreement (collectively, the “Notes”) and exercise of the warrants issued
pursuant to the Purchase Agreement (collectively, the “Warrants”), from at least 120% of the aggregate number of shares
of Common Stock then issuable upon full conversion of the Notes and exercise of the Warrants to at least 100% of such aggregate
number of shares.
Tenth Amendment
On July 13, 2018, we entered into a Tenth Amendment to Note
and Warrant Purchase Agreement (the “Tenth Amendment”) with the Existing Investors listed in Annex I to the Tenth
Amendment (the “Tenth Amendment Investors”) and the HealthCor Parties (solely in their capacity as Majority Holders
(acting together with the Tenth Amendment Investors) approving the Tenth Amendment and not as investors), pursuant to which we
sold and issued, for an aggregate of $1,000,000 in cash, to the Tenth Amendment Investors on such date additional notes in the
initial aggregate principal amount of $1,000,000, with a conversion price per share equal to $0.05 (subject to adjustment as described
therein) and a maturity date of July 12, 2028 (the “Tenth Amendment Supplemental Closing Notes”). The Tenth Amendment
Investors were composed entirely of our directors.
The Purchase Agreement and Tenth Amendment provide that we
grant to the Tenth Amendment Investors a security interest in our assets as collateral for payment of the Tenth Amendment Supplemental
Closing Notes, evidenced by the Amended and Restated Pledge and Security Agreement dated as of February 17, 2015 (the “Amended
and Restated Security Agreement”) and by the Amended and Restated Intellectual Property Security Agreement dated as of February 17,
2015 (the “Amended and Restated IP Security Agreement”).
The Purchase Agreement and the Tenth Amendment also provide
that we grant registration rights to the Tenth Amendment Investors for the Common Stock into which the Tenth Amendment Supplemental
Closing Notes may be converted as provided for by the Registration Rights Agreement dated as of April 20, 2011, as amended June
30, 2015, by and among the Company, the HealthCor Parties and the additional investors party thereto (the “Registration Rights
Agreement”).
The foregoing descriptions of the Purchase Agreement, the
First Amendment, the Second Amendment, the Third Amendment, the Fourth Amendment, the Fifth Amendment, the Sixth Amendment, the
Seventh Amendment, the Eighth Amendment, the Ninth Amendment, the Tenth Amendment, the Credit Agreement, the 2011 HealthCor Notes,
the 2012 HealthCor Notes, the 2014 HealthCor Notes, the 2015 Supplemental Notes, the Eighth Amendment Supplemental Closing Notes,
the Tenth Amendment Supplemental Closing Notes, the 2011 HealthCor Warrants, the 2014 Supplemental Warrants, the 2015 Supplemental
Warrants, the Sixth Amendment Supplemental Warrants, the Eighth Amendment Supplemental Warrants, the 2011 Allonges, the 2012 Allonges,
the 2014 Allonges, the 2015 Allonge, the 2018 Allonge, the Amended and Restated Security Agreement, the Amended and Restated IP
Security Agreement and the Registration Rights Agreement are qualified, in their entirety, by reference to each such agreement
or instrument, copies of which are attached as exhibits to this Current Report on Form 8-K and are incorporated by reference in
response to this Item 2.03.