The Company’s current portion of outstanding notes payable are summarized as follows:

	As of December 31,
	2018		2017
Line of credit	$	—	$	49,702
BPI France notes, short-term portion		71,596		—
Total notes payable	$	71,596	$	49,702

The Company’s long-term portion of outstanding notes payable as well as other long-term liabilities are summarized as follows:

	As of December 31,
	2018		2017
BPI France notes, long-term portion	$	501,174	$	599,927
Deferred rent, long-term portion		1,045,807		386,489
Common stock warrant liability (see Note 12)		65,000		3,400,869
Embedded derivative (see Note 10)		—		27,236
Other		240,090		159,986
Total other long-term liabilities	$	1,852,071	$	4,574,507

On July 27, 2018, the Company renewed its existing line of credit agreement for a six-month term with an increase to the borrowing capacity from $250,000 to $1,750,000 subject to a minimum liquidity requirement equal to the outstanding balance of the line. There was no balance on this credit facility as of December 31, 2018. The annual interest rate was 8%, and the Company incurred interest expense of $2,889 for the year ended December 31, 2018. The line of credit expired in January 2019.

Altimmune France has two non-interest-bearing research and development funding arrangements with BPI France that were entered into in December 2013 to provide Altimmune France up to €750,000 in research funding in the first arrangement and up to €250,000 in the second arrangement. Altimmune France was permitted to draw 50% of the funds upon the signing of the arrangements, an additional 30% contingent upon a financial audit and technical progress report, and the remaining amounts at the completion of the research and development project being funded by the arrangements. In October 2016, the Company and BPI agreed to extend the term on the arrangement by two years. Each of the two obligations is repayable in sixteen quarterly installments from June 2019 through March 2023. The total amount advanced under the arrangements was €500,000 as of December 31, 2018 and 2017 ($572,770 and $599,927 as of December 31, 2018 and 2017, respectively). As of December 31, 2018, $71,596 on this note is classified as short term, and $501,174 as long term.

Deferred rent, long-term portion, includes the difference between rent expense recognized and rental payments made, and lease incentive obligations. Lease incentive obligations represent lease incentives and allowances provided by our landlord for the construction of leasehold improvements located at our new office and laboratory facilities. The Company records lease incentive obligations as construction costs are incurred and billable, up to the maximum allowance amount. Lease incentive obligations are amortized on a straight-line basis over the lease term as a reduction of rent expense. The company completed the new facility adding leasehold incentives and improvements increasing deferred rent. During the years ended December 31, 2018 and 2017, the Company recorded $115,782 and $29,854, respectively, of amortization as a reduction of rent expense.

In conjunction with the First Exchange (as defined in Note 12) the Company issued convertible notes (the “Exchange Notes”) with an aggregate principal value of $1,500,000, which were initially convertible into up to 73,530 shares of our common stock at the note holder’s option on the maturity date. The Exchange Notes were also convertible in the event of default, at which time the balance of the notes increases by 112% and was convertible at a share price equal to the lower of $20.40 per share or 75% of the weighted average price of common stock during the twenty consecutive trading day period immediately preceding the event of default. In the event the weighted average price of common stock as defined above is below $4.50 per share, then a supplemental cash payment was due to the note holder.

The Exchange Notes were due to mature on December 29, 2018, when the entire principal and any unpaid interest was due. The Exchange Notes earned interest at a stated rate of 1% each month and interest was payable on the last business day of each month. The Company fully redeemed the notes and accrued interest in cash in October 2018.

The conversion and redemption options embedded in the Exchange Notes qualified for derivative accounting under ASC 815-15 “Derivatives and Hedging”. The fair value of the derivative liability at the date of issuance resulted in a discount to the Exchange Notes of $180,611 which was accreted into interest expense over the term of the convertible note. Debt issuance costs of $58,172 were capitalized and was recognized in interest expense over the term of the notes. In addition, the Company paid the holders of the Exchange Notes and additional $54,226 of interest earned. During the year ended December 31, 2018, total interest expense recognized on the Exchange Notes was $293,009.