7. Debt

Total debt consists of the following:



	June 30, 2019			December 31, 2018
Convertible Senior Notes	$	47,112		$	113,980
Unamortized debt issuance cost ⁽¹⁾	(36		)	(438		)
Total debt, carrying value	$	47,076		$	113,542
Total short-term debt, carrying value	$	47,076		$	113,542

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⁽¹⁾	Unamortized debt issuance cost is related to Convertible Senior Notes.

Convertible Senior Notes

On August 12, 2014, the Company issued $230.0 million aggregate principal amount of its 0.75% Convertible Senior Notes due in 2019 (the “2019 Notes”). The 2019 Notes mature on August 15, 2019, and bear interest at a rate of 0.75% per annum payable semi-annually in arrears on February 15 and August 15 of each year. The Company accounted for the $230.0 million face value of the debt as a liability and capitalized approximately $7.1 million of financing fees, related to the issuance which are presented net of the face value of the 2019 Notes on the Condensed Consolidated Balance Sheets.

The 2019 Notes are senior, unsecured obligations of the Company, and are convertible into shares of its common stock based on a conversion rate of 18.8072 shares per $1,000 principal amount of 2019 Notes which is equivalent to an initial conversion price of approximately $53.17 per share. The Company will satisfy any conversion of the 2019 Notes with shares of the Company’s common stock. The 2019 Notes are convertible at the note holders’ option prior to their maturity and if specified corporate transactions occur. The issue price of the 2019 Notes was equal to their face amount.

Holders of the 2019 Notes who convert their notes in connection with a qualifying fundamental change, as defined in the related indenture, may be entitled to a make-whole premium in the form of an increase in the conversion rate. Additionally, following the occurrence of a fundamental change, holders may require that the Company repurchase some or all of the 2019 Notes for cash at a repurchase price equal to 100% of the principal amount of the notes being repurchased, plus accrued and unpaid interest, if any. As of June 30, 2019, none of these conditions existed with respect to the 2019 Notes.

The 2019 Notes are the Company’s direct senior unsecured obligations and rank equal in right of payment to all of the Company’s existing and future unsecured and unsubordinated indebtedness.

At June 30, 2019, the carrying amount of the liability was $47.1 million and the outstanding principal of the 2019 Notes was $47.1 million, with an effective interest rate of approximately 1.37%. The fair value of the 2019 Notes was $46.9 million at June 30, 2019. The fair value of the liability of the 2019 Notes was determined using a discounted cash flow model based on current market interest rates available to the Company. These inputs are corroborated by observable market data for similar liabilities and therefore classified within Level 2 of the fair-value hierarchy.

The Company is required to meet all SEC filing requirements and deadlines to be compliant with the 2019 Notes. In the event that the Company does not meet the filing requirements, the Company will be in default under the 2019 Notes unless it elects to pay the noteholders additional interest of 0.25% up to 180 days from the date of the notice of default and 0.50% thereafter up to 360 days. The Company may agree to pay additional interest to the holders by notifying holders and the trustee within 90 days from the notice of default. If the Company decides to pay the additional interest but has not remedied its failure to meet all SEC filing requirements within 360 days from the notice of default, it will be in default. If the Company fails to elect to pay the additional interest, it will be in default if it does not remedy its failure to meet all SEC filing requirements within the 90 days from the notice of default.

The Company received a notice of default from holders of more than 25% of the outstanding principal amount of the 2019 Notes on October 13, 2017. In accordance with the terms of the 2019 Notes, the Company elected to begin paying additional interest starting January 11, 2018 (the 90^th day following the Company’s receipt of the notice of default). As a result of the Company regaining compliance with its SEC filing requirements, the Company was no longer required to pay the additional interest as of July 9, 2018. The Company was required to record a derivative related to this contingent interest as a liability and expense in its financial statements due to the late filings of the Company’s quarterly reports on Form 10-Q in 2017. At June 30, 2019, the recorded contingent interest derivative liability within accrued expenses was zero as a result of Company regaining compliance with its SEC filing requirements.

Interest expense

The following table summarizes the Company’s interest expense:



	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Convertible Senior Notes
Amortization of debt issuance costs	82		353		237		706
Interest on borrowings	106		431		297		862
Additional interest on default	—		63		—		192
Capital leases	—		241		—		483
Other	275		230		514		322
Total	$	463	$	1,318	$	1,048	$	2,565